Hirbaye Gemachu, Tola Eyob Hirpa, Moje Nebyou, Sori Teshale
School of Veterinary Medicine, Wollega University, Nekemte, Ethiopia.
College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, Ethiopia.
Vet Med (Auckl). 2024 Mar 11;15:81-90. doi: 10.2147/VMRR.S452153. eCollection 2024.
Infectious bronchitis (IB) is an economically important disease in poultry with worldwide distribution. The occurrence of IB has been reported both in commercial and backyard poultry in Ethiopia, although comprehensive information lacks available prevalence of the disease and the circulating serotypes.
A cross-sectional study was conducted from November 2021 to June 2022 in seven commercial farms found in East Shewa, Central Ethiopia. Serological assay using indirect ELISA, virus isolation techniques in embryonated eggs, and molecular techniques such as one-step reverse transcriptase polymerase chain reaction (RT-PCR) and nested polymerase chain reaction (PCR) targeting a 466 bp S1 gene were employed.
A total of 196 blood samples, 7 pools (35) of swab samples, and 5 pools of tracheal samples were investigated. The results of serological analysis revealed that 97.96% (192/196; 95% CI: 94.86-99.44) of the sera samples were found to be positive for antibodies against IBV. Out of the 7 pools of swab and 5 pools of tracheal tissue samples analyzed using RT-PCR 33.3% (4/12) of them gave positive results all from swab samples. The RT-PCR-positive samples were subjected to a nested PCR yielding 295bp and 154bp indicating the circulation of Mass and 793/B (4/91) strains of IBV, respectively. The 12 pools of samples inoculated into embryonated egg showed cytopathic changes such as congestion, bleeding, and deformation only after three passages.
Two serotypes of IBV are circulating in Ethiopian chickens, and molecular identification of the Massachusetts serotype is the first report in Ethiopia. Further epidemiological investigation is needed in order to devise effective control measures.
传染性支气管炎（IB）是一种在全球范围内分布的对家禽具有重要经济影响的疾病。在埃塞俄比亚，商业家禽场和后院家禽中均有IB发生的报道，不过关于该病的流行率及流行血清型缺乏全面信息。
2021年11月至2022年6月在埃塞俄比亚中部东谢瓦的7个商业养殖场开展了一项横断面研究。采用了间接ELISA血清学检测、鸡胚病毒分离技术以及针对466bp S1基因的一步法逆转录聚合酶链反应（RT-PCR）和巢式聚合酶链反应（PCR）等分子技术。
共调查了196份血液样本、7组（35份）拭子样本和5组气管样本。血清学分析结果显示，97.96%（192/196；95%可信区间：94.86 - 99.44）的血清样本检测出针对传染性支气管炎病毒（IBV）的抗体呈阳性。在使用RT-PCR分析的7组拭子样本和5组气管组织样本中，33.3%（4/12）呈阳性结果，且均来自拭子样本。RT-PCR阳性样本进行巢式PCR，分别产生295bp和154bp条带，表明分别有Mass和793/B（4/91）株IBV在流行。接种到鸡胚中的12组样本仅在传代三次后出现了如充血、出血和变形等细胞病变。
两种血清型的IBV在埃塞俄比亚鸡群中流行，马萨诸塞血清型的分子鉴定在埃塞俄比亚属首次报道。为制定有效的控制措施，需要进一步开展流行病学调查。
