Strydom Christine, Abolnik Celia
SMT Veterinary Laboratory, Irene, Pretoria 0178, South Africa; Deltamune (Pty) Ltd, Roodeplaat, Pretoria, 0039, South Africa; Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, 0110, South Africa.
Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, 0110, South Africa.
Virus Res. 2025 May;355:199568. doi: 10.1016/j.virusres.2025.199568. Epub 2025 Apr 1.
Infectious bronchitis virus (IBV) affects the respiratory, urogenital and reproductive systems of chickens and causes major economic losses. Biosecurity and vaccinations are used to limit the disease's impact, and identifying the circulating strains is important for selecting appropriate vaccines. The partial spike (S1) genes of 364 IBVs, isolated from commercial chickens in Botswana, Eswatini, Namibia and South Africa from 2010 to 2020, were phylogenetically analyzed. Seven genotypes were identified: 184 viruses (50,5 %) were classified as genotype GI-19 (QX) and 78 (21,4 %) were GI-1 (Mass/H120). Thirty-nine (10,7 %) were genotype GI-13 (4/91), 29 (8,0 %) were GVI-1 (TC07-2), 19 (5,2 %) were GI-23 (Variant 2), and 13 (3,6 %) were GI-11 (UFMG/G-Brazil). Two (0.5 %) viruses belonged to the GIV-1 (DE/072/92) genotype. Genotype GI-11 had not been reported outside South America before but has evidently circulated in South Africa for at least a decade. Similarly, genotype GVI-1, previously thought to be restricted to Asia, has been present in southern Africa since at least 2010. Prior to 2013, only Mass and H120 vaccines were permitted to be used in South Africa, but since 2013 793/B (GI-13), QX (GI-19), 4-91 (GI-13) and Variant 2 (GI-23) live attenuated vaccines were permitted. Accordingly, the four IBV variants we identified were putative recombinants of genotypes G1-1 and G1-19, G1-13 and G1-19, or G1-13 and unknown IBV strains, but these variant viruses did not spread extensively or persist in the region. The phylogenetic evidence points to imported contaminated poultry and poultry products as the source of new IBV genotypes in southern Africa.
传染性支气管炎病毒（IBV）会影响鸡的呼吸系统、泌尿生殖系统和生殖系统，并造成重大经济损失。生物安全措施和疫苗接种被用于限制该疾病的影响，而识别流行毒株对于选择合适的疫苗很重要。对2010年至2020年期间从博茨瓦纳、斯威士兰、纳米比亚和南非的商业鸡群中分离出的364株IBV的部分刺突（S1）基因进行了系统发育分析。鉴定出了7种基因型：184株病毒（50.5%）被归类为GI-19（QX）基因型，78株（21.4%）为GI-1（Mass/H120）。39株（10.7%）为GI-13（4/91）基因型，29株（8.0%）为GVI-1（TC07-2），19株（5.2%）为GI-23（Variant 2），13株（3.6%）为GI-11（UFMG/G-巴西）。2株（0.5%）病毒属于GIV-1（DE/072/92）基因型。GI-11基因型此前在南美洲以外未被报道，但显然已在南非传播了至少十年。同样，GVI-1基因型此前被认为仅限于亚洲，至少自2010年以来就已在南部非洲出现。2013年之前，南非只允许使用Mass和H120疫苗，但自2013年以来，793/B（GI-13）、QX（GI-19）、4-91（GI-13）和Variant 2（GI-23）减毒活疫苗被允许使用。因此，我们鉴定出的四种IBV变体是GI-1和GI-19、GI-13和GI-19或GI-13和未知IBV毒株基因型的推定重组体，但这些变体病毒并未在该地区广泛传播或持续存在。系统发育证据表明，进口的受污染家禽和家禽产品是南部非洲新IBV基因型的来源。
