Tapeworms are flat, elongated, ribbon-like worms that are parasitic to humans. The adult tapeworm lives in the intestinal tract of humans, while the larval stage of the tapeworm is in the tissues of the animal or fish host. Tapeworms are hermaphroditic, meaning they have both male and female reproductive organs. Humans become infected with tapeworm disease through eating undercooked or raw beef, pork, fish or through the accidental ingestion of the tapeworm egg.
Abdominal Effects
For most tapeworms, the disease in humans depends on the tapeworm species, the size and the number of worms present. Many times, tapeworm infections are asymptomatic and go unnoticed by the individual. Tapeworms such as Taenia saginata, because of its large size, may cause some abdominal discomfort. According to the U.S. Centers for Disease Control and Prevention, symptoms of some tapeworm infections have been attributed to toxic products of the worm itself, nervous disturbances and digestive disorders. Diarrhea is a symptom of tapeworm infections that is seen in young children. Massive infections of certain tapeworms can result in obstruction of the bile ducts or intestines.
Anemia
Infection with the fish tapeworm, Diphyllobothrium latum, can result in a pernicious anemia and an eventual nervous system disturbance due to a vitamin B12 deficiency. According to Ruth Leventhal, Ph.D., professor of biology from Pennsylvania State University, the fish tapeworm has the ability to utilize up to 100 percent of dietary B12 in a small percentage of infected persons. Because this tapeworm is found in freshwater fish in cold waters, it is mostly seen in people of temperate regions such as Alaska, Canada and Scandinavia. According to the book, "New Guinea Tapeworms and Jewish Grandmothers" by Robert Desowitz, Ph.D., this infection was common among Jewish woman in New York City in the 1930s who, during the preparation of gefilte fish, would taste the fish to determine if it was cooked properly. Oftentimes, the fish was still quite raw when it was taste tested.
Cysticercosis
While infection with the pork tapeworm, Taenia solium, through eating undercooked or raw pork usually results in generally mild symptoms, ingestion of the Taenia solium egg has an altogether different outcome. When a person ingests eggs from a tapeworm carrier, they hatch in the small intestine and the larval stage migrates to various parts of the body such as muscle, the eyes, liver and brain and forms a cystercerci. Symptoms of cysticercosis vary on the location of the cyticerci and include; headache, seizures, mental disturbances and lesions on the heart or eyes. In the case of neurocysticercosis, symptoms can become suddenly fatal.
References
- "Medical Parasitology: A Self-Instructional Text;" Ruth Leventhal, Ph.D.; 1996
- U.S. Centers for Disease Control and Prevention: Cysticercosis
- U.S. Centers for Disease Control and Prevention: Diphyllobothriasis
