Climate change lets mosquitoes flourish in L.A.
EXPERTS CITE SPECIES OF AGGRESSIVE BITERS
LOS ANGELES • Many try and fail to make it in L.A. But one group is proving unstoppable: mosquitoes, which have taken over Southern California and are driving the humans here crazy.
New invasive, disease-bearing species originating from Asia and Africa are thriving in the increasingly long, hot and humid summers afflicting this region thanks to climate change, according to numerous public health officials. Their growing numbers are baffling and infuriating Angelenos, who, until recently, considered themselves largely exempt from the buzzing bloodsuckers that make summers miserable in much of the rest of the country.
Experts say they're here to stay. And even though mosquitoes don't pose the same danger to lives and livelihoods as wildfires or drought — at least not yet — they have become a biting reminder of an increasingly inhospitable natural world where climate change seems to pose constant new hazards.
“Californians have never experienced mosquito bites like they currently are having to endure due to these new daytime biters,” said Susanne Kluh, director of scientific-technical services at the Greater Los Angeles County Vector Control District. “This is really, really putting a big burden on our lifestyle. It's life-changing for Californians.”
Kluh's agency, funded by property taxes, is one of several in Southern California that aim to help residents control mosquitoes and detect and stop the spread of any diseases they may carry.
“Mosquitoes in L.A. seems like yet another sign that the world is crumbling around us,” said Tatiana Krokar, a 49-year-old sketch comedian who lives in the Silver Lake neighbourhood. “I mean, what's next — plague of locusts? Lake of fire?”
Many Los Angeles residents like Krokar have the impression that mosquitoes are new in town, but that's not technically the case. A small brown mosquito with the scientific name Culex has long resided here, emerging at dawn and dusk to bite birds and occasionally people. The Culex can spread West Nile virus but are often unobtrusive, and many people barely knew they existed.
What's new is a blackand-white-striped insect called Aedes, a non-native variety that includes yellow fever mosquitoes and Asian tiger mosquitoes. The yellow fever mosquitoes in particular — technically known as Aedes aegypti — are aggressive biters drawn to humans at all hours. They breed in standing water, and their eggs can lie dormant for months or even years on dry surfaces. In addition to yellow fever, they can transmit Zika, dengue fever and other diseases to humans and pets.
Populations of these frightening insects have grown steadily around Southern California in the past several years, even explosively in some areas. Residents are increasingly aware of and alarmed about their presence, and the mosquitoes are overwhelming the efforts of local government agencies to control them.
There have been no recent instances in Southern California of tropical diseases such as yellow fever or Zika spreading within the community, but officials fear that could happen and prove life-threatening for the public, given the growth of the mosquito populations in the area.
“These threats will continue to move and put our population at risk, so we need to all stay vigilant,” said Dr. Umme-aiman Halai, a medical epidemiologist at the L.A. County Department of Public Health. “A mosquito in one person's backyard affects the entire community.”
The best advice scientists and public health officials have for residents is to eliminate any standing water where mosquitoes love to breed. But it has to be a neighbourhood effort, since mosquitoes can easily travel from one yard to another, and despite the drought many Southern Californians are reluctant to limit watering their lush greenery and well-tended lawns, where water can collect within plant fronds or around sprinkler systems. Kluh expressed some frustration that L.A. residents have gone from not knowing her agency existed to finding it useless since she and her staff are unable to make mosquitoes disappear from people's yards.
“Despite our best efforts, the population is still growing,” Kluh said. “Every year the numbers in our traps have been multiplying. They just keep biting people like crazy.”
Jessie Schiewe, 32, a writer who lives with her fiancé and two chihuahuas in the Eagle Rock neighbourhood, says “I itch every bump — I can't stop myself!” Like other sufferers, Schiewe is left to endure the mosquitoes through a variety of methods, donning long sleeves and pants while watering, purchasing dubious mosquito-control gadgets from the internet or simply hiding inside, with the doors closed when she'd rather be out on the porch.
“After a hot day, you want to cool down and sit outside and smoke a joint and then you're bombarded,” said Schiewe, a native Angeleno who doesn't remember mosquitoes ever being a problem when she was growing up (marijuana is legal for recreational use in California). “It's frustrating because it's like, let me go outside and enjoy my space. ... You're not paying rent here!”
The invasive mosquitoes are thought to have arrived in Southern California through various means, including in shipments of “lucky bamboo,” the decorative bamboo arrangements that are meant to bring good fortune and have been transported from Asia, already prepared in small vases of water.
A number of scientists say climate change has played a role in the mosquitoes' spread, with California summers growing longer and hotter. Less rainfall is creating ripe conditions for wildfires, yet at the same time, rising ocean temperatures have led to more humidity.
“These are tropical mosquitoes, so the fact they were able to entrench themselves in our Mediterranean climate — or what should be a Mediterranean climate — boggled our minds at first,” said Levy Sun, communications director of mosquito and vector control in San Gabriel Valley, just east of L.A. “They just erupted across Southern California in a few short years.”
Longer term, the picture could shift if climate change continues to worsen the drought, ultimately forcing Californians to cut back on water use and abandon lawns and greenery in favour of succulents or rock gardens.