DNA detection of Toxoplasma gondii in sheep milk and blood samples in relation to phase of infection

•The article provides information about PCR ability to detect DNA of T. gondii in milk and blood.•Phase of infection determined by ELISA is compared to ability of PCR to detect parasite's DNA.•The lack of studies about toxoplasmosis in sheep milk in Slovakia is the reason to make this study. Toxoplasma gondii is a worldwide parasite that is important both for veterinary medicine (economic losses in the herd) and for public health (immunocompromised patients and pregnant women). An important source of Toxoplasma infection in humans is consumption of contaminated meat and milk (undercooked meat and unpasteurized milk). Small ruminants are important in both milk and meat production throughout the world because of free-range husbandry. The purpose of our study was to detect the presence of T. gondii DNA in ewes’ milk 1 month after the term, and to determine the relationship between the occurrence of this DNA in blood and milk based on the phase of infection. Using enzyme-linked immunosorbent assay (ELISA) the animals were divided into two groups (immunoglobulin M positive (IgM+), IgM−). With real-time polymerase chain reaction (PCR), T. gondii DNA was detected in seven milk samples (28%) and five blood samples (20%) of the IgM+ group (25 samples). In the IgM− group T. gondii DNA was detected in two milk samples (3.6%) out of 55 samples.