Trichinellosis is a parasitic disease that can be transmitted to people. It is caused by a type of worm known as a nematode. The name of the disease comes from the scientific name for the worm, Trichinella spiralis. Humans become infected when they eat undercooked infected meat, usually pork or bear, although other animals can also be infected with this nematode. Natural infections occur in wild meat-eating animals; most mammals are susceptible.
Infection occurs when an animal eats meat with cysts containing the Trichinella larvae. The life cycle continues inside the animal, with larvae eventually migrating throughout the body, where they form cysts in muscles. Larvae may remain viable in the cysts for years, and their development continues only if they are ingested by another suitable host. If larvae pass through the intestine and are eliminated in the feces before maturation, they may be infective to other animals.
Generally, there are no signs of the disease, and most infections in domestic and wild animals go undiagnosed. In humans, heavy infections may produce serious illness and occasionally death. Although diagnosis before death in animals other than humans is rare, trichinellosis may be suspected if there is a history of eating either rodents or raw, infected meat.
Treatment is generally impractical in animals. Making sure that ingestion of viable Trichinella cysts in muscle does not occur is the best way to prevent disease in both animals and humans. Raw or improperly cooked meat should not be fed to cats. Cooking meat to an internal temperature of at least 145°F (63°C) will kill the cysts. Freezing cannot be relied on to kill cysts in meat other than pork.
Last full review/revision July 2011 by Otto M. Radostits, CM, DVM, MSc, DACVIM (Deceased); Eugene D. Janzen, DVM, MVS; Jodie Low Choy, BVMS; Dennis W. Macy, MS, DACVIM; Dudley L. McCaw, DVM, DACVIM (Small Animal, Oncology); Barton W. Rohrbach, VMD, MPH, DACVPM; J. Glenn Songer, PhD; Richard A. Squires, BVSc (Hons), PhD, DVR, DACVIM, DECVIM-CA, MRCVS; Bert E. Stromberg, PhD; Joseph Taboada, DVM, DACVIM; Charles O. Thoen, DVM, PhD; John F. Timoney, MVB, PhD, Dsc, MRCVS; Ian Tizard, BVMS, PhD, DACVM; Max J. Appel, DMV, PhD; David A. Ashford, DVM, MPH, DS; Stephen C. Barr, BVSc, MVS, PhD, DACVIM; J. P. Dubey, MVSc, PhD; Paul Ettestad, DVM, MS; Craig E. Greene, DVM, MS; Delores E. Hill, PhD; Johnny D. Hoskins, DVM, PhD