TRICHINELLOSIS (Trichinosis)

Description
Trichinellosis is a parasitic disease caused by eating raw or undercooked meat of animals infected with the larvae of a type of worm called Trichinella. Infection occurs commonly in certain wild carnivorous (meat-eating) animals but can also occur in domestic pigs. On the Continent, there have been a number of recent outbreaks associated with eating undercooked horse meat.
Severity of the disease generally depends on the numbers of larvae eaten. Trichinellosis can be very mild; so mild it goes unnoticed. Most cases are unpleasant and resolve fully with proper treatment. Very occasionally, it can be so severe that it is fatal.
Symptoms
Symptoms vary considerably. The first symptoms can involve swelling of the eyes. This will often be accompanied by gastroenteritis symptoms such as diarrhoea, vomiting, and abdominal discomfort. There may also be fatigue, fever headaches, shivering, cough, aching joints and muscle pains. If the infection is severe, patients may have difficulty coordinating movements, and have heart and breathing problems. In the most severe cases, death can occur.
For mild to moderate infections, most symptoms subside within a few months. Fatigue, weakness, and diarrhoea may last for a number of months.
How does infection occur in humans and animals?
When a human or animal eats meat that contains infective Trichinella cysts, the acid in the stomach dissolves the hard covering of the cyst releasing the larvae which pass into the small intestine and, in a couple of days become mature. Adult females lay eggs that develop into larvae, travel through the arteries, and are transported to muscles. Within the muscles, the larvae curl into a ball and encyst (become enclosed in a capsule). Infection occurs when these encysted larvae are consumed in meat. Proper cooking kills the encysted larvae.
Who is at risk of trichinellosis?
Anyone who eats raw or undercooked meats is at risk. The worm can potentially affect most animal species but is generally present at higher levels in wild meat-eating animals. The meats most commonly implicated in the EU include wild boar meat, cured fermented pork-based sausage, and horse meat. In other parts of the world, bear, wild cat (such as cougar), fox, dog, wolf, seal, or walrus have been implicated.
Can trichinellosis spread from an infected person to other people?
No, infection can ONLY occur by eating raw or undercooked meat containing Trichinella larvae.
Diagnosis
The presence of gastroenteritis, myalgia (muscle aches), facial oedema (swelling), or subconjunctival haemorrhages (bleeding into the whites of the eye), and an increase in eosinophils (a type of white blood cell) levels would suggest trichinellosis. It can be difficult to differentiate trichinellosis from diseases such as influenza and typhoid. A simple blood test usually confirms the diagnosis. If diagnosis is proving difficult, occasionally a sample of muscle from the shoulder (muscle biopsy) is taken.
Treatment
There is a range of safe and effective antiparasitic medications to cure trichinellosis.
Prevention

Effective ways of removing risk from food

Cook meat products until the juices run clear
Freezing pork less than 6 inches thick for 20 days at -15oC will kill any larvae
Freezing wild game meats, unlike freezing pork products, is not guaranteed to kill all larvae.

Dealing with known high-risk categories of meat

Pork-based fermented meat products (traditional sausage products) should be bought from an approved reliable source, and ideally cooked prior to consumption.
Wild game meat, including wild boar meat should be handled hygienically while raw, and cooked thoroughly prior to consumption.

Methods which are not effective in removing risk for food

Curing (salting), fermenting, pickling, drying, smoking, or microwaving meat does not consistently kill infective worms.

Reference
http://www.ndsc.ie/hpsc/A-Z/Zoonotic/Trichinellosis/Factsheet/

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