Two more tropical mosquitoes shown to be carrying mosquitoes have been found on the U.S. mainland for the first time, caught near the Florida Everglades.
Scientists say this could raise the risk of mosquito-borne viruses reaching people and birds, but it’s too early for health officials to sound the alarm. The new arrivals from South American and the Carribean are known as Culex panocossa and Aedomyia squamipennis. They were trapped in October near rural areas bordering the Everglades National Park by University of Florida Institute of Food and Agricultural Sciences entomologist Nathan Burkett-Cadena and Florida Medical Entomology Laboratory researcher Erik Blosser.
In the traps, it was discovered that the native species of mosquito were heavily crowded out by the two new invaders. Both species can be found on a few Caribbean islands as well as from Mexico into South America. They lay their eggs on water lettuce — invasive weeds that float in the canals, drainage ditches and other waterways crisscrossing Florida neighborhoods.
“‘Hundreds’ is substantial, particularly when you get a hundred from a single trap. This is not a single specimen that blew in from a storm — this is a reproducing species,” Burkett-Cadena said. About fifteen invasive mosquitoes now call Florida home, including nine that have arrived in the last decade. One, Aedes aegypti, is blamed for the dangerous Zika virus spreading, along with chikungunya and dengue fever.
The new unfortunate arrivals are another sign of climate change, tourism, and trade making Florida more hospitable for exotic species. Health officials downplayed the immediate cause for concern, saying that more research is still needed.
“We have seen in Florida some invasive mosquito species that have become significant and others that have not,” Florida Department of Health spokeswoman Mara Gambineri said in an email Tuesday. One of roughly 200 mosquito species worldwide known to transmit diseases to humans, Culex panocossa can spread Venezuelan equine encephalitis, a family of viruses that includes the Everglades virus. The native Florida mosquitos that the scientists were hoping to trap also can infect humans with the Everglades virus, but it rarely has to chance to since they stick to their natural habitat deep in the wetlands.
The new Culex species in Florida live closer to civilization, potentially increasing the risk of Everglades virus exposure, Burkett-Cadena said.
Aedeomyia squamipennis spreads bird malaria, including the kinds that have devastated Hawaii’s native bird populations. These parasites already are found in Florida, but the introduction of a new carrier that feeds predominantly on birds could be worrisome for struggling Florida birds, Burkett-Cadena said.
