Trichinella spiralis is a nematode that parasitises rats and pigs, and is only transmitted to humans if they eat partially cooked infected pork, usually as sausage or ham.

Bear meat is another source. Symptoms result from invasion of intestinal submucosa by ingested larvae, which develop into adult worms, and the secondary invasion of striated muscle by fresh larvae produced by these adult worms. Outbreaks have occurred in the UK, as well as in other countries where pork is eaten.


The clinical features of trichinosis are determined by the larval numbers. A light infection with a few worms may be asymptomatic; a heavy infection causes nausea and diarrhoea 24–48 hours after the infected meal. A few days later, the symptoms associated with larval invasion predominate: there is fever and oedema of the face, eyelids and conjunctivae; invasion of the diaphragm may cause pain, cough and dyspnoea; and involvement of the muscles of the limbs, chest and mouth causes stiffness, pain and tenderness in affected muscles. Larval

migration may cause acute myocarditis and encephalitis. An eosinophilia is usually found after the second week. An intense infection may prove fatal but those who survive recover completely.


Commonly, a group of people who have eaten infected pork from a common source develop symptoms at about the same time. Biopsy from the deltoid or gastrocnemius muscle after the third week of symptoms may reveal encysted larvae. Serological tests are also helpful.


The medicines that can be thought of use are: -

  • Iodum
  • Acetic acid
  • Merc bin iod
  • Phosphorus