Researchers have found that two breeds of mosquitoes common in Florida have become resistant to pyrethroids, a class of insecticide commonly used against them.

Dr. Keira Lucas, Director of Research for the Collier Mosquito Control District, participated in published studies showing the resistance.

“We have over 40 kinds of mosquitoes here in Collier County. The only two that we have identified resistance in is aedes aegypti and culex quinquefasciatus. The problem is that they are the disease vectors,” Lucas said.

The aedes aegypti mosquito is known to transmit such diseases as dengue fever and Zika while culex quinquefasciatus transmits West Nile virus, among others.

Losing a previously dependable weapon against these transmitters of disease is worrying. But having come up against this for two types of mosquito now, mosquito control experts are ready with alternatives.

“Pyrethroids aren’t going to work with this mosquito; we are going to have to use a larvicide to target the juvenile form of this mosquito, or a different type of adulticide. Which would be an organophosphate,” said Lucas.

With an outbreak of dengue fever currently ongoing in the Keys and West Nile reported this week in Lee and Collier counties, experts will stay vigilant.