But there are also other parasites people can get from an infected restaurant cheff, by eating raw salads, raw fruits & vegetables, or by drinking infected water.
People who have used Antibiotics are more likely to contract parasitic worms and parasitic animals.
The life cycle of Diphyllobothrium latum starts, when immature eggs are passed in the feces of an infected human. The eggs mature in water within three weeks and form oncospheres. Larvae called coracidia hatch and get eaten by freshwater crustaceans such as copepod. After ingestion coracidia develop into procercoid larvae. If the copepod is eaten by a small fish (second intermediate host), the procercoid larvae penetrate the gut and migrate to muscle tissue where they develop into plerocercoid larvae (sparganum), the infective stage for humans. Usually a third intermediate host is needed because humans do not usually eat raw fish this small. If a trout, walleyed pike or perch eats the smaller fish, the plerocercoid larvae once again penetrate the gut and migrate to fish flesh. If a human eats the infected fish raw or undercooked the plerocercoid larvae develop into adults in the small intestine. The adults attach to the intestinal mucosa with two shallow, bilateral grooves (bothria) of their scolex. The scolex is 3 mm long and 1 mm wide. The long, flat body consists of segments, proglottids, that are produced by the neck. Full grown proglottids are about 10 mm wide and 3 mm long. As proglottids mature, they release eggs and eventually break off from the body. A Diphyllobothrium latum proglottid is characterized by a rosette-shaped uterus at its center. The eggs are microscopic, ellipsoidal or oval measuring 55Ė75 Ķm by 40Ė50 Ķm. They are passed in the feces unembryonated (immature). From the start of the infection it takes about six weeks for the eggs to appear in the feces. One adult Tapeworm can shed up to a million eggs per day or over 300 million eggs per year. It can grow over 10 meters long and live up to 20 years.
Diphyllobothriasis is usually asymptomatic. In some cases it causes severe vitamin B12 deficiency because D. latum can absorb most of the B12 intake. In some cases it can lead to neurological symptoms. Diphyllobothriasis symptoms include:
obstruction of the bowel
pernicious anemia (caused by vitamin B12 deficiency) which can lead to
subacute combined degeneration of spinal cord
Migrating proglottids can cause inflammation of the bile duct or the gall bladder.
Diphyllobothriasis is diagnosed by examining a stool sample to find eggs or sometimes proglottids. Identification is restricted to genus level which actually does not matter when treating the disease since all Diphyllobothrium species respond to the same drugs. When doing research the specific worm species can be identified by performing PCR on purified eggs.
Diphyllobothriasis was previously treated with praziquantel or niclosamide. Praziquantel has some side effects that are very similar to diphyllobothriasis symptoms. Niclosamide is not absorbed in the gastrointestinal tract and has usually no side effects. However, these drugs are not reliable in cutting the scolex loose. If the head is left in the intestinal wall it will regrow. The best method is a diatrizoic acid injection into the duodenal wall. The diatrizoic acid causes all worms to detach leaving nothing behind. Niclosamide or praziquantel should only be used, if endoscopic treatment is not available.
In the 14th episode of season 3 of House entitled "Insensitive", the primary patient is a girl who has CIPA . She is ultimately diagnosed with Diphyllobothrium causing vitamin B12 deficiency.