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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