Frössling Jenny, Uggla Arvid, Björkman Camilla
Department of Clinical Sciences, Swedish University of Agricultural Sciences, PO Box 7019, SE-750 07 Uppsala, Sweden.
Vet Parasitol. 2005 Mar 31;128(3-4):209-18. doi: 10.1016/j.vetpar.2004.12.006. Epub 2005 Jan 25.
In this long-term study, the changes in within-herd Neospora caninum seroprevalences and the relative importance of horizontal and vertical parasite transmission in Swedish dairy herds were investigated. The within-herd prevalences varied between 5.8% and 65.0% when the herds were first sampled. Comparing the prevalences of year 2000 with those found 2-3 years later, nine out of 14 investigated herds had a similar or lower within-herd prevalence while five herds had an increased portion of seropositive individuals. Three herds were free or almost free from infection at their last sampling. Changes in prevalence were not related to the level of prevalence that each herd had when first sampled. Antibody avidity measurements revealed that the majority of seropositive individuals in all herds were chronically infected. Dam-calf pair investigations and inspection of genealogic trees supplemented with antibody test results showed that vertical transmission was by far the dominant transmission route in all herds. Taken together, these results indicate that the prevalence of N. caninum infection in Swedish dairy cattle can be successfully reduced if actions to eliminate infection in a herd are combined with preventive measures to avoid re-infection.
在这项长期研究中，调查了瑞典奶牛群内犬新孢子虫血清阳性率的变化以及寄生虫水平传播和垂直传播的相对重要性。首次对牛群进行采样时，群内患病率在5.8%至65.0%之间变化。将2000年的患病率与2至3年后的患病率进行比较，在14个调查牛群中，有9个牛群的群内患病率相似或更低，而有5个牛群的血清阳性个体比例增加。在最后一次采样时，有3个牛群未感染或几乎未感染。患病率的变化与每个牛群首次采样时的患病率水平无关。抗体亲和力测量显示，所有牛群中大多数血清阳性个体为慢性感染。对母牛-犊牛对的调查以及结合抗体检测结果对系谱树的检查表明，垂直传播是所有牛群中迄今为止的主要传播途径。综上所述，这些结果表明，如果将消除牛群感染的措施与预防再次感染的措施相结合，瑞典奶牛犬新孢子虫感染的患病率可以成功降低。
