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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #381373

Research Project: Immune, Molecular, and Ecological Approaches for Attenuating GI Nematode Infections of Ruminants

Location: Animal Parasitic Diseases Laboratory

Title: Genetic evidence substantiates transmission of Trichinella spiralis from one swine farm to another

item BILSKA-ZAJAC, EWA - National Veterinary Research Institute
item TONANZI, DANIELE - Istituto Superiore Di Sanita
item POZIO, EDOARDO - Istituto Superiore Di Sanita
item ROZYCKI, MIROSLAW - National Veterinary Research Institute
item CENCEK, TOMASZ - National Veterinary Research Institute
item Thompson, Peter
item Rosenthal, Benjamin
item LA ROSA, GUISEPPE - Istituto Superiore Di Sanita

Submitted to: Parasites & Vectors
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/24/2021
Publication Date: 7/9/2021
Citation: Bilska-Zajac, E., Tonanzi, D., Pozio, E., Rozycki, M., Cencek, T., Thompson, P.C., Rosenthal, B.M., La Rosa, G. 2021. Genetic structure uniformity substantiates transmission of Trichinella spiralis from one swine farm to another. Parasites & Vectors. 14:359.

Interpretive Summary: Previously, genetic investigations into outbreaks of the zoonotic parasite Trichinella spiralis have not had the resolution to discriminate between potential sources of infection due to the similarity of these parasites throughout Europe. We therefore used highly variable short tandem repeat molecular markers to examine T. spiralis outbreaks at two farms in Poland to determine whether they had a common source of infection. We found that the parasites from the pigs and rats captured on the farms were genetically nearly identical and differed significantly from parasites isolated from wild boars in the same geographic area. This study provides a new molecular tool that can be used to identify genetic commonalities among parasite outbreaks and distinguish them from unrelated potential sources of infection in the environment. The results will be of interest to veterinarians, public health and food safety authorities, epidemiologists, and livestock producers.

Technical Abstract: Trichinella spiralis ranks seventh in the risk ranking of foodborne parasites. It causes a majority of human cases of trichinellosis and is the most frequent cause of Trichinella outbreaks on pig farms and in wild boar, worldwide. Veterinary inspectors seek the source of outbreaks in hopes of limiting spread and stopping transmission. Such epidemiological investigations can hardly use molecular tools due to the complex genetic structure of these zoonotic pathogens. A prior report successfully applied hypervariable microsatellite markers to trace the origins of an oubreak of Trichinella britovi. Here, we sought to determine whether such an approach could be applied to Trichinella spiralis, which (in Europe, as a whole) harbors far less genetic variation. To do so, we characterized genetic variation in the parasites derived from two farm outbreaks, as well as from wild boars in the vicinity of these farms. Notably uniform parasite populations constituted each farm outbreak, and the parasites from the first and second outbreaks resembled each other to a notable degree, indicating epidemiological link between them. Wild boars harbored genetically more variable larval cohorts, distinguishing them from parasites isolated from domestic pigs. Microsatellite markers succeeded in distinguishing isolates of highly homogeneous T. spiralis, aiding efforts to track transmission. Each outbreak was composed of a homogenous group of parasites, suggesting a point source of contamination and, consequently, a common source for infection in each.