Neurocysticercosis in the United States

Neurocysticercosis (NCC) is typically considered a disease of the developing world. Nonetheless, NCC is also diagnosed in the developed world. The rise in the number of cases of NCC in developed countries, especially in the United States of America, has largely been driven by the influx of immigrants from endemic to non-endemic regions and the widespread access to neuroimaging. Cases of local transmission have also been documented particularly in the setting of a tapeworm carrier present in the household, which highlights the relevance of NCC as a public health problem in the USA. Although accurate incidence data in the USA are not available, estimates range from 0·2 to 0·6 cases per 100 000 general population and 1·5-5·8 cases per 100 000 Hispanics. We estimate that between 1320 and 5050 new cases of NCC occur every year in the USA. The number of NCC cases reported in the literature in the USA increased from 1494 prior to 2004 to 4632 after that date. Parenchymal cases remain the most commonly reported form of the disease; however, a slight increase in the percentage of extraparenchymal cases has been described in the most recent series. NCC is associated with significant morbidity resulting from hydrocephalus, cerebral edema, and seizures. Although uncommon, NCC is also a cause of premature death in the USA with a calculated annual age-adjusted mortality rate of at least 0·06 per million population.