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 #313291

Title: Genetic characterization of Toxoplasma gondii isolates from Portugal, Austria, and Israel reveals higher genetic variability within the type II lineage

item VERMA, SHIV - Non ARS Employee
item AJZENBERG, DANIEL - Hospital And University Center Of Limoges
item RIVERA-SANCHEZ, ANN - University Of Tennessee
item SU, CHUNLEI - University Of Tennessee
item Dubey, Jitender

Submitted to: Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/7/2015
Publication Date: 2/13/2015
Citation: Verma, S., Ajzenberg, D., Rivera-Sanchez, A., Su, C., Dubey, J.P. 2015. Genetic characterization of Toxoplasma gondii isolates from Portugal, Austria, and Israel reveals higher genetic variability within the type II lineage. Parasitology. 142:948-957.

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. Most people infected with Toxoplasma remain asymptomatic while some become ill and some die. The parasite strain is thought to be one determinant in the epidemiology of clinical toxoplasmosis in humans. In the present study of 90 isolates of Toxoplasma, the authors found higher genetic variability among isolates recovered from asymptomatic hosts, and the results varied with the genetic analysis method used. The results will be of interest to biologists, and parasitologists.

Technical Abstract: This study compared genetic diversity of Toxoplasma gondii isolates from Portugal, Austria and Israel. For this, we genotyped 90 T. gondii isolates (16 from Portugal, 67 from Austria and 7 from Israel) using 10 nested PCR-restriction length polymorphism (RFLP) genetic markers and 15 microsatellite (MS) markers. By PCR-RFLP typing, 7 isolates from Portugal chickens were identified as type II (ToxoDB #1 or #3), 4 were type III (ToxoDB #2), and the remaining 4 isolates have unique genotype pattern were designated as ToxoDB #254. One mouse virulent isolate from a bovine fetus (Bos taurus) in Portugal was type I (ToxoDB #10) at all loci and designated as TgCowPr1. All 67 isolates from Austria and 7 from Israel were type II (ToxoDB #1 or #3). By microsatellite typing, many additional genetic variations were revealed among the type II and type III isolates. Phylogenetic analysis showed that isolates from the same geographical locations tend to cluster together, and there is little overlapping of genotypes among different locations. This study demonstrated that the microsatellite markers can provide higher discriminatory power to reveal association of genotypes with geographical locations. Future studies of the type II strains in Europe by these microsatellite markers will be useful to reveal transmission patterns of the parasite.