In the past 50 years, Angiostrongylus cantonensis, the most common cause of eosinophilic
meningitis, has spread from Southeast Asia to the South Pacific, Africa, India, the Caribbean, and recently, to Australia and North America, mainly carried by cargo ship rats. Humans are accidental, "dead-end" hosts infected by eating larvae from snails, slugs, or contaminated, uncooked vegetables. These larvae migrate to the brain, spinal cord, and nerve roots, causing
eosinophilia in both spinal fluid and peripheral blood. Infected patients present with severe
headache,
vomiting,
paresthesias, weakness, and occasionally visual disturbances and extraocular muscular
paralysis. Most patients have a full recovery; however, heavy
infections can lead to chronic, disabling disease and even death. There is no proven treatment for this disease. In the authors' experience,
corticosteroids have been helpful in severe cases to relieve intracranial pressure as well as
neurologic symptoms due to inflammatory responses to migrating and eventually dying worms.