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.

Background. Bovine rotavirus (BRV) and bovine coronavirus (BCoV) are the most common viral agents in neonatal calf diarrhea and result in serious economic consequences. The aim of the study was to determine the epidemiology of those viruses in randomly selected dairy farms of Addis Ababa. Methods. A cross-sectional study was conducted from November 2018 to April 2019 using a probability proportional to size (PPS) sampling technique. A total of 110 calves, less than 30 days of age, from 57 dairy herds were involved in the study. Associated factors of herds and calves were collected using semistructured interviews from farm owners and through physical observation of selected calves. Fecal samples were collected and analyzed using the sandwich ELISA method. Data generated from both semistructured interviews and laboratory investigation were analyzed using STATA_MP version 15. Results. From the total 110 calves, 42 (38.18%) had diarrhea during the survey. The prevalence of bovine rotavirus and coronavirus was 3.64% (4/110) and 0.91% (1/110), respectively. Diarrhea, feeding colostrum timing, and sex of the neonatal calves had statistically significant association with bovine rotavirus infection ( p < 0.05 ). All rotavirus-positive neonatal calves were identified in small scale dairy farms and in dairy farms that reported mortality though they lack statistically significant association. Only one coronavirus case was detected among the neonatal calves. The case was identified among small scale herds and in a herd with diarrheal cases. The sex of the coronavirus calf was female, diarrheic, and among 11-20 days old. Conclusion. The prevalence of rotavirus and coronavirus infections in neonatal calves was seldom in dairy farms of the study area. Rotavirus was more common than coronavirus, and further studies should be initiated on other (infectious and noninfectious) causes of neonatal calf diarrhea in the area.

Background: Bovine rotavirus (BRV) and coronavirus (BCoV) are most commonly associated etiologies from viral causative agents of neonatal calf diarrhea. A cross-sectional study was carried out in randomly selected dairy farms of Addis Ababa from November 2018 to April 2019 with the objectives of estimating the prevalence of bovine rota and coronavirus infection in diarrheic and nondiarrheic calves and determining the associated risk factors. A probability proportional to size sampling technique (PPS) was used and accordingly, the study involved a total of 110 calves under 30 days of age from 57 dairy herds of which 34 (59.6%), 18 (31.6%) and 5 (8.8%) were small scale, medium scale and large scale farms respectively. As well risk factors associated with herd and calves were obtained from an interview of farm owners.Results: By using sandwich enzyme-linked immunosorbent assay (ELISA) test, out of these 110 calves, 4 (3.64%) were found positive for rotavirus while only 1 (0.91%) was found positive for coronavirus infection. Data generated from both interview and laboratory investigation was analyzed using SPSS version 20. As a result, prevalence of rotavirus infection showed a significant difference (P<0.05) with respect to sex, diarrhea status, colostrum timing and consistency of diarrhea. However, prevalence of coronavirus infection showed significant difference (P<0.05) only with consistency of diarrhea. Conclusions:In conclusion, rotavirus and coronavirus infection in neonatal calves in this finding showed as there is less prevalence in dairy farms of the study area; therefore, effort should be initiated for further studies on other (infectious and non-infectious) causes of calf diarrhea in this area.