van der Poel Wim H M, van der Heide Reina, Verschoor Froukje, Gelderblom Hans, Vinjé Jan, Koopmans Marion P G
Microbiological Laboratory for Health Protection (MGB), National Institute for Public Health and the Environment (RIVM), P.O. Box 1, Antonie van Leeuwenhoeklaan 9, 3720 BA Bilthoven, The Netherlands.
Vet Microbiol. 2003 Apr 29;92(4):297-309. doi: 10.1016/s0378-1135(02)00421-2.
"Norwalk-like viruses" (NLVs) are the most common cause of acute non-bacterial gastroenteritis in humans. Cattle may be a reservoir of NLVs although never bovine NLVs have been found in humans. To gain more insight into the epidemiology of NLV, infections in cattle in The Netherlands were studied. Individual faecal samples from a large dairy herd and 243 pooled samples from veal calf farms were analysed for NLV by RT-PCR. Calves under 3 months of age in the dairy herd were sampled three to five times with 3-week intervals, whereas dairy cattle were sampled twice with a 2-month interval. In 31.6% (77/243) of the veal calf farm samples and in 4.2% (13/312) of the individual dairy cattle samples NLV was detected. The mean age of virus positive dairy cattle was 2.5 months. The highest numbers of NLV positive veal calf farms in The Netherlands were found in the regions with the highest number of veal calf farms. NLV infected veal calf farms were detected in every month throughout the study period. Cattle appeared to be hosts of NLVs, and virus shedding was weakly associated with diarrhoea. Complete ORF2 sequences were obtained from two calf NLVs and phylogenetic analyses suggested that these strains belong to a distinct cluster (GGIII/2) in between GGI and GGII NLVs of humans. Overall, genetic variation between strains as determined by sequence analysis of the P1/P2 capsid region was limited to 14.6%. Our data shows that NLV is endemic in the cattle population in The Netherlands and genetically distinct from NLVs in humans.
“诺如样病毒”（NLVs）是人类急性非细菌性肠胃炎最常见的病因。牛可能是诺如样病毒的宿主，尽管在人类中从未发现过牛诺如样病毒。为了更深入了解诺如样病毒的流行病学情况，对荷兰牛群中的感染情况进行了研究。通过逆转录聚合酶链反应（RT-PCR）分析了来自一个大型奶牛场的个体粪便样本以及来自犊牛养殖场的243份混合样本中的诺如样病毒。奶牛场中3个月龄以下的犊牛每隔3周采样三到五次，而奶牛每隔2个月采样两次。在犊牛养殖场样本中有31.6%（77/243）检测到诺如样病毒，在个体奶牛样本中有4.2%（13/312）检测到。病毒呈阳性的奶牛的平均年龄为2.5个月。在荷兰，犊牛养殖场数量最多的地区发现的诺如样病毒呈阳性的犊牛养殖场数量也最多。在整个研究期间的每个月都检测到了感染诺如样病毒的犊牛养殖场。牛似乎是诺如样病毒的宿主，并且病毒排出与腹泻的关联较弱。从两株犊牛诺如样病毒中获得了完整的开放阅读框2（ORF2）序列，系统发育分析表明这些菌株属于人类诺如样病毒GI和GII之间的一个独特簇（GGIII/2）。总体而言，通过对P1/P2衣壳区域的序列分析确定的菌株间遗传变异仅限于14.6%。我们的数据表明，诺如样病毒在荷兰的牛群中呈地方性流行，并且在基因上与人类诺如样病毒不同。
