In April, Digital Journal reported on six people being infected with the rat lungworm in the space of three months on the Hawaiian island of Maui. This is a concern because the incidence of the disease had tripled over the past decade.
Rat lungworm, also known as Angiostrongylus cantonensis, is a parasitic nematode or roundworm. When the parasite infects humans, it causes meningitis or angiostrongyliasis. It is endemic to Hawaii, but because of a warming climate, has now been found in California, Alabama, Louisiana and Florida, reports Gizmodo.
Life cycle of rat lungworm
In a study published in PLOS one on the roundworm’s geographical distribution, scientists from the University of Florida found that the parasite’s distribution in Florida was far greater than anyone realized. The study also added credence to the idea that climate change is playing a significant role in the subtropical worm’s spread.
The rat lungworm has a rather nasty life cycle that involves two species. Snails ingest the roundworm larva by eating infected rat feces. The rats, in turn, eat the infected snails, and the cycle goes on. But when a human, or even a family pet, either eat snails, crustaceans or frogs, which can all be infected with the parasite, they can get the disease. It is also possible to contract the parasite when eating leafy vegetables grown outdoors and not properly washed well.
If a human does ingest the parasite, it moves to the brain to mature. It then dies, causing eosinophilic meningitis. In the rat, the parasite migrates back to the rodent’s bloodstream. The parasite was first identified in 1935 in rats from China.
Significance of findings in Florida
The five Florida counties where the parasite was found include Leon, Alachua, Saint Johns, Orange, and Hillsborough. All of these counties are in the north or central region of the state. The author’s of the study say the finding is concerning. “The ability for this historically subtropical nematode to thrive in a more temperate climate is alarming.”
The study also notes that with climate change and rising average temperatures, we can expect to see the range of this parasite expand even further. Heather Stockdale Warden, an infectious disease researcher at the University of Florida and lead author of the study, said in a statement. “The reality is that it is probably in more counties than we found it in, and it is also probably more prevalent in the southeastern U.S. than we think.”
Another significant finding should be noted – The three snail (gastropod) species that tested positive for the parasite had never before been documented as hosts. More worrisome, two of the snails have ranges that go far beyond Florida, with one being found throughout the temperate United States.
