Also see Humanopathogenic worms
Cook pork and wild game to at least 170°F (77°C), or until the juices run clear. Alternately, pieces of pork less than six inches (15cm) thick may be frozen for 20 days at 5°F (-15°C) to kill the little fuckers, but wild game cannot be reliably decontaminated this way.
Trichinosis (or trichinellosis) was first described in 1835 by James Paget, a medical student in London. He observed a dissection of a patient who had died of tuberculosis. The surgeons noticed that his diaphragm was sandy in consistency, and dulled their instruments. Paget stole a sample of the lung tissue after the doctors left to examine on his own. He cut open the grains, and found a tiny worm, visible with a hand lens, coiled up inside each one. He then examined them with a microscope (one that belonged, incidentally, to Robert Brown, of Brownian motion fame.) Further examination by others confirmed that a new pathogen had been discovered. Richard Owen, assistant curator of the Royal College of Surgeons, wrote up the findings and presented them without crediting Paget.
German pathologist Rudolph Virchow elucidated the life cycle of the trichina worm by feeding the flesh of an infected cadaver to a dog, and then dissecting the poor beast. He also determined that thorough cooking could kill the disease, which was rather an unpopular notion in a nation very fond of very lightly cooked pork. In fact, the German Veterinarians' Society assigned a veterinarian to denounce Virchow's findings, but when he proffered a bit of rawfleisch (very lightly smoke-cured ham) infected with trichinosis to the veterinarian, in front of a crowd, the man declined. Thus Virchow became famous.
Trichinosis is a disease transmitted by consumption of undercooked meats, particularly pork and certain types of wild game. Trichinosis is caused by roundworms of genus Trichinella, most importantly Trichinella spiralis. Infection occurs worldwide, but it is uncommon in the United States and other areas with adequate inspection of agricultural products.
The lifecycle of a Trichinella worm
The digestive tract
The disease begins when you eat meat with Trichinella larvae in small cysts in the muscle tissue. The outer covering on the cysts dissolves in the stomach and the worms mature in the small intestine within one to two days. There, they reproduce, turning your digestive tract into a giant worm orgy-cum-nursery.
Intestinal symptoms typically start several days after infection, and disappear within ten days after initial consumption of tainted food. At this point, they include typical gastrointestinal complaints: nausea, diarrhea, vomiting, fever, and abdominal pain. Because these symptoms resemble many other illnesses, including mild food poisoning, trichinosis is often misdiagnosed in its early stages. The adult females can remain attached to the villi lining the intestine releasing larvae for up to four weeks, until finally being expelled in the feces. The new larvae then travel through the intestinal wall and travel through the lymphatic and circulatory systems, finding suitable cells to set up shop inside.
The muscles
That's what the little bastards do - they move into the cells of the body and take them over, using the cellular machinery for their own nefarious ends. In that they resemble viruses, which also require other organisms' cells to complete their life cycle. The trichina worms curl up within cells. A trichina worm can enter any cell in the body, but most cell types can't support the parasite permanently. Trichina worms can only establish themselves permanently within skeletal muscle cells, forming cysts and eventually causing new blood vessels to grow around the cysts. The cells' own nuclei atrophy over time, turning them into nurse cells for the organisms. These cysts in the muscular tissue are permanent, and if the host organism is eaten, they reproduce again in the digestive tract, completing their life cycle.
This phase of illness begins around two weeks after the parasites are consumed. It begins with severe myalgia (muscle pains), swelling and pain around the eyes, and petechial hemorrhages particularly visible in the nails, conjunctiva, and mucus membranes. In severe cases (severity is generally related to the number of parasites consumed), they can cause damage to the nervous system or swelling of the heart.
Medical
Many mild cases are asymptomatic. In cases with only minor symptoms, they resolve within two or three weeks. Worse infections may cause symptoms for several months. Death is rare, and is associated with particularly heavy consumption of the parasites and immune-compromised patients. Death is usually due to pneumonia, encephalitis, or heart failure.
There is no cure once the parasites are established in the muscle tissue. If the infection is diagnosed while in the intestinal stage, abendazole, mebendazole, or thiabendazole may be used to kill those parasites. If the muscle is infected, analgesics and antipyretics can be used to relieve symptoms. Severe inflammation can be treated with steroids. That's it, though - once the suckers are in, they're in for good. So don't let that happen. Infection is prevented by thoroughly cooking pork and wild game, or freezing it for several days (though Arctic species infected with Trichonella nativa are less susceptible to freezing.)
Incidence
It takes two organisms for the trichina worm to complete its life cycle - the encysted larvae in the muscles are consumed by an organism, where they reproduce. The larvae establish themselves in the muscle, and remain essentially dormant until that organism is eaten. In pig farming, trichinosis occurs when the animals are given feed containing animal tissue. Developing countries where pigs are frequently raised on kitchen scraps provide an excellent mechanism for the disease to be transmitted, which explains why it's endemic in many parts of the world but relatively uncommon in the United States and Europe.
About forty cases occur per year in the United States, and the incidence is low in Europe as well, in both cases due to inspection of pork and regulation of animal feed. Most cases in these parts of the world are related to consumption of wild game, though a small portion of domestic pork in the United States is infected. Occasional cases also result from non-commercial pork grown by small farms, especially in poorer areas of Europe. The disease is much more common in Latin America and is considered endemic in China and Japan. Up to 20% of pigs on Chinese farms are infected.
Trichinosis and the kosher law
When trichinosis was first described, it was seized upon as an explanation for the Biblical prohibition on pork consumption. Pigs are not kosher - in fact, beyond not meeting the criteria defining kosher mammals (since they don't chew their cud), they are particularly singled out as unacceptable for Jewish people, and pork is also the only type of meat proscribed to Muslims.
This is an unsatisfactory explanation. As anthropologist Marvin Harris discusses in his book Good to Eat (a fascinating discussion of dietary laws and taboos in different cultures), trichinosis is only occasionally fatal and often symptomless, and in many cases symptoms do not quickly follow consumption of tainted flesh. Theologists liked this explanation, as it seemed to provide a rational basis for holy law; in reality, all meat is a potential vector for disease. Tapeworms and brucellosis may be easily contracted from kosher meat, and anthrax was fairly common throughout Europe and Asia until Louis Pasteur invented a vaccine for it in 1881. Anthrax is usually fatal, and quite quickly so. Yet there is no Biblical injunction on the consumption of beef, mutton, or goat. (Harris provides an interesting justification in terms of the costs and benefits of farming pigs in the Middle East, but I fear I've digressed enough.)
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