Human neurotrichinellosis, United States

Authors: MADARIAGA, M - UNIV OF NEBRASKA; CACHAY, E - UNIV OF NEBRASKA; Zarlenga, Dante

Submitted to: American Society of Tropical Medicine and Hygiene
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2007
Publication Date: 8/10/2007
Citation: Madariaga, M., Cachay, E.R., Zarlenga, D.S. 2007. Human neurotrichinellosis, United States. Journal of Clinical Microbiology. 77(2):347-9.

Interpretive Summary: Although the United States does not require inspection of pork products for Trichinella, the number of cases of trichinellosis derived from domestic meat sources has been progressively declining. Globally, however, outbreaks of the disease still occur frequently in regions where the guidelines for meat inspection are lacking or poorly regulated. In Alaska, where the inhabitants consume a greater proportion of wild animal meat (particularly bear meat) in their diets, and where freeze-resistant species of Trichinella are normally found, a higher incidence of trichinellosis has been reported. However, cases of neurotrichinellosis have not been documented in recent years due either to low incidence or more likely, to misdiagnosis. To this end, we report the diagnosis of neurotrichinellosis in a patient that frequents consumption of wild game meat. The diagnosis of neurotrichinellosis is clinical but occasionally multifocal where small lesions in the cerebral cortex and white matter can be identified using computed tomography or magnetic resonance imaging analyses. This diagnosis raises the awareness of clinicians to the fact that Trichinellosis is a cosmopolitan parasite genus that should be considered in patients with eosinophilia, neurological abnormalities, elevation in specific muscle enzymes, diets that frequent wild game consumption, and who are unresponsive to conventional treatments such as antibiotics.

Technical Abstract: Parasites of the genus Trichinella are globally-distributed, tissue-dwelling nematodes that predominantly infect mammals, though certain species are known to infect birds and reptiles as well. Human trichinellosis occurs by the ingestion of raw or improperly cooked meat harboring the infective muscle larvae. In severe cases, the disease may cause neurological manifestations including encephalitis and even death. Herein, we report a case of neurotrichinellosis in the United States, a condition seldom considered in clinical practice, but should be taken into account when evaluating patients with eosinophilia, muscle enzyme elevation and neurological abnormalities in the setting of wild game consumption.