A rare parasitic infection called "rat lungworm" has spread across the United States, and is now considered to be endemic. The infection invades the human brain.
Rat lungworm or Angiostrongylus cantonensis is a parasitic nematode that starts as an infection in rat's lungs, blood, and brain. The rat will defecate worm larvae that will spread to other species like snails, slugs, and freshwater shrimp. The transmission will happen when a person eats these intermediate hosts.
The parasitic infection invades the brain. It can cause parasitic meningitis and will produce symptoms like tremors, pain, and inflammation. If left untreated, the condition will be fatal.
In the past two decades, there have been only two cases of infections in Hawaii. However, in the last three months, there have been six reported cases in Maui in rapid succession.
Health officials in Hawaii have warned the residents not to touch snails or slugs with bare hands because of this rare parasitic infection. Rat lungworm have also appeared in other states like California, Alabama, Louisiana, Florida, and along the Gulf Coast, according to a study published in the Journal of Parasitology.
The parasitic infection has been prevalent in parts of Asia and the Caribbean. The first known case of rat lungworm infection reported was in Taiwan in 1944. Health officials believe that it is now endemic in the United States because of infected rats on container ships, and by intermediate hosts.
Peter Hotez, the Dean of the National School of Tropical Medicine at Baylor College of Medicine, believes that the parasitic infection was introduced in the United Sates because of globalization, like snails or slugs brought by the ship coming from Asia. Its geographical distribution changed dramatically after few decades.
About 30 countries have documented cases of rat lungworm infection. Health officials are worried because some of the cases have appeared in areas that are thought to be unsuitable for the infection. One recent case occurred in Oklahoma, but rat lungworm cannot survive in this area.
Scientists assumed that this is likely due to climate change. Most new infections are caused by pathogens present in the environment because of uncertainty, selective advantage, or changes in ecological or social conditions, according to a report by the World Health Organization in 2004.
At the moment, there is no known cure for the parasitic infection, the severity also varies wildly, and it is often difficult to diagnose.