Detection of Toxoplasma gondii DNA in Sheep and Goat Milk in Northwest of Iran by PCR-RFLP

Background: Toxoplasmosis is a widespread disease in humans and many other species of warm-blooded animals. Among livestock animals, sheep and goat are more widely infected by Toxoplasma gondii. This parasite is a major cause of abortion, with significant economic losses for sheep and goat breeders. Objectives: The polymerase chain reaction (PCR) method was employed to detect of the T. gondii DNA in the milk of sheep and goats based on its B1 gene. Materials and methods: A total of 625 milk samples were collected from 345 sheep and 280 goats from randomly selected flocks of North-West of Iran. Results: Of 625 examined milk samples, 19 animals (3.04%) yielded a specific T. gondii B1 fragment (529 bp), of which T. gondii was detected in 16 (4.63%) sheep and 3 (1.07%) goat milk samples. Restriction fragment length polymorphism (RFLP) analysis of the PCR products of T. gondii with AluI restriction enzyme produced only one distinct pattern among all positive samples, which indicates that one RFLP profile of T. gondii exists in the study area. Conclusions: Presence of T. gondii DNA in the milk of sheep and goats raises the possibility that this parasite is transmitted through consumption of raw milk. Since sheep and goats are important milk sources in Iran, there is a high risk of contamination through milk from these hosts due to their susceptibility to infection. Further studies are required on milk producing animals to implement effective control strategies against toxoplasmosis.