Lundén A, Näsholm A, Uggla A
Department of Parasitology, Swedish University of Agricultural Sciences and National Veterinary Institute, Uppsala.
Acta Vet Scand. 1994;35(3):273-81. doi: 10.1186/BF03548332.
The infection rate of Toxoplasma gondii was studied during 6 years in a sheep flock in central Sweden. The flock consisted of 165-249 breeding ewes of which 20-35% were lambs less than 1 year old. Most ewes were slaughtered when 5 years old. The sheep were kept indoors from end of September to early May. Lambing took place in March and April. Individual serum samples were collected twice a year, once just before turning the sheep out to pasture in the spring and again after housing in the autumn. Sera were analysed by ELISA for antibodies to T. gondii. The seroprevalence varied between 10% and 45% during the 6 years of observation. Seroconversion was detected predominantly at the autumn sampling, indicating that in most cases infection was acquired at pasture. Subclinical effects of T. gondii infection on lamb weight, litter size, total litter weight and ewe weight were also studied. Lambs born to chronically infected ewes were lighter at birth than those of uninfected ewes, but this disparity was no longer evident at weaning.
在瑞典中部的一个羊群中，对弓形虫的感染率进行了为期6年的研究。该羊群由165 - 249只繁殖母羊组成，其中20 - 35%是不到1岁的羔羊。大多数母羊在5岁时被屠宰。这些羊从9月底到次年5月初都圈养在室内。产羔在3月和4月进行。每年采集两次个体血清样本，一次是在春季将羊放归牧场之前，另一次是在秋季圈养之后。通过酶联免疫吸附测定（ELISA）分析血清中针对弓形虫的抗体。在6年的观察期内，血清阳性率在10%至45%之间波动。血清转化主要在秋季采样时检测到，这表明在大多数情况下，感染是在牧场获得的。还研究了弓形虫感染对羔羊体重、产仔数、总产仔体重和母羊体重的亚临床影响。慢性感染母羊所生的羔羊出生时比未感染母羊所生的羔羊轻，但这种差异在断奶时不再明显。
