Trichinella spiralis

Physiology and Structure
  • Trichinella spiralis is the etiologic agent of trichinosis.
  • The adult form usually lives in the duodenal and jejunal mucosa of flesh-eating mammals worldwide.
  •  The infectious larvae is found in the muscles of carnivorous and omnivorous animals.
  • Infection begins when meat containing the larvae is digested.
  • The development of it into an adult takes about 2 days.
  • A fertilized female can produce up to 1500 larvae in 1 to 3 months.
  • The encysted larvae remain viable for many years and are infectious if ingested by a new animal host.





Trichinella spiralis




Lifecycle of Trichinella spiralis



 Clinical Symptoms
  • Victims have minimal or no symptoms.

  • Victims with no more then 10 larvae per gram of tissue are asymptomatic whereas people infected with around 100 larvae have the significant disease. Victims who are infected with at least 1000 to 3000 larvae have a serious case.

  • Patients with mild infections may experience influenza-like syndrome with slight fever and mild diarrhea.
  • Those who suffer from extensive larval migration would experience persistent fever, gastrointestinal distress, muscle pain, etc.
  • In heavy infections, severe neurologic symptoms (e.g psychosis, meningoencephalitis and cerebrovascular accident) may occur.
  • For lethal trichinosis, the patient dies 4 to 6 weeks after infection due to respiratory arrest and muscle destruction.
Treatment, Prevention and Control
  • Treatment is primarily symptomatic as there are no good antiparasitic agents for tissue larvae.
  • Adult worms are usually treated with mebendazole, with would halt the production of new larvae.
  • Microwave cooking, drying or smoking the meat do not kill the larvae.
  • Feeding of garbage to pigs is not encouraged in order to control transmission.
  • Quick freezing of pork at -40 °C destroys the organisms.