What causes Diphyllobothriasis?
The fish tapeworm (Diphyllobothrium latum), is the largest parasite that infects humans. Humans become infected when they eat raw or undercooked freshwater fish that contain fish tapeworm cysts. The infection is seen in many areas where humans eat uncooked or undercooked fish from rivers or lakes such as:
Eastern Europe North and South America Scandinavia Some Asian countries
After a person has eaten infected fish, the larva begins to grow in the intestine. Larvae are fully grown in 3 - 6 weeks. The adult worm, which is segmented, may reach a length of 30 feet. Eggs are formed in each segment of the worm and are passed in the stool. Sometimes, parts of the worm may also be passed in the stool. Fish tapeworm infection may lead to vitamin B12 deficiency and megaloblastic anemia. </s>