Abstract Toxoplasmosis is a worldwide zoonosis that affects man and homeothermic animals, caused by the protozoan Toxoplasma gondii. This parasite is responsible for congenital diseases, miscarriage and stillbirth in some species, such as sheep. Although outbreaks of abortion are considered important, descriptions of these outbreaks in ewes in Brazil are rare, even though infection is highly prevalent, and isolates are very virulent. Studies have shown a strong association between the presence of antibodies against the parasite in mothers and a low occurrence of reproductive problems by T. gondii during pregnancy. The objective of the study was to evaluate the occurrence of T. gondii infection in sheep from the semi-arid region of Paraiba State, Brazil, and to determine if these animals acquire the infection in the first year of life, before the beginning of the reproductive phase. This was done by monitoring the dynamics of anti-T. gondii antibodies by indirect fluorescence antibody test (IFAT ≥ 64) in animal serum from birth to 12 months of age, obtained once a month. Fifty-six crossbreed females and their 61 offspring, belonging to seven semi-intensive farms (representative of the region's farms) were evaluated. Of the 61 lambs studied, 55.7% (34/61) (IC 95% 44.9%-71.4%) were antibody negative at the end of 12 months, as only presumed colostrum antibodies were detected in these animals or they remained negative throughout the study. The remaining 44.3% (27/61) (IC 95% 28.6%-55.1%) were either presenting high antibody titres since the first examination (5/27; 18.5%), or became seropositive in the first year of life (22/27; 81.5%). Antibody titres ranged from 64 to 65,356 and the variables analysed (presence of cats, type of water supplied, type of flock, sanitary management and existence of sewage within the property) were not associated with the seroconversion of the lambs. The study concludes that about half of the ewes were seronegative at the age of one year, the time of their first gestation and, probably, they are more susceptible to reproductive problems caused by this coccidia.

中文翻译：

---

巴西帕拉伊巴州雌性羔羊弓形虫抗体的纵向研究

摘要 弓形虫病是一种世界范围的人畜共患病，由原生动物弓形虫引起，影响人类和恒温动物。这种寄生虫会导致某些物种（例如绵羊）的先天性疾病、流产和死产。尽管流产暴发被认为很重要，但巴西母羊中这些暴发的描述很少见，尽管感染非常普遍，而且分离株的毒力很强。研究表明，母亲体内存在抗寄生虫的抗体与怀孕期间弓形虫的生殖问题发生率低之间存在很强的关联。该研究的目的是评估来自巴西帕拉伊巴州半干旱地区的绵羊中弓形虫感染的发生情况，并确定这些动物是否在出生后的第一年就感染了弓形虫。在生殖阶段开始之前。这是通过监测抗 T 的动力学来完成的。刚地抗体通过间接荧光抗体试验（IFAT≥64）在出生至12月龄的动物血清中检测，每月获得一次。对属于七个半精养农场（代表该地区农场）的 56 只杂交雌性及其 61 只后代进行了评估。在研究的 61 只羔羊中，55.7% (34/61) (IC 95% 44.9%-71.4%) 在 12 个月结束时抗体呈阴性，因为在这些动物中仅检测到推测的初乳抗体，或者在整个研究过程中保持阴性. 其余 44.3% (27/61) (IC 95% 28.6%-55.1%) 自第一次检查以来抗体滴度较高 (5/27; 18.5%)，或在出生后的第一年呈血清阳性 (22/ 27；81.5%）。抗体滴度范围为 64 至 65，356 和分析的变量（猫的存在、供水类型、羊群类型、卫生管理和财产内是否存在污水）与羔羊的血清转化无关。该研究得出的结论是，大约一半的母羊在一岁时，即第一次怀孕的时候血清学呈阴性，并且可能更容易受到这种球虫引起的生殖问题的影响。