Watch out for 'day biters' this Halloween -- and beyond

This Halloween, scary little monsters could be waiting to bite your arms and ankles – and some don’t wait until dark. They bite in broad daylight.

Mosquitoes seem to be particularly voracious this late October, ready to stick it to this evening’s trick-or-treaters. (They’ve certainly been nibbling on this gardener during late afternoons and evenings.)

An alert by the Sacramento-Yolo Mosquito & Vector Control District brings additional cause for alarm: The Asian tiger mosquito has been found for the first time in Sacramento County.

Aedes albopictus is the second invasive mosquito species to be detected in Sacramento County, joining the yellow fever mosquito (Aedes aegypti). Both are small, dark mosquitoes that bite aggressively during the day. And both have the potential to transmit deadly viruses.

This is how the vector experts found the first tiger mosquito, according to the district’s press release: “The initial detection came as a result of a call from a resident in Carmichael who had reported being bitten during the day. District staff conducted a backyard inspection and found a single mosquito larva in a watering can. In response to this initial finding, field technicians conducted door to door inspections in other homes throughout the neighborhood and found additional Aedes albopictus adult mosquitoes and larvae in surrounding areas.”

Both the tiger and yellow fever mosquitoes lay their eggs in all sorts of vessels – anything that can hold a few spoonfuls of water. When moisture collects in that container, the eggs hatch.

“Now that we have found this second species of invasive mosquitoes, our goal is to limit their expansion as best we can,” said district manager Gary Goodman. “We are mobilizing and responding quickly in order to protect the residents we serve.”

Besides both being day biters, both species of invasive mosquitoes can breed indoor or outdoors, making them doubly hard to control.

“They lay eggs above water in containers such as flower pots, pet dishes, bird baths, kids toys, tin cans, tires and other containers as small as a bottle cap that are commonly found in backyards,” says the vector district.

“Public cooperation is very important and we need your help,” said Goodman. “If you are being bitten by mosquitoes or notice them in your yard, please give the District a call to request a free inspection.”

Although they haven’t done it yet (at least as far as authorities know), both species can transmit several dangerous viruses including dengue, chikungunya, Zika and yellow fever. To do so, the insects need to bite someone carrying that virus.

In Carmichael, vector district field technicians will conduct door-to-door inspections to look for potential mosquito breeding sites, making appropriate treatments as necessary and talking to residents about preventive measures around their home, says the district.