Zoonoses

Taeniasis/Cysticercosis

The two most important Taeniae for humans are T. solium and T. saginata.

Life cycle
The adult worm lives in the intestine of humans. These humans shed the proglottids containing the eggs in their faeces. The eggs are ingested by bovines (T. saginata) or swine (T. solium) where a cysticercus is developed in the muscle. Humans acquire the infection by ingestion of raw beef/pork containing the cysticercus. For T. saginata humans are the final host. This is also true for T. solium but in T. solium humans can also be the intermediate host. This is the stage in which health problems occur for T. solium.

For T. solium autoinfection is a possible route of infection. This means that humans can become infected with the eggs spread by other humans or themselves and develop cysticerci in their tissues. This is an important way of infection of humans.

Clinical features
The great majority of T. saginata and T. solium carriers are unaware of their infection. However carriers of T. solium carry a substantial risk of acquiring cysticercosis by faeco-oral autoinfection and members of their households are also at increased risk.

Cysticercosis
Human cysticercosis is caused by the development of T. solium cysticerci in tissues of humans. The location that most often prompt a medical consultation is the central nervous system, followed by the eye and its surrounding tissues. Symptoms are for example epileptiform attacks, headaches, learning difficulties and convulsions.

Distribution
T. solium and T. saginata are distributed worldwide. T. saginata can be found worldwide in countries where cattle are raised for human consumption; T. solium where swine are raised for human consumption. The frequency has decreased in developed countries owing to stricter meat inspection, better hygiene and better sanitary facilities. The distribution of cysticercosis coincides with the distribution of T. solium. In Ethiopia, Kenya and the Democratic Republic of Congo around 10% of the population is infected, in Madagascar even 16%.

Prevention
Prevention is based on strict meat inspection, health education, cooking pork and beef well, hygiene, and widespread sanitary installations.

Treatment
Treatment of cysticercosis is very difficult with varying success: praziquantel + corticosteroids + albendazole. Treatment of taeniasis is easy using praziquantel.

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