Content area
Full Text
The immense burden of epilepsy is a growing problem in developing countries where the incidence of epilepsy may be higher than in western countries. 1 Three quarters of the 50 million people with epilepsy live in the poor countries of the world and up to 94% are untreated. 2 3 Extending appropriate services to these people will be one of the great challenges of the new millenium. Unfortunately little is known about the causes of epilepsy in developing countries. However, many studies from Latin America have shown that infection of the brain by the larvae of the pork tapewormTaenia solium is an important cause of epileptic seizures in endemic communities. 4-6 Many recent reviews have covered in detail the pathology, 7 parasitology, 8 clinical features, 6 and diagnostic criteria 9 of neurocysticercosis. This review concentrates on recent developments in the immunopathogenesis of neurocysticercosis, the controversy over clinical classification, and the evidence base for different treatment approaches. The challenges for the population control of cysticercosis and epilepsy in the developing world are summarised.
Neurocysticercosis
EPIDEMIOLOGY
Taenia solium is endemic in Latin America, India, and China, and may also be endemic in sub-Saharan Africa, although there are few studies. 10 11 Poor hygiene and living conditions, allowing pigs access to human faeces, put people at risk of developing cysticercosis. 4 12-15 In endemic countries, the disease is also widely prevalent in urban, middle class areas. 16 Migration from the countryside and the rise of urban slums obviously influence the changing epidemiology of cysticercosis. T solium infections have also been imported by migrant workers into the United States. 17
Neurocysticercosis is of great economic relevance, resulting from the cost of medical treatment, lost working days, and losses due to livestock condemnation. A minimum estimate of the cost of admissions to hospital and wage loss for neurocysticercosis in the United States (a non-endemic country) was $8.8 million annually, wheres estimated treatment costs in Mexico were $89 million, and Brazil $85 million. 18
PATHOLOGY
Life cycle biology
In the first stage, the human host ingests diseased (measly) pork containing viable cysticerci, from within which the scolex of the metacestode evaginates in the gut and attaches to the intestinal mucosa. 8 The tapeworm matures over 2-3 months to achieve a...