Serological evidence of Toxoplasma gondii and Neospora caninum infection in black-boned sheep and goats in southwest China.

Toxoplasma gondii and Neospora caninum are two closely related protozoan parasites which can cause abortion and significant economic losses in sheep and goats. However, it is yet to know whether black-bone sheep and goats are infected with T. gondii and N. caninum in China. In the present investigation, the seroprevalence and risk factors of T. gondii and N. caninum infections in black-boned sheep and goats were investigated in Yunnan Province, subtropical southwest China between July and August of 2017. A total of 481 serum samples were tested for T. gondii antibodies using the Modified Agglutination Test (MAT), and 468 serum samples were examined for N. caninum antibodies by indirect Enzyme-Linked Immunosorbent Assay (iELISA). The overall seroprevalence of T. gondii in black-boned sheep and goats was 36.80% (177/481, 95% CI 32.49-41.11), and 40 out of 468 serum samples were N. caninum-seropositive (8.55%, 95% CI 6.02-11.08). There was significant difference in the seroprevalence of T. gondii infection in different regions (χ2 = 19.869, df = 2, P<0.01). As for the seroprevalence of N. caninum infection, region (χ2 = 8.558, df = 2, P<0.05), age (χ2 = 16.631, df = 3, P < 0.01), gender (χ2 = 11.219, df = 1, P < 0.01) and species (χ2 = 8.673, df = 1, P < 0.01) were the risk factors. In addition, the seroprevalence of coinfection of T. gondii and N. caninum in black-boned sheep and goats was 3.63% (17/468, 95% CI 1.94-5.32). To our knowledge, this is the first report of T. gondii and N. caninum seroprevalence in black-boned sheep and goats in China, which provided base-line data for the execution of control strategies and measures against T. gondii and N. caninum infection in black-boned sheep and goats.