Why more mosquitoes are showing up in LA, and what happens when they draw our blood

People who’ve been doing a safe little backyard BBQ or early evening walk at the park have probably battled dreaded mosquitoes. It seems like there have been more mosquitoes this year. They spread all kinds of diseases. On Wednesday, Orange County announced its first death of the year from West Nile Virus. In South LA, an elderly patient died last month. What’s going on with all the mosquitoes this year?

Lila Higgins, senior manager for community science at the Natural History Museum of Los Angeles County, says she never experienced mosquitoes where she lives in Koreatown until recently.

She says LA actually got new species of mosquitoes around 2011. “We have the Asian tiger mosquito, the yellow fever mosquito, and the Australian backyard mosquito. All three of those are not originally from the Los Angeles area. And they are here now. Their numbers have gone up in the last couple years. And one of their common names is ankle biters.”

She clarifies that only female mosquitoes bite humans. “They’re looking for a blood meal. And that blood meal is something that they need so they can lay eggs. So it’s the females that bite us. The males, they actually just eat nectar.”

She continues, “As they are ready to suck out some blood, some of their saliva goes in. And the proteins in that saliva cause mild immune reactions by us. So that’s where the redness and the swelling — the little bumps — come from each mosquito bite.”