Submitted to: Parasitology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/1/2007
Publication Date: 3/1/2008
Citation: Lindstrom, I., Sundar, N., Lindh, J., Kironde, F., Kwok, O.C., Kabasa, J.D., Dubey, J.P., Smith, J.E. 2008. Isolation and genotyping of Toxoplasma gondii from Ugandan chickens reveals frequent multiple infections. Parasitology. 135:39-45. Interpretive Summary: Toxoplasma gondii is a single-celled parasite of all warm-blooded hosts worldwide. It causes mental retardation and loss of vision in children, and abortion in livestock. Cats are the main reservoir of T. gondii because they are the only hosts that can excrete the resistant stage (oocyst) of the parasite in the feces. Humans become infected by eating undercooked meat from infected animals and food and water contaminated with oocysts. Scientists at the Beltsville Agricultural Research Center and Leeds Univ., England report for the first time genetic characterization of Toxoplasma isolates from chickens from Uganda. The results will be of interest to biologists, parasitologists, and veterinarians.
Technical Abstract: The genetic makeup of an infecting Toxoplasma gondii strain may be important for the outcome of infection and the risk of reactivation of chronic disease. In order to survey the distribution of different genotypes within an area, free-range chickens act as a good model species. In this study 85 chickens were used to investigate the prevalence, genotype and mouse virulence of T. gondii in Kampala, Uganda. Antibodies were detected in 40 chickens, of which 20 had MAT-titers of 1:20 or higher and were also positive by PCR. Genotyping of five loci (SAG1, SAG2, SAG3, BTUB and GRA6) showed that six strains belonged to genotype I, eight to type II and one to type III. Five chickens had multiple infections; three individuals with type I plus type II and a further two harboring type I, II and III strains. Isolates were obtained from 9 chickens via bioassay in mice, six were type II strains and three were from animals with mixed infection. This is the first set of African T. gondii strains to be genotyped at multiple loci and in addition to the three predominant lineages we found a small number of new polymorphisms and a high frequency of multiple infection.