Taenia solium:The Never Ending Cycle

Dear Mom and Dad,

            My research on Taenia solium in Japan has moved to Mexico. As globally distributed disease, Taenia solium has the ability to impact almost anyone. More research on the life cycle and how people get infected must be done to prevent it or create immunity towards it. In the life cycle of T. solium, humans are the definitive host, passing eggs (gravid proglottids) through their feces and surviving up to months in the environment (CDC et al., 2008). Pigs become infected with the eggs when they ingest the plants from the environment. Oncospheres hatch in the pigs intestine and attack the intestinal wall. The oncospheres then travel to the striated muscle and develop into cysticerci. The cysticercus can survive for years inside the pig. Humans are then infected by ingesting raw or undercooked infected pork (CDC et al., 2008). The cycle is repetitious and hazardous.

            In the human intestine, adult Taenia solium tapeworms can grow from to 2-7 meters! The adults produce proglottids which mature, then detach from the tapeworm and approximately 6 are passed through the stool per day. The eggs contained in the proglottids are only released after they are passed through with the feces. T. solium adults on average have 1000 proglittids, but can produce up to 50,000 eggs per proglottid! (CDC et al., 2008). This is an exponentially growing problem and a continuing circle of infection that needs more study. Continuing research in Mexico is being done about the development of Taenia solium metacestodes in pigs.

            A recent study here in Mexico took twelve, two month old male and female piglets and fed each one 100,000 eggs to infect them. Through the course of the infection the piglets were humanely killed to be necropsied (animal autopsy) (Garrido et al., 2007).  The piglets were examined thoroughly for metacestodes. To their surprise they found hemorrhages in the liver and the small intestine early in the infection, numerous vesicular cysts in the muscles of the leg, and a parasitic cyst in the right temporal lobe of the right cerebral hemisphere (Garrido et al., 2007). No metacestodes were found, but is thought to be due to immunity. The more research that is done about the life cycle of Taenia solium, the more understanding we will have about the severity of this parasite. Unfortunately research is not asexual, it cannot do itself, I have to do it, and so I will write to you soon!

大きな愛情と関心をもって

Tara

Literature Cited

Center for Disease Control and Prevention, 2008. “Lifecycle of Taenia spp.”. http://www.dpd.cdc.gov/dpdx/HTML/ImageLibrary/S-Z/Taeniasis/body_ Taeniasis_il6.htm

Garrido G. S., Aluja A. S., F.C. Casas, 2007. Early stages of development of the Taenia solium metacestode in pigs. Journal of Parasitology 93:2, 238-241.

Pechenik, Jan. A Short Guide to Writing About Biology. 7^th: Longman: Pearson Education Inc., 2010. 71-81, 146-7, 157-162, 162-191, 194-201, 201-207