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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: Seroprevalence and correlates of Toxoplasma gondii infection in domestic sheep in Michoacán State, Mexico

Authors
item Alvarado-Equivel, C -
item Silva-Aguilar, D -
item Villena, I -
item Dubey, Jitender

Submitted to: Preventive Veterinary Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 26, 2013
Publication Date: November 1, 2013
Citation: Alvarado-Equivel, C., Silva-Aguilar, D., Villena, I., Dubey, J.P. 2013. Seroprevalence and correlates of Toxoplasma gondii infection in domestic sheep in Michoacán State, Mexico. Preventive Veterinary Medicine. 112:433-437.

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. Lamb and mutton have repeatedly been identified as a major source of human infection. Little is known, however, about rates of infection in Mexico, one of our biggest trading partners. In the present paper authors report high seroprevalence Toxoplasma infection in sheep in Mexico and risk factors associated with infection. The results will be of interest to biologists, and Parasitologists.

Technical Abstract: Toxoplasma gondii infection in sheep is of public health and economic importance. Seroprevalence of T. gondii infection and correlates were determined in 405 sheep from 7 farms in 4 geographical regions in Michoacán State, Mexico using the modified agglutination test (MAT). General sheep and environmental characteristics were obtained by a questionnaire. All sheep were raised in semi-extensive conditions in temperate climate. Antibodies to T. gondii were found in 121 (29.9%) of the 405 sheep with MAT titers of 1:25 in 46, 1:50 in 20, 1:100 in 7, 1:200 in 5, 1:400 in 7, 1:800 in 11, 1:1600 in 5, and 1:3200 or higher in 20. Seropositivity did not vary significantly with age, sex or breed. In contrast, seroprevalence varied among farms, geographic region, municipality, altitude, mean annual temperature, and mean annual rainfall. The median seroprevalence in farms was 32.6% (range 7.1% - 71.4%). Sheep raised in farms at =1900 meters above sea level had a higher seroprevalence (44.1%) than those in farms at lower sea level (16.3%). Sheep raised in municipalities with =17.7°C mean annual temperature had a higher seroprevalence (37.2%) than those in municipalities with higher mean annual temperature (14.1%). Sheep raised in a municipality with 600 mm of mean annual rainfall had a higher seroprevalence (71.4%) than municipalities with higher mean annual rainfall (29.1%). This is the first report on the seroprevalence and correlates of T. gondii infection in sheep in Michoacán State, Mexico. The role of environmental characteristics for T. gondii infection in sheep deserves further research.

Last Modified: 9/23/2014
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