"Trichinellosis" - what is it, definition of the term
The disease caused by larvae of Trichinella species is a zoonotic parasitic infection acquired primarily through ingestion of raw or undercooked muscle tissue containing encysted larvae, frequently derived from rodents such as rats and mice or from pork. After consumption, larvae are released in the intestine, mature into adult worms, reproduce, and the newly formed larvae travel via the bloodstream to skeletal muscle where they encyst, leading to gastrointestinal disturbances followed by fever, muscle pain, and eosinophilia. Diagnosis relies on serological tests and, when necessary, muscle biopsy; treatment consists of anthelmintic agents such as albendazole or mebendazole together with supportive measures.
Detailed information
The parasitic disease caused by Trichinella species is transmitted to rodents primarily through ingestion of infected meat or carrion. Adult worms colonize the intestinal mucosa of rats and mice, where they reproduce and release newborn larvae. These larvae penetrate the intestinal wall, enter the bloodstream, and become encysted in skeletal muscle fibers, where they remain viable for months.
In rodent hosts, the acute phase appears within 3–5 days after infection and is characterized by diarrhea, abdominal cramping, and reduced food intake. The subsequent muscular phase manifests as weakness, reduced locomotor activity, and visible nodules in the diaphragm and forelimb muscles. Mortality rates increase in young or immunocompromised individuals, especially when parasite burden exceeds 500 larvae per gram of muscle.
Diagnosis relies on several methods:
- Direct microscopic examination of muscle biopsies for encapsulated larvae.
- Serological assays detecting specific IgG antibodies, useful for early detection before muscle encystation.
- Polymerase chain reaction (PCR) targeting Trichinella DNA in tissue samples, providing species-level identification.
Therapeutic management includes administration of anthelmintics such as albendazole (15 mg/kg twice daily for 7 days) or mebendazole (25 mg/kg twice daily for 5 days). Supportive care, including fluid replacement and analgesics, mitigates gastrointestinal symptoms and muscle pain.
Control measures focus on interrupting the life cycle in rodent populations:
- Eliminate access to raw meat, offal, and carrion.
- Implement regular rodent control programs using bait stations and traps.
- Conduct environmental sanitation to reduce contamination of feed and water sources.
- Monitor wildlife reservoirs, as spillover from wild carnivores can reintroduce infection into laboratory or domestic settings.
Preventive strategies for laboratory colonies involve quarantine of new animals, routine serological screening, and strict adherence to biosecurity protocols to avoid accidental introduction of the parasite.