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Getu Ayele,1 Belayneh Getachew,1 Fufa Dawo Bari,2 Berecha Bayissa,1 Ayelech Muluneh,3 Takele Abayneh,1 Esayas Gelaye,1 Bedaso Mammo Edao2 1Research and Development Directorate, National Veterinary Institute, Bishoftu, Oromia, Ethiopia; 2Department of Microbiology, Immunology and Vet Public Health, College of Veterinary Medicine, Addis Ababa University, Bishoftu, Oromia, Ethiopia; 3Department of Microbiology, Animal Health Institute, Sebeta, Oromia, EthiopiaCorrespondence: Bedaso Mammo Edao, Email edaobedaso@gmail.comIntroduction: Foot-and-mouth disease is globally one of the most economically important viral diseases of cloven-hoofed animals that can be controlled by different strategies, where vaccination plays an important role. Selection of adjuvant added to vaccine preparation is crucial in ensuring the protective effect of the vaccine. Aluminum hydroxide gel mixed with saponin (AS) is widely used adjuvant, with its suboptimal immune response in FMD vaccine. The present study was undertaken to evaluate different ingredients of adjuvants for inactivated trivalent (A, O and SAT 2) FMD vaccine and to demonstrate the effect of booster dose in cattle.Methods: Cattle were grouped into five; four experimental and one control, with six animals in each group and immunized with trivalent vaccine with various formulations of adjuvants. Immune response was measured using Solid Phase Competitive Enzyme Linked Immune Sorbent Assay (SPCE).Results: The antibody level in cattle immunised with a vaccine formulation containing a mixture of aluminum hydroxide gel and saponin (AS) were significantly lower than AS boosted group for the three serotypes (p< 0.05, t-test), which directs the need for booster dose. Whereas the antibody response in the AS + oil group was higher followed by oil alone. The AS preparation with a booster dose has shown better immune response compared to the group without.Conclusion: The findings of this study could suggest that oil based and AS with oil could replace the conventional aluminum hydroxide gel and saponin adjuvants in FMD vaccine preparations. Challenge test was not successful indicating the need for further research on the virus infectivity.Keywords: adjuvant, foot and mouth disease, immune response, serotype

Wakjira Kebede,1 Molalegne Bitew,2 Fufa Dawo Bari,3 Bedaso Mammo Edao,3 Hawa Mohammed,1 Martha Yami,1 Belayneh Getachew,1 Takele Abayneh,1 Esayas Gelaye1 1National Veterinary Institute, Bishoftu, Ethiopia; 2Ethiopian Biotechnology Institute, Addis Ababa, Ethiopia; 3College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, EthiopiaCorrespondence: Esayas GelayeNational Veterinary Institute (NVI), PO Box: 19, Bishoftu, EthiopiaTel +251 923625362Fax +251 114339300Email esayasgelaye@gmail.comFufa Dawo BariCollege of Veterinary Medicine and Agriculture, Addis Ababa University, PO Box: 34, Bishoftu, EthiopiaTel +251 929190312Fax +251 114339933Email fufa.dawo@aau.edu.etIntroduction: Infectious bursal disease virus (IBDV) is an avian viral pathogen that causes infectious bursal disease (IBD) of chickens. The disease has been endemic in Ethiopia since 2002, and vaccination has been practiced as the major means of disease prevention and control. An IBD vaccine is produced in Ethiopia using primary chicken embryo fibroblast (CEF) cell, which is time-consuming, laborious, and uneconomical. The present study was carried out to develop cell-based IBDV LC-75 vaccine using Vero cells and to evaluate the safety, immunogenicity and protection level.Methods: Identity of the vaccine seed was confirmed with gene-specific primers using reverse transcription polymerase chain reaction (RT-PCR). Confluent monolayer of Vero cells was infected with vaccine virus and serial passage continued till passage 10. A characteristic virus-induced cytopathic effect (CPE) was observed starting from passage 2 on the third day post-infection. The infectious titer of adapted virus showed a linear increment along the passage level. The virus-induced specific antibody was determined using indirect ELISA after vaccination of chicks through ocular route.Results: The antibody titer measured from Vero cells vaccinated chicks revealed similar level with the currently available CEF cell-based vaccine, hence no significant difference. Chicks vaccinated with Vero cell adapted virus showed complete protection against very virulent IBDV, while unvaccinated group had 60% morbidity and 25% mortality.Conclusion: It is concluded that the IBDV vaccine strain well adapted on Vero cells and found to be immunogenic induces antibody development and successfully protects chicks against challenge with the circulating field IBDV isolate. Hence, it is recommended to produce IBD vaccine using Vero cell culture at the industrial scale to conquer the limitations caused by using CEF cells and thus to vaccinate chicks population to protect against the circulating IBDV infection.Keywords: antibody, chicks, IBD vaccine, immunogenicity, protection, Vero cell

Background Foot-and-mouth disease is globally one of the most economically important viral diseases of cloven-hoofed animals that can be controlled by different strategies, where vaccination plays an important role. Selection of the adjuvants,that added to the vaccine is crucial in ensuring the protective effect of the vaccine. Aluminum hydroxide gel and saponin (AS) is widely used adjuvant, with its poor immune response in FMD vaccine. The present study was undertaken to evaluate different ingredients of adjuvants for inactivated trivalent (A, O and SAT 2) FMD vaccine and to demonstrate the effect of booster dose in cattle. Results Cattle were grouped into five; four experimental and one control, with six animals in each group and immunized with trivalent vaccine with various formulations of adjuvants. Immune response was measured using Solid Phase Competitive Enzyme Linked Immune Sorbent Assay (SPCE). The antibody level in cattle immunised with a vaccine formulation containing a mixture of aluminum hydroxide gel and saponin (AS) were significantly lower than AS boosted group for the three serotypes (p t. test), which directs the need for booster dose. Whereas the antibody response in the AS + oil group was higher followed by oil alone, AS boosted and AS at 95% CI. Conclusion The findings of this study could suggest that oil based and AS with oil could replace the conventional aluminum hydroxide gel and saponin adjuvants in FMD vaccine preparations. On different note, challenge test was not successful in this study indicating the need for further research on the virus infectivity.

The aim of the current study was to assess the major animal health problems and their impact on beef cattle production in Doba district of West Harerghe Zone, Ethiopia. The study area was purposively selected, and a simple random sampling method was used to selected households’ fatteners from each kebele and interviewed using structured questionnaires. The present study showed that the overall prevalence of the diseases was internal and external parasite 93.3%, bloat 53.3%, black leg 71.1%, pasteurolosis 71.8%, wound 71.8%, FMD 22.2%, and anthrax 13.33% which affect fattening cattle, respectively, in the study area. All the respondents (100%) involved in the study were experienced with deworming of their animals to protect from parasites. But, only 46.7% and 42.2% of the respondents have accessed veterinary services with limited regularity and vaccination program, respectively, in the study area. Hence, the beef cattle fatting sector should be supported through considering alleviating the major disease affecting this sector and encouraging the farmers’ indigenous knowledge practice with technology.

Foot and mouth disease is a devastating and a highly contagious disease of cloven-hoofed animals as a result of loss of production...

Background: Infectious bursal disease virus (IBDV) is an avian viral pathogen that causes infectious bursal disease (IBD) of chickens. The disease is endemic in Ethiopia since 2002 and vaccination is the major means of disease prevention and control. IBD vaccine is produced in Ethiopia using primary chicken embryo fibroblast (CEF) cell; which is time-consuming, laborious, and uneconomical. The present study was carried out to develop cell-based IBDV LC-75 vaccine using Vero cells, and to evaluate the immunogenicity and protection level.Results: Identity of the vaccine seed was confirmed using gene-specific primers using reverse transcription polymerase chain reaction. Confluent monolayer of Vero cells was infected with vaccine virus and serial passage continued till passage ten. Characteristic virus induced cytopathic effect was observed starting from passage 2 on the third day post-infection. The infectious titer of adapted virus showed a linear increment along the passage level. Virus induced specific antibody was determined using indirect ELISA after vaccination of 14 days old chicks through ocular route. Accordingly, the antibody titer measured from Vero cells vaccinated chicks revealed similar level with the currently available CEF cell-based vaccine. Chicks vaccinated with Vero cell adapted virus showed complete protection against very virulent IBDV, while unvaccinated group had 60% morbidity and 25% mortality.Conclusions: The IBDV vaccine strain well adapted on Vero cells and found to be immunogenic induces antibodies development and successfully protects chicks against challenging with the circulating field IBDV isolate. Hence, it is recommended to produce IBD vaccine using Vero cell culture with enough quantity to conquer the limitations using CEF cells and thus to vaccinate chicks to protect against IBDV infection.

Rotavirus is a major pathogen responsible for diarrheal disease in calves, resulting in loss of productivity and economy of farmers. However, various facets of diarrheal disease caused by rotavirus in calves in the world are inadequately understood, considering that diarrheal disease caused by rotavirus is a vital health problem in calves that interrupts production benefits with reduced weight gain and increased mortality, and its potential for zoonotic spread. The pathological changes made by rotavirus are almost exclusively limited to the small intestine that leads to diarrhea. It is environmentally distributed worldwide and was extensively studied. Reassortment is one of the important mechanisms for generating genetic diversity of rotaviruses and eventually for viral evolution. So, the primary strategy is to reduce the burden of rotavirus infections by practicing early colostrum’s feeding in newborn calves, using vaccine, and improving livestock management. Rotaviruses have a wide host range, infecting many animal species as well as humans. As it was found that certain animal rotavirus strains had antigenic similarities to some human strains, this may be an indication for an animal to play a role as a source of rotavirus infection in humans. Groups A to C have been shown to infect both humans and animals. The most commonly detected strains in both human and animals are G2, G3, G4, and G9, P [6]. Therefore, this review was made to get overview epidemiology status and zoonotic importance of bovine rotavirus.

Fufa Dawo Bari Department of Microbiology, Immunology and Veterinary Public Health, College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, EthiopiaCorrespondence: Fufa Dawo BariDepartment of Microbiology, Immunology and Veterinary Public Health, College of Veterinary Medicine and Agriculture, Addis Ababa University, P O Box 34, Bishoftu, EthiopiaTel +251 929190312Fax +251 114339933Email fufa.dawo@aau.edu.etIntroduction: In 2017 infectious bursal disease viruses (IBDVs) were reclassified into genogroups based on nature of clustering on a phylogenetic tree constructed using VP2 gene sequence data rather than according to their pathotype and/or antigenic types. Ethiopian IBD viruses were not reclassified according to the proposed genogrouping.Methods: In order to genogroup the Ethiopian IBDVs, available VP2 gene sequences data together with reference strain sequences were retrieved from GenBank and genogrouped as recently recommended based on evolutionary tree reconstruction and determination of their clustering on the phylogenetic tree.Results: The Ethiopian IBDVs were grouped into genogroups 1 and 3 that antigenically represent classically virulent and very virulent IBDVs, respectively. The genogroup 1 IBDVs were clustered with the vaccine strain while the genogroup 3 viruses were clustered with four known viruses belonging to sub-genogroup 3a and sub-genogroup 3b. Almost half of the Ethiopian IBDVs reported did not cluster with the specific sub-groups of genogroup 3; rather, the isolates were clustered differently suggesting they deserve a different sub-genogroup tentatively proposed as 3d. The two genogroups observed based on clustering on a phylogenetic tree were supported by corresponding deduced amino acid changes in similar positions in VP2 sequences. In addition, virulence marker amino acid genes coupled with second major hydrophilic region (amino acid positions 314– 325) were predicted in these sequences that could be responsible for the occurrence of IBD outbreaks.Conclusion: A new sub-genogroup of IBDVs, 3d, were observed in the sequences that could be one of the reasons for the frequent occurrence of IBD outbreaks and questions the protective potential of the existing vaccine. To institute disease control in the country, the effectiveness of the vaccine in use needs to be assessed in vivo against both genogroups 1 and 3 viruses and all three sub-genogroup 3 viruses circulating in the country.Keywords: infectious bursal disease virus, VP2 gene sequence, genogroups, sub-genogroups, virulent strains

Background: Coronavirus and Rotavirus are most commonly associated etiologies for calves’ diarrhea resulting in loss of productivity and economy of farmers. However, various facets of diarrheal disease caused by coronavirus and rotavirus in calves in Ethiopia are inadequately understood. A cross sectional study was conducted with the aim of isolation and molecular characterization of coronavirus and rotavirus from calves in central part of Oromia (Bishoftu, Sebata, Holeta and Addis Ababa), Ethiopia from November 2018 to May 2019. The four study areas were purposively selected and fecal samples were collected by simple random sampling for diagnosis of coronavirus and rotavirus infection by using antigen detection Enzyme linked immunosorbent assay (Ag-ELISA) kit. In addition, this study was carried out to have insight in prevalence and associated risk factors of coronavirus and rotavirus infection in calves. Result: During the study 83 diarrheic and 162 non-diarrheic fecal samples collected from calves less than 4 weeks of age were screened for coronavirus and rotavirus. Of the 83 diarrheic samples, 1 sample (1.2%) was positive for coronavirus antigen (Ag) and 6 samples (7.2%) were found to be positive for rotavirus antigen (Ag) by Ag-ELISA. All the non-diarrheic samples were negative for both coronavirus and rotavirus Ag. The overall prevalence of coronavirus and rotavirus infection in calves were estimated as 0.4% (1/245) and 2.45% (6/245) respectively. All samples (7) of ELISA test positive of both coronavirus and rotavirus were propagated in Madin Darby bovine kidney cells (MDBK). After 3 subsequent passages, progressive cytopathic effect (CPE) i.e. rounding, detachment as well as destruction of mono-layer cell of five sample (1 sample of coronavirus and 4 sample of rotavirus) (71.4%) were observed. At the molecular stage, reverse transcriptase polymerase chain reaction (RT-PCR) technique was used to determine the presence of coronavirus and rotavirus nucleic acid by using specific primers. The 5 samples that were coronavirus and rotavirus antigen positive by ELISA and develop CPE on cell culture were also positive on RT-PCR technique. Infection prevalence peaked have been obtained at 1st and 2nd weeks of age in male calves. Conclusion: Diarrheal disease caused by coronavirus and rotavirus has a great health problem in calves that interrupts production benefits with reduced weight gain and increased mortality, and its potential for zoonotic spread. So the present findings show coronavirus and rotavirus infection in calves in Ethiopia that needs to be addressed by practicing early colostrums feeding in newborn calves, using vaccine, or improving livestock management.

A cross-sectional study was conducted to isolate and identify bacterial species from the respiratory tract of apparently healthy and pneumonic camels in Asayita and Dubti woredas in the Afar Region, Ethiopia. From a total of 74 lung tissue and 74 tracheal swab samples Staphylococcus aureus, 16.3%, Streptococcus equi subsp. equi, 13.0%, and Pasteurella multocida, 10.9%, were dominant isolates from pneumonic lungs; Escherichia coli, 12.7%, Proteus species, 10.9%, and Klebsiella pneumoniae, 9.1%, were the majority in the normal lungs. The majority of the isolates colonized both anatomical sites investigated. There was a statistically significant association between the health status of the camels as well as the anatomical site studied with the isolation rates of the major respiratory pathogens (p

Background: Foot-and-mouth disease (FMD) is one of the contagious and the most economically devastating viral diseases caused by the FMD virus. The present study was conducted with the aim of molecular characterization of the FMD virus isolated from outbreaks that occurred in cattle in two different districts of Amhara regional state of Ethiopia. Samples collected from outbreaks were isolated on BHK-21 cell and serotype were detected using antigen detection ELISA. Phylogenetic and amino acid variability analyses of isolated viruses were undertaken after sequencing the VP1 gene in World Reference Laboratory, Pirbright, UK.Result: In the present study only serotypes O was found in the samples analysed using antigen detection ELISA and in 10 out of 13 (76.9%) cultured samples, virus were isolated on BHK-21 cells. Phylogenetic analysis of these isolates revealed that, they belonged to East Africa topotype-3 (EA-3) and shared 96.6% nucleotide similarity with Sudan’s isolates. A total of 10.3% amino acid variations were recorded between VP1 gene sequences of the field isolates of serotype O FMDV and vaccine strain (O/ETH/38/2005) used in Ethiopia for vacccine production.Conclusion: The phylogenetic analysis serotype O detected in this study revealed that the virus was clustered with East African topotype-3 (EA-3) and exhibited high genetic similarity with isolates from Sudan. A number of amino acid variations were also noted at different sites of VP1 gene when comparing field isolates with the vaccine strain. Thus, to enhance control of FMD in Ethiopia, detailed molecular analysis of the field isolates along with in-vitro vaccine matching tests need to be undertaken at frequent intervals to assess the protective potential of the vaccine strain in use.

Foot and mouth disease (FMD) is a trans-boundary viral disease that causes huge economic losses. A field based outbreak study was conducted in September 2016/ 2017 to identify and genetically characterize O serotype from clinical and asymptomatic cases at Welmera district Menagesha kolobo kelebe of central Oromia. The investigation was purposively conducted in the respective farms where outbreak occurred. Accordingly, 50 dairy cattle were clinically examined and about 20 (40%) animals showed sign and clinical lesions of the disease. Accordingly, active epithelial tissues and probang samples were taken from acutely and severely infected animals for virus isolation, typing and genetic detection. These clinical samples were processed for antigen typing and O serotype was isolated from clinical and asymptomatic cases in the farm. The genetic material of this strain was tested by rRT- PCR and the viral genome was detected in the epithelial tissues and probang samples. In conclusion, the study showed that O serotype was circulating in the district. Therefore, foot and mouth disease control should be established based on the availability of potent and matched vaccines against the circulating field strains.

Epitopes on the surface of the foot-and-mouth disease virus (FMDV) capsid have been identified by monoclonal antibody (mAb) escape mutant studies leading to the designation of four antigenic sites in serotype A FMDV. Previous work focused on viruses isolated mainly from Asia, Europe and Latin America. In this study we report on the prediction of epitopes in African serotype A FMDVs and testing of selected epitopes using reverse genetics. Twenty-four capsid amino acid residues were predicted to be of antigenic significance by analysing the capsid sequences (n = 56) using in silico methods, and six residues by correlating capsid sequence with serum–virus neutralization data. The predicted residues were distributed on the surface-exposed capsid regions, VP1–VP3. The significance of residue changes at eight of the predicted epitopes was tested by site-directed mutagenesis using a cDNA clone resulting in the generation of 12 mutant viruses involving seven sites. The effect of the amino acid substitutions on the antigenic nature of the virus was assessed by virus neutralization (VN) test. Mutations at four different positions, namely VP1-43, VP1-45, VP2-191 and VP3-132, led to significant reduction in VN titre (P value = 0.05, 0.05, 0.001 and 0.05, respectively). This is the first time, to our knowledge, that the antigenic regions encompassing amino acids VP1-43 to -45 (equivalent to antigenic site 3 in serotype O), VP2-191 and VP3-132 have been predicted as epitopes and evaluated serologically for serotype A FMDVs. This identifies novel capsid epitopes of recently circulating serotype A FMDVs in East Africa.

Serological diagnostic tests procedures. Procedures and principles of the test during the study were discussed in detail. (DOCX 12Â kb)

Antigen detection ELISA procedures. Antigen detection ELISA procedures and result interpretation during the study were discussed in detail. (DOCX 13Â kb)

Middle East respiratory syndrome (MERS) is a respiratory disease caused by a newly recognized Middle East respiratory syndrome-coronavirus (MERS-CoV). It is an RNA virus, with positive sense, single-stranded RNA genomes of 30.1 kilobase (kb). Based on its genome sequence, the virus has been classified within lineage 2C of the genus Betacoronavirus. The disease was first reported in 2012 and is now spreading to different parts of the world. Dromedary camels (Camelus dromedarius) are suggested to be the primary animal host that acts as a source of human infection by MERS-CoV. Most patients with MERS-CoV infection have been severely ill with pneumonia and acute respiratory distress syndrome, and some showed acute kidney injury. There is no specific vaccine or treatment for MERS-CoV infection other than supportive treatment. Collection of the specimens from lower respiratory tract, upper respiratory tract and serum for isolation and characterization of the virus using different techniques such as real time reverse transcription polymerase chain reaction (RT-rt PCR) and serological tests are recommended. Up to June 18, 2015, 498 of the 1327 cases have died with case fatality rate of ~38% [1]. This emerging infectious disease is a threat to human health. Proper infection-control measures including contact and airborne precautions should be implemented while managing patients with suspected MERS-CoV infection.

Vaccine strain selection for emerging foot-and-mouth disease virus (FMDV) outbreaks in enzootic countries can be addressed through antigenic and genetic characterisation of recently circulating viruses. A total of 56 serotype A FMDVs isolated between 1998 and 2012, from Central, East and North African countries were characterised antigenically by virus neutralisation test using antisera to three existing and four candidate vaccine strains and, genetically by characterising the full capsid sequence data. A Bayesian analysis of the capsid sequence data revealed the viruses to be of either African or Asian topotypes with subdivision of the African topotype viruses into four genotypes (Genotypes I, II, IV and VII). The existing vaccine strains were found to be least cross-reactive (good matches observed for only 5.4–46.4% of the sampled viruses). Three bovine antisera, raised against A-EA-2007, A-EA-1981 and A-EA-1984 viruses, exhibited broad cross-neutralisation, towards more than 85% of the circulating viruses. Of the three vaccines, A-EA-2007 was the best showing more than 90% in-vitro cross-protection, as well as being the most recent amongst the vaccine strains used in this study. It therefore appears antigenically suitable as a vaccine strain to be used in the region in FMD control programmes.

A cross sectional study of caprine tuberculosis was conducted on randomly selected 630 goats at, Adami Tulu Agricultural Research Centre and, smallholder farmers found around the research centre from December 2005 to June 2006. Single intradermal tuberculin test, post mortem examination of suspected goats and bacteriological culture of the pathogen were carried out to confirm the pathogen. Taking the cut off value at 3.5 mm, there was significant difference (p 0.05). Goats under smallholder conditions are 3.1 times at risk of acquiring mycobacterial infection than those under on-station condition. Gross tuberculous lesions were detected in two of the eight tuberculin positive (suspected) goats that were slaughtered for confirmation of tuberculosis lesion, sampling and culture for further confirmation of mycobacterial growth. Mycobacterial growth and acid fast bacilli were confirmed in those goats with gross tuberculosis lesions. In conclusion, this study showed the occurrence of tuberculosis in goats in Adami Tulu area. Further studies and confirmation of mycobacterial species and strains which infect goats and probably humans are necessary, especially in areas that consume raw goats’ milk like pastoral and agro-pastoral areas so that at least awareness, concerning the transmission of the disease from goats' milk and meat can be created. Key words: Caprine tuberculosis, goats, prevalence, tuberculin test, post mortem lesion.

Background Toxoplasmosis is a major public health concern in many countries of the world. A cross-sectional and follow up experimental study designs were used for seroepidemiological and bioassay studies, respectively from November 2012 to April 2013. The objectives were to estimate the seroprevalence of T. gondii infection, to assess risk factors and to isolate the parasite from camels in the Fentale district, Ethiopia. A direct agglutination test (DAT) and indirect enzyme linked immunosorbent assay (ELISA) kits were used to test camel sera. Hearts and tongues (each 25 g) from 31 seropositive camels were bioassayed in mice. Associations between seroprevalence and potential risk factors (collected using a questionnaire survey) were analyzed using logistic regression. Results An overall T. gondii prevalence of 49.62% (220/455) by DAT and 40.49% (179/451) by indirect ELISA test were detected. Herd level seroprevalence of 96.77% (30/31) (95% CI: 83.30– 99.92) by DAT was recorded and it was significantly higher in areas where wild felids are present (P = 0.038). Multivariable logistic regression showed that the likelihood of acquiring T. gondii infection was significantly higher in camels in the Ilala pastoral association [PA] (82.26%) (Adjusted Odds ratio [aOR] = 10.8; P

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