[Epidemiology of cysticercosis and neurocysticercosis].Med Sante Trop. 2014 Oct-Dec; 24(4):367-74.MS
Within the genus Taenia, three species are human parasites: T. solium, T. saginata and a new uncommon species, T. asiatica, described recently in Asia. T. saginata and T. solium live as adult tapeworms in human intestines, where they cause taeniasis. T. saginata is widely present worldwide, in all regions where cattle are bred. T. solium is endemic in many countries where livestock and consumption of pigs are common. Cattle and pigs become infected by ingesting eggs emitted by humans into the environment and serve as the respective intermediate hosts of these helminths and host larval forms, or metacestodes or cysticerci. Cysticerci develop into adult worms in the human intestines after a person has eaten contaminated raw or undercooked meat. In the T. solium, eggs are also human contaminants. Humans, like swine, can develop cysticercosis after ingesting eggs with water or contaminated food, or via dirty hands. The clinical manifestations of cysticercosis are highly variable both in kind and in severity. The period between initial infection and the onset of symptoms can also vary. The clinical expression of cysticercosis is generally dependent on the number, size and location of the cysts, as well as the host immune response to the parasite. The preferred locations are the muscles, subcutaneous tissues, central nervous system (CNS), and eyes. Subcutaneous and muscular forms are often asymptomatic. Severe cysticercosis is due to larvae located in human CNS - neurocysticercosis. The World Health Organization (WHO) lists neurocysticercosis as a neglected tropical disease. It estimates that about 50 million people worldwide have neurocysticercosis in the world and that it causes about 50,000 deaths each year. Its most frequent clinical manifestations are seizures, intracranial hypertension, neurological deficits, and sometimes psychiatric manifestations. It is also responsible for more than 50% of the cases of late-onset epilepsy in developing countries. The T. solium taeniasis/cysticercosis complex is endemic in many developing countries in sub-Saharan Africa, Latin America, and Asia. Although T. solium had virtually disappeared in developed countries due to industrialization, improved methods of husbandry, and health checks, cysticercosis and neurocysticercosis are diagnosed anew in North America, Europe and Australia due to increased immigration from endemic areas. Cysticercosis is considered an eradicable disease. Although theoretically feasible, this concept has been replaced by projects to control and reduce the impact of cysticercosis on human health (through mass treatment of people, veterinary control of pigs, improved farming techniques, and health education).