Rat lungworm disease could become more widespread globally, prompting a study authored by Hawaii researchers to increase awareness of the disease within the medical community.
Neuroangiostrongyliasis, or NAS, also known as rat lungworm disease, is caused by a parasitic nematode that completes its life cycle in snails, slugs and rats — although dozens of other species can be carriers, including humans. In humans the disease can cause an inflammatory reaction, potentially leading to eosinophilic meningitis, paralysis or even death.
With warming driven by climate change, the parasite potentially can move north on the mainland and lead to more cases, an American Journal of Tropical Medicine and Hygiene study published in November said. The study was authored by researchers from the University of Hawaii and the University of California.
Climate change also will allow the parasite to move to higher elevations in Hawaii where it is currently too cold, although it’s not clear whether this will affect the spread of the disease in the state.
Around the world, instances of the parasite and rat lungworm will increase where it is currently not found.
“Globally, of course, case numbers will increase as the parasite spreads to regions where it is currently absent,” said Robert Cowie, a research professor at the University of Hawaii’s Pacific Biosciences Research Center and one of the study’s authors, in an email. “And this is one of the key purposes of our paper — to broaden the education of medical practitioners in such regions regarding rat lungworm disease so that they are ready and aware of it, can diagnose it and know how to treat it.”
Better awareness in the medical community will reduce the likelihood of sick people being misdiagnosed and speed up proper treatment.
Cowie said that even in Hawaii many medical practitioners have heard about rat lungworm disease but know “next to nothing” about it.
In the U.S. a majority of human infections of the parasite are found in the Hawaiian Islands, the study found. In the state, more than 180 human cases have been reported. It is also widely spread in animals in Florida.
The parasitic nematode is the primary cause of eosinophilic meningitis worldwide, although cases are low. There are about 3,000 reported cases in the medical literature, the study said, but gray-literature records suggest more than 7,000 cases and likely many more that have gone unreported.