Scientists explore new ways to target mosquitos as warming climate expands threat

Mosquitoes, despite lacking sharp teeth or claws, are responsible for more human deaths than any other animal. As the climate warms, mosquito season is extending, allowing them to spread diseases more efficiently. Ben Tracy, with Climate Central, reports on innovative methods scientists are employing to combat these pests. Tristan Hallum, Director of Scientific Programs at the San Gabriel Valley Mosquito and Vector Control District, describes receiving a shipment of 600 male Aedes aegypti mosquitoes from Kentucky.

These mosquitoes are being used to target invasive species that can transmit diseases like Zika, West Nile virus, and dengue fever. Every week, the San Gabriel Valley Mosquito Control District releases 30,000 mosquitoes containing a bacteria that inhibits disease transmission. Previous studies have demonstrated that this method can reduce disease transmission by up to 95%.

As global temperatures rise, mosquito seasons are becoming longer, with nearly 95% of cities analyzed experiencing more days each year suitable for disease-spreading mosquitoes. Tristan Hallum notes that the traditional mosquito season, which once spanned from May to September, now necessitates year-round control efforts. The mosquitoes used in these releases are male, which do not bite humans.

Stephen Dobson, President of MosquitoMate, supplies these mosquitoes. His team breeds the specific species, the yellow fever mosquito, in their lab and ships them to various control districts. These male mosquitoes carry a naturally occurring bacteria called Wolbachia, which renders them sterile and prevents females from reproducing.

This approach has been found to reduce certain mosquito populations by 70 to 95%. The World Mosquito Program is using similar methods in 16 countries, including Brazil, where it produces 110 million Wolbachia mosquitoes weekly. In some areas, dengue cases have dropped by 89%. As temperatures continue to increase and the atmosphere becomes more humid, the conditions become increasingly favorable for mosquitoes, allowing them to expand their range into previously unlivable areas.