There are three main types of intestinal fluke, which is a type of parasite which invades the intestinal tracts of humans and other animals. Fasciolopsis buski is the first species, and it often infects the intestines of both humans and animals, such as pigs. It is the largest known fluke to live in human hosts. Paragonimus westermani, or the oriental lung fluke is another type found mostly in Asian countries. The last of the most common types is the Fasciola hepatica, also known as the sheep liver fluke.
While the fasciolopsis buski is the variety most commonly known as intestinal fluke, the other types may originate in the intestines before invading other areas of the body. Fasciolopsis buski can cause illness in hosts and may lead to ulcers, abdominal pain, allergic reactions, and other complications. It is the largest known intestinal fluke to invade the bodies of humans, and it is spread primarily through vegetables like watercress and water chestnuts.
The sheep liver fluke is also spread through water grown vegetables, although it is rarer than the fasciolopsis buski and can cause more serious problems within the body. This type of intestinal fluke can eventually attach itself to the gallbladder and cause extreme inflammation and pain. Other symptoms include jaundice, fever, nausea and vomiting, and coughing.
Paragonimus westermani begins as an intestinal fluke and eventually burrows into the body and can infect the lungs and brain. Those who are infected with this type of parasite will eventually develop a severe cough and may begin coughing up blood. If the worm makes its way into the brain, severe neurological damage can occur.
Most types of intestinal fluke are rare in industrialized nations due to more stringent food sales and sanitation practices. Some areas of Asia are prone to parasites, especially those who eat large amounts of water grown vegetables and certain types of crayfish or crabs. Medications can often be used to kill and remove the parasites, although lasting damage may be suffered if they have spread beyond the intestines and into other organ systems.
Occasionally these rare worms can cause infection in industrialized countries if infected food is transported there. Symptoms may be vague at first, and doctors may not immediately suspect intestinal fluke infestation because it so rarely occurs in these areas. Patients should inform their doctors if they have consumed watercress, water chestnuts, bamboo, crab, or crayfish prior to becoming ill. This is especially important if the food was not cooked or may have been undercooked.