Onyango J, Mata F, McCormick W, Chapman S
Department of Animal Management and Veterinary Health, University of Northampton, Moulton Campus, Northampton NN3 7RR, UK.
Newcastle University, School of Agriculture, Food and Rural Development, Newcastle-Upon-Tyne NE1 7RU, UK.
Vet Rec. 2014 Oct 4;175(13):326. doi: 10.1136/vr.102353. Epub 2014 Jul 4.
Orf is a viral disease found in English sheep flocks which can cause economic losses. It is a zoonosis with little epidemiological research available in the UK. In 2012, 3000 questionnaires were sent to English sheep farms in order to investigate the prevalence of orf, determine vaccination efficacy and to identify some of the potential risk factors. The usable response rate was 25.4 per cent. The usable farms (N=762 in the years 2011 and 2012) were used to model the percentage of animals affected on the farm, and the probability of a farm being found with the disease. The disease prevalence (DP) was standardised for the year and calculated as 1.88 per cent for ewes and 19.53 per cent for lambs. The disease risk ratio (RR) for the use of the vaccine was calculated as 2.04 for ewes and 0.75 for lambs, and therefore, the study found that lamb vaccination was beneficial (RR <1). Weed infestation and an increased number of orphan lambs were associated with increased cases of orf. We conclude that the DP in ewes and lambs affect each other, though the impact is higher for lambs in the presence of increasing prevalence in ewes. A short lambing season lowers the probability of a farm experiencing cases of orf. Vaccination was effective in lambs but not in ewes, though lambs benefitted when ewes were vaccinated (reduced orf prevalence in lambs born from vaccinated ewes), probably because any unvaccinated ewes may have been carriers that could spread the virus to the new-born lambs.
羊口疮是一种在英国羊群中发现的病毒性疾病，会造成经济损失。它是一种人畜共患病，在英国几乎没有相关流行病学研究。2012年，向英国养羊场发放了3000份调查问卷，以调查羊口疮的流行情况，确定疫苗接种效果，并识别一些潜在风险因素。有效回复率为25.4%。利用有效农场（2011年和2012年为N = 762）来模拟农场中受感染动物的百分比以及农场发现该病的概率。对疾病流行率（DP）进行了年度标准化计算，母羊为1.88%，羔羊为19.53%。计算出母羊使用疫苗的疾病风险比（RR）为2.04，羔羊为0.75，因此，该研究发现给羔羊接种疫苗是有益的（RR <1）。杂草丛生和孤儿羔羊数量增加与羊口疮病例增多有关。我们得出结论，母羊和羔羊的疾病流行率相互影响，不过在母羊患病率上升的情况下，对羔羊的影响更大。较短的产羔季节降低了农场出现羊口疮病例的概率。疫苗接种对羔羊有效，但对母羊无效，不过当母羊接种疫苗时羔羊会受益（接种疫苗的母羊所生羔羊的羊口疮患病率降低），可能是因为任何未接种疫苗的母羊可能是病毒携带者，会将病毒传播给新生羔羊。
