26 results on '"Christopher A. L. Oura"'
Search Results
2. Virome of
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Stephen, Sameroff, Rafal, Tokarz, Marko, Vucelja, Komal, Jain, Alexandra, Oleynik, Marko, Boljfetić, Linda, Bjedov, Rachel A, Yates, Josip, Margaletić, Christopher A L, Oura, Walter Ian, Lipkin, Lidija, Cvetko Krajinović, and Alemka, Markotić
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Ixodes ,Ixodidae ,Croatia ,Virome ,Animals ,Humans ,Dermacentor - Abstract
Tick-borne diseases are a serious threat to both public and veterinary health. In this study, we used high-throughput sequencing to characterize the virome of three tick species implicated in the spread of vector-borne disease throughout Croatia. Ten viruses were identified, including seven potential novel species within the viral families
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- 2022
3. Characterization of novel, pathogenic field strains of infectious bronchitis virus (IBV) in poultry in Trinidad and Tobago
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Gianpiero Zamperin, Adelaide Milani, Isabella Monne, Christopher A. L. Oura, Gabriel Brown, Christine V.F. Carrington, Alice Fusaro, Arianne Brown Jordan, and Lemar Blake
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Turkeys ,animal structures ,Lineage (genetic) ,040301 veterinary sciences ,Infectious bronchitis virus ,Biology ,Recombinant virus ,Quail ,Virus ,0403 veterinary science ,03 medical and health sciences ,Geese ,Animals ,Respiratory Tract Infections ,Phylogeny ,Poultry Diseases ,030304 developmental biology ,0303 health sciences ,General Veterinary ,General Immunology and Microbiology ,Phylogenetic tree ,Sequence Analysis, RNA ,Vaccination ,Outbreak ,Viral Vaccines ,04 agricultural and veterinary sciences ,General Medicine ,Virology ,Ducks ,Trinidad and Tobago ,Turkey coronavirus ,embryonic structures ,RNA, Viral ,Coronavirus Infections ,Chickens - Abstract
Avian coronaviruses, including infectious bronchitis virus (IBV) and turkey coronavirus (TCoV), are economically important viruses affecting poultry worldwide. IBV is responsible for causing severe losses to the commercial poultry sector globally. The objectives of this study were to identify the viruses that were causing outbreaks of severe respiratory disease in chickens in Trinidad and Tobago (TT) and to characterize the strains. Swab samples were collected from birds showing severe respiratory signs in five farms on the island of Trinidad. Samples were tested for the presence of IBV, as well as avian influenza virus (AIV), Newcastle disease virus (NDV) and avian metapneumovirus (aMPV) by real-time reverse transcription polymerase chain reaction (qRT-PCR). All samples from the five farms tested negative for AIV, NDV and aMPV; however, samples from clinically affected birds in all five of the farms tested positive for IBV. Genetic data revealed the presence of TCoV in chickens on two of the farms. Interestingly, these two farms had never reared turkeys. Phylogenetic analysis showed that IBV S1 sequences formed two distinct clusters. Two sequences grouped with vaccine strains within the GI-1 lineage, whereas three sequences grouped together, but separately from other defined lineages, forming a likely new lineage of IBV. Pairwise comparison revealed that the three unique variant strains within the distinct lineage of IBV were significantly different in their S1 nucleotide coding regions from viruses in the closest lineage (16% difference) and locally used vaccine strains (20% difference). Results also suggested that one of the samples was a recombinant virus, generated from a recombination event between a Trinidad virus of the GI-1 lineage and a Trinidad virus of the newly defined lineage. Many amino acid differences were also observed between the S1 coding regions of the circulating field and vaccine strains, indicating that the IBV vaccines may not be protective. Vaccine-challenge studies are however needed to prove this.
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- 2020
4. Multilocus genotyping of Theileria parva isolates associated with a live vaccination trial in Kenya provides evidence for transmission of immunizing parasites into local tick and cattle populations
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David Odongo, Robert A. Skilton, Christopher A. L. Oura, P.R. Spooner, Richard P. Bishop, and Subhash Morzaria
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Veterinary medicine ,Genotype ,040301 veterinary sciences ,Theileria parva ,Population ,Cattle Diseases ,Tick ,Vaccines, Attenuated ,Polymerase Chain Reaction ,0403 veterinary science ,03 medical and health sciences ,Ticks ,parasitic diseases ,Animals ,East Coast fever ,Uganda ,education ,030304 developmental biology ,0303 health sciences ,education.field_of_study ,General Veterinary ,General Immunology and Microbiology ,biology ,Vaccination ,Vaccine trial ,04 agricultural and veterinary sciences ,General Medicine ,biology.organism_classification ,Kenya ,Theileriasis ,Variable number tandem repeat ,Tick-Borne Diseases ,Cattle ,Immunization ,Multilocus Sequence Typing - Abstract
The live infection and treatment (ITM) vaccination procedure using the trivalent Muguga cocktail is increasingly being used to control East Coast fever, with potential implications for Theileria parva population genetic structure in the field. Transmission of the Kiambu V T. parva component to unvaccinated cattle has previously been described in Uganda. We monitored the T. parva carrier state in vaccinated and control animals on a farm in West Kenya where an ITM stabilate derived from the Kenyan T. parva Marikebuni stock was evaluated for field efficacy. A nested PCR-based Marikebuni-specific marker identified a carrier state in nine of ten vaccinated animals, detectable for a period of two years. We used 22 variable number tandem repeat (VNTR) markers to determine multilocus genotypes (MLGs) of 19 T. parva schizont-infected lymphocyte isolates derived from cattle and field ticks. Two isolates from unimmunized cattle were identical to the Marikebuni vaccination stock. Two cattle isolates were identical to a Muguga cocktail component Kiambu V. Seven isolates from ticks exhibited MLGs that were identical to the Serengeti/Muguga vaccine stocks. Six cattle and two tick-derived stocks exhibited unique MLGs. The data strongly suggest transmission of immunizing genotypes, from Marikebuni vaccine-induced carrier cattle to unimmunized cattle. It is possible that genotypes similar to those in the Muguga cocktail are present in the field in Western Kenya. An alternative hypothesis is that these parasites may have originated from vaccine trial sites in Eastern Uganda. If correct, this suggests that T. parva stocks used for immunization can potentially be disseminated 125 km beyond the immediate vaccination site. Regardless of their origin, the data provide evidence that genotypes similar to those in the Muguga cocktail are circulating in the field in East Africa, alleviating concerns about dissemination of 'alien' T. parva germplasm through live vaccination.
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- 2020
5. Identification and characterization of epizootic hemorrhagic disease virus serotype 6 in cattle co-infected with bluetongue virus in Trinidad, West Indies
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Hayley Hicks, Lara E. Harrup, Paulina Rajko-Nenow, Tamiko Brown-Joseph, Christine V.F. Carrington, Christopher A. L. Oura, Carrie Batten, and Nikita Sahadeo
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Male ,Serotype ,Cattle Diseases ,Hemorrhagic Disease Virus, Epizootic ,BTV co-circulation ,Trinidad ,Serogroup ,Bluetongue ,Microbiology ,Article ,Virus ,03 medical and health sciences ,Animals ,Clade ,Phylogeny ,030304 developmental biology ,0303 health sciences ,General Veterinary ,Phylogenetic tree ,biology ,030306 microbiology ,Strain (biology) ,Epizootic hemorrhagic disease virus ,virus diseases ,Culicoides ,General Medicine ,EHDV serotypes ,Virology ,3. Good health ,EHDV evolution rate ,Trinidad and Tobago ,cattle ,biology.protein ,RNA, Viral ,Capsid Proteins ,Female ,Antibody ,Martinique ,Bluetongue virus - Abstract
Highlights • Epizootic haemorrhagic disease virus serotype 6 (EHDV-6) is circulating in Trinidad. • EHDV is infecting cattle at a slower rate than BTV. • EHDV appears to have a faster viral evolution rate than BTV. • The EHDV-6 Trinidad strain (VP-2) falls within the eastern topotype clade that is likely to have originated from Australia., Epizootic hemorrhagic disease virus (EHDV) is an economically important virus that can cause severe clinical disease in deer and to a lesser extent cattle. This study set out to determine and characterize which EHDV serotypes were circulating in Trinidad. Serum and whole blood samples were collected monthly for six months from a cohort of cattle imported to Trinidad from the USA. Results revealed that all the cattle seroconverted to EHDV within six months of their arrival, with EHDV RNA being detected in the samples just prior to antibodies, as expected. Serotyping assays revealed that a single serotype (EHDV-6) was circulating in the cattle. Sequencing of the surface viral protein (VP2) of EHDV-6, followed by phylogenetic analysis, revealed that the Trinidad EHDV-6 strain was closely related to EHDV-6 viruses found in Guadeloupe (2010), Martinique (2010) and USA (2006), with 96–97.2% nucleotide identity. The Trinidad EHDV-6 VP-2 shared 97.2% identity with the Australian EHDV-6 prototype strain, classifying it within the eastern topotype clade. Bayesian coalescent analysis support Australia as the most probable source for the EHDV-6 VP2 sequences in the Americas and Caribbean region and suggests that the they diverged from the Australian prototype strain around 1966 (95% HPD 1941–1979).
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- 2019
6. An international, interlaboratory ring trial confirms the feasibility of an open-source, extraction-less 'direct' RT-qPCR method for reliable detection of SARS-CoV-2 RNA in clinical samples
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Anderson V. dePaula, Maria Cassia Mendes-Correa, Viviane A. Parisi, Camila Malta Romano, Emily A. Bruce, Clement Meseko, Thiago José Dionísio, Marielton dos Passos Cunha, Ismaila Shittu, Bernard Mari, Syril D Pettit, Bitrus Inuwa, Susan D. Hester, Rebekah E. Dumm, Keith R. Jerome, Ana Paula Pessoa Vilela, Jessica W. Crothers, Carlos Ferreira dos Santos, Ollivier Hyrien, O. O. Oladipo, Rebecca M. Harris, Leah C. Wehmas, Roger Chammas, Margaret G. Mills, Meei-Li Huang, A. C. A. Campos, Adamson S Muula, Pascal Barby, Luiz Gustavo Bentim Góes, Arianne Brown, Rajhab S. Mkakosya, Julien Fassy, Lemar Blake, Jose R W Martínez, Jason Botten, Cecilia Vial, Constance A Mitchell, Tonney S. Nyirenda, Christopher A. L. Oura, Paola Minoprio, Pablo Vial, Caroline Lacoux, and Thais Francini Garbieri
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Coronavirus disease 2019 (COVID-19) ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Concordance ,Real-Time Polymerase Chain Reaction ,medicine.disease_cause ,Sensitivity and Specificity ,Article ,Specimen Handling ,law.invention ,COVID-19 Testing ,law ,Nasopharynx ,medicine ,Humans ,Serologic Tests ,Pandemics ,Polymerase chain reaction ,Coronavirus ,SARS-CoV-2 ,business.industry ,COVID-19 ,RNA ,Reverse Transcription ,Virology ,Open source ,Feasibility Studies ,RNA, Viral ,Oral pharyngeal ,business - Abstract
Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) is used worldwide to test and trace the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). "Extraction-less" or "direct" real time-reverse transcription polymerase chain reaction (RT-PCR) is a transparent and accessible qualitative method for SARS-CoV-2 detection from nasopharyngeal or oral pharyngeal samples with the potential to generate actionable data more quickly, at a lower cost, and with fewer experimental resources than full RT-qPCR. This study engaged 10 global testing sites, including laboratories currently experiencing testing limitations due to reagent or equipment shortages, in an international interlaboratory ring trial. Participating laboratories were provided a common protocol, common reagents, aliquots of identical pooled clinical samples, and purified nucleic acids and used their existing in-house equipment. We observed 100% concordance across laboratories in the correct identification of all positive and negative samples, with highly similar cycle threshold values. The test also performed well when applied to locally collected patient nasopharyngeal samples, provided the viral transport media did not contain charcoal or guanidine, both of which appeared to potently inhibit the RT-PCR reaction. Our results suggest that direct RT-PCR assay methods can be clearly translated across sites utilizing readily available equipment and expertise and are thus a feasible option for more efficient COVID-19 coronavirus disease testing as demanded by the continuing pandemic.
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- 2021
7. Virome of Ixodes ricinus, Dermacentor reticulatus, and Haemaphysalis concinna Ticks from Croatia
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Stephen Sameroff, Rafal Tokarz, Marko Vucelja, Komal Jain, Alexandra Oleynik, Marko Boljfetić, Linda Bjedov, Rachel A. Yates, Josip Margaletić, Christopher A. L. Oura, Walter Ian Lipkin, Lidija Cvetko Krajinović, and Alemka Markotić
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Bunyavirales ,tick-borne diseases ,Croatia ,Flaviviridae ,BIOMEDICINE AND HEALTHCARE. Clinical Medical Sciences. Infectology ,high throughput sequencing ,Rhabdoviridae ,Nyamiviridae ,Infectious Diseases ,Virology ,BIOMEDICINA I ZDRAVSTVO. Kliničke medicinske znanosti. Infektologija - Abstract
Tick-borne diseases are a serious threat to both public and veterinary health. In this study, we used high-throughput sequencing to characterize the virome of three tick species implicated in the spread of vector-borne disease throughout Croatia. Ten viruses were identified, including seven potential novel species within the viral families Flaviviridae, Nyamiviridae, Rhabdoviridae, Peribunyaviridae, Phenuiviridae, and Nairoviridae.
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- 2022
8. Serological evidence for eight globally important poultry viruses in Trinidad & Tobago
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Jamie Sookhoo, Judy Molawatti-Bisnath, Christopher A. L. Oura, Arianne Brown Jordan, Paul Crooks, Zul Mohammed, Lemar Blake, and Christine V.F. Carrington
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Veterinary medicine ,animal structures ,040301 veterinary sciences ,Avian adenovirus ,Infectious bronchitis virus ,Newcastle disease ,Infectious bursal disease ,0403 veterinary science ,Food Animals ,Seroepidemiologic Studies ,Prevalence ,medicine ,Animals ,Seroprevalence ,Poultry Diseases ,biology ,0402 animal and dairy science ,Outbreak ,04 agricultural and veterinary sciences ,medicine.disease ,biology.organism_classification ,040201 dairy & animal science ,Virology ,Avian pneumovirus ,Trinidad and Tobago ,Virus Diseases ,Female ,Animal Science and Zoology ,Flock ,Chickens - Abstract
Viruses affecting poultry cause significant levels of disease leading to severe economic losses among poultry farmers worldwide. The Americas region continues to be vulnerable to the spread of poultry viruses across the continents and Caribbean island chains. In Trinidad and Tobago (T&T) there is limited information on the viruses circulating in poultry. Many flock are vulnerable to infection and there are occasional outbreaks of disease resulting in high levels of morbidity and mortality. This study aims to identify important viruses of poultry circulating in T&T through a broad-based surveillance approach. Serum samples from 29 layer farms in Trinidad and 14 layer farms in Tobago were collected from the eldest laying hens. Samples were tested from unvaccinated birds for antibodies by enzyme-linked immunosorbent assay (ELISA) against Avian influenza virus (AIV), Infectious bronchitis virus (IBV), Newcastle disease virus (NDV), Infectious laryngotracheitis virus (ILTV), Avian pneumovirus (APV), Infectious bursal disease virus (IBDV), Fowl adenovirus Gp1 (FADV) and Egg drop syndrome virus (EDSV). In Trinidad, the estimated true seroprevalence levels of antibodies were 0% (CI 95%: 0-0%) for AIV, 100% (CI 95%: 97-100%) for IBV, 79.8% (CI 95%: 70.6-86.9%) for NDV, 1% (CI 95%: 0-2.6%) for ILTV, 67.55% (CI 95%: 62.3-72.4%) for APV, 94.93% (CI 95%: 88.0-98.6%) for IBDV, 100% (CI 95%: 99.7-100%) for FADV and 67.8% (CI 95%: 62.4-72.8%) for EDSV. In Tobago, seroprevalence levels were 0% (CI 95%: 0-0%) for AIV, 100% (CI 95%: 95.6-100%) for IBV, 80.5% (CI 95%: 70.1-88.5%) for NDV, 29.9% (CI 95%: 20.8-40.6%) for ILTV, 100% (CI 95%: 97.7-100%) for APV, 97.1% (CI95%: 89.9-100%) for IBDV, 100% (CI 95%: 97.5-100%) for FADV and 100% (CI 95%: 99-100%) for EDSV. The results reveal strong evidence for the circulation of IBV, NDV, APV, IBDV, FADV and EDSV in layer poultry on both islands, as well as ILTV in Tobago.
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- 2018
9. Novel quaranjavirus and other viral sequences identified from ticks parasitizing hunted wildlife in Trinidad and Tobago
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Rafal Tokarz, Stephen Sameroff, Alexandra Oleynik, Christopher A. L. Oura, Komal Jain, Christine V.F. Carrington, and W. Ian Lipkin
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0301 basic medicine ,food.ingredient ,Ixodidae ,030231 tropical medicine ,Wildlife ,Zoology ,Biology ,Tick ,Microbiology ,DNA sequencing ,Viral Proteins ,03 medical and health sciences ,0302 clinical medicine ,food ,Orthomyxoviridae Infections ,medicine ,Animals ,Haemaphysalis juxtakochi ,Phylogeny ,Tetraviridae ,Tick-borne disease ,Deer ,Quaranjavirus ,Orthomyxoviridae ,biology.organism_classification ,medicine.disease ,Tick Infestations ,Trinidad and Tobago ,030104 developmental biology ,Infectious Diseases ,Insect Science ,Iguanas ,Parasitology ,Arthropod Vector - Abstract
Hunters are at a higher risk for exposure to zoonotic pathogens due to their close interactions with wildlife and arthropod vectors. In this study, high throughput sequencing was used to explore the viromes of two tick species, Amblyomma dissimile and Haemaphysalis juxtakochi, removed from hunted wildlife in Trinidad and Tobago. We identified sequences from 3 new viral species, from the viral families Orthomyxoviridae, Chuviridae and Tetraviridae in A. dissimile.
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- 2021
10. The Serological Prevalence of Rabies Virus-Neutralizing Antibodies in the Bat Population on the Caribbean Island of Trinidad
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Vernie Ramkissoon, George Legall, Lauren Greenberg, Janine F.R. Seetahal, Tony Schountz, Christine V.F. Carrington, Christopher A. L. Oura, Manuel J. Sanchez-Vazquez, Shamjeet Singh, Vincent J. Munster, and Panayampalli Subbian Satheshkumar
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Male ,0301 basic medicine ,Rabies ,030231 tropical medicine ,Population ,lcsh:QR1-502 ,bats ,serology ,Zoology ,Biology ,Antibodies, Viral ,Trinidad ,medicine.disease_cause ,lcsh:Microbiology ,Article ,03 medical and health sciences ,0302 clinical medicine ,Seroepidemiologic Studies ,Chiroptera ,Virology ,medicine ,Animals ,Seroprevalence ,virus neutralizing antibodies ,Rabies transmission ,education ,Lyssavirus ,Artibeus ,Epizootic ,Caribbean ,education.field_of_study ,Rabies virus ,medicine.disease ,biology.organism_classification ,Antibodies, Neutralizing ,Trinidad and Tobago ,030104 developmental biology ,Infectious Diseases ,Female - Abstract
Rabies virus (RABV) is the only lyssavirus known to be present within the Caribbean. The island of Trinidad, is richly diverse in chiropteran fauna and endemic for bat-transmitted rabies with low RABV isolation rates observed in this population. We aimed to determine the seroprevalence of rabies virus neutralizing antibodies (RVNA) in light of spatio-temporal and bat demographic factors to infer the extent of natural exposure to RABV in the Trinidadian bat population. RVNA titers were determined by the RABV micro-neutralization test on 383 bat samples representing 21 species, comprising 30.9% of local bat diversity, from 31 locations across the island over 5 years. RVNA was positively detected in 33 samples (8.6%) representing 6 bat species (mainly frugivorous) with titers ranging from 0.1 to 19 IU/mL (mean 1.66 IU/mL). The analyses based on a multivariable binomial generalised linear mixed-effects model showed that bat age and year of capture were significant predictors of seropositivity. Thus, juvenile bats were more likely to be seropositive when compared to adults (estimate 1.13, p = 0.04) which may suggest early exposure to the RABV with possible implications for viral amplification in this population. Temporal variation in rabies seropositivity, 2012&ndash, 2014 versus 2015&ndash, 2017 (estimate 1.07, p = 0.03) may have been related to the prevailing rabies epizootic situation. Regarding other factors investigated, RVNA was found in bats from both rural and non-rural areas, as well as in both hematophagous and non-hematophagous bat species. The most common seropositive species, Artibeus jamaicensis planirostris is ubiquitous throughout the island which may potentially facilitate human exposure. The findings of this study should be factored into public health assessments on the potential for rabies transmission by non-hematophagous bats in Trinidad.
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- 2020
11. African swine fever: Update on Eastern, Central and Southern Africa
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Leopold K. Mulumba-Mfumu, Kapanga C. Madimba, Mary Louise Penrith, Etienne Thiry, Claude Saegerman, Karl Ståhl, Ndeji T. Mukalakata, Charles Masembe, Eric Kawaya Kazadi, Linda K. Dixon, Christopher A. L. Oura, and Erika Chenais
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040301 veterinary sciences ,Swine ,Population ,Africa, Southern ,Disease Outbreaks ,0403 veterinary science ,03 medical and health sciences ,Pig farming ,Animals ,Africa, Central ,education ,Socioeconomics ,African Swine Fever ,030304 developmental biology ,0303 health sciences ,education.field_of_study ,General Veterinary ,General Immunology and Microbiology ,African swine fever ,business.industry ,Outbreak ,04 agricultural and veterinary sciences ,General Medicine ,Africa, Eastern ,Livelihood ,Geography ,Spite ,Sylvatic cycle ,Livestock ,business - Abstract
Control of African swine fever (ASF) in countries in Eastern, Central and Southern Africa (ECSA) is particularly complex owing to the presence of all three known epidemiological cycles of maintenance of the virus, namely an ancient sylvatic cycle involving the natural hosts and vectors of the disease as well as domestic cycles with and without involvement of natural vectors. While the situation is well documented in some of the countries, for others very little information is available. In spite of the unfavourable ASF situation, the pig population in the sub-region has grown exponentially in recent decades and is likely to continue to grow in response to rapid urban growth resulting in increasing demand for animal protein by populations that are no longer engaged in livestock production. Better management of ASF will be essential to permit the pig sector to reach its full potential as a supplier of high quality protein and a source of income to improve livelihoods and create wealth. No vaccine is currently available and it is likely that, in the near future, the sub-region will continue to rely on the implementation of preventive measures, based on the epidemiology of the disease, to avoid both the devastating losses that outbreaks can cause and the risk the sub-region poses to other parts of Africa and the world. The current situation in the ECSA sub-region is reviewed and gaps in knowledge are identified in order to support ongoing strategy development for managing ASF in endemic areas.
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- 2018
12. Identification of four serotypes of fowl adenovirus in clinically affected commercial poultry co-infected with chicken infectious anaemia virus in Trinidad and Tobago
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Judy Bisnath, Chad Ramgattie, Lemar Blake, Christopher A. L. Oura, Arianne Brown Jordan, and Christine V.F. Carrington
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Serotype ,040301 veterinary sciences ,Adenoviridae Infections ,Biology ,Serogroup ,Infectious bursal disease virus ,Virus ,Infectious bursal disease ,Adenoviridae ,0403 veterinary science ,03 medical and health sciences ,medicine ,Animals ,Circoviridae Infections ,Hexon protein ,Pathogen ,Phylogeny ,Poultry Diseases ,030304 developmental biology ,Hepatitis ,0303 health sciences ,General Veterinary ,General Immunology and Microbiology ,business.industry ,Coinfection ,04 agricultural and veterinary sciences ,General Medicine ,Poultry farming ,medicine.disease ,Birnaviridae Infections ,Virology ,Trinidad and Tobago ,Female ,Flock ,business ,Chickens ,Chicken anemia virus - Abstract
Fowl adenovirus (FAdV), which causes the high-impact diseases such as inclusion body hepatitis and hepatitis-hydropericardium syndrome, is of major concern to the poultry industry internationally. This study was carried out in direct response to mortality rates of up to 75% in commercial broiler flocks in Trinidad, West Indies. Symptoms in 3- to 8-week-old broilers and 13- to 18-week-old pullets pointed to infection with an immunosuppressive viral pathogen. The objectives of the study were to determine whether the infectious agent FAdV, along with other viral pathogens, was responsible for the clinical disease, and to obtain information on the serotypes of FAdV that were infecting the birds. Tissue samples from clinically affected birds from eight different farms were tested for chicken infectious anaemia virus (CIAV) and infectious bursal disease virus (IBDV) by real-time reverse transcription polymerase chain reaction (PCR) and for FAdV by conventional PCR. The birds tested positive for FAdV and CIAV, but negative for IBDV. The gene corresponding to the L1 loop of the hexon protein for FAdV was amplified and sequenced. Phylogenetic analysis of seven FAdV strains inferred that four serotypes were likely to be circulating in the chickens. Well supported genetic relatedness was observed for serotype 8a (97.8%), 8b (97.8%), 9 (95.8%) and 11 (98.8%-99.5%). This is the first published report from Trinidad and Tobago on the presence and circulation of pathogenic FAdV strains, in combination with CIAV, in poultry. The data demonstrate a possible need for the introduction of serotype-specific vaccines against FAdV, as well as vaccines against CIAV, in broilers in the region and emphasize the importance of maintaining high levels of biosecurity on farms to prevent the spread of these potentially devastating viruses between farms.
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- 2018
13. A Review of Eight High-Priority, Economically Important Viral Pathogens of Poultry within the Caribbean Region
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Arianne Brown Jordan, Dane Hartley, Victor Gongora, and Christopher A. L. Oura
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0301 basic medicine ,infectious bronchitis virus ,animal structures ,040301 veterinary sciences ,viruses ,Newcastle disease virus ,infectious bursal disease ,Infectious bronchitis virus ,Review ,avian influenza virus ,egg drop syndrome virus ,Newcastle disease ,Virus ,Infectious bursal disease ,Serology ,0403 veterinary science ,03 medical and health sciences ,Caribbean region ,medicine ,avian metapneumovirus ,Metapneumovirus ,Caribbean ,lcsh:Veterinary medicine ,General Veterinary ,biology ,Outbreak ,04 agricultural and veterinary sciences ,medicine.disease ,biology.organism_classification ,Virology ,030104 developmental biology ,infectious laryngotracheitis virus ,lcsh:SF600-1100 ,fowl adenovirus group 1 - Abstract
Viral pathogens cause devastating economic losses in poultry industries worldwide. The Caribbean region, which boasts some of the highest rates of poultry consumption in the world, is no exception. This review summarizes evidence for the circulation and spread of eight high-priority, economically important poultry viruses across the Caribbean region. Avian influenza virus (AIV), infectious bronchitis virus (IBV), Newcastle disease virus (NDV), infectious laryngotracheitis virus (ILTV), avian metapneumovirus (aMPV), infectious bursal disease virus (IBDV), fowl adenovirus group 1 (FADV Gp1), and egg drop syndrome virus (EDSV) were selected for review. This review of serological, molecular, and phylogenetic studies across Caribbean countries reveals evidence for sporadic outbreaks of respiratory disease caused by notifiable viral pathogens (AIV, IBV, NDV, and ILTV), as well as outbreaks of diseases caused by immunosuppressive viral pathogens (IBDV and FADV Gp1). This review highlights the need to strengthen current levels of surveillance and reporting for poultry diseases in domestic and wild bird populations across the Caribbean, as well as the need to strengthen the diagnostic capacity and capability of Caribbean national veterinary diagnostic laboratories.
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- 2018
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14. Bluetongue virus infection in naïve cattle: Identification of circulating serotypes and associated Culicoides biting midge species in Trinidad
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R. Ramdeen, Tamiko Brown-Joseph, John Flannery, Vernie Ramkissoon, Lara E. Harrup, Lorraine Frost, Carrie Batten, Christine V.F. Carrington, Hayley Hicks, and Christopher A. L. Oura
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0301 basic medicine ,Serotype ,Male ,Veterinary medicine ,040301 veterinary sciences ,Virus isolation ,viruses ,Biting midge ,Cattle Diseases ,Biology ,Antibodies, Viral ,Ceratopogonidae ,Serogroup ,Microbiology ,Bluetongue ,Virus ,Article ,Serology ,0403 veterinary science ,03 medical and health sciences ,Animals ,2. Zero hunger ,General Veterinary ,business.industry ,virus diseases ,04 agricultural and veterinary sciences ,General Medicine ,Virology ,3. Good health ,Insect Vectors ,030104 developmental biology ,Trinidad and Tobago ,Livestock ,Cattle ,Female ,business ,Bluetongue virus - Abstract
Highlights • High prevalence of bluetongue virus in Trinidad. • Identification of six bluetongue virus serotypes in Trinidad. • First isolation of BTV-2 and BTV-5 in Trinidad. • Risk of emergence of reassortant viruses., To better understand risks associated with trading cattle, it is important to know which serotypes of Bluetongue virus (BTV) are circulating within the exporting and importing country. Hence, this study was conducted to identify the circulating serotypes of BTV in Trinidad. Blood samples were collected monthly from sixty BTV- naïve imported cattle over a six month period after their arrival in the country. Virological (PCR and virus isolation) and serological (ELISA) analyses were carried out on the samples and CDC light traps were placed near the cattle enclosure to trap and identify the species of Culicoides biting midges that were present. All of the cattle seroconverted for BTV antibodies within three months of their arrival in the country and real-time reverse transcription PCR (rRT-PCR) detected BTV-RNA in the samples throughout the remainder of the study. The patterns of infection observed in the cattle indicated serial infections with multiple serotypes. A combination of BTV serotype-specific rRT-PCR on the original blood samples and virus isolation followed by serotype-specific rRT-PCR on selected samples, confirmed the presence of BTV serotypes 1, 2, 3, 5, 12 and 17. This is the first report of BTV-2 and BTV-5 in Trinidad. Light-suction traps placed in close proximity to the cattle predominantly trapped Culicoides insignis Lutz 1913 species (96%), with a further six Culicoides species making up the remaining 4% of trapped samples. The circulation of multiple BTV serotypes in Trinidad underlines the need for regular surveillance, which will contribute to the development of risk assessments for trade in livestock.
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- 2017
15. A possible role for domestic dogs in the spread of African horse sickness virus
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Christopher A. L. Oura
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Culicoides imicola ,food.ingredient ,040301 veterinary sciences ,030231 tropical medicine ,Horse meat ,African Horse Sickness Virus ,Zoology ,African swine fever virus ,0403 veterinary science ,03 medical and health sciences ,Dogs ,0302 clinical medicine ,food ,African Horse Sickness ,Animals ,General Veterinary ,biology ,Outbreak ,04 agricultural and veterinary sciences ,General Medicine ,biology.organism_classification ,Culicoides ,Animals, Domestic ,Vector (epidemiology) ,African horse sickness - Abstract
African horse sickness (AHS) is well known as one of the worst diseases affecting horses out there. Just like both Ebola in people and African swine fever virus in pigs, it causes severe haemorrhage and oedema in all organ systems. Affected horses essentially suffocate as their lungs fill with fluid. The disease is caused by infection with African horse sickness virus (AHSV), which is transmitted between equids by certain species of Culicoides biting midges and is not thought to be transmitted by other means. Although currently confined to sub-Saharan Africa, the virus has a history of spreading outside Africa, where it has caused devastating outbreaks in the Middle East, as well as in Spain and Portugal. Given the recent northward expansion of the main African vector of AHSV ( Culicoides imicola ) into the Mediterranean basin of Europe, the threat posed from AHSV in Europe is increasing. We have known for some time that domestic dogs are capable of being infected with AHSV and, apart from horses, the domestic dog is the only other species known to contract the severe form of the disease.1,2 Until recently, in all reported field outbreaks in dogs, there have been well-documented histories of eating of horse meat, so it was thought that the dogs were most likely being infected through the ingestion of infected horse meat, rather than through the bites of infected Culicoides midges. This made dogs a dead-end host of the virus, so it was generally believed that they did not play a significant role in the …
- Published
- 2018
16. NOVEL POXVIRAL INFECTION IN THREE FINCH SPECIES ILLEGALLY IMPORTED INTO TRINIDAD, WEST INDIES, WITH IMPLICATIONS FOR NATIVE BIRDS
- Author
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Christine V.F. Carrington, Nikita Sahadeo, Rod Suepaul, Lana Gyan, Vernie Ramkissoon, Janine F.R. Seetahal, Varsha V. Ramoutar, and Christopher A. L. Oura
- Subjects
Sporophila intermedia ,animal structures ,040301 veterinary sciences ,Sequence analysis ,Zoology ,Oryzoborus angolensis ,Genome, Viral ,Poxviridae Infections ,030308 mycology & parasitology ,Songbirds ,0403 veterinary science ,03 medical and health sciences ,Oryzoborus crassirostris ,biology.animal ,Animals ,Seedeater ,Phylogeny ,Finch ,0303 health sciences ,Caribbean island ,General Veterinary ,biology ,Phylogenetic tree ,Bird Diseases ,Poxviridae ,Commerce ,virus diseases ,Sequence Analysis, DNA ,04 agricultural and veterinary sciences ,General Medicine ,biology.organism_classification ,Trinidad and Tobago ,Animal Science and Zoology ,Finches ,Animal Distribution - Abstract
Oryzoborus angolensis (Lesser Seed-Finch), Oryzoborus crassirostris (Large-billed Seed-Finch), and Sporophila intermedia (Grey Seedeater) are finch species native to the Caribbean island of Trinidad. These species are locally trapped and kept for their song, but with declining native populations, enthusiasts have turned to illegally importing birds from the South American mainland. The smuggling of wild birds from South America poses significant disease risks to the native bird species of Trinidad. Herein we describe the first case of poxviral infection in these illegally imported birds in Trinidad and partial genome sequence of the causative agent. Phylogenetic analysis of the 4b core protein sequence indicated that the avian poxvirus identified was most closely related to a 2012 avian pox sequence from Brazil, with 96.2% and 98.1% identity at the nucleotide and amino acid level.
- Published
- 2019
17. Evidence of vertical transmission of lumpy skin disease virus in Rhipicephalus decoloratus ticks
- Author
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Simon Carpenter, Jimmy Clement Lubinga, Jacobus A.W. Coetzer, Milana Troskie, Eeva S.M. Tuppurainen, W. H. Stoltsz, Christopher A. L. Oura, and Estelle Hildegard Venter
- Subjects
Veterinary medicine ,biology ,Transmission (medicine) ,business.industry ,Lumpy Skin Disease ,biology.organism_classification ,Microbiology ,Lumpy skin disease virus ,Capripoxvirus ,Rhipicephalus ,Infectious Diseases ,Larva ,Insect Science ,Rhipicephalus decoloratus ,Animals ,Cattle ,Female ,Parasitology ,Livestock ,Socioeconomics ,International development ,business ,Biological sciences - Abstract
Lumpy skin disease (LSD) is an economically important acute or sub-acute disease of cattle that occurs across Africa and in the Middle East. The aim of this study was to assess whether Rhipicephalus decoloratus ticks were able to transmit lumpy skin disease virus (LSDV) transovarially. Uninfected, laboratory-bred R. decoloratus larvae were placed to feed on experimentally infected "donor" cattle. After completion of the life cycle on donor animals, fully engorged adult female ticks were harvested and allowed to lay eggs. Larvae that hatched from these eggs were then transferred to feed on uninfected "recipient" cattle. The latter became viraemic and showed mild clinical disease with characteristic skin lesions and markedly enlarged precrural and subscapular lymph nodes. This is the first report of transovarial transmission of poxviruses by R. decoloratus ticks, and the importance of this mode of transmission in the spread of LSDV in endemic settings requires further investigation.
- Published
- 2013
18. African swine fever among slaughter pigs in Mubende district, Uganda
- Author
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Demelash Biffa, Adrian Muwonge, Hetron Mweemba Munang'andu, Eystein Skjerve, Clovice Kankya, James Oloya, and Christopher A. L. Oura
- Subjects
Male ,Veterinary medicine ,Swine ,Cross-sectional study ,Immunoblotting ,Enzyme-Linked Immunosorbent Assay ,Antibodies, Viral ,African swine fever virus ,Disease Outbreaks ,Food Animals ,Risk Factors ,Seroepidemiologic Studies ,Prevalence ,Animals ,Medicine ,Immunoblot Assay ,Uganda ,African Swine Fever ,Endemic disease ,biology ,African swine fever ,business.industry ,Outbreak ,biology.organism_classification ,Serum samples ,African Swine Fever Virus ,Cross-Sectional Studies ,Logistic Models ,Female ,Animal Science and Zoology ,Autopsy ,business ,Abattoirs - Abstract
Owing to frequent reports of suspected outbreaks and the presence of reservoir hosts and vectors (warthogs, bushpigs and O. moubata ticks), African swine fever (ASF) is believed to be an endemic disease in Uganda. There have, however, been very few studies carried out to confirm its existence in Uganda. This study was carried out to describe the prevalence of ASF based on pathologic lesions and analysis of serum samples from slaughtered pigs during a suspected outbreak in the Mubende district of Uganda. The study was based on visits to 22 slaughterhouses where individual pigs were randomly selected for a detailed ante-mortem and post-mortem inspections. Sera were also collected for laboratory analysis. A total of 997 pigs (53.7% male and 46.3% female) were examined for lesions suggestive of ASF and sero-positivity of sera for ASF antibodies. The sera were tested using enzyme-linked immunosorbent assay (ELISA) and positive samples were further confirmed with an immunoblot assay. The results showed that 3.8% (38/997) of the pigs examined had clinical signs and post-mortem lesions suggestive of ASF. Two of 997 (0.2%) sera analysed were positive for ASF antibodies. Of the sub-counties investigated, Bagezza (12%) and Kiyuni (11%) had the highest prevalence of lesions suggestive of ASF based on ante- and post-mortem examination results, while Mubende town council (1.7%) had the lowest. This study found a low number of pigs (3.8%) with lesions suggestive of ASF at slaughter and an even lower number of pigs (0.2%) that were seropositive at slaughter, however a significantly higher number of pigs were slaughtered during the outbreak as a strategy for farmers to avoid losses associated with mortality.
- Published
- 2012
19. No evidence for replication of a field strain of bluetongue virus serotype 1 in the blood of domestic dogs
- Author
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M. El Harrak, Christopher A. L. Oura, Nadia Touil, Ghizlane Sebbar, C. Loutfi, and O. Fassi-Fehri
- Subjects
Serotype ,General Veterinary ,Strain (chemistry) ,Transmission (medicine) ,viruses ,Biology ,Antibodies, Viral ,Real-Time Polymerase Chain Reaction ,Virus Replication ,Bluetongue ,Virology ,Virus ,Persistence (computer science) ,Dogs ,Viral replication ,Animals ,RNA, Viral ,Viral rna ,Viremia ,Bluetongue virus serotype ,Bluetongue virus - Abstract
Summary The potential role of domestic dogs in the long-distance transmission of bluetongue virus (BTV) is currently unproven. This study set out, through an experimental infection study, to investigate whether domestic dogs mount a viraemia post-infection with a field strain of BTV serotype 1. All six experimentally infected dogs seroconverted within 14 days and viral RNA was detected in the blood of the dogs, albeit at significantly lower levels than that seen in domestic ruminants. There was no clear evidence for viral replication in the dogs as no increase in viral RNA was observed in, and it was not possible isolate virus from, the blood of the dogs. There was however evidence for a persistence of viral RNA in the blood of the dogs, which may be evidence for a low level of replication or could be indicative of persistence of the viral inoculum.
- Published
- 2014
20. Serosurvey for Infectious Agents Associated with Subfertility and Abortion in Dairy Cattle in Trinidad and Tobago, West Indies
- Author
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Janelle St Aime, M.J. Morris, Jamie Sookhoo, Edward H Amoroso, Arianne Brown Jordan, Justine John, Gervaise Sarjusingh, Lemar Blake, Christopher A. L. Oura, and Sheliza Ali
- Subjects
Veterinary medicine ,040301 veterinary sciences ,animal diseases ,Brucella abortus ,Neospora caninum ,Abortion ,Article ,Virus ,0403 veterinary science ,Infectious bovine rhinotracheitis virus ,parasitic diseases ,Seroprevalence ,Dairy cattle ,West indies ,lcsh:Veterinary medicine ,General Veterinary ,biology ,Bovine Viral Diarrhoea virus (BVDV) ,0402 animal and dairy science ,virus diseases ,04 agricultural and veterinary sciences ,biology.organism_classification ,040201 dairy & animal science ,Trinidad and Tobago ,ELISA ,Infectious Bovine Rhinotracheitis virus (IBRV) ,lcsh:SF600-1100 ,Mixed infection - Abstract
Despite frequent reports of subfertility and abortion in dairy cattle in Trinidad and Tobago (T&T), little is known about the potential infectious and non-infectious causes. This study set out to investigate possible infectious causes of reproductive problems by measuring the seroprevalence of four of the most significant reproductive pathogens in dairy cattle worldwide: Brucella abortus (B. abortus); Neospora caninum (N. caninum), Bovine Viral Diarrhoea virus (BVDV), and Infectious Bovine Rhinotracheitis virus (IBRV). These four reproductive pathogens have been suspected to be present in dairy cattle in T&T for some time but, previously, studies have not been carried out to confirm their presence. Bulk milk samples were collected from 92 dairy farms across Trinidad, representing a total of 1177 dairy cattle. Four dairy farms were selected for individual milk sampling to assess in-farm seroprevalence levels. Milk samples were tested for antibodies to the four pathogens by commercial ELISA kits. The overall farm seroprevalence was 62% for N. caninium and 23% for IBRV, and no antibodies were detected in any of the bulk milk samples for B. abortus or BVDV. Mixed infections for IBRV and N. caninum were common. Seroprevalence levels were between 8% and 65% for N. caninum and between 3% and 53% IBRV on the four individual farms. These results reveal the presence of IBRV and N. caninum for the first time on the island of Trinidad and importantly reveal no evidence for the circulation of BVDV or B. abortus in dairy cattle in Trinidad.
- Published
- 2018
21. Evaluation of the Safety and Efficacy of a Live Attenuated Thermostable Rift Valley Fever Vaccine in Sheep, Goats and Cattle
- Author
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Khalid Omari Tadlaoui, Jazouli M, Y. Naouli, Elharrak M, Daouam S, Christopher A. L. Oura, Ghzal F, Arkam Ae, and Moulay Mustapha Ennaji
- Subjects
Veterinary medicine ,biology ,business.industry ,Immunology ,medicine.disease ,Virology ,Virus ,West africa ,Attenuated strain ,Vaccination ,Diva ,Drug Discovery ,biology.protein ,Immunology and Allergy ,Medicine ,Livestock ,Rift Valley fever ,Antibody ,business - Abstract
Rift valley fever (RVF) is a highly significant vector-borne disease causing huge economic loses in livestock (ruminants and camels) and also human fatalities. The disease is endemic in most Sub-Saharan African countries, including West Africa, and has been present in the Middle East since 2010. Vaccination is considered to be the most effective way to prevent and control the expansion of the disease. Currently available attenuated live vaccines for RVF have significant limitations in that they are either thermolabile (CL13 strain vaccine) or causes abortion and teratogenic effects (Smithburn strain vaccine). This study therefore set out to develop a safe and effective thermostable live attenuated RVF vaccine. The existing CL13 vaccine, which is a naturally attenuated strain, was made thermostable through three cycles of heating (56°C) and selection. The resulting candidate vaccine (CL13T) was stable at 4°C for 20 months and shows significantly improved levels of thermostability over the existing CL13 vaccine. A pilot batch of the CL13T vaccine was produced and tested for safety and efficacy in cattle, sheep and goats. The vaccine was found to be safe, with no clinical signs or side effects observed in vaccinated animals, and there was no evidence for circulation of the virus in the blood of animals post-vaccination. On testing for efficacy in cattle, sheep and goats, through the detection of neutralizing antibodies post-vaccination, good levels of neutralizing antibodies were detected for a minimum of one year in sheep and goats, and neutralizing antibodies were detected for least 4 months in cattle. This new thermostable vaccine could represent an efficient tool for the control of rift valley fever in endemic countries. The vaccine also has the potential to be used, along with an appropriate diagnostic test, to differentiate vaccinated from infected animals (DIVA).
- Published
- 2015
22. Evaluation of the safety, immunogenicity and efficacy of three capripoxvirus vaccine strains against lumpy skin disease virus
- Author
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François Roger, Getnet Abie, Eeva S.M. Tuppurainen, Daniel Gizaw, Alehegn Wubete, Gelagay Ayelet, Christopher A. L. Oura, Berecha Bayissa, Getachew Gari, Hagos Asgedom, and Membere Kidane
- Subjects
Maladie de la peau ,Lumpy Skin Disease ,L73 - Maladies des animaux ,Antibodies, Viral ,Capripoxvirus ,Vaccine strain ,Immunologie ,biology ,Immunogenicity ,Vaccination ,Lumpy skin disease virus ,Infectious Diseases ,Molecular Medicine ,Efficacité d'utilisation ,Vaccin ,Vaccines, Attenuated ,Immune system ,Lumpy skin disease ,medicine ,Potency ,Animals ,Test biologique ,Bovin ,Sheep ,General Veterinary ,General Immunology and Microbiology ,business.industry ,Immunogénétique ,Public Health, Environmental and Occupational Health ,Viral Vaccines ,biology.organism_classification ,medicine.disease ,Virology ,Biosécurité ,Immunology ,Cattle ,Ethiopia ,business - Abstract
The safety, immunogenicity and efficacy of three commercially available vaccines against lumpy skin disease (LSD) in cattle have been evaluated using a combination of vaccine challenge experiments and the monitoring of immune responses in vaccinated animals in the field. The three vaccines evaluated in the study included two locally produced (Ethiopian) vaccines (lumpy skin disease virus (LSDV) Neethling and Kenyan sheep and goat pox (KSGP) O-180 strain vaccines) and a Gorgan goat pox (GTP) vaccine manufactured by Jordan Bio-Industries Centre (JOVAC). The latter vaccine was evaluated for the first time in cattle against LSDV. The Ethiopian Neethling and KSGPO-180 vaccines failed to provide protection in cattle against LSDV, whereas the Gorgan GTP vaccine protected all the vaccinated calves from clinical signs of LSD. There was no significant difference in protective efficacy detected between two dosage levels (P = 0.2, P = 0.25, and P = 0.1 for KSGP, Neethling and Gorgan vaccines, respectively). Additionally, the Gorgan GTP vaccinated cattle showed stronger levels of cellular immune responses measured using Delayed-Type Hypersensitivity (DTH) reactions at the vaccination site indicating higher levels of immunogenicity produced by the GTPV vaccine in cattle, as opposed to the other two vaccines. This study indicated, for the first time, that the Gorgan GTP vaccine can effectively protect cattle against LSDV and that the Neethling and KSGP O-180 vaccine were not protective. The results emphasise the need for molecular characterization of the Neethling and KSGP O-180 vaccine seed viruses used for vaccine production in Ethiopia. In addition, the potency and efficacy testing process of the Ethiopian LSD Neethling and KSGP O-180 vaccines should be re-evaluated.
- Published
- 2014
23. A One Health approach to the control of zoonotic vectorborne pathogens
- Author
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Christopher A. L. Oura
- Subjects
Veterinary Medicine ,Veterinary medicine ,General Veterinary ,business.industry ,Outbreak ,General Medicine ,Disease Vectors ,Global Health ,World health ,One Health ,Multidisciplinary approach ,Environmental health ,Zoonoses ,Communicable Disease Control ,Global health ,Medicine ,Animals ,Humans ,business - Abstract
In the fourth article in Veterinary Record's series of articles promoting One Health, Chris Oura discusses the threats posed to both animal and human populations by vectorborne diseases and how a multidisciplinary approach would be effective in reducing the risks and managing outbreaks.
- Published
- 2014
24. Systematic characterization of porcine ileal Peyer's patch, I. Apoptosis-sensitive immature B cells are the predominant cell type
- Author
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Haru-Hisa Takamatsu, J. K. Andersen, Sharon M. Brookes, Christopher A. L. Oura, R. E. M. Parkhouse, and L. Pullen
- Subjects
Pathology ,medicine.medical_specialty ,Cell type ,biology ,medicine.diagnostic_test ,medicine.drug_class ,CD3 ,Immunology ,Peyer's patch ,Monoclonal antibody ,Molecular biology ,In vitro ,Flow cytometry ,medicine.anatomical_structure ,medicine ,biology.protein ,Immunology and Allergy ,DNA fragmentation ,Antibody - Abstract
It is now apparent that the Peyer's patches of some species exhibit structural, functional and developmental heterogeneity. In sheep, for example, the ileal Peyer's patch (IPP) is the primary, antigen-independent site for the generation of the primary immunoglobulin repertoire and consequent production of the systemic B-cell pool. The pig has three distinct Peyer's patches, including an IPP, but the functional status of this organ, as primary or secondary lymphoid tissue, is not clear. Here, we have systematically characterized pig IPP follicular lymphocytes and show that about 90% B cells that are positive for surface immunoglobulin G (sIgM+) and express an immature phenotype characterized by expression of myeloid marker sWC3 (74-22-15) and two molecules recognized by IPP B-cell-specific monoclonal antibodies (F10/4, F12/35). Extensive apoptosis in vivo and in vitro was demonstrated by electron microscopy, immunohistology with TdT-mediated dUTP nick end labelling, DNA analysis and fluorescence-activated cell sorter analysis. Thus, when isolated IPP follicular cells were incubated at 37 degrees in vitro, the majority of them became apoptotic. The few that survived, however, had lost their expression of sWC3, F10/4, F12/35, but showed an increased expression of sIgM and major histocompatibility complex class II indicating that such surviving cells were of a more mature phenotype. Although more T cells were observed in porcine IPP follicles than in sheep IPP, CD3+ cells comprised less than 5% of the IPP follicular lymphocytes. Thus, the results clearly indicate that pig IPP is equivalent to sheep IPP.
- Published
- 1999
25. A reliable and reproducible experimental challenge model for peste des petits ruminants virus
- Author
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Satya Parida, Mustapha Hammouchi, Nadia Chaffai, Carrie Batten, Nezha Messoudi, C. Loutfi, Nadia Touil, Bachir Harif, Gizlane Sebbar, Christopher A. L. Oura, and Mehdi El Harrak
- Subjects
Microbiology (medical) ,Peste-des-Petits-Ruminants ,Goats ,fungi ,food and beverages ,Biology ,Vaccine efficacy ,Virology ,Peste-des-petits-ruminants virus ,Clinical Veterinary Microbiology ,Disease Models, Animal ,Animals ,Experimental challenge - Abstract
Experimental challenge protocols that consistently reproduce clinical signs of peste des petits ruminants in Alpine goats infected with a tissue culture-passaged peste des petits ruminants virus are described. The protocols can be used to carry out quality-controlled vaccine efficacy and pathogenesis studies under experimental conditions.
- Published
- 2012
26. African horse sickness outbreaks caused by multiple virus types in Ethiopia
- Author
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Peter P. C. Mertens, K. Bachanek-Bankowska, Carrie Batten, Shiferaw Jenberie, Anthony J. Wilson, Esayas Gelaye, Sushila Maan, N. Aklilu, Alebachew Belay, Christopher A. L. Oura, Yilkal Asfaw, and Gelagay Ayelet
- Subjects
Serotype ,Veterinary medicine ,African Horse Sickness Virus ,Disease ,Disease Outbreaks ,African Horse Sickness ,Medicine ,Animals ,Horses ,Antigens, Viral ,Retrospective Studies ,Orbivirus ,General Veterinary ,General Immunology and Microbiology ,biology ,business.industry ,Reverse Transcriptase Polymerase Chain Reaction ,Viral Core Proteins ,Horse ,Outbreak ,General Medicine ,biology.organism_classification ,3. Good health ,Virus type ,Virus Diseases ,DNA, Viral ,African horse sickness ,Ethiopia ,business - Abstract
Summary African horse sickness (AHS) is associated with high morbidity and mortality in equids, especially horses. A retrospective analysis was carried out concerning 737 AHS outbreaks that occurred during 2007–2010 in Ethiopia. A total of ten outbreaks were investigated in the study period. All four forms of the disease (pulmonary, cardiac, horse sickness fever and the combined form) were observed, with the cardiac form being the most prevalent. Multiple African horse sickness virus serotypes (AHSV-2, AHSV-4, AHSV-6, AHSV-8 and AHSV-9) were detected by molecular methods (type-specific real-time RT-PCR assays), and fourteen isolates were derived from blood and tissue samples collected during 2009–2010. This is the first report of AHSV-4, AHSV-6 or AHSV-8 in Ethiopia.
- Published
- 2012
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