Project Number: 1245-42000-016-00
Project Type: Appropriated

Start Date: Jan 19, 2011
End Date: Jan 18, 2016

Objective:
1) Determine what genetic and genomic features distinguish Trichinella spiralis from Trichinella murrelli. 2) Utilize genomics to determine if microsatellite loci can be used to trace zoonotic outbreaks of Trichinella spiralis. 3) Determine the genetic features that account for the epidemic spread of certain strains of Toxoplasma gondii.

Approach:
Investigations will be conducted to clarify how infections in wildlife influence the safety of pastured pork. Accordingly, first identify heritable differences between two related species of Trichinella, only one of which (T. spiralis) severely compromises pork safety by evading swine immunity. The other, Trichinella murrelli, predominates in North American wildlife but fails to thrive in swine. By comparing the genomes of these two parasites, the intent is to establish a basis for exploring what makes pigs so especially vulnerable to T. spiralis. Secondly, develop the means to trace chains of transmission of Trichinella spp. Using markers which have already established the long-term dispersal history of T. spiralis (to the Americas in the pigs and rats brought by European colonists), researchers will attempt to discriminate instances of persistent on-farm transmission from sporadic introductions of T. spiralis to swine herds. Finally, the genetics of T. gondii reproduction will be characterized. Both sexual and asexual reproduction can occur in T. gondii, and available data provide conflicting evidence as to the relative importance of each reproductive mode. These incongruous data leave in doubt whether this parasite evolves as an assemblage of distinct lineages, or whether it more closely resembles a coherent, interbreeding species. Additional data are needed to better resolve how T. gondii propagates and evolves. These results will help determine whether particular strains pose elevated food safety risk will help anticipate this parasite's evolutionary response to preventative interventions.