Sequencing of the VP2 region was carried out to identify amino acid mismatches between vaccine strains and field isolates of infectious bursal disease virus (IBDV). Viruses were isolated in chicken embryo fibroblast (DF-1) cells using pooled samples of bursa collected from nine outbreaks, which affected 30,250 chickens in five localities, with an overall mortality of 47.87%. Virus strains were identified by comparing the deduced amino acid sequence between positions 232 and 446 of the immunodominant VP2 epitope. All of the pooled samples were positive for IBDV. RT-PCR yielded a 645-bp DNA fragment of the VP2 gene. Phylogenetic analysis of this fragment revealed clustering of these isolates with very virulent IBDV strains. The amino acid sequences of these isolates were identical to those of the European very virulent strains UK 661 and DV 86, except at position 222, but differed from the vaccine strains used in Ethiopia, suggesting the possible introduction of virulent virus strains to Ethiopia from Europe. Our study demonstrates the widespread presence of very virulent strains of IBDV on poultry farms in Ethiopia and demonstrates the need to evaluate the protective level of existing vaccines against circulating field viruses.

Sheep pox, goat pox, and lumpy skin diseases are economically significant and contagious viral diseases of sheep, goats and cattle, respectively, caused by the genus Capripoxvirus (CaPV) of the family Poxviridae. Currently, CaPV infection of small ruminants (sheep and goats) has been distributed widely and are prevalent in Central Africa, the Middle East, Europe and Asia. This disease poses challenges to food production and distribution, affecting rural livelihoods in most African countries, including Ethiopia. Transmission occurs mainly by direct or indirect contact with infected animals. They cause high morbidity (75-100% in endemic areas) and mortality (10-85%). Additionally, the mortality rate can approach 100% in susceptible animals. Diagnosis largely relies on clinical symptoms, confirmed by laboratory testing using real-time PCR, electron microscopy, virus isolation, serology and histology. Control and eradication of sheep pox virus (SPPV), goat pox virus (GTPV), and lumpy skin disease (LSDV) depend on timely recognition of disease eruption, vector control, and movement restriction. To date, attenuated vaccines originating from KSGPV O-180 strains are effective and widely used in Ethiopia to control CaPV throughout the country. This vaccine strain is clinically safe to control CaPV in small ruminants but not in cattle which may be associated with insufficient vaccination coverage and the production of low-quality vaccines.

Pasteurella multocida can infect a multitude of wild and domesticated animals, with infections in cattle resulting in hemorrhagic septicemia (HS) or contributing to bovine respiratory disease (BRD) complex. Current cattle vaccines against P. multocida consist of inactivated bacteria, which only offer limited and serogroup specific protection. Here, we describe a newly identified surface lipoprotein, PmSLP, that is present in nearly all annotated P. multocida strains isolated from cattle. Bovine associated variants span three of the four identified phylogenetic clusters, with PmSLP-1 and PmSLP-2 being restricted to BRD associated isolates and PmSLP-3 being restricted to isolates associated with HS. Recombinantly expressed, soluble PmSLP-1 (BRD-PmSLP) and PmSLP-3 (HS-PmSLP) vaccines were both able to provide full protection in a mouse sepsis model against the matched P. multocida strain, however no cross-protection and minimal serum IgG cross-reactivity was identified. Full protection against both challenge strains was achieved with a bivalent vaccine containing both BRD-PmSLP and HS-PmSLP, with serum IgG from immunized mice being highly reactive to both variants. Year-long stability studies with lyophilized antigen stored under various temperatures show no appreciable difference in biophysical properties or loss of efficacy in the mouse challenge model. PmSLP-1 and PmSLP-3 vaccines were each evaluated for immunogenicity in two independent cattle trials involving animals of different age ranges and breeds. In all four trials, vaccination with PmSLP resulted in an increase in antigen specific serum IgG over baseline. In a blinded cattle challenge study with a recently isolated HS strain, the matched HS-PmSLP vaccine showed strong efficacy (75–87.5% survival compared to 0% in the control group). Together, these data suggest that cattle vaccines composed of PmSLP antigens can be a practical and effective solution for preventing HS and BRD related P. multocida infections.

A cross-sectional study was conducted at Butajira Municipality abattoir from December, 2009 to April 2010 to investigate the epidemiology of bovine tuberculosis (bTB) in Butajira, Southern Ethiopia. Postmortem examination, mycobacterial culturing and multiplex genus typing techniques were used. An overall prevalence of 9% (40/446) of the animals examined harbor gross tuberculous lesions up on detailed post-mortem examination. Statistically significant difference was observed in the prevalence of bTB between different age groups (χ 2 = 11.441, p= 0.003) and body condition scoring (χ 2 = 10.384, p = 0.006). Higher prevalence of bTB was observed in older animals and animals with poor body condition. Bacteriological culture of the 40 samples gave growth on 13 with 9 of them acid fast Bacilli (AFB) positive. Genus typing of the AFB positive isolates by multiplex polymerase chain reaction (m-PCR) revealed seven non-tuberculous mycobacterium (NTM) and 1 Mycobacterium tuberculosis complex (MTBC) isolates. Further characterization of the isolates at specific species and investigation of the disease is recommended for controlling it in livestock and safeguard public health.

Introduction 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.