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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.

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.

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.

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.