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United States Department of Agriculture

Agricultural Research Service

Research Project: INTEGRATED APPROACH TO THE DETECTION AND CONTROL OF FOODBORNE PARASITES AND THE IMPACT ON FOOD SAFETY

Location: Animal Parasitic Diseases

Title: Genetic diversity of Toxoplama gondii isolates from Ethiopian feral cats

Authors
item Dubey, Jitender
item Choudhary, Shanti -
item Tilahun, Getachew -
item Tiao, Nary -
item Gebreyes, Wondwossen -
item Su, Chunlei -

Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 17, 2013
Publication Date: August 1, 2013
Citation: Dubey, J.P., Choudhary, S., Tilahun, G., Tiao, N., Gebreyes, W., Su, C. 2013. Genetic diversity of Toxoplama gondii isolates from Ethiopian feral cats. Veterinary Parasitology. 196:206-208.

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. However, only a small percentage of exposed adult humans or other animals develop clinical signs of disease. It is unknown whether the severity of toxoplasmosis in immunocompetent hosts is due to the parasite strain, host variability, or to other factors. Recently, attention has been focused on the genetic variability among T. gondii isolates from apparently healthy and sick hosts. Severe cases of toxoplasmosis that have been reported in immunocompetent patients are considered to be due to infection with atypical T. gondii genotypes. Nothing is known of genetic diversity of Toxoplasma from any host in Ethiopia.In the present report scientists document genetic characteristics of Toxoplasma from cats in Ethiopia for the first time. The results will be of interest to biologists, parasitologists, and public health workers.

Technical Abstract: Recent studies indicate greater genetic variability among isolates of Toxoplasma gondii worldwide than previously thought. However, there is no information on genetic diversity of T. gondii from any host in Ethiopia. In the present study, genotyping was performed on viable T. gondii isolates by bioassays in mice from tissues and feces of 27 cats from Ethiopia. Viable T. gondii was isolated from hearts of 26 cats, feces alone of 1 cat, and feces and tissues of 6 cats; in total there were 33 isolates. Genotyping was performed on DNA from cell-cultured derived T. gondii tachyzoites and by using 10 PCR-restriction fragment length polymorphism markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico). Four genotypes were recognized, including ToxoDB #1(Type II clonal, nine isolates), ToxoDB #2 (Type III, five isolates), Toxo DB #3 (Type II variant, ten isolates), and ToxoDB #20 (nine isolates). Of interest is the isolation of different genotypes from tissues and feces of two cats, suggesting re-infection or mixed strain T. gondii infection. These findings are of epidemiological significance with respect to shedding of oocysts by cats. This is the first report of genotyping of T. gondii from any host in Ethiopia.

Last Modified: 11/28/2014
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