ACTA FAC. MED. NAISS. 2006;  23 (4): 215-222

  Review article

Natasa Miladinovic-Tasic^1,2, Suzana Tasic^1,2, Milena Misic¹

¹Department of Microbiology and Parasitology, Faculty of Medicine, Nis
²Department of Parasitology and Micology, Public Health Institute Nis

    SUMMARY

Trichinosis is caused by worms of the phylum Nematodes, the classis Aphasmadia, the genus Trichinella, and the most commonly species Trichinella spiralis. Humans are infected incidentally when they eat inadequately cooked meat containing larvae of Trichinella species.

Although 11 species (genotypes) of Trichinella currently exist, only 8 species are described taxonomically on the basis of genetic, biochemical, and biological data.

Rats and pigs are the animals most commonly associated with trichinosis, however, depending on the region, walruses, seals, bears, polar bears, cats, raccoons, wolves, foxes and approximately 150 various species of mammals may also be infected. The global prevalence of trichinosa is difficult to evaluate but as many as 11 million people may be infected.

With improved therapy, the mortality rate has decreased to approximately 0.3%. Death occurs primarily because of myocarditis or central nervous system involvement, usually during the third to fifth weeks after ingestion.

Laboratory and immunodiagnostic findings are important for the diagnosis of trichinosis. Other methods are electromyelography, muscle biopsy and polimerasa chain reaction (PCR). Diagnostic methods in patients with central nervous system involvement are computerized tomography (CT scanning) of the brain with or without contrast, magnetic resonance (MRI) and the lumbar puncture – citological examination. Diagnostic method in patients with cardiac involvement is electrocardiography (ECG).

In moderate-to-heavy infections, the goal is to stop the larval invasion into the host muscle. Within 1 week of ingestion of contaminated meat, administer antihelmintic drugs witch are effective against larvae and adult worms limited to the intestinal lumen. Steroids may decrease inflammation but may also hinder the eradication of the adult worm, resulting in a prolonged production of larvae.

Adequate cooking and freezing methods of meat prevent infection by any species of Trichinella in humans. The most effective way is cooking meat at 71°C for 1 minute. Also, Trichinella species can typically be killed by adequate cooling to - 60°C for 2 minutes or - 55°C for 6 minutes.

Key words: trichinosis, Trichinella spiralis, prevalence, diagnostic methods, prevention