Home HEALTH Yes, you’re being bugged by a new (for us, anyway) mosquito – The Mercury News

Yes, you’re being bugged by a new (for us, anyway) mosquito – The Mercury News

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Yes, you’re being bugged by a new (for us, anyway) mosquito – The Mercury News

Ouch… No, scratch that. Not all of the many, many mosquito bites you’ve suffered this summer – those bites that, weirdly, are mostly around your ankles – are super painful. But they are itchy. And they’re potentially bad news.

The ankle biters are invaders, varieties of a non-indigenous mosquito species – Aedes – that’s only recently arrived in Southern California. And these new-to-the-neighborhood bugs have the potential to carry a host of diseases that previously haven’t been common to the region.

Here’s what you should know about our new blood enemies:

What is Aedes?

Technically, two types of Aedes – both of which can be identified by black and gray spots and longish (for mosquitoes) tails – have been identified in big numbers in Southern California.

One, Aedes albopictus, commonly called the Asian tiger mosquito is, as the name suggests, from Asia. The other, Aedes aegyptai, is believed to be from South America and goes by a scary common name – the yellow fever mosquito. One or both versions of Aedes have been reported in Los Angeles, Orange, Riverside and San Bernardino counties.

The Asian Tiger initially popped up in Southern California in the early 2000s, was briefly driven away, and returned to stay in 2011, according to published reports. The South American invader has been here for about five years, but vector control agencies in Los Angeles, Orange, Riverside and San Bernardino have seen populations grow quickly in the past two years.

The South American biter is generally viewed as tougher to control than the Asian Tiger and it carries the potential to spread more disease.

  • The Orange County Mosquito and Vector Control District sprays DeltaGard, a water-based public health mosquito control product, while canvasing a neighborhood in Anaheim on Tuesday, Sept. 10, 2019. A reported increase of West Nile Virus activity in Anaheim and Buena Park resulted in three days of spraying a 4.5 square mile area containing approximately 8,883 properties. (Photo by Kevin Sullivan, Orange County Register/SCNG)

  • Orange County Mosquito and Vector Control District Technician John Savage measures the breeze before canvasing a neighborhood in Anaheim on Tuesday, Sept. 10, 2019. Savage was driving a truck-mounted spraying unit to deliver DeltaGard, a water-based public health mosquito control product, after a reported increase of West Nile Virus activity in Anaheim and Buena Park. (Photo by Kevin Sullivan, Orange County Register/SCNG)

  • The Orange County Mosquito and Vector Control District sprays DeltaGard, a water-based public health mosquito control product, while canvasing a neighborhood in Anaheim on Tuesday, Sept. 10, 2019. A reported increase of West Nile Virus activity in Anaheim and Buena Park resulted in three days of spraying a 4.5 square mile area containing approximately 8,883 properties. (Photo by Kevin Sullivan, Orange County Register/SCNG)

  • Orange County Mosquito and Vector Control District Technician John Savage, left, and Assistant Vector Ecologist Kiet Nguyen, inspect their truck-mounted spraying unit before canvasing a neighborhood in Anaheim on Tuesday, Sept. 10, 2019. They were part of a team spraying DeltaGard, a water-based public health mosquito control product, after a reported increase of West Nile Virus activity in Anaheim and Buena Park. (Photo by Kevin Sullivan, Orange County Register/SCNG)

  • Orange County Mosquito and Vector Control District GIS Coordinator John Newton and Assistant Vector Ecologist Kiet Nguyen, at right, go over their planned route before canvasing a neighborhood in Anaheim on Tuesday, Sept. 10, 2019. They were part of a team using a truck-mounted spraying unit to deliver DeltaGard, a water-based public health mosquito control product, after a reported increase of West Nile Virus activity in Anaheim and Buena Park. (Photo by Kevin Sullivan, Orange County Register/SCNG)

Why does a new mosquito matter?

A couple of reasons.

First, until now, Southern California has been the rare warm-weather region blessed with fairly mellow mosquitoes.

The mosquito that’s indigenous to our area, Culex (typically called the common house mosquito), isn’t particularly aggressive, dining on humans only when they can’t get their preferred meal, bird blood.

Also, Culex mosquitoes need a few centimeters of standing water – such as a puddle in an abandoned pool or an overflow from your garden – to lay their eggs. That requirement makes it easier for local vector control departments to develop strategies to control Culex mosquitoes.

The invaders are different.

Aedes mosquitoes prefer human blood and bite repeatedly, particularly right after sunrise. They also don’t need much water (an overturned soda cap or the merest hint of a puddle can do the trick) to breed, making them difficult to control. Some viable Aedes eggs even have been found clinging to the dry surface of a container even after all water has been removed, a level of biological tenacity that presents a new challenge for vector control agencies.

If Aedes sticks around, the kind of routine human vs. mosquito cage match that’s common in Florida or Louisiana also could become the norm in Southern California.

The other issue is disease.

Culex mosquitoes can carry West Nile, a disease that is debilitating and occasionally lethal for humans. California has had 62 human cases of West Nile so far in 2019.  As of Sept. 6, that included five cases in Los Angeles, one in Orange County and two each in Riverside and San Bernardino counties, according to WestNile.ca.gov.

Aedes mosquitoes can transmit West Nile, but they also can carry a host of other diseases – dengue fever, chikungunya, Zika and yellow fever, among others – that aren’t common in Southern California. Those tropical diseases haven’t popped up regionally, yet, and there’s no guarantee that they will. But the emergence of Aedes drastically ups the odds.

Is climate change a factor in this?

Yes and no.

Vector control agencies in Southern California note that both the Asian tiger and yellow fever mosquitoes came to the region through trade, probably by tagging along in products shipped to the region. So climate change didn’t drive Aedes here.

But warm weather does lead to more mosquitoes, and above-normal winter temperatures can mean longer mosquito breeding seasons. A hotter planet will be one with more mosquito bites.

That’s a potentially dangerous fact.

A recent study by researchers from Georgetown, University of Florida and Stanford, among others, looked at how global warming will change mosquito populations, and how the spread of those bugs will mean a corresponding spread of tropical diseases to non-tropical places. Those researchers predict global warming will boost the number of tropical disease infections by as much as one billion per year. At least some of those infections figure to hit people in Southern California.

So, how do we kill these suckers?

The regional war against mosquitoes generally rests on three things. 1. Public education (getting people to drain standing water from their gardens and pools, etc.). 2. Spraying some mosquito death fog. 3. Tossing so-called “mosquitofish” (Gambusia affinis) into standing water as a way to wipe out mosquito eggs.

On a personal level, people in Southern California have found they get fewer bites by keeping screens closed and wearing EPA-approved insect repellent.

But the fight to eradicate Aedes might include something else – genetic warfare.

In Brazil, three years ago, bug experts from the World Health Organization released sterile and genetically modified bugs to reduce the growth of yellow fever mosquitoes. In Fresno, two years ago, a subsidiary of the company that runs Google released some 20 million stale male mosquitoes to wipe out another population of yellow fever mosquitoes. Both of those programs helped push down local mosquito populations.

Earlier this summer, bug experts began releasing sterile male Asian tiger mosquitoes in south El Monte, and sterile male yellow fever mosquitoes in part of East Los Angeles, to reduce those bug populations in those areas. It’s unclear if those strategies will be effective or affordable, but it’s a potential sign of the future.

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