Newspaper article St Louis Post-Dispatch (MO)

Mosquito Control Efforts in St. Louis Take New Tactics with Zika Threat

Newspaper article St Louis Post-Dispatch (MO)

Mosquito Control Efforts in St. Louis Take New Tactics with Zika Threat

Article excerpt

The flying, biting bugs of summer could carry a new disease this year, and pest control workers are preparing for battle.

Every spring and summer, local health departments and private companies fight mosquitoes by killing their larvae in water sources and spraying pesticides to target the flying adults.

The mosquito control efforts have historically been aimed at the Culex species that carries West Nile virus, St. Louis encephalitis and other diseases.

Now a different species of mosquito threatens to spread the Zika virus, which has caused severe birth defects and other debilitating conditions across Latin America in the last year. It's the first mosquito-borne virus known to be transmitted sexually and from a mother to her fetus.

The best way to stop a virus like Zika is to kill its primary vector the Aedes aegypti and Aedes albopictus species of mosquitoes.

No one has caught the Zika virus from a mosquito in the U.S. But the two types of Zika-carrying mosquitoes do circulate across much of the country. The Aedes aegypti mosquito, considered most likely to spread Zika because it prefers to feed on people, is primarily found in Southern states. Aedes albopictus mosquitoes have been found in the St. Louis region but feed primarily on birds and other animals and plants.

If the virus takes hold in the U.S., which some health experts have said is most likely in Texas and Florida, the old methods of mosquito control will need an overhaul. Traditionally, larvicides are dropped in standing water, sewers and drainage ditches where Culex mosquitoes breed. Trucks spray pesticides down rural and city roads at night, when the mosquitoes fly around in a broad range.

But the Aedes mosquitoes are well adapted to urban living, can breed in pools of water as small as a bottle cap and prefer to bite during the day. Wide-scale insecticide spraying is not expected to be effective at targeting Aedes' short flight paths. Ideally, prevention efforts for Zika would involve inspections and treatments around every home and backyard in areas where the virus has been found.

"That's a level of intensity we've not seen before," said Dave McLaughlin, a spokesman for Clarke mosquito control based in St. Charles, Ill. "It's as if you vacuum your house and it looks clean, but now you need a different vacuum, a different method to get deeper into the fibers, and you need to do it more often."

U.S. COULD BE SPARED

There are reasons to be optimistic that the U.S. will be spared from Zika outbreaks. Other diseases carried by the Aedes mosquitoes, including dengue, chikungunya and yellow fever, have never gained traction in the continental U.S. in part because of the widespread use of air conditioning and window screens.

The most common mosquito-borne illness in the U.S. is West Nile virus, which usually causes no symptoms or mild fever, aches and pains. In rare cases, the illness can attack the nervous system and cause brain swelling and death. Locally, West Nile activity peaked in 2002, when about 120 people were sickened in the St. Louis area.

After the virus was nearly eliminated in 2010, with just three cases recorded statewide, Missouri's case count was back up to 29 last year. The mosquito population, and its ability to transmit disease, is highly dependent on weather patterns.

"Just because we don't see as many human cases one season doesn't mean the next season we won't," said Jim Sayers, acting supervisor for vector control with St. …

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