Trichinellosis is a zoonosis caused by a parasite, Trichinella, which is transmitted from animals to humans through the ingestion of contaminated meat. Rare disease, about 20 cases have been recorded over 20 years in France. Focus with Isabelle Vallée, Head of the Parasitic Molecular Biology and Immunology Unit (BIPAR).
Definition: what is trichinae free?
Trichinellosis is one zoonosisi.e., a disease in which the pathogen is transmitted from animals to humans by ingestion of meat contaminated with a worm, Trichinella, primarily pork or wild boar meat and more exceptionally horsemeat. Quite rare disease in France, the parasite circulates more in the countries of Eastern Europe as Balkans, Poland or Romania.
How many cases of trichinae in France?
According to the National Agency for Food, Environmental and Occupational Health and Safety (Anses), the parasite in France is concentrated in areas of high biodiversity, mainly located in mountainous areas in the south of France. “Over the last twenty years there has been one twenty cases natives due to consumption of contaminated meat, mainly wild boar“, explains Isabelle Vallée, Head of the Department of Molecular Biology and Parasitic Immunology (BIPAR), at ANSES Animal Health Laboratory.About two animals a year are tested positive to the parasite. “
What are the symptoms of trichinosis?
Animals usually carry the parasite in a way asymptomatic in their muscles. In most cases symptoms in men develop according to the development of the parasitic cycle and the area of the body where it is found:
► In the first week, the parasite is released to intestinal mucosa and this creates abdominal pain, diarrhea And sometimes vomiting.
► Then the parasite migrates into muscles talks lymphatic and blood vessels and this generates one fever high, visual disturbancesa edema of the facel which can also be generalized and myalgi (muscle pain).
The parasite affects many wild animals but also humans because it is transmitted by consumption of contaminated meat raw or undercooked. The disease is due Trichinella spiralis parasitea species of nematodes, worms of 1.5 mm for the male and 2 to 3 mm for the female. Worms grow inside their host and the ingested larvae mature within 24 to 36 hours at the level of the lining of the small intestine. Once the parasite is installed, the adult worms mate and produce larvae, which migrate from the intestine to the muscles, where they cyst and can live for several years. Muscle larvae are microscopic (approx. 0.8 mm) and are therefore not visible to the naked eye in the flesh.
With regard to meat, you should know that European and international rules (EU Regulation 2015/1375, OIE, CODEX Alimentarius) impose slaughterhouse inspection pork and other sensitive species (wild boar, horse) to diagnose the parasite thanks to muscle samples. Isabelle Vallée would like to reassure: “All meat marketed from a susceptible species is systematically tested by veterinary services so there is nothing to worry about.“As for man, a clinical study allows the physician to get an idea of the origin of the pathology if the patient declares to have ingested venison. “In general, there are no isolated cases, but rather grouped cases – family, group of friends, wedding guests – all gathered around the same food source.“Secondly serological tests performed but the test enzyme immunoassay ELISA then confirmed by Western Blot test further confirm infection. ONE muscle biopsy can also be performed, but the results are not always reliable if the infection is low.
What is the treatment for trichinellosis?
“When the diagnosis is made, the parasite is already installed in the muscles and stays there for years.warns Isabelle Vallée, and there is none no treatment to remove it.“However, anthelmintika (worm control) benzimidazoles (known to be nematocides) combined with corticosteroids can be effective to reduce the parasite load residues in the intestine, reduce symptoms and improve the patient’s living conditions.
Adequate cooking of meat is thorough cooking at 71 ° C
Sanitary inspections are usually carried out systematically at the slaughterhouse on marketed farmed meat. But on the individual level, it is strong recommended that hunters get the meat checked of approved departmental veterinary laboratories (list available on the Ministry of Agriculture’s website). Hunters can also contact their hunting association, who will be able to tell them what instructions they need. “When you can not have your meat checked, you have to cook it well. “ Ideally, adequate cooking of the meat pre-cooked at 71 ° C. “This heart cooking, formerly known by hunters to kill all pathogens, actually causes the death of the parasite“, Confirms Isabelle Vallée.
Thanks to Isabelle Vallée, Head of the Parasitic Molecular Biology and Immunology Unit (BIPAR), at the ANSES Animal Health Laboratory (Maisons-Alfort).