Trichinosis

Trichinosis, trichinellosis or trichiniasis is a parasitic disease caused by roundworms of the genus Trichinella. Several subspecies cause human disease, but T. spiralis is the most known. Infection may occur without symptoms, while intestinal invasion can cause diarrhea, abdominal pain or vomiting. Larval migration into muscle tissue (one week after being infected) can cause edema of the face or around the eyes, conjunctivitis, fever, muscle pains, splinter hemorrhages, rashes, and peripheral eosinophilia. Life-threatening cases can result in myocarditis, central nervous system involvement, and pneumonitis. Larval encystment in the muscles causes pain and weakness, followed by slow progression of symptoms.Trichinosis is mainly caused by eating undercooked meat containing encysted larval Trichinella. In the stomach the larvae are exposed to stomach acid and pepsin which releases them from their cysts. They then start invading wall of the small intestine, where they develop into adult worms. Females are 2.2 mm in length; males 1.2 mm. The life span in the small intestine is about four weeks. After 1 week, the females release more larvae that migrate to voluntarily controlled muscles where they encyst. Diagnosis is usually made based on symptoms, and is confirmed by serology or by finding encysted or non-encysted larvae in biopsy or autopsy samples.The best way to prevent trichinellosis is to cook meat to safe temperatures. Using food thermometers can make sure the temperature inside the meat is high enough to kill the parasites. The meat should not be tasted until it is completely cooked. Once infection has been verified treatment with antiparasitic drugs such as albendazole or mebendazole should be started at once. A fast response may help kill adult worms and thereby stop further release of larvae. Once the larvae have established in muscle cells, usually by 3 to 4 weeks after infection, treatment may not completely get rid of the infection or symptoms. Both drugs are considered safe but have been associated with side effects such as bone marrow suppression. Patients on longer courses should be monitored though regular blood counts to detect adverse effects quickly and then discontinue treatment. Both medicines should be treated with caution during pregnancy or children under the age of 2 years, but the WHO weighs the benefits of treatment higher than the risks. In addition to antiparasitic medication, treatment with steroids is sometimes required in severe cases.Trichinosis can be acquired by eating both domestic and wild animals, but is not soil-transmitted.