Brook Emily, Hart C Anthony, French Nigel, Christley Robert
Department of Veterinary Clinical Science, University of Liverpool, Leahurst, Neston, UK.
Vet Parasitol. 2008 Mar 25;152(1-2):46-52. doi: 10.1016/j.vetpar.2007.12.003. Epub 2007 Dec 8.
A cross-sectional study was designed to investigate the prevalence and risk factors for Cryptosporidium infection in young calves. Forty-one farms in a discrete, densely farmed 100 km2 area of North West England were visited over a 3-week period and 215 faecal samples were collected from young calves. Farms were not selected on the basis of existing scour problems. At the time of sampling, several investigator-observed variables were recorded at the pen, animal and stool levels. Samples were screened and 60/215 were confirmed as positive by PCR of the 18S rRNA gene. Risk factors for infection were explored using multilevel multivariable logistic regression with farm as a random effect. Age was significant in the final model, with a higher risk of infection in calves aged 8-21 days, when compared to those aged 0-7 days. The depth of the bedding was also significant in the final model, with calves housed in bedding 11-15 cm deep being at lower risk of infection than those on beds 0-5 cm deep. Consistency of the faeces was highly correlated with age and colour of the faeces and was not significantly associated with infection when these variables, and clustering at farm-level, were accounted for. This is interesting as Cryptosporidium is considered to be a primary enteropathogen. The results suggest that intervention strategies should be targeted at calves under 21 days old. These animals represent a significant reservoir of infection on the farm and may also pose a risk to public health, assuming that the species and genotypes shed are zoonotic pathogens.
一项横断面研究旨在调查幼龄犊牛隐孢子虫感染的患病率及危险因素。在为期3周的时间里，对英格兰西北部一个面积100平方公里、养殖密集且分布离散的地区的41个农场进行了走访，并从幼龄犊牛身上采集了215份粪便样本。农场并非根据现有的腹泻问题来选择。在采样时，在畜栏、动物和粪便层面记录了几个由调查人员观察到的变量。对样本进行了筛查，通过18S rRNA基因的PCR检测，215份样本中有60份被确认为阳性。使用以农场为随机效应的多水平多变量逻辑回归分析来探究感染的危险因素。年龄在最终模型中具有显著意义，与0至7日龄的犊牛相比，8至21日龄的犊牛感染风险更高。垫料深度在最终模型中也具有显著意义，与垫料深度为0至5厘米的犊牛相比，垫料深度为11至15厘米的犊牛感染风险较低。粪便的稠度与年龄和粪便颜色高度相关，在考虑这些变量以及农场层面的聚类情况时，与感染并无显著关联。这很有意思，因为隐孢子虫被认为是一种主要的肠道病原体。结果表明，干预策略应针对21日龄以下的犊牛。这些动物是农场中重要的感染源，并且假设排出的物种和基因型是人畜共患病原体，它们也可能对公共卫生构成风险。
