As the large, invasive Burmese python eats its way through south Florida's mammals, the mosquitoes in the area have fewer types of animals to bite. Now, more mosquitoes are drawing blood from a rat that carries a virus dangerous to humans.

One of the only mammals left in the Everglades for mosquitoes to bite is the hispid cotton rat, a rodent which is one of the only known hosts of a mosquito-borne virus called the Everglades virus. The virus causes fever, headache and even encephalitis in rare cases.

More mosquitoes biting the cotton rat could increase the spread of the Everglades virus, said Nathan Burkett-Cadena, a UF/IFAS assistant professor of entomology.

Burkett-Cadena led a team of graduate students, Isaiah Hoyer and Lary Reeves, and postdoctoral fellow Erik Blosser, to conduct research in the Everglades. There, researchers collected mosquitoes and then determined which animals the mosquitoes were biting through animal DNA in the mosquito's gut.

The researchers compared their results to findings from a 1979 study done with the same mosquito species and at the same site, long before the Burmese python became established in the Everglades.

Burkett-Cadena's team found that the mosquito species known as Culex cedecei took nearly 77 percent of its blood meals from the hispid cotton rat in 2016. That's up 422 percent from its intake of 15 percent in 1979.

Field studies from the Everglades in 1979 showed Culex cedecei fed about half the time from rodents and the other half from other mammals, including the raccoon, the Virginia opossum and the white-tailed deer. Now, they take about three-quarters of their blood meals from the rodents in question because the python is eating up many of the other mammals, said Burkett-Cadena.

"As far as I am aware, this is the first time that researchers have found that an invasive predator (such as the python) has caused an increase in contact between mosquitoes and hosts of a human pathogen," said Burkett-Cadena, a faculty member with the UF/IFAS Florida Medical Entomology Laboratory in Vero Beach, Florida.

The latest study is published in the journal Biology Letters.

Materials provided by University of Florida Institute of Food and Agricultural Sciences. Original written by Brad Buck. Note: Content may be edited for style and length.

Disclaimer: DoveMed is not responsible for the accuracy of the adapted version of news releases posted to DoveMed by contributing universities and institutions.

References:

Isaiah J. Hoyer, Erik M. Blosser, Carolina Acevedo, Anna Carels Thompson, Lawrence E. Reeves, Nathan D. Burkett-Cadena. (2017). Mammal decline, linked to invasive Burmese python, shifts host use of vector mosquito towards reservoir hosts of a zoonotic disease. Biology Letters. DOI: 10.1098/rsbl.2017.0353