<p>Estimated marginal means (cattle).</p>

Toxoplasmosis, caused by the intracellular protozoan parasite Toxoplasma gondii, is a zoonotic disease affecting almost all warm-blooded vertebrates. Despite its importance to both humans and animals, research on toxoplasmosis in Armenia has been limited, with a notable 35-year gap in studies focused on host animals. This study aimed to conduct a survey of T. gondii seroprevalence among livestock in Armenia. A total of 1996 serum samples of sheep, pigs, and cattle were collected from the northern provinces (Shirak, Lori, Tavush) of Armenia and screened by the ELISA test for the presence of total anti-Toxoplasma IgG and IgM antibodies. In the present study, the overall seroprevalence of T. gondii in livestock from northern Armenia was 15.5% (308/1,982; 95% CI: 14.0–17.2). The overall prevalence of infection among sheep was 22.5% (196/870; 95% CI: 19.8–25.5), pigs 28.6% (4/14; 95% CI: 8.4–58.1), and cattle 10.1% (112/1,112; 95% CI: 8.4–12.0). After excluding pigs due to insufficient sample size, a Pearson’s chi-square test demonstrated a strong and statistically significant association between host species and T. gondii infection status (χ² = 58.31, df = 1, p < 0.001). To investigate environmental determinants of infection, species-specific logistic regression models were fitted using temperature and elevation as continuous predictors. In cattle, none of the environmental variables showed statistically significant associations with seropositivity, and model fit did not improve over the null model. In contrast, sheep displayed a strong and non-linear relationship between seropositivity and elevation. The likelihood of infection decreased from low to mid altitudes and rose slightly at the highest elevations. Temperature showed no detectable effect in either species. These findings reveal clear species-specific differences in environmental sensitivity and highlight elevation as a key ecological factor shaping T. gondii exposure risks in sheep.刚地弓形虫（Toxoplasma gondii）是一种胞内寄生原生动物，由其引发的弓形虫病是一种人畜共患病，可感染几乎所有恒温脊椎动物。尽管该病对人类与畜禽均具有重要公共卫生价值，但亚美尼亚地区的弓形虫病研究却相对有限，其中针对宿主动物的相关研究更是存在长达35年的研究空白。本研究旨在针对亚美尼亚地区家畜的刚地弓形虫血清阳性率（seroprevalence）开展流行病学调查。 研究共采集了来自亚美尼亚北部省份（希拉克州、洛里州、塔武什州）的1996份绵羊、猪和牛的血清样本，采用酶联免疫吸附试验（ELISA）检测总抗弓形虫IgG与IgM抗体。本研究中，亚美尼亚北部家畜的刚地弓形虫总体血清阳性率为15.5%（308/1982；95%置信区间：14.0–17.2）。其中绵羊的总体感染率为22.5%（196/870；95%置信区间：19.8–25.5），猪为28.6%（4/14；95%置信区间：8.4–58.1），牛为10.1%（112/1112；95%置信区间：8.4–12.0）。 在因样本量不足排除猪数据后，皮尔逊卡方检验（Pearson’s chi-square test）结果显示，宿主物种与刚地弓形虫感染状态之间存在显著且较强的统计学关联（χ²=58.31，自由度df=1，p<0.001）。为探究感染的环境影响因素，本研究以温度与海拔作为连续预测变量，构建了物种特异性逻辑回归模型（logistic regression models）。结果表明，在牛群中，未发现任何环境变量与血清阳性存在统计学关联，模型拟合度亦未优于零假设模型。与之相反，绵羊的血清阳性率与海拔之间呈现出显著的非线性关系：感染风险随海拔从低到中海拔区域逐渐降低，在最高海拔区间则略有上升。温度对两种宿主的感染风险均未表现出可检测的影响。 本研究结果揭示了不同宿主物种在环境敏感性上的显著差异，并指出海拔是影响绵羊刚地弓形虫暴露风险的关键生态因子。