Trichinosis (also called trichinellosis, trichiniasis, or trichinelliasis) is an illness caused by parasites, called roundworms (Trichinella spp.), that can infect and damage many different tissues of the body. Even though the parasites are able to pass through the intestinal tract and other tissues, muscle tissues are where the majority of these roundworms stay. Trichinosis is usually characterized by two phases; the initial phase (intestinal) of abdominal discomfort, nausea, and diarrhea that begins one to two days after ingestion. The second phase of trichinosis (muscle) muscle aches, itching, fever, chills, and joint pains that begins about two to eight weeks after ingestion.
Trichinosis is caused by Trichinella species (also called intestinal worms, parasitic nematodes, and roundworms) that first enter the body when meat containing the Trichinella cysts (roundworm larvae) is eaten. For humans, undercooked or raw pork and pork products have been the meats most frequently accountable for transmitting the Trichinella parasites. Trichinosis is a food-borne infection that is not contagious from one human to another unless infected human muscle is eaten. However, almost any carnivore (meat eater) or omnivore (eats meat and plants for food) can both become infected and, if eaten, can transmit the disease to other carnivores and omnivores. For example, undercooked or raw bear meat can contain livable Trichinella cysts. Therefore, if humans, dogs, or pigs consume the infected bear meat, they can also become infected. In rare situations, larvae that unintentionally reaches cattle feed can infect cattle. There are six species of Trichinella that are known to infect humans: T. spiralis, T. britovi, T. pseudospiralis, T. nativa, T. nelsoni, and T. murrelli. There are two other known species of Trichinella that are not known to infect humans (T. papuae, and T. zimbabwensis), as well as several unnamed species that do infect humans.
Most cases of trichinosis are self limiting and require no medical treatment for the patient to fully recover. For more severe cases, there are medications that work effectively to kill the adult round worms, the larvae, and another medication to treat inflamed muscle tissues. Some patients with more severe symptoms may develop complications like heart muscle inflammation, pulmonary problems, lung hemorrhaging, and various central nervous system (CNS) problems. The prognosis for nearly all patients is very good, with the exception of patients with central nervous system complications, as CNS problems can remain at some degree for many years.
The best way to prevent trichinosis is to fully cook meat, especially pork, prior to eating. The heat will kill any live Trichinella cysts and prevent the spread of illness. It is also wise to disinfect any surfaces that came in contact with the raw meat.
