Fish tapeworms, the largest parasite that infects humans

Tapeworms are long, ribbon like worms that sometimes grow to a length of several feet. Three species of tapeworms are recognized, the pork tapeworm, the beef tapeworm and the fish tapeworm.

Tapeworms in the intestine usually cause no symptoms but may cause abdominal discomfort, diarrhea and loss of appetite.

Tapeworms cause 2 major types of zoonotic disease syndromes, depending on whether humans are the definitive or intermediate host.

When human serve as definitive hosts, adult tapeworms infect the GI tract and interfere with nutrition.

Consumers in western Canada and Alaska become infected by eating raw or undercooked and improperly smoke salmon.

The larval worms are encysted in salmon flesh, usually sockeye salmon, which become infected as young fish during their rather long sojourn in fresh water.

The fish tapeworm is a broad, long worm; often grow to lengths of 3-7 feet at maturity.
Fish tapeworms, the largest parasite that infects humans

Taeniasis

Taeniasis
There are two forms of taeniasis. Taenia saginata is the cause of beef tapeworm disease, and Taenia solium of pork tapeworm disease. Humans are the definitive reservoir of these infections, with the animals acting as intermediary hosts. Two stages of each of the disease occur in the animal hosts. After the ingestion of larvae by the animals, the adult worms develop in the intestinal tract.

In addition to the intestinal tract stage there is a larval stage, in which the parasite finds its way into the general circulation and localizes in various tissues and organs, especially the muscles, where encystment of the larvae occurs. People contract the disease through eating improperly cooked meat. The ancient Greeks, Arabs, and Jews recognized these parasites diseases in animals, including the intestinal phase and the cystic stage; but it was not until the nineteenth century that the two were traced to a common source.

Beef tapeworm in humans exists only in the alimentary tract; a cystic stage rarely occurs. The symptoms are mild and indistinct, and the diagnosis is established by finding the segmented worms in the feces. The disease is relatively rare in the United States because of good animal husbandry.

Taeniasis in man due to the pork tapeworm, T. solium, is more serous infection because the encystment of larvae in the tissues occurs more frequently. Localization in the brain can cause epilepsy and the manifestation of brain tumor.

Since man is the definitive host, both beef and pork tapeworm disease in animals are propagated by the dissemination of contaminated human feces in the feeding areas of cattle and swine. The incidence of the human diseases is thus related to the sanitary habits of people. Prevention of the disease involves careful disposal of human feces, proper examination of animals in abattoirs and thorough cooking of meat.
Taeniasis

Other Important Food Infections

Other Important of Food Infections
Tuberculosis (caused by Corynebacterium tuberculosis) and brucellosis (caused by Brucella melitensis and also known as undulant fever) are disease that in the past were transmitted through milk but have been controlled in recent years by heat pasteurization of milk and the testing of dairy herds, which eliminated infected animals.

The ingestion of foods may be involved in infectious hepatitis when infected food handlers who careless in their personal habits are involved in preparing and/or serving food to others, or when contaminated shellfish are eaten raw or without adequate cooking.

Taenia solium (a tapeworm that may infest pork), Taenia saginata (a tapeworm sometimes found in beef), and Diphyllobothrium latum (tapeworm sometimes found in fish) all cause illness in humans, but none of these pose any hazard when foods are thoroughly cooked. Small worms of the genus Anisakis may also infected fish and cause illness in humans when the infected fish is not properly cooked.

Yersinia enterocolitica is another psychotropic organism that has been the causative foodborne pathogen in raw and pasteurized milk, and contaminated water. It is destroyed by normal pasteurization. Yersiniosis usually results in enterocolitis, characterized by diarrhea, fever and severe abdominal pain in the lower right quadrant. This illness has been incorrectly diagnosed as appendicitis and has resulted in unnecessary appendectomies. The organism is widely distributed and outbreaks have been traced to a wide variety of foods, such as milk that had contaminated chocolate syrup added to it after pasteurization and tofu that was packed in contaminated spring water.
Other Important Food Infections