Trichinella Nativa Outbreak With Rare Thrombotic Complications Associated With Meat From a Black Bear Hunted in Northern Ontario

Background. Although trichinellosis is known to cause thrombotic disease, serious thrombotic events are rare and have not been previously associated with Trichinella nativa infection. Methods. Patient interviews and medical chart reviews were conducted on 10 men who became ill following consumption of a common source of black bear meat. Trichinella serology on patient sera as well as polymerase chain reaction (PCR) and larval identification of the meat samples was conducted. Results. All 10 exposed individuals developed an acute illness clinically compatible with trichinellosis, characterized by fever, abdominal pain, and diarrhea, along with eosinophilia ranging from 0.9 x 10(9)/L to 6.1 x 10(9)/L. Within 2 weeks of the diarrheal illness, systemic symptoms developed in all exposed individuals characterized by fever, myalgia, periorbital edema, and fatigue. ST-elevation myocardial infarction and sinus venous tract thrombosis occurred as a complication of trichinellosis in 2 patients. Acute serology was nonreactive in all patients, though convalescent serology was reactive in 6 of 8 (75%) patients for whom sera was available. Multiplex PCR identified T. nativa from the bear meat, and was corroborated by microscopic larval identification. Conclusions. We report a 100% attack rate of T. nativa from bear meat among those who were exposed, and demonstrate that this species can cause serious thrombotic complications of trichinellosis in humans. Education of hunters and the public regarding the importance of proper preparation of wild game prior to ingestion is warranted.