80 results on '"Okoth, E."'
Search Results
2. Risk factors for rotavirus infection in pigs in Busia and Teso subcounties, Western Kenya
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Amimo, J. O., Otieno, T. F., Okoth, E., Onono, J. O., and Bett, B.
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- 2017
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3. Comparison of African swine fever virus prevalence and risk in two contrasting pig-farming systems in South-west and Central Kenya
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Okoth, E., Gallardo, C., Macharia, J.M., Omore, A., Pelayo, V., Bulimo, D.W., Arias, M., Kitala, P., Baboon, K., Lekolol, I., Mijele, D., and Bishop, R.P.
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- 2013
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- View/download PDF
4. Comparative evaluation of novel African swine fever virus (ASF) antibody detection techniques derived from specific ASF viral genotypes with the OIE internationally prescribed serological tests
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Gallardo, C., Soler, A., Nieto, R., Carrascosa, A.L., De Mia, G.M., Bishop, R.P., Martins, C., Fasina, F.O., Couacy-Hymman, E., Heath, L., Pelayo, V., Martín, E., Simón, A., Martín, R., Okurut, A.R., Lekolol, I., Okoth, E., and Arias, M.
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- 2013
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5. TB training in Kenya: building capacity for care and prevention
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Angala, P., primary, Dlodlo, R. A., additional, Wanjala, S., additional, Mamo, G., additional, Mugambi-Nyaboga, L., additional, Onyango Okoth, E., additional, Macharia, S., additional, Maina, M., additional, Wachira, S., additional, Owuor, K., additional, Masini, E., additional, Wekesa, P., additional, Carter, E. J., additional, and Mungai, B., additional
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- 2022
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6. Physico-Chemical, Microbiological and Sensory Characteristics of Papaya Pulp-Milk Blends Fermented with a Probiotic Starter Culture
- Author
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Waweru, D. M., primary, Onyango, A. N., additional, Okoth, E. M., additional, Rimberia, F. K., additional, Mathara, J. M., additional, and Makokha, A. O., additional
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- 2021
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7. Comparative genomics of swine leukocyte antigen class I of Nigerian and Kenyan pigs
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Oluwole, O. O., primary, Bayene, D., additional, Okoth, E., additional, Roger, P., additional, and Omitogun, G. O., additional
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- 2020
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8. Multi-locus sequence typing of African swine fever viruses from endemic regions of Kenya and Eastern Uganda (2011–2013) reveals rapid B602L central variable region evolution
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Onzere, C. K., primary, Bastos, A. D., additional, Okoth, E. A., additional, Lichoti, J. K., additional, Bochere, E. N., additional, Owido, M. G., additional, Ndambuki, G., additional, Bronsvoort, M., additional, and Bishop, R. P., additional
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- 2017
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9. Chimpanzee adenovirus vaccine provides multispecies protection against Rift valley fever
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Gm, Warimwe, Gesharisha J, Bv, Carr, Otieno S, Otingah K, Wright D, Charleston B, Okoth E, Lg, Elena, Lorenzo G, Ayman el-B, Nk, Alharbi, Ma, Al-Dubaib, Brun A, Sc, Gilbert, Nene V, and Adrian Hill
- Subjects
Vaccines, Synthetic ,Camelus ,Sheep ,Pan troglodytes ,Rift Valley Fever ,Goats ,Vaccination ,Saudi Arabia ,Viral Vaccines ,Rift Valley fever virus ,Antibodies, Neutralizing ,Article ,United Kingdom ,Viral Envelope Proteins ,Adenovirus Vaccines ,Animals ,Humans ,Cattle - Abstract
Rift Valley Fever virus (RVFV) causes recurrent outbreaks of acute life-threatening human and livestock illness in Africa and the Arabian Peninsula. No licensed vaccines are currently available for humans and those widely used in livestock have major safety concerns. A 'One Health' vaccine development approach, in which the same vaccine is co-developed for multiple susceptible species, is an attractive strategy for RVFV. Here, we utilized a replication-deficient chimpanzee adenovirus vaccine platform with an established human and livestock safety profile, ChAdOx1, to develop a vaccine for use against RVFV in both livestock and humans. We show that single-dose immunization with ChAdOx1-GnGc vaccine, encoding RVFV envelope glycoproteins, elicits high-titre RVFV-neutralizing antibody and provides solid protection against RVFV challenge in the most susceptible natural target species of the virus-sheep, goats and cattle. In addition we demonstrate induction of RVFV-neutralizing antibody by ChAdOx1-GnGc vaccination in dromedary camels, further illustrating the potency of replication-deficient chimpanzee adenovirus vaccine platforms. Thus, ChAdOx1-GnGc warrants evaluation in human clinical trials and could potentially address the unmet human and livestock vaccine needs.
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- 2016
10. First Complete Genome Sequences of Porcine Bocavirus Strains from East Africa
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Amimo, J. O., primary, Njuguna, J., additional, Machuka, E., additional, Okoth, E., additional, and Djikeng, A., additional
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- 2017
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11. Chimpanzee adenovirus vaccine provides multispecies protection against Rift valley fever
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Lorenzo, Gema [0000-0003-1869-9051], Warimwe, G. M., Gesharisha, J., Carr, B. V., Otieno, S., Otingah, K., Wright, Danny, Charleston, B., Okoth, E., López-Gil, E., Ayman, E. B., Alharbi, N. K., Al-dubaib, M. A., Brun Torres, Alejandro, Gilbert, S., Nene, V., Hill, A. V. S., Lorenzo, Gema, Lorenzo, Gema [0000-0003-1869-9051], Warimwe, G. M., Gesharisha, J., Carr, B. V., Otieno, S., Otingah, K., Wright, Danny, Charleston, B., Okoth, E., López-Gil, E., Ayman, E. B., Alharbi, N. K., Al-dubaib, M. A., Brun Torres, Alejandro, Gilbert, S., Nene, V., Hill, A. V. S., and Lorenzo, Gema
- Abstract
Rift Valley Fever virus (RVFV) causes recurrent outbreaks of acute life-threatening human and livestock illness in Africa and the Arabian Peninsula. No licensed vaccines are currently available for humans and those widely used in livestock have major safety concerns. A One Health vaccine development approach, in which the same vaccine is co-developed for multiple susceptible species, is an attractive strategy for RVFV. Here, we utilized a replication-deficient chimpanzee adenovirus vaccine platform with an established human and livestock safety profile, ChAdOx1, to develop a vaccine for use against RVFV in both livestock and humans. We show that single-dose immunization with ChAdOx1-GnGc vaccine, encoding RVFV envelope glycoproteins, elicits high-titre RVFV-neutralizing antibody and provides solid protection against RVFV challenge in the most susceptible natural target species of the virus-sheep, goats and cattle. In addition we demonstrate induction of RVFV-neutralizing antibody by ChAdOx1-GnGc vaccination in dromedary camels, further illustrating the potency of replication-deficient chimpanzee adenovirus vaccine platforms. Thus, ChAdOx1-GnGc warrants evaluation in human clinical trials and could potentially address the unmet human and livestock vaccine needs.
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- 2016
12. Risk factors for rotavirus infection in pigs in Busia and Teso subcounties, Western Kenya
- Author
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Amimo, J. O., primary, Otieno, T. F., additional, Okoth, E., additional, Onono, J. O., additional, and Bett, B., additional
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- 2016
- Full Text
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13. Comparative analysis of the complete genome sequences of Kenyan African swine fever virus isolates within p72 genotypes IX and X
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Gallardo, Carmina [0000-0003-3293-306X], Bishop, Richard, Fleischauer, C., de Villiers, E. P., Okoth, E., Arias, Marisa, Gallardo, Carmina, Upton, C., Gallardo, Carmina [0000-0003-3293-306X], Bishop, Richard, Fleischauer, C., de Villiers, E. P., Okoth, E., Arias, Marisa, Gallardo, Carmina, and Upton, C.
- Abstract
Twelve complete African swine fever virus (ASFV) genome sequences are currently publicly available and these include only one sequence from East Africa. We describe genome sequencing and annotation of a recent pig-derived p72 genotype IX, and a tick-derived genotype X isolate from Kenya using the Illumina platform and comparison with the Kenya 1950 isolate. The three genomes constitute a cluster that was phylogenetically distinct from other ASFV genomes, but 98–99 % conserved within the group. Vector-based compositional analysis of the complete genomes produced a similar topology. Of the 125 previously identified ‘core’ ASFV genes, two ORFs of unassigned function were absent from the genotype IX sequence which was 184 kb in size as compared to 191 kb for the genotype X. There were multiple differences among East African genomes in the 360 and 110 multicopy gene families. The gene corresponding to 360-19R has transposed to the 5′ variable region in both genotype X isolates. Additionally, there is a 110 ORF in the tick-derived genotype X isolate formed by fusion of 13L and 14L that is unique among ASFV genomes. In future, functional analysis based on the variations in the multicopy families may reveal whether they contribute to the observed differences in virulence between genotpye IX and X viruses. © 2015, Springer Science+Business Media New York.
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- 2015
14. Element specific transfer from a parasite-fish host assemblage to children
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Oyoo Okoth, E., Admiraal, Wim, and Aquatic Environmental Ecology (IBED, FNWI)
- Abstract
Metalen in oppervlaktewater worden doorgegeven via aquatische voedselketens, waardoor de metalen accumuleren in vis die weer door mensen wordt geconsumeerd. De mechanismen waarop de doorgifte van metalen berust zijn veelal onbekend. Dit geldt met name voor de rol van parasieten, die vaak niet betrokken worden in voedselwebanalyses omdat het onopvallende organismen zijn waarvan wordt aangenomen dat ze in lage dichtheden voorkomen. Bekend is echter dat parasieten de metaalopname door hun gastheren kunnen beïnvloeden. Elijah Oyoo-Okoth richtte zich op de rol van parasieten bij de opname van elementen door vissen, en de doorgifte van deze elementen aan menselijke consumenten. Hij deed dit aan de hand van een vissoort die in het Victoriameer sterk geparasiteerd wordt door lintwormen. De vis maakt een belangrijk deel uit van het dieet van kinderen uit gemeenschappen langs de kust van het meer. Uit zijn resultaten blijkt dat de elementhuishouding van de vis sterk gemodificeerd werd door de lintworm. De concentraties essentiële metalen in geparasiteerde vis namen af door competitie tussen parasiet en gastheer, terwijl van de niet-essentiële metalen verhoogde concentraties in beide organismen werden aangetoond. De elementconcentraties in het haar en de nagels van de omwonende kinderen weerspiegelden hun consumptiepatronen. De parasiet modificeerde de elementverhoudingen van de vis, waardoor de doorgifte van elementen van de vis op de kinderen veranderde. Visparasieten modificeren daarmee de risico’s van metaalaccumulatie voor menselijke consumenten.
- Published
- 2012
15. Comparison of African swine fever virus prevalence and risk in two contrasting pig-farming systems in South-west and Central Kenya
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Gallardo, Carmina [0000-0003-3293-306X], Okoth, E., Gallardo, Carmina, Macharia, J. M., Omore, A., Pelayo, V., Bulimo, D. W., Arias, Marisa, Kitala, P., Baboon, K., Lekolol, I., Mijele, D., Bishop, Richard, Gallardo, Carmina [0000-0003-3293-306X], Okoth, E., Gallardo, Carmina, Macharia, J. M., Omore, A., Pelayo, V., Bulimo, D. W., Arias, Marisa, Kitala, P., Baboon, K., Lekolol, I., Mijele, D., and Bishop, Richard
- Abstract
We describe a horizontal survey of African swine fever virus (ASFV) prevalence and risk factors associated with virus infection in domestic pigs in two contrasting production systems in Kenya. A free range/tethering, low input production system in Ndhiwa District of South-western Kenya is compared with a medium input stall fed production system in Kiambu District of Central Kenya. Analysis of variance (ANOVA) of data derived from cluster analysis showed that number of animals, number of breeding sows and number of weaner pigs were a significant factor in classifying farms in Nhiwa and Kiambu. Analysis of blood and serum samples using a PCR assay demonstrated an average animal level positivity to ASFV of 28% in two independent samplings in South-western Kenya and 0% PCR positivity in Central Kenya. No animals were sero-positive in either study site using the OIE indirect-ELISA and none of the animals sampled exhibited clinical symptoms of ASF. The farms that contained ASFV positive pigs in Ndhiwa District were located in divisions bordering the Ruma National Park from which bushpig (Potamochoerus larvatus) incursions into farms had been reported. ASFV prevalence (P<0.05) was significantly higher at distances between 6 and 16. km from the National Park than at distances closer or further away. One of the 8 bushpigs sampled from the park, from which tissues were obtained was PCR positive for ASFV. The data therefore indicated a potential role for the bushpig in virus transmission in South-western Kenya, but there was no evidence of a direct sylvatic virus transmission cycle in Central Kenya. ASF control strategies implemented in these areas will need to take these epidemiological findings into consideration. © 2012 Elsevier B.V.
- Published
- 2013
16. Comparative evaluation of novel African swine fever virus (ASF) antibody detection techniques derived from specific ASF viral genotypes with the OIE internationally prescribed serological tests
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Couacy-Hymann, E. [0000-0003-2593-6932], Gallardo, Carmina [0000-0003-3293-306X], Gallardo, Carmina, Soler, Alejandro, Nieto Martínez, Raquel, Carrascosa, A. L., De Mia, G. M., Bishop, Richard, Martins, Carlos, Fasina, F. O., Couacy-Hymann, E., Heath, L., Pelayo, V., Martín, Elena, Simón, Alicia, Martín-Hernández, Raquel, Okurut, A. R., Lekolol, I., Okoth, E., Arias, Marisa, Couacy-Hymann, E. [0000-0003-2593-6932], Gallardo, Carmina [0000-0003-3293-306X], Gallardo, Carmina, Soler, Alejandro, Nieto Martínez, Raquel, Carrascosa, A. L., De Mia, G. M., Bishop, Richard, Martins, Carlos, Fasina, F. O., Couacy-Hymann, E., Heath, L., Pelayo, V., Martín, Elena, Simón, Alicia, Martín-Hernández, Raquel, Okurut, A. R., Lekolol, I., Okoth, E., and Arias, Marisa
- Abstract
The presence of antibodies against African swine fever (ASF), a complex fatal notifiable OIE disease of swine, is always indicative of previous infection, since there is no vaccine that is currently used in the field. The early appearance and subsequent long-term persistence of antibodies combined with cost-effectiveness make antibody detection techniques essential in control programmes. Recent reports appear to indicate that the serological tests recommended by the OIE for ASF monitoring are much less effective in East and Southern Africa where viral genetic and antigenic diversity is the greatest. We report herein an extensive analysis including more than 1000 field and experimental infection sera, in which the OIE recommended tests are compared with antigen-specific ELISAs and immuno-peroxidase staining of cells (IPT). The antibody detection results generated using new antigen-specific tests, developed in this study, which are based on production of antigen fractions generated by infection and virus purification from COS-1 cells, showed strong concordance with the OIE tests. We therefore conclude that the lack of success is not attributable to antigenic polymorphism and may be related to the specific characteristics of the local breeds African pigs. © 2012 Elsevier B.V.
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- 2013
17. African swine fever viruses with two different genotypes, both of which occur in domestic pigs, are associated with ticks and adult warthogs, respectively, at a single geographical site
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Gallardo, Carmina [0000-0003-3293-306X], Gallardo, Carmina, Okoth, E., Pelayo, V., Anchuelo, R., Martín, Elena, Simón, Alicia, Llorente, Alicia, Nieto Martínez, Raquel, Soler, Alejandro, Martín, Raquel, Arias, Marisa, Bishop, Richard, Gallardo, Carmina [0000-0003-3293-306X], Gallardo, Carmina, Okoth, E., Pelayo, V., Anchuelo, R., Martín, Elena, Simón, Alicia, Llorente, Alicia, Nieto Martínez, Raquel, Soler, Alejandro, Martín, Raquel, Arias, Marisa, and Bishop, Richard
- Abstract
The role of the ancestral sylvatic cycle of the African swine fever virus (ASFV) is not well understood in the endemic areas of eastern Africa. We therefore analysed the ASF infection status on samples collected from 51 free-ranging warthogs (Phacocherus africanus) and 1576 Ornithodorus porcinus ticks from 26 independent warthog burrows at a single ranch in Kenya. Abattoir samples from 83 domestic pigs without clinical symptoms, originating from specific locations with no recent reported ASF outbreaks were included in this study. All samples were derived from areas of central Kenya, where ASF outbreaks have been reported in the past. Infection with ASFV was confirmed in 22% of O. porcinus pools, 3.22% of adult warthog serum samples and 49% of domestic pig serum samples by using p72-based PCR. All of the warthog sera were positive for anti-ASFV antibodies, investigated by using ELISA, but none of the domestic pig sera were positive. Twenty O. porcinus-, 12 domestic pig- and three warthogderived viruses were genotyped at four polymorphic loci. The ASFV isolates from ticks and domestic pigs clustered within p72 genotype X. By contrast, ASF viruses genotyped directly from warthog sera, at same locality as the tick isolates, were within p72 genotype IX and genetically similar to viruses causing recent ASF outbreaks in Kenya and Uganda. This represents the first report of the co-existence of different ASFV genotypes in warthog burrow-associated ticks and adult wild warthogs. The data from this and earlier studies suggest transfer of viruses of at least two different p72 genotypes, from wild to domestic pigs in East Africa. © 2011 SGM.
- Published
- 2011
18. Enhanced discrimination of African swine fever virus isolates through nucleotide sequencing of the p54, p72, and pB602L (CVR) genes
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Gallardo, Carmina [0000-0003-3293-306X], Gallardo, Carmina, Mwaengo, D. M., Macharia, J. M., Arias, Marisa, Taracha, E. A., Soler, Alejandro, Okoth, E., Martín, Elena, Kasiti, J., Bishop, Richard, Gallardo, Carmina [0000-0003-3293-306X], Gallardo, Carmina, Mwaengo, D. M., Macharia, J. M., Arias, Marisa, Taracha, E. A., Soler, Alejandro, Okoth, E., Martín, Elena, Kasiti, J., and Bishop, Richard
- Abstract
Complete sequencing of p54-gene from 67 European, American, and West and East African Swine Fever virus (ASFV) isolates revealed that West African and European ASFV isolates classified within the predominant Genotype I according to partial sequencing of p72 were discriminated into four major sub-types on the basis of their p54 sequences. This highlighted the value of p54 gene sequencing as an additional, intermediate-resolution, molecular epidemiological tool for typing of ASFV viruses. We further evaluated p54-based genotyping, in combination with partial sequences of two other genes, for determining the genetic relationships and origin of viruses responsible for disease outbreaks in Kenya. Animals from Western and central Kenya were confirmed as being infected with ASFV using a p72 gene-based PCR assay, following outbreaks of severe hemorrhagic disease in domestic pigs in 2006 and 2007. Eleven hemadsorbing viruses were isolated in macrophage culture and genotyped using a combination of full-length p54-gene sequencing, partial p72-gene sequencing, and analysis of tetrameric amino acid repeat regions within the variable region of the B602L gene (CVR). The data revealed that these isolates were identical in their p72 and p54 sequence to viruses responsible for ASF outbreaks in Uganda in 2003. There was a minor difference in the number of tetrameric repeats within the B602L sequence of the Kenyan isolates that caused the second Kenyan outbreak in 2007. A practical implication of the genetic similarity of the Kenyan and Ugandan viral isolates is that ASF control requires a regional approach. © 2008 Springer Science+Business Media, LLC.
- Published
- 2009
19. Growth performance, survival, feed utilization and nutrient utilization of African catfish (Clarias gariepinus) larvae co-fed Artemia and a micro-diet containing freshwater atyid shrimp (Caridina nilotica) during weaning
- Author
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CHEPKIRUI-BOIT, V., primary, NGUGI, C.C., additional, BOWMAN, J., additional, OYOO-OKOTH, E., additional, RASOWO, J., additional, MUGO-BUNDI, J., additional, and CHEROP, L., additional
- Published
- 2011
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20. African swine fever viruses with two different genotypes, both of which occur in domestic pigs, are associated with ticks and adult warthogs, respectively, at a single geographical site
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Gallardo, C., primary, Okoth, E., additional, Pelayo, V., additional, Anchuelo, R., additional, Martin, E., additional, Simon, A., additional, Llorente, A., additional, Nieto, R., additional, Soler, A., additional, Martin, R., additional, Arias, M., additional, and Bishop, R. P., additional
- Published
- 2010
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21. Molecular Epidemiology of Peste Des Petits Ruminants Virus in West Africa: Is Lineage IV Replacing Lineage II in Burkina Faso?
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Biguezoton AS, Ilboudo GS, Wieland B, Sawadogo RW, Dah FF, Sidibe CAK, Zoungrana A, Okoth E, and Dione M
- Subjects
- Animals, Burkina Faso epidemiology, Molecular Epidemiology, Phylogeny, Ruminants, Goats, Peste-des-petits-ruminants virus genetics, Peste-des-Petits-Ruminants epidemiology, Goat Diseases epidemiology
- Abstract
This study aimed at investigating the genetic lineages of peste des petits ruminants virus (PPRV) currently circulating in Burkina Faso. As part of PPR surveillance in 2021 and 2022, suspected outbreaks in different regions were investigated. A risk map was produced to determine high-risk areas for PPR transmission. Based on alerts, samples were obtained from three regions and all sampled localities were confirmed to fall within PPR high risk areas. We collected swab samples from the eyes, mouth, and nose of sick goats. Some tissue samples were also collected from dead animals suspected to be infected by PPRV. In total, samples from 28 goats were analysed. Virus confirmation was performed with RT-PCR amplification targeting the nucleocapsid (N) gene. Partial N gene sequencing (350 bp) was carried out using the RT-PCR products of positives samples to characterise the circulating lineages. Eleven sequences, including ten new sequences, have been obtained. Our study identified the presence of the PPRV lineage IV in the three studied regions in Burkina Faso with a genetic heterogeneity recorded for the sequences analysed. Previously published data and results of this study suggest that PPRV lineage IV seems to be replacing lineage II in Burkina Faso.
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- 2024
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22. Transcriptome analysis reveals gene expression changes of pigs infected with non-lethal African swine fever virus.
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Feng W, Zhou L, Du H, Okoth E, Mrode R, Jin W, Hu Z, and Liu JF
- Abstract
African swine fever (ASF) is an important viral disease of swine caused by the African swine fever virus (ASFV), which threatens swine production profoundly. To better understand the gene expression changes when pig infected with ASFV, RNA sequencing was performed to characterize differentially expressed genes (DEGs) of six tissues from Kenya domestic pigs and Landrace × Yorkshire (L/Y) pigs infected with ASFV Kenya1033 in vivo. As results, a total of 209, 522, 34, 505, 634 and 138 DEGs (q-value < 0.05 and |Log2foldchange| values >2) were detected in the kidney, liver, mesenteric lymph node, peripheral blood mononuclear cell, submandibular lymph node and spleen, respectively. The expression profiles of DEGs shared in the multiple tissues illustrated variation in regulation function in the different tissues. Functional annotation analysis and interaction of proteins encoded by DEGs revealed that genes including IFIT1, IFITM1, MX1, OASL, ISG15, SAMHD1, IFINA1, S100A12 and S100A8 enriched in the immune and antivirus pathways were significantly changed when the hosts were infected with ASFV. The genes mentioned could play crucial roles in the process of the reaction to non-lethal ASF infection, which may will help to improve the ASF tolerance in the pig population through molecular breeding strategies.
- Published
- 2023
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23. Comparative Genomic Analysis of Warthog and Sus Scrofa Identifies Adaptive Genes Associated with African Swine Fever.
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Feng W, Zhou L, Zhao P, Du H, Diao C, Zhang Y, Liu Z, Jin W, Yu J, Han J, Okoth E, Mrode R, and Liu JF
- Abstract
Background: As warthogs ( Phacochoerus africanus ) have innate immunity against African swine fever (ASF), it is critical to understand the evolutionary novelty of warthogs to explain their specific ASF resistance., Methods: Here, we present two completed new genomes of one warthog and one Kenyan domestic pig as fundamental genomic references to elucidate the genetic mechanisms of ASF tolerance., Results: Multiple genomic variations, including gene losses, independent contraction, and the expansion of specific gene families, likely molded the warthog genome to adapt to the environment. Importantly, the analysis of the presence and absence of genomic sequences revealed that the DNA sequence of the warthog genome had an absence of the gene lactate dehydrogenase B ( LDHB ) on chromosome 2 compared with the reference genome. The overexpression and siRNA of LDHB inhibited the replication of the African swine fever virus. Combined with large-scale sequencing data from 42 pigs worldwide, the contraction and expansion of tripartite motif-containing (TRIM) gene families revealed that TRIM family genes in the warthog genome are potentially responsible for its tolerance to ASF., Conclusion: Our results will help improve the understanding of genetic resistance to ASF in pigs.
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- 2023
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24. Ex-ante impact of pest des petits ruminant control on micro and macro socioeconomic indicators in Senegal: A system dynamics modelling approach.
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Aboah J, Apolloni A, Duboz R, Wieland B, Kotchofa P, Okoth E, and Dione M
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- Animals, Senegal, Goats, Income, Goat Diseases prevention & control, Peste-des-Petits-Ruminants prevention & control, Peste-des-petits-ruminants virus
- Abstract
Vaccination is considered as the main tool for the Global Control and Eradication Strategy for peste des petits ruminants (PPR), and the efficacity of the PPR-vaccine in conferring long-life immunity has been established. Despite this, previous studies asserted that vaccination can be expensive and consequently, the effectiveness of disease control may not necessarily translate to overall profit for farmers. Also, the consequences of PPR control on socioeconomic indicators like food and nutrition security at a macro-national level have not been explored thoroughly. Therefore, this study seeks to assess ex-ante the impact of PPR control strategies on farm-level profitability and the socioeconomic consequences concerning food and nutrition security at a national level in Senegal. A bi-level system dynamics model, compartmentalised into five modules consisting of integrated production-epidemiological, economics, disease control, marketing, and policy modules, was developed with the STELLA Architect software, validated, and simulated for 30 years at a weekly timestep. The model was parameterised with data from household surveys from pastoral areas in Northern Senegal and relevant existing data. Nine vaccination scenarios were examined considering different vaccination parameters (vaccination coverage, vaccine wastage, and the provision of government subsidies). The findings indicate that compared to a no-vaccination scenario, all the vaccination scenarios for both 26.5% (actual vaccination coverage) and 70% (expected vaccination coverage) resulted in statistically significant differences in the gross margin earnings and the potential per capita consumption for the supply of mutton and goat meat. At the prevailing vaccination coverage (with or without the provision of government subsidies), farm households will earn an average gross margin of $69.43 (annually) more than without vaccination, and the average per capita consumption for mutton and goat meat will increase by 1.13kg/person/year. When the vaccination coverage is increased to the prescribed threshold for PPR eradication (i.e., 70%), with or without the provision of government subsidies, the average gross margin earnings would be $72.23 annually and the per capita consumption will increase by 1.23kg/person/year compared to the baseline (without vaccination). This study's findings offer an empirical justification for a sustainable approach to PPR eradication. The information on the socioeconomic benefits of vaccination can be promoted via sensitization campaigns to stimulate farmers' uptake of the practice. This study can inform investment in PPR control., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Aboah et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2023
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25. Special Issue "African Swine Fever and Other Swine Viral Diseases in Africa".
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Penrith ML, Okoth E, and Livio Heath
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- Animals, Swine, Africa epidemiology, Agriculture, Disease Outbreaks, Sus scrofa, African Swine Fever epidemiology, African Swine Fever Virus, Swine Diseases
- Abstract
African swine fever (ASF) has become the swine disease of most global concern since its second escape from Africa in 2007 resulted in its spread to five continents and the consequent devastation of industrial to subsistence pig farming [...]., Competing Interests: The authors declare no conflict of interest.
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- 2023
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26. African Suid Genomes Provide Insights into the Local Adaptation to Diverse African Environments.
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Xie HB, Yan C, Adeola AC, Wang K, Huang CP, Xu MM, Qiu Q, Yin X, Fan CY, Ma YF, Yin TT, Gao Y, Deng JK, Okeyoyin AO, Oluwole OO, Omotosho O, Okoro VMO, Omitogun OG, Dawuda PM, Olaogun SC, Nneji LM, Ayoola AO, Sanke OJ, Luka PD, Okoth E, Lekolool I, Mijele D, Bishop RP, Han J, Wang W, Peng MS, and Zhang YP
- Subjects
- Animals, Swine, Phylogeny, Species Specificity, Africa, Adaptation, Physiological genetics
- Abstract
African wild suids consist of several endemic species that represent ancient members of the family Suidae and have colonized diverse habitats on the African continent. However, limited genomic resources for African wild suids hinder our understanding of their evolution and genetic diversity. In this study, we assembled high-quality genomes of a common warthog (Phacochoerus africanus), a red river hog (Potamochoerus porcus), as well as an East Asian Diannan small-ear pig (Sus scrofa). Phylogenetic analysis showed that common warthog and red river hog diverged from their common ancestor around the Miocene/Pliocene boundary, putatively predating their entry into Africa. We detected species-specific selective signals associated with sensory perception and interferon signaling pathways in common warthog and red river hog, respectively, which contributed to their local adaptation to savannah and tropical rainforest environments, respectively. The structural variation and evolving signals in genes involved in T-cell immunity, viral infection, and lymphoid development were identified in their ancestral lineage. Our results provide new insights into the evolutionary histories and divergent genetic adaptations of African suids., (© The Author(s) 2022. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.)
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- 2022
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27. The African Swine Fever Isolate ASFV-Kenya-IX-1033 Is Highly Virulent and Stable after Propagation in the Wild Boar Cell Line WSL.
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Hemmink JD, Abkallo HM, Henson SP, Khazalwa EM, Oduor B, Lacasta A, Okoth E, Riitho V, Fuchs W, Bishop RP, and Steinaa L
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- Animals, Cell Line, Kenya, Nucleotides, Sus scrofa, Swine, Vaccines, Attenuated, African Swine Fever, African Swine Fever Virus
- Abstract
We describe the characterization of an African swine fever genotype IX virus (ASFV-Kenya-IX-1033), which was isolated from a domestic pig in western Kenya during a reported outbreak. This includes the efficiency of virus replication and in vivo virulence, together with genome stability and virulence, following passage in blood macrophages and in a wild boar lung cell line (WSL). The ASFV-Kenya-IX-1033 stock retained its ability to replicate in primary macrophages and retained virulence in vivo, following more than 20 passages in a WSL. At the whole genome level, a few single-nucleotide differences were observed between the macrophage and WSL-propagated viruses. Thus, we propose that the WSL is suitable for the production of live-attenuated ASFV vaccine candidates based on the modification of this wild-type isolate. The genome sequences for ASFV-Kenya-IX-1033 propagated in macrophages and in WSL cells were submitted to GenBank, and a challenge model based on the isolate was developed. This will aid the development of vaccines against the genotype IX ASFV circulating in eastern and central Africa., Competing Interests: The authors declare that they have no conflicts of interest.
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- 2022
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28. Peste des Petits Ruminants (PPR) Vaccination Cost Estimates in Burkina Faso.
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Ilboudo GS, Kane PA, Kotchofa P, Okoth E, Maiga A, and Dione M
- Abstract
Every year the government organizes country-wide vaccination campaigns targeting peste des petits ruminants (PPR) for small ruminants (sheep and goats). Despite the heavy investment in vaccination, no study has either rigorously estimated or described the cost of vaccine delivery. This study aimed to fill this gap by assessing and describing the cost of delivery of vaccines against PPR using the 2020 vaccination campaign data. The microcosting approach based on the World Health Organization (WHO) guidelines to construct comprehensive multiyear plans (cMYP) for human immunization programs was used. The cost data is presented for the public and private vaccine delivery channels separately and analyzed using three approaches considering activity lines, inputs, and nature of cost (fixed versus variable). Results show that the unit cost of vaccinating a sheep or goat is estimated at XOF 169 (USD 0.3) and XOF 103 (USD 0.18) through the public and private channels, respectively. Using the activity line framework, we found that the field activities including charges for vaccinator, cost of vaccination materials, and field transportation account for more than 50% of the vaccination cost. In terms of inputs, the personnel cost is the most significant contributor with 65%. Fixed costs are higher in the public sector with up to 46% compared to the private sector which is estimated to take 26% of the cost. This study informs veterinary services' investment decision options for a better allocation of resources in implementing PPR and other small ruminant disease control efforts in Burkina Faso and the Sahel.
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- 2022
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29. Clinical outcomes among adolescents living with HIV in Kenya following initiation on antiretroviral treatment.
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Kose J, Tiam A, Siamba S, Lenz C, Okoth E, Wolters T, van de Vijver D, and Rakhmanina N
- Abstract
In Kenya, HIV/AIDS remains a leading cause of morbidity and mortality among adolescents living with HIV (ALHIV). Our study evaluated associations between demographic and healthcare factors and HIV treatment outcomes among ALHIV in care in Kenya. This retrospective cohort study evaluated the clinical outcomes of newly diagnosed ALHIV enrolled in HIV care during January 2017-June 2018 at 32 healthcare facilities in Homabay and Kakamega Counties. Demographic and clinical data were abstracted from patient clinical records and registers during the follow up study period January 2017-through May 2019. ALHIV were stratified by age (10-14 versus 15-19 years). Categorical variables were summarized using descriptive statistics; continuous variables were analyzed using mean values. The latest available treatment and virological outcomes for ALHIV were assessed. 330 ALHIV were included in the study (mean age 15.9 years; 81.8% female, 63.0% receiving HIV care at lower-level healthcare facilities). Most (93.2%) were initiated on ART within 14 days of diagnosis; 91.4% initiated EFV-based regimens. Of those on ART, only 44.6% were active on care at the end of the study period. Of those eligible for viral load testing, 83.9% were tested with 84.4% viral suppression rate. Retention in care was higher at higher-level facilities (67.5%) compared to lower-level facilities (28.6%). Factors associated with higher retention in care were school attendance (aRR = 1.453), receipt of disclosure support (aRR = 13.315), and receiving care at a high-level health facility (aRR = 0.751). Factors associated with viral suppression included older age (15-19 years) (aRR = 1.249) and pre-ART clinical WHO stage I/II (RR = .668). Viral suppression was higher among older ALHIV. Studies are needed to evaluate effective interventions to improve outcomes among ALHIV in Kenya., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Kose et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2022
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30. Detection of African swine fever virus genotype XV in a sylvatic cycle in Saadani National Park, Tanzania.
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Peter E, Machuka E, Githae D, Okoth E, Cleaveland S, Shirima G, Kusiluka L, and Pelle R
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- African Swine Fever epidemiology, Animals, Asymptomatic Infections epidemiology, Disease Outbreaks veterinary, Genotype, Ornithodoros virology, Phylogeny, Polymerase Chain Reaction veterinary, Swine, Tanzania epidemiology, Tick Infestations epidemiology, Tick Infestations veterinary, African Swine Fever virology, African Swine Fever Virus genetics
- Abstract
African swine fever (ASF) is a severe haemorrhagic disease of domestic pigs caused by ASF virus (ASFV). ASFV is transmitted by soft ticks (Ornithodoros moubata complex group) and by direct transmission. In Africa, ASF is maintained in transmission cycles of asymptomatic infection involving wild suids, mainly warthogs (Phacochoerus africanus). ASF outbreaks have been reported in many parts of Tanzania; however, active surveillance has been limited to pig farms in a few geographical locations. There is an information gap on whether and where the sylvatic cycle may occur independently of domestic pigs. To explore the existence of a sylvatic cycle in Saadani National Park in Tanzania, blood and serum samples were collected from 19 warthogs selected using convenience sampling along vehicle-accessible transects within the national park. The ticks were sampled from warthog burrows. Blood samples and ticks were subjected to ASFV molecular diagnosis (PCR) and genotyping, and warthog sera were subjected to serological (indirect ELISA) testing for ASFV antibody detection. All warthog blood samples were PCR-negative, but 16/19 (84%) of the warthog sera were seropositive by ELISA confirming exposure of warthogs to ASFV. Of the ticks sampled, 20/111 (18%) were positive for ASFV by conventional PCR. Sequencing of the p72 virus gene fragments showed that ASF viruses detected in ticks belonged to genotype XV. The results confirm the existence of a sylvatic cycle of ASFV in Saadani National Park, Tanzania, that involves ticks and warthogs independent of domestic pigs. Our findings suggest that genotype XV previously reported in 2008 in Tanzania is likely to be widely distributed and involved in both wild and domestic infection cycles. Whole-genome sequencing and analysis of the ASFV genotype XV circulating in Tanzania is recommended to determine the phylogeny of the viruses., (© 2020 The Authors. Transboundary and Emerging Diseases published by Wiley-VCH GmbH.)
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- 2021
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31. The first complete genome sequence of the African swine fever virus genotype X and serogroup 7 isolated in domestic pigs from the Democratic Republic of Congo.
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Bisimwa PN, Ongus JR, Steinaa L, Bisimwa EB, Bochere E, Machuka EM, Entfellner JD, Okoth E, and Pelle R
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- African Swine Fever epidemiology, African Swine Fever Virus classification, Animals, DNA, Viral genetics, Democratic Republic of the Congo, High-Throughput Nucleotide Sequencing, Phylogeny, Sequence Analysis, DNA, Serogroup, Swine, Viral Proteins genetics, African Swine Fever virology, African Swine Fever Virus genetics, Genome, Viral, Genotype, Sus scrofa virology, Whole Genome Sequencing
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Background: African swine fever (ASF), a highly contagious hemorrhagic disease, affects domestic pigs in the Democratic Republic of Congo (DRC) where regular outbreaks are reported leading to high mortality rates approaching 100% in the affected regions. No study on the characteristics of the complete genome of strains responsible for ASF outbreaks in the South Kivu province of DRC is available, limited a better understanding of molecular evolution and spread of this virus within the country. The present study aimed at determining the complete genome sequence of ASFV strains genotype X involved in 2018-2019 ASF disease outbreaks in South Kivu province of DRC., Materials and Methods: Genomic DNA of a spleen sample from an ASFV genotype X-positive domestic pig in Uvira, during the 2018-2019 outbreaks in South Kivu, was sequenced using the Illumina HiSeq X platform. Obtained trimmed reads using Geneious Prime 2020.0.4 were blasted against a pig reference genome then contigs were generated from the unmapped reads enriched in ASFV DNA using Spades implemented in Geneious 2020.0.4. The assembly of the complete genome sequence of ASFV was achieved from the longest overlapping contigs. The new genome was annotated with the genome annotation transfer utility (GATU) software and the CLC Genomics Workbench 8 software was further used to search for any ORFs that failed to be identified by GATU. Subsequent analyses of the newly determined Uvira ASFV genotype X genome were done using BLAST for databases search, CLUSTAL W for multiple sequences alignments and MEGA X for phylogeny., Results: 42 Gbp paired-end reads of 150 bp long were obtained containing about 0.1% of ASFV DNA. The assembled Uvira ASFV genome, termed Uvira B53, was 180,916 bp long that could be assembled in 2 contigs. The Uvira B53genome had a GC content of 38.5%, encoded 168 open reading frames (ORFs) and had 98.8% nucleotide identity with the reference ASFV genotype X Kenya 1950. The phylogenetic relationship with selected representative genomes clustered the Uvira B53 strain together with ASFV genotype X reported to date (Kenya 1950 and Ken05/Tk1). Multiple genome sequences comparison with the two reference ASFV genotype X strains showed that 130 of the 168 ORFs were fully conserved in the Uvira B53. The other 38 ORFs were divergent mainly due to SNPs and indels (deletions and insertions). Most of 46 multigene family (MGF) genes identified were affected by various genetic variations. However, 8 MGF ORFs present in Kenya 1950 and Ken05/Tk1 were absent from the Uvira B53 genome including three members of MGF 360, four of MGF 110 and one of MGF 100 while one MGF ORF (MGF 360-1L) at the left end of the genome was truncated in Uvira B53. Moreover, ORFs DP96R and p285L were also absent in the Uvira B53 genome. In contrast, the ORF MGF 110-5L present in Uvira B53 and Ken05/Tk1 was missing in Kenya 1950. The analysis of the intergenic region between the I73R and I329L genes also revealed sequence variations between the three genotype X strains mainly characterized by a deletion of 69 bp in Uvira B53 and 36 bp in Kenya 1950, compared to Ken05/Tk1. Assessment of the CD2v (EP402R) antigen unveiled the presence of SNPs and indels particularly in the PPPKPY tandem repeat region between selected variants representing the eight serogroups reported to date. Uvira B53 had identical CD2v variable region to the Uganda (KM609361) strain, the only other ASFV serogroup 7 reported to date., Conclusion: We report the first complete genome sequence of an African swine fever virus (ASFV) p72 genotype X and CD2v serogroup 7, termed Uvira B53. This study provides additional insights on genetic characteristics and evolution of ASFV useful for tracing the geographical spread of ASF and essential for improved design of control and management strategies against ASF.
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- 2021
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32. Field validation of clinical and laboratory diagnosis of wildebeest associated malignant catarrhal fever in cattle.
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Orono SA, Gitao GC, Mpatswenumugabo JP, Chepkwony M, Mutisya C, Okoth E, Bronsvoort BMC, Russell GC, Nene V, and Cook EAJ
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- Animals, Cattle, DNA, Viral, Enzyme-Linked Immunosorbent Assay methods, Female, Gammaherpesvirinae genetics, Gammaherpesvirinae immunology, Kenya, Male, Malignant Catarrh virology, Polymerase Chain Reaction methods, Retrospective Studies, Sensitivity and Specificity, Clinical Laboratory Techniques veterinary, Enzyme-Linked Immunosorbent Assay veterinary, Malignant Catarrh diagnosis, Polymerase Chain Reaction veterinary
- Abstract
Background: Wildebeest associated malignant catarrhal fever (WA-MCF) is a fatal disease of cattle. Outbreaks are seasonal and associated with close interaction between cattle and calving wildebeest. In Kenya, WA-MCF has a dramatic effect on cattle-keepers who lose up to 10% of their cattle herds per year. The objective of this study was to report the impact of WA-MCF on a commercial ranch and assess the performance of clinical diagnosis compared to laboratory diagnosis as a disease management tool. A retrospective study of WA-MCF in cattle was conducted from 2014 to 2016 at Kapiti Plains Ranch Ltd., Kenya. During this period, 325 animals showed clinical signs of WA-MCF and of these, 123 were opportunistically sampled. In addition, 51 clinically healthy animals were sampled. Nested polymerase chain reaction (PCR) and indirect enzyme linked immunosorbent assay (ELISA) were used to confirm clinically diagnosed cases of WA-MCF. A latent class model (LCM) was used to evaluate the diagnostic parameters of clinical diagnosis and the tests in the absence of a gold standard., Results: By PCR, 94% (95% C.I. 89-97%) of clinically affected animals were positive to WA-MCF while 63% (95% C.I. 54-71%) were positive by indirect ELISA. The LCM demonstrated the indirect ELISA had poor sensitivity 63.3% (95% PCI 54.4-71.7%) and specificity 62.6% (95% PCI 39.2-84.9%) while the nested PCR performed better with sensitivity 96.1% (95% PCI 90.7-99.7%) and specificity 92.9% (95% PCI 76.1-99.8%). The sensitivity and specificity of clinical diagnosis were 99.1% (95% PCI 96.8-100.0%) and 71.5% (95% PCI 48.0-97.2%) respectively., Conclusions: Clinical diagnosis was demonstrated to be an effective method to identify affected animals although animals may be incorrectly classified resulting in financial loss. The study revealed indirect ELISA as a poor test and nested PCR to be a more appropriate confirmatory test for diagnosing acute WA-MCF. However, the logistics of PCR make it unsuitable for field diagnosis of WA-MCF. The future of WA-MCF diagnosis should be aimed at development of penside techniques, which will allow for fast detection in the field.
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- 2019
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33. Impact of a Comprehensive Adolescent-Focused Case Finding Intervention on Uptake of HIV Testing and Linkage to Care Among Adolescents in Western Kenya.
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Kose J, Tiam A, Ochuka B, Okoth E, Sunguti J, Waweru M, Mwangi E, Wolters T, and Rakhmanina N
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- Adolescent, Child, Female, HIV Infections drug therapy, Health Facilities, Humans, Kenya, Male, Non-Randomized Controlled Trials as Topic, Young Adult, Capacity Building, HIV Infections diagnosis, Health Services Accessibility, Mass Screening organization & administration
- Abstract
Background: Low HIV testing uptake prevents identification of adolescents living with HIV and linkage to care and treatment. We implemented an innovative service package at health care facilities to improve HIV testing uptake and linkage to care among adolescents aged 10-19 years in Western Kenya., Methods: This quasi-experimental study used preintervention and postintervention data at 139 health care facilities (hospitals, health centers, and dispensaries). The package included health worker capacity building, program performance monitoring tools, adolescent-focused HIV risk screening tool, and adolescent-friendly hours.The study population was divided into early (10-14 years) and late (15-19 years) age cohorts. Implementation began in July 2016, with preintervention data collected during January-March 2016 and postintervention data collected during January-March 2017. Descriptive statistics were used to analyze the numbers of adolescents tested for HIV, testing HIV-positive, and linked to care services. Preintervention and postintervention demographic and testing data were compared using the Poisson mean test. χ testing was used to compare the linkage to care rates., Results: During the preintervention period, 25,520 adolescents were tested, 198 testing HIV-positive (0.8%) compared with 77,644 adolescents tested with 534 testing HIV-positive (0.7%) during the postintervention period (both P-values <0.001). The proportion of HIV-positive adolescents linked to care increased from 61.6% to 94.0% (P < 0.001). The increase in linkage to care was observed among both age cohorts and within each facility type (both P-values <0.001)., Conclusions: The adolescent-focused case finding intervention package led to a significant increase in both HIV testing uptake and linkage to care services among adolescents in Western Kenya.
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- 2018
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34. Comparing performance of mothers using simplified mid-upper arm circumference (MUAC) classification devices with an improved MUAC insertion tape in Isiolo County, Kenya.
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Grant A, Njiru J, Okoth E, Awino I, Briend A, Murage S, Abdirahman S, and Myatt M
- Abstract
Background: A novel approach for improving community case-detection of acute malnutrition involves mothers/caregivers screening their children for acute malnutrition using a mid-upper arm circumference (MUAC) insertion tape. The objective of this study was to test three simple MUAC classification devices to determine whether they improved the sensitivity of mothers/caregivers at detecting acute malnutrition., Methods: Prospective, non-randomised, partially-blinded, clinical diagnostic trial describing and comparing the performance of three "Click-MUAC" devices and a MUAC insertion tape. The study took place in twenty-one health facilities providing integrated management of acute malnutrition (IMAM) services in Isiolo County, Kenya. Mothers/caregivers classified their child ( n =1040), aged 6-59 months, using the "Click-MUAC" devices and a MUAC insertion tape. These classifications were compared to a "gold standard" classification (the mean of three measurements taken by a research assistant using the MUAC insertion tape)., Results: The sensitivity of mother/caregiver classifications was high for all devices (>93% for severe acute malnutrition (SAM), defined by MUAC < 115 mm, and > 90% for global acute malnutrition (GAM), defined by MUAC < 125 mm). Mother/caregiver sensitivity for SAM and GAM classification was higher using the MUAC insertion tape (100% sensitivity for SAM and 99% sensitivity for GAM) than using "Click-MUAC" devices. Younden's J for SAM classification, and sensitivity for GAM classification, were significantly higher for the MUAC insertion tape (99% and 99% respectively). Specificity was high for all devices (>96%) with no significant difference between the "Click-MUAC" devices and the MUAC insertion tape., Conclusions: The results of this study indicate that, although the "Click-MUAC" devices performed well, the MUAC insertion tape performed best. The results for sensitivity are higher than found in previous studies. The high sensitivity for both SAM and GAM classification by mothers/caregivers with the MUAC insertion tape could be due to the use of an improved MUAC tape design which has a number of new design features. The one-on-one demonstration provided to mothers/caregivers on the use of the devices may also have helped improve sensitivity. The results of this study provide evidence that mothers/caregivers can perform sensitive and specific classifications of their child's nutritional status using MUAC., Trial Registrations: Clinical trials registration number: NCT02833740., Competing Interests: The study protocol was granted ethical approval by the African Medical and Research Foundation (AMREF) Ethics and Scientific Review Committee, Kenya (ESRC number P249/2016). The study is registered at clinicaltrials.gov (Trial number: NCT02833740). Consent was obtained by the data collection team in either written or verbal form and was recorded through signature or thumb prints on individual consent forms.Not applicable.The authors declare that they have no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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- 2018
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35. Genetic diversity, breed composition and admixture of Kenyan domestic pigs.
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Mujibi FD, Okoth E, Cheruiyot EK, Onzere C, Bishop RP, Fèvre EM, Thomas L, Masembe C, Plastow G, and Rothschild M
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- Animals, Kenya, Polymorphism, Single Nucleotide, Animals, Domestic genetics, Genetic Variation, Swine genetics
- Abstract
The genetic diversity of African pigs, whether domestic or wild has not been widely studied and there is very limited published information available. Available data suggests that African domestic pigs originate from different domestication centers as opposed to international commercial breeds. We evaluated two domestic pig populations in Western Kenya, in order to characterize the genetic diversity, breed composition and admixture of the pigs in an area known to be endemic for African swine fever (ASF). One of the reasons for characterizing these specific populations is the fact that a proportion of indigenous pigs have tested ASF virus (ASFv) positive but do not present with clinical symptoms of disease indicating some form of tolerance to infection. Pigs were genotyped using either the porcine SNP60 or SNP80 chip. Village pigs were sourced from Busia and Homabay counties in Kenya. Because bush pigs (Potamochoerus larvatus) and warthogs (Phacochoerus spp.) are known to be tolerant to ASFv infection (exhibiting no clinical symptoms despite infection), they were included in the study to assess whether domestic pigs have similar genomic signatures. Additionally, samples representing European wild boar and international commercial breeds were included as references, given their potential contribution to the genetic make-up of the target domestic populations. The data indicate that village pigs in Busia are a non-homogenous admixed population with significant introgression of genes from international commercial breeds. Pigs from Homabay by contrast, represent a homogenous population with a "local indigenous' composition that is distinct from the international breeds, and clusters more closely with the European wild boar than African wild pigs. Interestingly, village pigs from Busia that tested negative by PCR for ASFv genotype IX, had significantly higher local ancestry (>54%) compared to those testing positive, which contained more commercial breed gene introgression. This may have implication for breed selection and utilization in ASF endemic areas. A genome wide scan detected several regions under preferential selection with signatures for pigs from Busia and Homabay being very distinct. Additionally, there was no similarity in specific genes under selection between the wild pigs and domestic pigs despite having some broad areas under similar selection signatures. These results provide a basis to explore possible genetic determinants underlying tolerance to infection by ASFv genotypes and suggests multiple pathways for genetically mediated ASFv tolerance given the diversity of selection signatures observed among the populations studied.
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- 2018
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36. Cluster randomized trial comparing school-based mass drug administration schedules in areas of western Kenya with moderate initial prevalence of Schistosoma mansoni infections.
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Karanja DMS, Awino EK, Wiegand RE, Okoth E, Abudho BO, Mwinzi PNM, Montgomery SP, and Secor WE
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- Animals, Child, Feces parasitology, Female, Humans, Kenya epidemiology, Male, Praziquantel therapeutic use, Prevalence, Schistosoma mansoni isolation & purification, Schistosomiasis mansoni drug therapy, Schistosomiasis mansoni epidemiology, Schools, Students, Time Factors, World Health Organization, Drug Administration Schedule, Praziquantel administration & dosage, Schistosoma mansoni drug effects, Schistosomiasis mansoni prevention & control, Schistosomicides administration & dosage
- Abstract
Background: Mass drug administration (MDA) using praziquantel is the WHO-recommended approach for control of schistosomiasis. However, few studies have compared the impact of different schedules of MDA on the resultant infection levels. We wished to evaluate whether annual MDA was more effective than less frequent treatments for reducing community-level prevalence and intensity of Schistosoma mansoni infections., Methods: We performed a cluster randomized trial (ISRCTN 14849830) of 3 different MDA frequencies over a 5 year period in 75 villages with moderate (10%-24%) initial prevalence of S. mansoni in school children in western Kenya. Praziquantel was distributed by school teachers to students either annually, the first 2 years, or every other year over a 4 year period. Prevalence and intensity of infection were measured by stool examination in 9-12 year old students using the Kato-Katz method at baseline, each treatment year, and for the final evaluation at year 5. S. mansoni prevalence and intensity were also measured in first year students at baseline and year 5., Results: Twenty-five schools were randomly assigned to each arm. S. mansoni prevalence and infection intensity in 9-12 year old students significantly decreased within each arm from baseline to year 5 but there were no differences between arms. There were no differences in infection levels in first year students either within or between arms., Conclusions: Strategies employing 2 or 4 rounds of MDA had a similar impact in schools with moderate initial prevalence, suggesting that schistosomiasis control can be sustained by school-based MDA, even if provided only every other year.
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- 2017
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37. First Detection of Rotavirus Group C in Asymptomatic Pigs of Smallholder Farms in East Africa.
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Amimo JO, Machuka EM, and Okoth E
- Abstract
Abstract : Group C rotavirus (RVC) has been described to be a causative agent of gastroenteritis in humans and animals including pigs, cows, and dogs. Fecal samples collected from asymptomatic pigs in smallholder swine farms in Kenya and Uganda were screened for the presence of group C rotaviruses (RVC) using a reverse transcription-polymerase chain reaction assay. A total of 446 samples were tested and 37 were positive (8.3%). A significantly larger ( p < 0.05) number of RVC-positive samples was detected in groups of older pigs (5-6 months) than in younger piglets (1-2 months). There were no significant differences in the RVC detection rate between the pigs that were full time housed/tethered and those that were free range combined with housing/tethering. After compiling these data with diagnostic results for group A rotaviruses (RVA), 13 RVC-positive samples were also positive for RVA. This study provides the first evidence that porcine group C rotavirus may be detected frequently in asymptomatic piglets (aged < 1-6 months) in East Africa. The occurrence of RVC in mixed infections with RVA and other enteric pathogens requires further research to investigate the pathogenic potential of RVC in pigs., Competing Interests: The authors declare no conflict of interest.
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- 2017
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38. Cost-effectiveness of condom uterine balloon tamponade to control severe postpartum hemorrhage in Kenya.
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Mvundura M, Kokonya D, Abu-Haydar E, Okoth E, Herrick T, Mukabi J, Carlson L, Oguttu M, and Burke T
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- Adult, Cross-Sectional Studies, Female, Humans, Kenya, Maternal Health Services economics, Maternal Mortality, Perinatal Care economics, Postpartum Hemorrhage economics, Postpartum Hemorrhage mortality, Pregnancy, Condoms statistics & numerical data, Postpartum Hemorrhage therapy, Uterine Balloon Tamponade instrumentation
- Abstract
Objective: To evaluate the cost-effectiveness of condom uterine balloon tamponade (UBT) for control of severe postpartum hemorrhage (PPH) due to uterine atony versus standard PPH care in Kenya., Methods: A cross-sectional analysis was conducted using cost data collected from 30 facilities in Western Kenya from April 15 to July 16, 2015. Effectiveness data were derived from the published literature. The modeling analysis was performed from the health-system perspective for a cohort of women who gave birth in 2015. Sensitivity analyses tested the robustness of model estimates. Costs were in 2015 US dollars., Results: Compared with standard care with no uterine packing, condom UBT could prevent 1255 hospital transfers, 430 hysterectomies, and 44 maternal deaths. At $5 or $15 per UBT device, the incremental cost per disability-adjusted life year (DALY) averted was $26 or $40, respectively. If uterine packing was assumed to be done with standard care, the cost per DALY averted was $164 when the UBT price was $5 and $199 when the price was $15., Conclusion: Condom UBT was a highly cost-effective intervention for controlling severe PPH. This finding remained robust even when key model inputs were varied by wide margins., (© 2017 International Federation of Gynecology and Obstetrics.)
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- 2017
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39. Pig traders' networks on the Kenya-Uganda border highlight potential for mitigation of African swine fever virus transmission and improved ASF disease risk management.
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Lichoti JK, Davies J, Maru Y, Kitala PM, Githigia SM, Okoth E, Bukachi SA, Okuthe S, and Bishop RP
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- African Swine Fever epidemiology, African Swine Fever transmission, African Swine Fever Virus, Animal Husbandry, Animals, Commerce, Disease Outbreaks prevention & control, Disease Outbreaks veterinary, Health Knowledge, Attitudes, Practice, Humans, Interviews as Topic, Kenya epidemiology, Risk Factors, Risk Management, Swine, Uganda epidemiology, Abattoirs, African Swine Fever prevention & control, African Swine Fever psychology
- Abstract
We applied social network analysis to pig trader networks on the Kenya-Uganda border. Social network analysis is a recently developed tool, which is useful for understanding value chains and improving disease control policies. We interviewed a sample of 33 traders about their experiences with trade and African swine fever (ASF), analyzed the networks they generated in purchasing pigs and selling pork and their potential contribution to modulating dissemination of the ASF virus (ASFV). The majority of the traders were aware of clinical signs of ASF and the risk of trade transmitting ASFV. Most said they avoided buying pigs from ASF outbreak villages or sick pigs but their experiences also indicated that inadvertent purchase was relatively common. Traders had early knowledge of outbreaks since they were contacted by farmers who had heard rumours and wanted to sell their pigs to avoid the risk of them dying. Individual traders bought pigs in up to nine villages, and up to six traders operated in a village. Although each trade typically spanned less than 5km, networks of the various traders, comprising movements of pigs from source villages to slaughter slabs/sites and retail outlets, and movement of pork to villages where it was consumed, linked up indirectly across the 100km×50km study area and revealed several trade pathways across the Kenya-Uganda border. ASF could potentially spread across this area and beyond through sequential pig and pork transactions. Regulation of the pig and pork trade was minimal in practice. The risk of ASFV being spread by traders was compounded by their use of poorly constructed slaughter slabs/sites with open drainage, ineffective or non-existent meat inspection services, lack of provision for biosecurity in the value chain, and sales of pork to customers who were unaware of the risks to their own pigs from contact with ASF infected pork. More effective regulation is warranted. However, limitations on government capacity, together with the strong self-interest that established traders have in reducing the disruption and financial losses that outbreaks cause, highlight the importance of governments and traders co-developing an approach to ASF control. Formation of trader organizations or common interest groups warrants government support as an important step in engaging traders in developing and implementing effective approaches to reduce the risk of ASF outbreaks., (Copyright © 2017 Elsevier B.V. All rights reserved.)
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- 2017
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40. PCBs in fish and their cestode parasites in Lake Victoria.
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Oluoch-Otiego J, Oyoo-Okoth E, Kiptoo KK, Chemoiwa EJ, Ngugi CC, Simiyu G, Omutange ES, Ngure V, and Opiyo MA
- Subjects
- Animals, Cestoda growth & development, Cestoda metabolism, Cyprinidae metabolism, Kenya, Cestoda chemistry, Cyprinidae parasitology, Environmental Monitoring methods, Lakes chemistry, Polychlorinated Biphenyls analysis
- Abstract
Polychlorinated biphenyls (PCBs) are classified as persistent organic pollutants (POPs) regulated by the Stockholm Convention (2001). Although their production and use was stopped almost three decades ago, PCBs are environmental persistent, toxic, and bioaccumulate in biota. We assessed the levels of 7 PCB congeners (IUPAC nos. 28, 52, 101, 118, 138, 153, and 180) in sediment and fish (Oreochromis niloticus, Lates niloticus, and Rastrineobola argentea) and evaluated the potential of cestode fish endoparasite (Monobothrioides sp., Proteocephalaus sp., and Ligula intestinalis) as biomonitors of PCBs in Lake Victoria, Kenya. The median concentration of Σ7PCBs in sediments and fish were 2.2-96.3 μg/kg dw and 300-3,000 μg/kg lw, respectively. At all the sampling sites, CB138, CB153, and CB180 were the dominant PCB congeners in sediment and fish samples. Compared to the muscle of the piscine host, Proteocephalaus sp. (infecting L. niloticus) biomagnified PCBs ×6-14 while Monobothrioides sp. (infecting O. niloticus) biomagnified PCBs ×4-8. Meanwhile, L. intestinalis (infecting R. argentea) biomagnified PCBs ×8-16 compared to the muscle of unparasitized fish. We demonstrate the occurrence of moderate to high levels of PCB in sediments and fish in Lake Victoria. We also provide evidence that fish parasites bioaccumulate higher levels of PCBs than their piscine hosts and therefore provide a promising biomonitor of PCBs. We urge further a long-term study to validate the use of the above cestode fish parasites as biomonitoring tools for PCBs.
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- 2016
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41. Vector competence of Aedes aegypti in transmitting Chikungunya virus: effects and implications of extrinsic incubation temperature on dissemination and infection rates.
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Mbaika S, Lutomiah J, Chepkorir E, Mulwa F, Khayeka-Wandabwa C, Tigoi C, Oyoo-Okoth E, Mutisya J, Ng'ang'a Z, and Sang R
- Subjects
- Aedes physiology, Animals, Chikungunya Fever virology, Humans, Insect Vectors physiology, Temperature, Aedes virology, Chikungunya Fever transmission, Chikungunya virus physiology, Insect Vectors virology
- Abstract
Background: Aedes aegypti is a competent arthropod vector of chikungunya virus (CHIKV). The rate at which the virus disseminate in the vector is limited by temperature of their environment which can be an important determinant of geographical and seasonal limits to transmission by the arthropods in the tropics. This study investigated the vector competence of Ae. aegypti for CHIKV at ambient temperature of 32 and 26 °C (Coastal and Western Kenya respectively) reared at Extrinsic Incubation Temperature (EIT) of 32 and 26 °C that resembles those in the two regions., Methods: Ae. aegypti eggs were collected from coastal and Western Kenya, hatched in the insectary and reared to F1 generation. Four-day old mosquitoes were exposed to CHIKV through a membrane feeding. They were then incubated in temperatures mimicking the mean annual temperatures for Trans-Nzoia (26 °C) and Lamu (32 °C). After every 7, 10 and 13 days post infection (DPI); one third of exposed mosquitoes were sampled and assayed for virus infection and dissemination., Results: The midgut infection rates (MIR) of Ae. aegypti sampled from Coastal Region was significantly (p < 0.05) higher than those sampled from Western Kenya, with no statistical differences observed for the coastal Ae. aegypti at EIT 26 and at 32 °C. The MIR of Ae. aegypti from the Western Region was significantly (p < 0.05) affected by the EIT, with mosquito reared at EIT 32 °C exhibiting higher MIR than those reared at EIT 26 °C. There was a significant (p < 0.05) interactive effects of the region, EIT and DPI on MIR. The disseminated infection rates for the CHIKV in Ae. aegypti in the legs (DIR-L) was higher in mosquitoes sampled from Coast regardless of the EIT while those from Western Kenya, dissemination rates were significantly higher at higher EIT of 32 °C., Conclusions: Vector competence was higher in mosquito populations reared under high temperatures which weakens the midgut infection barrier. Hence, suggesting Lamu population is more susceptible to CHIKV therefore having a weaker mid gut infection barrier than the Trans Nzoia population. These underscores importance of examining the course of infection at various ambient temperatures and EIT between regions mosquito populations.
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- 2016
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42. Evaluation of a topical formulation of eprinomectin against Anopheles arabiensis when administered to Zebu cattle (Bos indicus) under field conditions.
- Author
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Lozano-Fuentes S, Kading RC, Hartman DA, Okoth E, Githaka N, Nene V, and Poché RM
- Subjects
- Administration, Topical, Animals, Cattle, Female, Ivermectin administration & dosage, Kenya, Male, Mosquito Vectors, Pilot Projects, Anopheles drug effects, Ectoparasitic Infestations prevention & control, Insecticides administration & dosage, Ivermectin analogs & derivatives
- Abstract
Background: Although vector control strategies, such as insecticide-treated bed nets (ITNs) and indoor residual spraying (IRS) have been effective in Kenya the transmission of malaria continues to afflict western Kenya. This residual transmission is driven in part by Anopheles arabiensis, known for its opportunistic blood feeding behaviour and propensity to feed outdoors. The objective of this research was to evaluate the efficacy of the drug eprinomectin at reducing malaria vector density when applied to cattle (Bos indicus), the primary source of blood for An. arabiensis, under field conditions., Methods: A pilot study was carried out in the Samia District of western Kenya from September to October of 2014. Treatment and control areas were randomly designated and comprised of 50 homes per study area. Before cattle treatments, baseline mosquito counts were performed after pyrethrum spray. Cows in the treatment area were administered topical applications of eprinomectin at 0.5 mg/kg once a week for two consecutive weeks. Mosquito collections were performed once each week for two weeks following the eprinomectin treatments. Mosquitoes were first identified morphologically and with molecular confirmation, then screened for sporozoite presence and host blood using PCR-based methods., Results: The indoor resting density of An. arabiensis was significantly reduced by 38 % in the treatment area compared to the control area at one-week post-treatment (Control mean females per hut = 1.33 95 % CI [1.08, 1.64]; Treatment = 0.79 [0.56, 1.07]). An increase in the indoor resting density of Anopheles gambiae s.s. and Anopheles funestus s.s. was observed in the treatment area in the absence of An. arabiensis. At two weeks post-treatment, the total number of mosquitoes for any species per hut was not significantly different between the treatment and control areas. No change was observed in An. arabiensis host preference as a result of treatment., Conclusions: Systemic drugs may be an important tool by which to supplement existing vector control interventions by significantly impacting outdoor malaria transmission driven by An. arabiensis through the treatment of cattle.
- Published
- 2016
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43. Recombinant Newcastle disease virus expressing African swine fever virus protein 72 is safe and immunogenic in mice.
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Chen X, Yang J, Ji Y, Okoth E, Liu B, Li X, Yin H, and Zhu Q
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- African Swine Fever immunology, African Swine Fever prevention & control, African Swine Fever virology, African Swine Fever Virus genetics, Animals, Antibodies, Viral blood, Capsid Proteins genetics, Cell Line, Chick Embryo, Chickens, Cricetinae, Female, Genetic Vectors, Immunoglobulin G blood, Interferon-gamma blood, Interleukin-4 blood, Mice, Mice, Inbred BALB C, Newcastle disease virus genetics, Newcastle disease virus metabolism, Swine, Vaccines, Attenuated genetics, Vaccines, Attenuated immunology, Vaccines, Attenuated pharmacology, Viral Vaccines genetics, Viral Vaccines pharmacology, African Swine Fever Virus immunology, Capsid Proteins biosynthesis, Capsid Proteins immunology, Newcastle disease virus immunology, Viral Vaccines immunology
- Abstract
African swine fever (ASF) is a lethal hemorrhagic disease that affects wild and domestic swine. The etiological agent of ASF is African swine fever virus (ASFV). Since the first case was described in Kenya in 1921, the disease has spread to many other countries. No commercial vaccines are available to prevent ASF. In this study, we generated a recombinant Newcastle disease virus (rNDV) expressing ASFV protein 72 (p72) by reverse genetics and evaluated its humoral and cellular immunogenicity in a mouse model. The recombinant virus, rNDV/p72, replicated well in embryonated chicken eggs and was safe to use in chicks and mice. The p72 gene in rNDV/p72 was stably maintained through ten passages. Mice immunized with rNDV/p72 developed high titers of ASFV p72 specific IgG antibody, and had higher levels of IgG1 than IgG2a. Immunization also elicited T-cell proliferation and secretion of IFN-γ and IL-4. Taken together, these results indicate that rNDV expressing ASFV p72 might be a potential vaccine candidate for preventing ASF.
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- 2016
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44. Social network analysis provides insights into African swine fever epidemiology.
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Lichoti JK, Davies J, Kitala PM, Githigia SM, Okoth E, Maru Y, Bukachi SA, and Bishop RP
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- African Swine Fever transmission, Animal Husbandry economics, Animals, Commerce, Community Networks, Kenya epidemiology, Swine, Swine Diseases transmission, Transportation, Uganda epidemiology, African Swine Fever epidemiology, Animal Husbandry methods, Swine Diseases epidemiology
- Abstract
Pig movements play a significant role in the spread of economically important infectious diseases such as the African swine fever. Characterization of movement networks between pig farms and through other types of farm and household enterprises that are involved in pig value chains can provide useful information on the role that different participants in the networks play in pathogen transmission. Analysis of social networks that underpin these pig movements can reveal pathways that are important in the transmission of disease, trade in commodities, the dissemination of information and the influence of behavioural norms. We assessed pig movements among pig keeping households within West Kenya and East Uganda and across the shared Kenya-Uganda border in the study region, to gain insight into within-country and trans-boundary pig movements. Villages were sampled using a randomized cluster design. Data were collected through interviews in 2012 and 2013 from 683 smallholder pig-keeping households in 34 villages. NodeXL software was used to describe pig movement networks at village level. The pig movement and trade networks were localized and based on close social networks involving family ties, friendships and relationships with neighbours. Pig movement network modularity ranged from 0.2 to 0.5 and exhibited good community structure within the network implying an easy flow of knowledge and adoption of new attitudes and beliefs, but also promoting an enhanced rate of disease transmission. The average path length of 5 defined using NodeXL, indicated that disease could easily reach every node in a cluster. Cross-border boar service between Uganda and Kenya was also recorded. Unmonitored trade in both directions was prevalent. While most pig transactions in the absence of disease, were at a small scale (<5km) and characterized by regular agistment, most pig sales during ASF outbreaks were to traders or other farmers from outside the sellers' village at a range of >10km. The close social relationships between actors in pig movement networks indicate the potential for possible interventions to develop shared norms and mutually accepted protocols amongst smallholder pig keepers to better manage the risk of ASF introduction and transmission., (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Published
- 2016
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45. Enhancing knowledge and awareness of biosecurity practices for control of African swine fever among smallholder pig farmers in four districts along the Kenya-Uganda border.
- Author
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Nantima N, Davies J, Dione M, Ocaido M, Okoth E, Mugisha A, and Bishop R
- Subjects
- Animals, Attitude, Farmers, Focus Groups, Geography, Kenya, Risk Factors, Surveys and Questionnaires, Sus scrofa, Swine, Uganda, African Swine Fever prevention & control, Agriculture methods, Animal Husbandry methods, Health Knowledge, Attitudes, Practice
- Abstract
A study was undertaken along the Kenya-Uganda border in four districts of Tororo and Busia (Uganda) and Busia and Teso (Kenya) to understand smallholder farmers' knowledge, practices and awareness of biosecurity measures. Information was collected by administering questionnaires to 645 randomly selected pig households in the study area. In addition, focus group discussions were carried out in 12 villages involving 248 people using a standardized list of questions. The outcome suggested that there was a very low level of awareness of biosecurity practices amongst smallholder farmers. We conclude that adoption of specific biosecurity practices by smallholder farmers is feasible but requires institutional support. There is a clear requirement for government authorities to sensitize farmers using approaches that allow active participation of farmers in the design, planning and implementation of biosecurity practices to enable enhanced adoption.
- Published
- 2016
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46. Chimpanzee Adenovirus Vaccine Provides Multispecies Protection against Rift Valley Fever.
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Warimwe GM, Gesharisha J, Carr BV, Otieno S, Otingah K, Wright D, Charleston B, Okoth E, Elena LG, Lorenzo G, Ayman el-B, Alharbi NK, Al-dubaib MA, Brun A, Gilbert SC, Nene V, and Hill AV
- Subjects
- Adenovirus Vaccines pharmacology, Animals, Camelus, Cattle, Goats, Humans, Pan troglodytes immunology, Pan troglodytes virology, Rift Valley Fever immunology, Rift Valley fever virus genetics, Rift Valley fever virus immunology, Saudi Arabia epidemiology, Sheep, United Kingdom epidemiology, Vaccination, Vaccines, Synthetic administration & dosage, Viral Envelope Proteins immunology, Adenovirus Vaccines administration & dosage, Antibodies, Neutralizing metabolism, Rift Valley Fever prevention & control, Rift Valley fever virus metabolism, Viral Envelope Proteins genetics, Viral Vaccines administration & dosage
- Abstract
Rift Valley Fever virus (RVFV) causes recurrent outbreaks of acute life-threatening human and livestock illness in Africa and the Arabian Peninsula. No licensed vaccines are currently available for humans and those widely used in livestock have major safety concerns. A 'One Health' vaccine development approach, in which the same vaccine is co-developed for multiple susceptible species, is an attractive strategy for RVFV. Here, we utilized a replication-deficient chimpanzee adenovirus vaccine platform with an established human and livestock safety profile, ChAdOx1, to develop a vaccine for use against RVFV in both livestock and humans. We show that single-dose immunization with ChAdOx1-GnGc vaccine, encoding RVFV envelope glycoproteins, elicits high-titre RVFV-neutralizing antibody and provides solid protection against RVFV challenge in the most susceptible natural target species of the virus-sheep, goats and cattle. In addition we demonstrate induction of RVFV-neutralizing antibody by ChAdOx1-GnGc vaccination in dromedary camels, further illustrating the potency of replication-deficient chimpanzee adenovirus vaccine platforms. Thus, ChAdOx1-GnGc warrants evaluation in human clinical trials and could potentially address the unmet human and livestock vaccine needs.
- Published
- 2016
- Full Text
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47. Determination of the minimum fully protective dose of adenovirus-based DIVA vaccine against peste des petits ruminants virus challenge in East African goats.
- Author
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Holzer B, Taylor G, Rajko-Nenow P, Hodgson S, Okoth E, Herbert R, Toye P, and Baron MD
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- Adenoviridae, Animals, Antibodies, Viral blood, Antibody Specificity, Chlorocebus aethiops, Glycoproteins immunology, Goat Diseases virology, Goats, Nucleocapsid Proteins immunology, Vero Cells, Viremia, Goat Diseases prevention & control, Peste-des-Petits-Ruminants prevention & control, Peste-des-petits-ruminants virus, Viral Vaccines immunology
- Abstract
Peste des petits ruminants virus (PPRV) causes an economically important disease of sheep and goats, primarily in developing countries. It is becoming the object of intensive international control efforts. Current vaccines do not allow vaccinated and infected animals to be distinguished (no DIVA capability). We have previously shown that recombinant, replication-defective, adenovirus expressing the PPRV H glycoprotein (AdH) gives full protection against wild type PPRV challenge. We have now tested lower doses of the vaccine, as well as AdH in combination with a similar construct expressing the PPRV F glycoprotein (AdF). We show here that, in a local breed of goat in a country where PPR disease is common (Kenya), as little as 10(7) pfu of AdH gives significant protection against PPRV challenge, while a vaccine consisting of 10(8) pfu of each of AdH and AdF gives apparently sterile protection. These findings underline the utility of these constructs as DIVA vaccines for use in PPR control.
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- 2016
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48. Functional analysis and transcriptional output of the Göttingen minipig genome.
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Heckel T, Schmucki R, Berrera M, Ringshandl S, Badi L, Steiner G, Ravon M, Küng E, Kuhn B, Kratochwil NA, Schmitt G, Kiialainen A, Nowaczyk C, Daff H, Khan AP, Lekolool I, Pelle R, Okoth E, Bishop R, Daubenberger C, Ebeling M, and Certa U
- Subjects
- Aging genetics, Animals, Chromosomes, Gene Expression, Gene Expression Profiling, Humans, Liver metabolism, Pharmaceutical Preparations metabolism, Pseudogenes, Species Specificity, Swine, Transcription, Genetic, Genome, Swine, Miniature genetics
- Abstract
Background: In the past decade the Göttingen minipig has gained increasing recognition as animal model in pharmaceutical and safety research because it recapitulates many aspects of human physiology and metabolism. Genome-based comparison of drug targets together with quantitative tissue expression analysis allows rational prediction of pharmacology and cross-reactivity of human drugs in animal models thereby improving drug attrition which is an important challenge in the process of drug development., Results: Here we present a new chromosome level based version of the Göttingen minipig genome together with a comparative transcriptional analysis of tissues with pharmaceutical relevance as basis for translational research. We relied on mapping and assembly of WGS (whole-genome-shotgun sequencing) derived reads to the reference genome of the Duroc pig and predict 19,228 human orthologous protein-coding genes. Genome-based prediction of the sequence of human drug targets enables the prediction of drug cross-reactivity based on conservation of binding sites. We further support the finding that the genome of Sus scrofa contains about ten-times less pseudogenized genes compared to other vertebrates. Among the functional human orthologs of these minipig pseudogenes we found HEPN1, a putative tumor suppressor gene. The genomes of Sus scrofa, the Tibetan boar, the African Bushpig, and the Warthog show sequence conservation of all inactivating HEPN1 mutations suggesting disruption before the evolutionary split of these pig species. We identify 133 Sus scrofa specific, conserved long non-coding RNAs (lncRNAs) in the minipig genome and show that these transcripts are highly conserved in the African pigs and the Tibetan boar suggesting functional significance. Using a new minipig specific microarray we show high conservation of gene expression signatures in 13 tissues with biomedical relevance between humans and adult minipigs. We underline this relationship for minipig and human liver where we could demonstrate similar expression levels for most phase I drug-metabolizing enzymes. Higher expression levels and metabolic activities were found for FMO1, AKR/CRs and for phase II drug metabolizing enzymes in minipig as compared to human. The variability of gene expression in equivalent human and minipig tissues is considerably higher in minipig organs, which is important for study design in case a human target belongs to this variable category in the minipig. The first analysis of gene expression in multiple tissues during development from young to adult shows that the majority of transcriptional programs are concluded four weeks after birth. This finding is in line with the advanced state of human postnatal organ development at comparative age categories and further supports the minipig as model for pediatric drug safety studies., Conclusions: Genome based assessment of sequence conservation combined with gene expression data in several tissues improves the translational value of the minipig for human drug development. The genome and gene expression data presented here are important resources for researchers using the minipig as model for biomedical research or commercial breeding. Potential impact of our data for comparative genomics, translational research, and experimental medicine are discussed.
- Published
- 2015
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49. Effects of dietary administration of stinging nettle (Urtica dioica) on the growth performance, biochemical, hematological and immunological parameters in juvenile and adult Victoria Labeo (Labeo victorianus) challenged with Aeromonas hydrophila.
- Author
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Ngugi CC, Oyoo-Okoth E, Mugo-Bundi J, Orina PS, Chemoiwa EJ, and Aloo PA
- Subjects
- Animals, Aquaculture methods, Blood Cell Count veterinary, Blood Glucose, Cholesterol blood, Dose-Response Relationship, Drug, Hematocrit, Hydrocortisone blood, Immunoglobulins blood, Muramidase metabolism, Probiotics administration & dosage, Probiotics metabolism, Respiratory Burst immunology, Triglycerides blood, Aeromonas hydrophila immunology, Cyprinidae growth & development, Cyprinidae immunology, Cyprinidae metabolism, Diet veterinary, Probiotics pharmacology, Urtica dioica metabolism
- Abstract
We investigated effects of dietary administration of stinging nettle (Urtica dioica) on growth performance, biochemical, hematological and immunological parameters in juvenile and adult Victoria Labeo (Labeo victorianus) against Aeromonas hydrophila. Fish were divided into 4 groups and fed for 4 and 16 weeks with 0%, 1%, 2% and 5% of U. dioica incorporated into the diet. Use of U. dioica in the diet resulted in improved biochemical, hematological and immunological parameters. Among the biochemical parameters; plasma cortisol, glucose, triglyceride and cholesterol decreased while total protein and albumin in fish increased with increasing dietary inclusion of U. dioica. Among the haematology parameters: red blood cell (RBC), white blood cell (WBC) counts, haematocrit (Htc), mean cell haemoglobin (MCH), mean cell haemoglobin concentration (MCHC) and netrophiles increased with increasing dietary inclusion levels of U. dioica, some depending on the fish age. Serum immunoglobulins, lysozyme activity and respiratory burst were the main immunological parameters in the adult and juvenile L. victorianus measured and they all increased with increasing herbal inclusion of U. dioica in the diet. Dietary incorporation of U. dioica at 5% showed significantly higher relative percentage survival (up to 95%) against A. hydrophila. The current results demonstrate that using U. dioica can stimulate fish immunity and make L. victorianus more resistant to bacterial infection (A. hydrophila)., (Copyright © 2015 Elsevier Ltd. All rights reserved.)
- Published
- 2015
- Full Text
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50. Estimating the Basic Reproductive Number (R0) for African Swine Fever Virus (ASFV) Transmission between Pig Herds in Uganda.
- Author
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Barongo MB, Ståhl K, Bett B, Bishop RP, Fèvre EM, Aliro T, Okoth E, Masembe C, Knobel D, and Ssematimba A
- Subjects
- Animals, Disease Outbreaks, Models, Statistical, Seasons, Sus scrofa, Swine, Uganda epidemiology, African Swine Fever epidemiology, African Swine Fever transmission, African Swine Fever Virus, Basic Reproduction Number
- Abstract
African swine fever (ASF) is a highly contagious, lethal and economically devastating haemorrhagic disease of domestic pigs. Insights into the dynamics and scale of virus transmission can be obtained from estimates of the basic reproduction number (R0). We estimate R0 for ASF virus in small holder, free-range pig production system in Gulu, Uganda. The estimation was based on data collected from outbreaks that affected 43 villages (out of the 289 villages with an overall pig population of 26,570) between April 2010 and November 2011. A total of 211 outbreaks met the criteria for inclusion in the study. Three methods were used, specifically; (i) GIS- based identification of the nearest infectious neighbour based on the Euclidean distance between outbreaks, (ii) epidemic doubling time, and (iii) a compartmental susceptible-infectious (SI) model. For implementation of the SI model, three approaches were used namely; curve fitting (CF), a linear regression model (LRM) and the SI/N proportion. The R0 estimates from the nearest infectious neighbour and epidemic doubling time methods were 3.24 and 1.63 respectively. Estimates from the SI-based method were 1.58 for the CF approach, 1.90 for the LRM, and 1.77 for the SI/N proportion. Since all these values were above one, they predict the observed persistence of the virus in the population. We hypothesize that the observed variation in the estimates is a consequence of the data used. Higher resolution and temporally better defined data would likely reduce this variation. This is the first estimate of R0 for ASFV in a free range smallholder pig keeping system in sub-Saharan Africa and highlights the requirement for more efficient application of available disease control measures.
- Published
- 2015
- Full Text
- View/download PDF
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