What is it about ?
Trichinella is a roundworm (nematode), a parasite that nestles in the body of humans and animals. The disease it causes is called trichinosis. Humans are infected by eating undercooked meat or raw, uninspected meat (pork, sausage, horse meat, or uncontrolled meat from wild animals like wild boar) that contains larvae of the worm. The larvae mature in the small intestine until adulthood, then in turn produce new larvae which enter the intestinal lining and reach the muscles through the bloodstream, where they become encysted.
What is its frequency?
Trichinosis is seen all over the world, but is rather rare. In Belgium, this parasite has almost disappeared. The risk of contamination is very low thanks to strict control of slaughter animals. The nematode Trichinella is found in living wild species. Therefore, careful control of all meat intended for consumption remains necessary. Infections are still sometimes detected in hunters who eat uncontrolled wild boar meat. The World Health Organization estimates that there are around 3,000 to 6,000 cases of human trichinosis per year worldwide.
How to recognize it?
Symptoms depend on the stage of infection.
The disease first manifests with digestive symptoms (nausea, vomiting and diarrhea) usually within a week of infection.
During the migration of larvae through the bloodstream and their encystment in the muscles (1 to 6 weeks after contamination), the patient may present all kinds of symptoms which vary according to the type and quantity of larvae: haemorrhages under the nails and in conjunctiva (in the white of the eye), fever, swelling of the face, headache, swollen and painful lymph nodes, rash, bronchitis or very sore, swollen and weakened muscles. Acute infections can also affect the muscle of the heart, causing arrhythmias. At the end of the process, the larvae encyst in the muscles. Muscles lose strength and chronic muscle pain appears. Less than 1 in 100 infected people die from exhaustion, pneumonia or heart problems.
How is the diagnosis made?
Your story and the clinical picture will put the doctor on the trail of trichinosis. Sometimes the disease causes almost no symptoms, especially in the presence of a small number of larvae, or it can be mistaken for the flu, for example. A blood test and / or a muscle biopsy can confirm the diagnosis. The biopsy involves taking a small piece of muscle to be examined and see the presence of larvae.
What can you do ?
In Belgium, the Federal Agency for the Safety of the Food Chain (AFSCA) controls, in accordance with European regulations, all pork, wild boar and horse meat intended for consumption, to detect the possible presence of the Trichinella nematode. . In principle, our meat is therefore safe to eat. It is recommended to freeze meat for more than 10 days at a temperature of -20 ° C or to cook it at a temperature above 80 ° C. Smoked or uncontrolled raw meat is always a possible source of Trichinella. This is why it is advisable to never eat raw or smoked meat when you are traveling. Meat obtained from hunting should always be prepared at sufficiently high temperatures.
What can your doctor do?
Trichinosis can only be detected after several weeks with a blood test or muscle biopsy. Therefore, if the doctor thinks that trichinosis is very likely, he will often start with a drug against parasitic worms (dewormer, anthelmintic) even before knowing the results of the examinations. He will advise you to get enough rest. In case of significant muscle inflammation, he will prescribe an anti-inflammatory drug and, if necessary, cortisone. In the event of cardiac arrhythmias, hospitalization may be required.
Want to know more?
- Healthy travel – IMT – Institute of Tropical Medicine
- Contact point for consumers – AFSCA – Federal Agency for the Safety of the Food Chain
- Non-steroidal anti-inflammatory drugs – CBIP – Belgian Center for Pharmacotherapeutic Information
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