Taeniasis and neurocysticercosis: Emerging public health problems

Abstract

Taenia, one of the earliest recognized helminths, is a comparatively large genus with 42 known valid species. Three most commonly recognized species of human importance are T. solium and T. asiatica (pork tapeworms) and T. saginata (beef tapeworm). Adult tapeworms reside in human intestine, and the disease is called taeniasis. The larva (cysticercus) of only T. solium can infect internal organs of human, known as cysticercosis; when the larva infects the central nervous system (CNS) of the host, it is known as neurocysticercosis (NCC). NCC is the most severe form of the disease with considerable morbidity and mortality. It is considered as the most common cause of community-acquired epileptic seizure disorders. The life cycle of T. solium involves two hosts: humans are the only definitive host and accidental intermediate host, while pig is the natural intermediate host. The eggs passed through faeces by T. solium carriers contaminate the environment. Both human and pig can get infection (cysticercosis/NCC) through ingestion of eggs, while human acquires taeniasis through consumption of cysticercotic pork. T. solium infection is highly endemic in Africa, Asia and Latin America. Now developed world is also facing this problem due to human migration from Taenia endemic areas. Therapeutic measures for NCC-related active epilepsy include anti-epileptic drug(s) with or without steroids: surgery/placement of shunt is indicated for patients with raised intracranial pressure. Antiparasitic drug to kill the brain cysticerci remains controversial. Treatment of choice for taeniasis is niclosamide; alternatives are praziquantel and albendazole. The following measures such as antiparasitic therapy to eliminate Taenia carriers in endemic populations, health education, toilet facilities and handwash with soap, control on sale of measly pork, restriction on pig roaming and pig vaccination, etc. may help to control the disease.