Seroepidemiological investigation of Toxoplasma gondi and Neospora caninum in local Deers in Erbil, Iraq.

Abstract

Toxoplasma gondii and Neospora caninum are important protozoan parasites affecting a wide range of domestic and wild animals. Data on their prevalence and risk factors in local deer in Iraq are lacking. A sero-epidemiological survey was conducted on 168 free-ranging deer across multiple locations in Erbil Governorate, northern Iraq, between 2024 and 2025. Blood samples were collected, and serum was analyzed for antibodies against T. gondii and N. caninum using a competitive ELISA. Demographic, management, and environmental data were recorded for each animal. Associations between seropositivity and potential risk factors were assessed using Chi-square or Fisher's exact tests, with binomial logistic regression used to estimate odds ratios (OR) and 95% confidence intervals (CI). Sex was not associated with infection risk, whereas adult deer (>4 years) showed higher seroprevalence of T. gondii (30.5% vs. 16.2% in fawns; OR = 2.26) and N. caninum (25.4% vs. 11.8%; OR = 2.56). A history of abortion was a strong predictor of infection, with affected does exhibiting higher odds for both parasites (T. gondii: OR = 3.53; N. caninum: OR = 3.46). Poor body condition was associated with significantly increased odds of infection (T. gondii: OR = 3.21; N. caninum: OR = 7.49). Environmental factors, including the presence of even a few free-roaming cats and canids, were linked to higher infection rates, while prior antiparasitic treatment was protective against T. gondii infection (OR = 0.27). This study provides the first evidence of T. gondii and N. caninum exposure in local deer in northern Iraq and identifies key host and environmental risk factors. Findings highlight the roles of age, reproductive history, body condition, and exposure to definitive hosts in shaping infection risk, emphasizing the need for integrated wildlife management and monitoring strategies to reduce protozoal transmission.