背景:小牛腹泻是全球畜牧业发病率和死亡率的主要原因,它可以由多种感染因子引起。在埃塞俄比亚,牛是畜牧业中最重要的经济物种,但与此同时,幼小动物由于小腿腹泻而发病率和死亡率很高。然而,缺乏包括牛肠道病原体的筛选和分子表征在内的研究。因此,我们的目的是检测和分子表征四种主要的肠道病原体在小牛腹泻,产肠毒素大肠杆菌(E.大肠杆菌K99+),隐孢子虫。,轮状病毒A(RVA),和牛冠状病毒(BCoV)在埃塞俄比亚中部的小牛中。该研究包括腹泻和非腹泻的小牛,并通过抗原ELISA和定量实时PCR(qPCR)分析粪便样品。阳性样品通过PCR基因分型进一步表征。
结果:使用qPCR在腹泻和非腹泻小牛中检测到所有四种病原体,进一步表征显示存在三种隐孢子虫。C.Andersoni,牛和C.ryanae。此外,RVA阳性样本的基因分型发现了一个常见的牛基因型G10P[11],以及更不寻常的G型,G24.据我们所知,这是埃塞俄比亚和非洲首次检测到G24RVA基因型。最后,对刺突基因的研究揭示了两种不同的BCoV菌株,一个经典的BCoV菌株和一个类牛CoV菌株。
结论:我们的结果表明隐孢子虫。,大肠杆菌K99+,RVA和BCoV在埃塞俄比亚中部的小牛中循环。此外,我们对罕见的RVAG型G24和类牛CoV的发现证明了遗传鉴定的重要性。
BACKGROUND: Calf diarrhea is a major cause of morbidity and mortality in the livestock sector worldwide and it can be caused by multiple infectious agents. In Ethiopia, cattle are the most economically important species within the livestock sector, but at the same time the young animals suffer from high rates of morbidity and mortality due to calf diarrhea. However, studies including both screening and molecular characterization of bovine enteric pathogens are lacking. Therefore, we aimed to both detect and molecularly characterize four of the major enteric pathogens in calf diarrhea, Enterotoxigenic Escherichia coli (E. coli K99 +), Cryptosporidium spp., rotavirus A (RVA), and bovine coronavirus (BCoV) in calves from central Ethiopia. Diarrheic and non-diarrheic calves were included in the study and fecal samples were analyzed with antigen-ELISA and quantitative real-time PCR (qPCR). Positive samples were further characterized by genotyping PCRs.
RESULTS: All four pathogens were detected in both diarrheic and non-diarrheic calves using qPCR and further characterization showed the presence of three Cryptosporidium species, C. andersoni, C. bovis and C. ryanae. Furthermore, genotyping of RVA-positive samples found a common bovine genotype G10P[11], as well as a more unusual G-type, G24. To our knowledge this is the first detection of the G24 RVA genotype in Ethiopia as well as in Africa. Lastly, investigation of the spike gene revealed two distinct BCoV strains, one classical BCoV strain and one bovine-like CoV strain.
CONCLUSIONS: Our results show that Cryptosporidium spp., E. coli K99 + , RVA and BCoV circulate in calves from central Ethiopia. Furthermore, our findings of the rare RVA G-type G24 and a bovine-like CoV demonstrates the importance of genetic characterization.