Neurocysticercosis: a major cause of neurological disease worldwide.

Neurocysticercosis, which is caused by infestation of the human CNS with the tissue cysts of Taenia solium, is arguably the most common parasitic disease of the human nervous system. While most of the details of the parasite's life cycle were known by the nineteenth century and most of the clinical manifestations of T. solium infection had been identified by the mid-twentieth century, concepts regarding the prevalence of infection, associated morbidity and mortality, treatment, and epidemiology have changed dramatically over the past 10 years. The increased ease of international travel, the increasing numbers of immigrants from developing countries, and the widespread use of improved diagnostic techniques have led to widespread recognition of neurocysticercosis as a common infection not only in developing countries but also in the United States. Large case series have been reported in the southwestern United States and other areas with large immigrant populations from Latin America [2-7]. Since neurocysticercosis is not a reportable disease, the total number of cases diagnosed in the United States is not known but is estimated at >1,000 new cases each year [2], and this number appears to be increasing. While most of these cases occur in patients infected in developing countries, the number of locally acquired infections is also increasing. The ancient Greeks recognized that intestinal tapeworms were associated with ingestion of meat. They referred to the "hailstones" in meat as cysticerci, meaning bladder-tails. During the nineteenth century, Leuckart identified the complete life cycle of T. solium and noted that human cysticercosis resulted from ingestion of parasite eggs shed by tapeworm carriers. Neurocysticercosis was a frequent finding in autopsy series reported from Europe in the nineteenth century. Studies