Trichinellosis

旋毛虫病

Evidence-backed information EN 5/7 applicable sections · ZH 5/7 applicable sections Updated Oct 23, 2026

Trichinellosis is a parasitic zoonosis caused by nematodes of the genus Trichinella, with T. spiralis being the most common species implicated in human disease ^[1]. It has been recognized among the most important food-borne parasites globally in terms of public health and socioeconomic impact ^[2], and is considered a re-emerging zoonosis owing to relaxed veterinary controls, increased meat trade, and sylvatic transmission ^[1]. In country-level reviews, such as in Iran, human trichinellosis appears of limited direct significance compared with other food-borne zoonoses, though wildlife reservoirs are documented ^[3].

Read the full clinical and epidemiological profile 6

Definition

Trichinellosis is a parasitic disease caused by roundworms of the Trichinella genus, acquired through ingestion of infected meat ^[1]. It is classified as a parasitic zoonosis transmitted from animals to humans via nematode larvae in muscle tissue ^[1]^[4].

Clinical features

Early intestinal invasion can produce diarrhea, abdominal pain, vomiting, nausea, heartburn, and dyspepsia, typically two to seven days after infection, while low worm burdens may be asymptomatic ^[1]. Around one week after infection, larval migration to voluntary muscles causes facial swelling, eye inflammation, fever, muscle pain, and rash ^[1]. Severe disease may involve central nervous system manifestations such as encephalopathy and neuromuscular disturbances, with eosinophilia presenting early and rising rapidly ^[1]^[4].

Epidemiology

Trichinellosis is ranked among the most consequential food-borne parasitic zoonoses for public health and trade ^[2]. It is viewed as re-emerging because of diminished control in domestic pig production, political transitions, climate change, and greater sylvatic transmission, with sociopolitical upheaval in Romania linked to increased incidence ^[1]. In Iran, most identified studies concerned wildlife, and only one detected anti-Trichinella IgG in 2.2% of 364 at-risk humans, suggesting limited direct human disease burden there ^[3].

Transmission

The disease spreads principally when undercooked meat containing Trichinella cysts is consumed ^[1]. Wild game such as bear is a frequent source in North America, though pork, boar, and dog meat can also transmit infection ^[1]. After ingestion, larvae are released in the stomach, invade the small intestinal wall, mature, and subsequently migrate to muscle where they encyst ^[1].

Prevention

Thorough cooking of meat is the primary preventive measure, and a food thermometer can confirm that internal temperatures are sufficient to eliminate larvae ^[1]. Because wild meat carries higher parasite likelihood, particular care is warranted with game species ^[1]. Relaxed legislation and veterinary oversight in domestic pig systems have contributed to re-emergence, indicating that sustained food-safety controls remain important ^[1].

References

1 Wikipedia contributors. Trichinosis - Wikipedia [Internet]. Wikipedia. cited 23 Oct 2026. Available from: https://en.wikipedia.org/wiki/Trichinosis
2 Ng-Nguyen D et al. A systematic review of taeniasis, cysticercosis and trichinellosis in Vietnam. Parasit Vectors. 2017 Mar 21. PMID: 28320455. doi: 10.1186/s13071-017-2085-9. PubMed: https://pubmed.ncbi.nlm.nih.gov/28320455/
3 Moazeni M et al. Epidemiology of taeniosis, cysticercosis and trichinellosis in Iran: A systematic review. Zoonoses Public Health. 2019 Feb. PMID: 30575317. doi: 10.1111/zph.12547. PubMed: https://pubmed.ncbi.nlm.nih.gov/30575317/
4 Bruschi F et al. Neurotrichinellosis. Handb Clin Neurol. 2013. PMID: 23829915. doi: 10.1016/B978-0-444-53490-3.00019-4. PubMed: https://pubmed.ncbi.nlm.nih.gov/23829915/