Angiostrongylus (Parastrongylus) cantonensis in the western hemisphere

Angiostrongylus (Parastrongylus) cantonensis, the rat lungworm, was once considered primarily endemic to Asia and the Pacific Basin. The nematode was first described from China, but throughout the years has been reported worldwide in rats, the molluscan intermediate host as well as humans. Angiostrongylus eosinophilic meningitis was first reported from Taiwan, followed 17 years later from Hawaii where a man died and the worm found in his brain. The parasite was not known to be in the Western Hemisphere until reports of eosinophilic meningitis in Cuba. Subsequently, the intermediate molluscan and definitive rodent hosts, as well as human infections, have been reported from many of the Caribbean Islands. In the continental United States, A. cantonensis was found in rats in New Orleans, Louisiana and locally collected molluscs were susceptible to experimental infections. The parasite was next found in primates in the Audubon Zoo in New Orleans. Snails and slugs collected from the zoo environment were also found infected with the larval stages of the parasite. One human case from Louisiana has been documented and more recently 12 American travelers to Jamaica returned home with the disease. The parasite is on the move with reports of infections in a horse from Mississippi and wildlife in Louisiana. There is now concern that in time the parasite will spread to infect wild and domestic animals and possibly humans elsewhere in the country. The question remains on how the parasite has moved from East to West. It may have been via infected molluscs stowawayed on ocean going ships, or more likely by infected stowaway rats that "jumped" ship and infected local molluscs. Many species of mollusc are susceptible to infection and are able to serve as intermediate host, but only rats can serve as definitive hosts.