Location: Animal Parasitic Diseases LaboratoryTitle: Toxoplasma gondii seroprevalence in donkeys (Equus asinus) from the U.S.A. and isolation of T. gondii from cats on donkey farms) Author
Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2013
Publication Date: 1/15/2014
Citation: Dubey, J.P., Ness, S.L., Kwok, O.C., Choudhary, S., Mittel, L., Divers, T. 2014. Toxoplasma gondii seroprevalence in donkeys (Equus asinus) from the U.S.A. and isolation of T. gondii from cats on donkey farms. Veterinary Parasitology. 199:18-23. 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 under cooked meat from infected animals and food and water contaminated with oocysts. Donkeys (Equus asinus) are used as companion animals, in leisure activities as working animals, and their meat and milk is used for human consumption in certain countries. There are more than 50000 donkeys in the US mostly used as companion animals. In the present study scientists found 6.4% donkeys positive for Toxoplasma antibodies but they were not sick. This is the first study of Toxoplasma infecytion in this animal in the US. The results will be of interest to biologists, parasitologists, and public health workers.
Technical Abstract: Donkeys (Equus asinus) are used as companion animals, in leisure activities as working animals, for onotherapy, and their meat and milk is used for human consumption in certain countries. Here we report first serological survey for Toxoplasma gondii in donkeys in the U.S.A. Serum samples were collected from 374 donkeys from 8 farms in 8 U.S.A. states and tested for T. gondii antibodies by the modified agglutination test (MAT); 24 of 374 (6.4%) of donkeys were seropositive with titers of 25 in 7 sera, titer of 50 in 11 sera, 100 in 3 sera, and 200 in 3 sera. Domestic cats (Felis catus) were present on 6 of the 8 farms. All 3 cats from 1 farm had MAT titers of 200. Brains and hearts of 3 seropositive cats were bioassayed in mice and viable T. gondii was isolated from the hearts of 2, but not from their brains. Toxoplasma gondii isolates from mouse tissues were further propagated in cell culture. Genetic typing using the DNA extracted from cell culture derived tachyzoites and 10 PCR-restriction fragment length polymorphism (RFLP) markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, PK1, L358, and Apico loci) revealed that both isolates were clonal Type II (ToxoDB PCR-RFLP genotype #1). This is the first serological survey for T. gondii in donkeys in the U.S.A.