What is trichinellosis?

Trichinellosis is a zoonotic parasitic infection caused by Trichinella roundworms — acquired by eating raw or undercooked meat (primarily pork, but also wild boar, bear, horse and other animals) containing encysted Trichinella larvae. The larvae are released in the stomach, mature to adults in the small intestine, produce more larvae, which migrate through the blood into muscles — where they encyst. The result is a two-phase illness: intestinal (GI symptoms) followed by muscular invasion (fever, myalgia, periorbital oedema, eosinophilia).

What animals carry Trichinella?

Trichinella infects a wide range of omnivorous and carnivorous animals: pigs (the primary source of human infection historically); wild boar/feral pigs; bears; walruses (Arctic Trichinella nativa); horses (several major outbreaks in France and Italy from horse meat); wild animals (foxes, badgers, wolves, raccoons, hyenas). The infection cycle in domestic pigs was historically maintained by feeding garbage containing pork scraps — now illegal in most countries. Wild animals maintain sylvatic cycles independent of domestic pigs.

What is the clinical presentation?

Two-phase illness: Intestinal phase (days 1-7 after ingestion): nausea, vomiting, abdominal cramps, diarrhoea — mild, similar to gastroenteritis. Muscular invasion phase (weeks 2-8): high fever; severe myalgia (especially masseters, diaphragm, biceps, eye muscles — reflecting larval penetration); bilateral periorbital oedema (characteristic — from periorbital muscle invasion); conjunctival haemorrhages; urticarial rash; marked eosinophilia (elevated on full blood count); elevated CK (muscle damage). Severe disease: myocarditis (palpitations, arrhythmias, heart failure — 10-20% of deaths); neurological (meningoencephalitis, paraparesis); pulmonary involvement.

How is trichinellosis diagnosed?

Clinical clues: myalgia + periorbital oedema + eosinophilia + relevant food exposure (pork, wild game) = suspect trichinellosis. Laboratory: eosinophilia (characteristic — often very marked >5x10⁹/L); elevated creatine kinase (CK) from myositis; elevated LDH; elevated IgE. Serology: anti-Trichinella IgG (ELISA, IFA) — positive by 2-3 weeks after infection. Muscle biopsy (deltoid/gastrocnemius): demonstration of encysted larvae — definitive diagnosis. Food testing: examination of the suspected meat source by digestion and microscopy.

How is trichinellosis prevented?

Cooking: thorough cooking of pork and game meat to an internal temperature of ≥71°C throughout kills Trichinella larvae. Freezing: -20°C for ≥18-24 days kills T. spiralis in pork (but NOT T. nativa in Arctic wildlife). Curing/smoking/microwave cooking do NOT reliably kill Trichinella. Traditional home-cured pork products (sausages, salami, cold cuts from non-controlled housing farms) carry risk. Official meat inspection (post-slaughter Trichinella testing of all pig carcasses) is standard practice in the EU and many other countries.

Is trichinellosis present in Georgia?

Yes — Trichinella has been documented in domestic pigs and wild boar in the Caucasus region including Georgia. Human trichinellosis outbreaks have been reported in Georgia, linked to consumption of traditional home-prepared pork products (sausages, smoked/raw pork). Wild boar hunting in Georgian forests creates additional exposure risk. PHIG monitors food-borne parasitic diseases including trichinellosis. Key prevention messages: cook pork thoroughly to ≥71°C; avoid home-cured or raw pork products from non-inspected sources.

How does GMJ News cover trichinellosis?

GMJ News covers WHO trichinellosis data, Georgian and Caucasus endemic risk, clinical presentation (periorbital oedema, eosinophilia), meat safety prevention (71°C), albendazole treatment, official meat inspection and wild boar risk. Trichinellosis is a food safety and public health concern directly relevant to PHIG's food safety programme and the Georgian Medical Journal's clinical coverage.

Home › Topics › Trichinellosis

Trichinellosis

GMJ News knowledge hub · last reviewed September 2026 · Georgian Medical Journal

Summary Statistics Glossary GMJ news FAQ Documents Organizations Research

Trichinellosis — caused by the parasitic nematode Trichinella spiralis and related species from eating raw or undercooked meat (primarily pork and wild game: boar, bear, horse, walrus) — is a WHO Neglected Tropical Disease causing approximately 10,000 cases per year globally with a distinctive two-phase illness: an initial intestinal phase (nausea, diarrhoea) followed by a muscular invasion phase with fever, severe myalgia, periorbital oedema and conjunctival haemorrhage from larvae migrating through muscle tissue (WHO). The Caucasus region — including Georgia — has documented trichinellosis in pigs and wild boar, with human cases linked to consumption of undercooked pork products. Prevention: cook pork and game to an internal temperature of ≥71°C.

Key messages

~10,000 cases/year from undercooked pork and wild game

Trichinellosis causes approximately 10,000 cases/year globally — from eating raw or undercooked pork, boar, bear, horse or other animals infected with Trichinella larvae. Cook meat to ≥71°C internal temperature to prevent infection (WHO).

Two-phase illness — GI then muscular

Trichinellosis has a characteristic two-phase illness: intestinal phase (days 1-7: nausea, vomiting, diarrhoea); muscular invasion phase (weeks 2-8: fever, myalgia, periorbital oedema, conjunctival haemorrhage, eosinophilia) as larvae migrate into muscle tissue.

Periorbital oedema — the clinical clue

Bilateral periorbital oedema (puffiness around the eyes) — from larvae migrating through periorbital tissues — is a characteristic and diagnostically helpful clinical sign of trichinellosis during the muscular invasion phase.

Georgia — wild boar risk

The Caucasus region including Georgia has documented Trichinella in domestic pigs and wild boar. Human cases are linked to consumption of undercooked pork products — particularly traditional homemade pork sausages and salami — and wild boar meat hunted in endemic areas.

Eosinophilia — the laboratory clue

Marked peripheral blood eosinophilia (elevated eosinophils) combined with elevated creatine kinase (muscle damage), serology and clinical features is the diagnostic hallmark. Muscle biopsy demonstrating encysted larvae confirms the diagnosis.

Albendazole kills intestinal worms

Albendazole (400mg twice daily × 8-14 days) is effective against intestinal-stage Trichinella (if given early) and may help reduce larval migration. Mebendazole is an alternative. Prednisone added for severe manifestations (myocarditis, neurological involvement).

Key statistics

~10K

trichinellosis cases/year globally (WHO estimate)

WHO

≥71°C

internal meat temperature that kills Trichinella larvae (prevention)

WHO

~2%

case fatality rate in severe outbreaks (myocarditis/neuro)

WHO

Massively underreported

true global burden far exceeds reported cases

WHO

Georgia

documented Trichinella in pigs and wild boar (Caucasus endemic)

ECDC/WHO

T. spiralis

most common species in pigs; T. nativa in Arctic (cold-resistant)

WHO

Trichinellosis cases by region — WHO/ICTV reported data

Source: WHO. E. Europe, China, South America and N. America (wildlife exposure) are highest-risk regions.

Glossary of key terms

Trichinella spiralis
WHOThe most common Trichinella species — primarily infecting domestic pigs and rats. The larva encysts within a modified muscle cell (the "nurse cell") — a specialised host cell that keeps the larva viable for years. Nurse cells are found in striated skeletal muscle — predominantly the diaphragm, masseter (jaw), tongue and intercostal muscles.

Nurse cell
WHO/PathologyA modified host myocyte (muscle cell) encapsulating a Trichinella larva — a unique host-parasite interaction where the parasite transforms its host cell into a nutritive capsule. The nurse cell secretes collagen, becomes angiogenic (sprouting new blood vessels) and maintains the larva in a dormant state for years (potentially decades in the host).

Trichinella nativa (Arctic species)
WHOA distinct Trichinella species found in Arctic and subarctic wildlife (bears, walruses, arctic foxes) — unique in being highly resistant to freezing (T. spiralis in pork is killed by freezing at -20°C for 3 weeks). T. nativa infects humans through eating raw or undercooked bear, walrus or seal meat. Northern Canada, Alaska and Greenland inuit communities are at risk.

Periorbital oedema
WHO/ClinicalBilateral facial/periorbital swelling during the muscular invasion phase — from Trichinella larvae penetrating periorbital muscles and local inflammatory oedema. A characteristic and highly suggestive sign of trichinellosis when present with eosinophilia and myalgia. Sometimes confused with allergic reaction or other oedema.

Muscle biopsy
WHO/DiagnosisDeltoid or gastrocnemius muscle biopsy demonstrating encysted Trichinella larvae — the definitive diagnostic test. Larvae appear as coiled worms (C-shaped) within the nurse cell capsule on H&E staining or digestion. Most useful after 3-4 weeks (when encystation is established).

Trichinella-free certification
EFSA/WHOIn the EU, pigs in "controlled housing" can be certified Trichinella-free and exempt from mandatory post-slaughter testing (official testing of all pig carcasses). This is a regulatory recognition of the effectiveness of strict hygiene management in intensive farming.

Latest GMJ coverage

Articles will appear here as the archive grows.

Trichinellosis

Key messages

Key statistics

Glossary of key terms

Latest GMJ coverage

Frequently asked questions 12 Q&A — structured for Google featured snippets and AI discovery

Knowledge hub: guidelines, conventions and reports

Organizations working in migration and health

Related health topics

Company