Trichinosis

Trichinosis, also known as trichinellosis, represents a helminthic infection caused by nematodes of the genus Trichinella, acquired through ingestion of undercooked infected meat, and is the commonest parasitic infection of muscle.

The most important reservoir is the domestic pig, although a variety of other animals, including horses and wild carnivores, can be the source of infection.

It is a bi-phasic disease characterised by a gastrointestinal (enteric) phase followed by a systemic (parenteral) phase.

The intestinal phase occurs within a few days of ingesting the parasite and manifests with gastrointestinal symptoms, such as abdominal pain, nausea, vomiting, and diarrhoea.

After the first week, larvae released from the cysts become adult worms and mate. The female parasites then release newborn larvae that disseminate, leading to the systemic phase. This phase manifests with fever, eosinophilic myositis, myalgia, and peri-orbital oedema. There may also be a skin rash and splinter haemorrhages

A blood count may show an eosinophilia and a muscle biopsy demonstrates parasites in various stages of development.

Disease severity can range from asymptomatic infection to fatal disease but a full recovery within 6 weeks to 6 months is the most common course.

Treatment is with albendazole or mebendazole and, occasionally, prednisolone.

Reference

1. Centers for Disease Control and Prevention. Trichinellosis (trichinosis): clinical overview of trichinellosis. May 2024 [internet publication].