Toxoplasma gondii is an important cosmopolitan opportunistic protozoan parasite, which threatens the health of human beings and animals. Genetic characterization of isolates from South America has revealed high genetic diversity. In contrast, isolates from North America and Europe were highly clonal, with 3 major lineages known as the Types I, II, and III. However, limited information on T. gondii genotypes has been reported in The People's Republic of China. Here we conducted a survey to determine genetic diversity of this parasite in wild birds of China. In total, tissues from breast muscle of 178 wild birds, including 98 common pheasants ( Phasianus colchicus ), 35 tree sparrows ( Passer montanus ), 22 house sparrows ( Passer domesticus ), 20 saxaul sparrows ( Passer ammodendri ), and 1 cinnamon sparrow ( Passer rutilans ), were tested for T. gondii infection, 4 of which were found to be positive for the T. gondii B1 gene by PCR amplification. These positive DNA samples were typed at 10 genetic markers, including 9 nuclear loci, i.e., SAG1, 5′- and 3′-SAG2, alternative SAG2, SAG3, GRA6, L358, PK1, c22-8, c29-2, and an apicoplast locus Apico. Of these, 3 isolates were genotyped with complete data for all loci, and 2 genotypes (Type I and Type II variant) were identified. This is the first report of genetic typing of T. gondii isolates from wild birds from different regions in China. The results suggest that the Type I and II variant strains are circulating in wild birds in China, and these birds are potential reservoirs for T. gondii transmission.
The seroprevalence of toxoplasmosis in pigs was examined in China's southern Guangdong Province from March 2008 through May 2009. A total of 1,022 serum samples was collected from 12 administrative cities and assayed for Toxoplasma gondii antibodies by enzyme-linked immunosorbent assay test. The seroprevalence ranged from 0 to 58.1% and the average T. gondii antibody-positive prevalence was 27.0% (276/1,022), with breeding boars having the highest level at 39.6% (38/96) followed by breeding sows at 36.9% (52/141). The results of the present survey indicate that T. gondii infection is a significant health problem in pigs and represents a public health concern in southern China.
The frequency of Toxoplasma gondii antibodies in stray and household dogs in Guangzhou, China was examined by ELISA on serum samples from 150 animals (36 strays and 114 from households) and the overall prevalence was 21.3%. The extent of infection in stray dogs (33.3%) was significantly higher ( P < 0.05) than in household dogs (17.5%). Infection in male and female dogs of both groups was not significantly different ( P ≥ 0.05), i.e., 31.8% versus 35.7% for male and female in stray dogs, and 14.5% versus 22.2% in household dogs. The results of the present investigation indicate that the seroprevalence of T. gondii infection in dogs was high in Guangzhou, especially in strays. Therefore, it is essential to implement integrated strategies to prevent and control T. gondii infection in both stray and household dogs.