Trichinosis is caused by eating raw or undercooked meat that contains larvae of a parasitic roundworm called *Trichinella*. When a person consumes meat infected with these larvae, the parasites enter the digestive system, where they mature into adult worms. These adult worms then produce new larvae that travel through the bloodstream and embed themselves in muscle tissues, causing the symptoms of trichinosis.
The main source of infection is typically pork, especially if it is not cooked thoroughly. However, trichinosis can also come from eating wild game such as bear, boar, or walrus meat that is infected. The larvae survive in the muscle tissue of these animals, and if the meat is eaten raw or undercooked, the larvae become active in the human digestive tract.
Once inside the intestines, the larvae develop into adult worms within a few days. The adults mate, and the females release newborn larvae that penetrate the intestinal wall and enter the bloodstream. These larvae then travel to skeletal muscles, where they form cysts. This muscle invasion causes muscle pain, tenderness, and swelling, which are hallmark symptoms of the disease.
The life cycle of *Trichinella* depends heavily on the consumption of infected meat. The parasite’s eggs are not passed in feces but remain inside the host’s muscles until eaten by another animal. This cycle continues primarily in carnivorous or omnivorous animals that consume raw or undercooked meat from infected animals.
Improper food handling and cooking practices are the main reasons trichinosis occurs. Meat that is not heated to a sufficient temperature (usually at least 71°C or 160°F) can harbor live larvae. Smoking, drying, or curing meat does not reliably kill the parasite. Therefore, eating meat prepared by these methods without proper cooking can also lead to infection.
In addition to pork and wild game, trichinosis can occasionally be contracted from other animals that carry the parasite, but these cases are less common. The risk is higher in areas where pigs are raised in conditions that allow them to scavenge or eat raw meat scraps, increasing the chance of infection.
Once infected, early symptoms may appear within a few days and include nausea, diarrhea, vomiting, fatigue, and abdominal pain. As the larvae migrate to muscles, symptoms such as muscle pain, swelling of the face (especially around the eyes), fever, and headaches develop. In severe cases, the infection can affect the heart and nervous system, leading to more serious complications.
Preventing trichinosis involves thoroughly cooking meat to safe temperatures, freezing pork at sufficiently low temperatures for an extended period to kill larvae, and avoiding consumption of raw or undercooked wild game. Proper hygiene and food safety practices in meat processing and preparation are essential to reduce the risk of infection.
In summary, trichinosis is caused by ingesting meat infected with *Trichinella* larvae, primarily from undercooked pork or wild game. The parasite’s life cycle involves maturation in the intestines and migration to muscles, causing a range of symptoms related to muscle inflammation and systemic infection. Cooking meat properly is the most effective way to prevent this parasitic disease.
