Skip to main content
ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #325158

Title: Isolation and RFLP genotyping of toxoplasma gondii in free-range chicken(Gallus domesticus) in Grenada, West Indies, revealed widespread and dominance of clonal type III parasites

item CHIKWETO, ALFRED - St George'S University
item SHARMA, RAVINDRA - St George'S University
item TIWARI, KESHAV - St George'S University
item VERMA, SHIV - Orise Fellow
item CALERO-BERNAL, RAFAEL - Orise Fellow
item JIANG, TIANTIAN - University Of Tennessee
item SU, CHUNLEI - University Of Tennessee
item Kwok, Oliver
item Dubey, Jitender

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/20/2016
Publication Date: 2/20/2017
Citation: Chikweto, A., Sharma, R., Tiwari, K., Verma, S.K., Calero-Bernal, R., Jiang, T., Su, C., Kwok, O.C., Dubey, J.P. 2017. Isolation, tissue distribution, and molecular characterization of Toxoplasma gondii from chickens in Granada, West Indies. Journal of Parasitology. 103(1):52-55.

Interpretive Summary: Human toxoplasmosis, caused by single-celled parasite, Toxoplasma gondii, accounts for an estimated one-fifth of all diagnosed foodborne infections in the United States, and one fifth of the economic costs attributable to any foodborne pathogen. Pregnant women and their fetuses are exposed to elevated health risks. The ingestion of under cooked infected meat is considered an important source of toxoplasmosis in humans. Chickens are important in the transmission of Toxoplasma both as direct source of infection for humans, and indirectly as prey for the reservoir host, cats. Cats can excrete millions of environmentally resistant stage (oocyst) in their feces. Humans can acquire toxoplasmosis by ingesting food and water contaminated with oocysts. In the present paper authors found T. gondii infection in 27% of 145 free-range chickens from Grenada, West Indies, and they isolated viable parasites from tissues of 20 chickens. Though a sample of such chickens showed more than half to be infected a decade ago, this appreciable prevalence poses an ongoing public health threat, especially for those with immune deficiencies or for pregnant women. The distribution of genotypes indicates that parasites throughout the Caribbean share commonalities and, though not entirely lacking in diversity, are far less variable than those identified from Amazonian habitats in neighboring South American locales. These results will be useful for public health workers, veterinarians, and parasitologists.

Technical Abstract: The objectives of the present cross sectional study were to estimate the prevalence and to isolate and genotype Toxoplasma gondii in free range chickens from Grenada, West Indies. Using the modified agglutination test, antibodies to T. gondii were found in 39 (26.9%) of 145 free-range chickens with titers of 25 in 7chickens; 50 in 6 chickens; 100 in 2 chickens; 200 or higher in 24 chickens. The hearts of the 39 seropositive chickens were bioassayed in mice; viable T. gondii was isolated from 20 and further propagated in cell culture. Genotyping of T. gondii DNA extracted from cell-cultured tachyzoites using the 10 PCR-restriction fragment length polymorphism (RFLP) markers; SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico revealed 4 genotypes, including ToxoDB PCR-RFLP #2 (Type III), #7, #13, and #259 (new). These results indicated that T. gondii population genetics in free-range chickens seems to be moderately diverse with ToxoDB #2 (Type III) as the most frequent (15/20=75%) compared to other genotypes in Grenada.