Waldeland H
Acta Vet Scand. 1977;18(2):227-36. doi: 10.1186/BF03548451.
The epidemiology of toxoplasmosis in sheep was studied during a period of 31/2 to 6 years in 4 flocks in which abortions from the infection previously had occurred. The epidemiological pattern indicated that a heavy contamination of the environment may persist for about 2 years. Even in flocks with an apparently normal reproductive performance, toxoplasmosis may cause barrenness, abortion or delivery of dead lambs in 1–2 % of the breeding ewes. The prevalence of infected sheep increased with the age. The incidence of infection was significantly lower in 6–12 months old lambs than in mature ewes. The incidence of infection was higher on lowland pastures than on mountain pastures in not populated areas. On lowland pastures the incidence of infection was lower during the summer than during the winter. kw|Keywords|k]toxoplasma infection; k]epidemiology; k]sheep {fn1|This work was supported by grants from the Norwegian Research Council for Science and for the Humanities.}
在4个曾出现过因弓形虫感染导致流产的羊群中，对弓形虫病在绵羊中的流行病学情况进行了为期3年半至6年的研究。流行病学模式表明，环境的重度污染可能会持续约2年。即使在繁殖性能看似正常的羊群中，弓形虫病也可能导致1%-2%的繁殖母羊不孕、流产或产出死羔。感染绵羊的患病率随年龄增长而增加。6至12月龄羔羊的感染率显著低于成年母羊。在无人居住地区，低地牧场的感染率高于山地牧场。在低地牧场，夏季的感染率低于冬季。[关键词]弓形虫感染；流行病学；绵羊{注1|本研究得到了挪威科学与人文研究理事会的资助。}
