Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2005
Publication Date: 9/5/2005
Citation: Gamble, H.R., Pozio, E., Lichtenfels, J.R., Zarlenga, D.S., Hill, D.E. 2005. Trichinella pseudospiralis from a wild pig in Texas. Veterinary Parasitology. 132:147-150. Interpretive Summary: Recent reports of outbreaks suggesting that the avian species of Trichinella, T. pseudospiralis, is a human pathogen, has prompted research on population differences and host specificities among genotypes that do not form a capsule within the muscles of infected animals. Herein, we have identified a non-encapsulated species of Trichinella from a wild pig in southwest United States. This species is not normally found in the US and has yet to be identified in association with the pig population of North America. The identification and genetic characterization of zoogeographical strains of T. pseudospiralis is of great significance because of the need to evaluate the role of wild hosts as harbingers of other than the common pig strain of Trichinella and therefore as alternative sources of human infection. These findings will assist researchers in determining whether certain populations of this species are more infectious to humans than others and offer further incite into the re-emergence of Trichinella in wild hosts in the US.
Technical Abstract: In December 2001, the routine inspection of a pure Russian boar (Sus scrofa) caught in Newcastle, Texas and intended for human consumption revealed the presence of Trichinella ssp. larvae upon microscopic examination. The absence of a cyst along with other biological and morphological analyses were consistent with the parasite belonging to the non-encapsulated clade. Genetic analysis by multiplex PCR indicated the species to be Trichinella pseudospiralis. Sequence data from the cytochrome oxidase I subunit, the large subunit mitochondrial ribosomal DNA, and expansion segment V genes were consistent with this being a Nearctic isolate. This is the second report of T. pseudospiralis in the United States but the first report within a southwest border state. In addition, this is the first time this species of parasite has been identified within a food animal in the U.S.