The Mosquitoes have Arrived

By Mary O’KEEFE

The Greater Los Angeles County Vector Control District [GLACVCD] has confirmed a West Nile virus [WNV] positive mosquito sample in LA County. The positive mosquito sample was collected from a trap in Long Beach.

GLACVCD monitors 35 cities and portions of the unincorporated area of LA County. Two trap sites are set in every city, said Anais Medina Diaz, spokeswoman for GLACVCD.

“We pooled 50 mosquitos [from Long Beach] and [sent them] for testing,” she added.

The results came back positive for WNV, a bird virus that is primarily transmitted among birds by mosquitos. WNV is transmitted to people and animals through the bite of an infected mosquito.

The virus was originally discovered in Africa. It migrated to the eastern United States in 1999, spread through the middle of the country and was first confirmed in California in 2003.

According to the GLACVCD, one in five persons infected with West Nile virus will exhibit symptoms that can include fever, headache, body aches, nausea and a skin rash. The symptoms, which occur between five and 15 days after being bitten by a mosquito, can last for several weeks. The symptoms can be severe and in some cases fatal. There is no cure for WNV.

There is another mosquito that GLAVCD is also watching for called Aedes.

“The Aedes mosquito [is known] to transmit diseases like the Zika virus,” she said.

Diaz added they are aggressive biters.

“They can bite the whole day,” she added.

Most mosquitos normally bite from dusk to dawn but the Aedes do not follow this pattern. Aedes mosquitos have been found in several counties including Los Angeles County; however, the diseases the mosquitos can carry have not been found in LA County.

“We don’t have any [evidence] that the mosquitos [here] have transmitted those diseases [like Zika],” she said. “No local cases.”

Aedes is a tropical mosquito not natural to California. Aedes are imported into the state by those who travel to more tropical areas then return to California.

GLACVCD is aggressively investigating to minimize risks, including going into neighborhoods.

There have been more mosquitos found in the state in part due to rising temperatures.

“Climate change does play a [role],” Diaz said. “Mosquitos thrive in warmer tropical weather.”

The recent shift of more rain and hotter temperatures have made a perfect environment for mosquitos to thrive and multiply. According to the National Oceanic and Atmospheric Administration (NOAA), July 2018 was the hottest on record in California. The average Earth temperature has increased by 1.4 degrees Fahrenheit since 1880, with two-thirds of the warming occurring since 1975.

The hot, humid weather creates the perfect incubator for mosquito eggs.

“Our mosquito [season] used to be from May to October but now runs from March to December,” Diaz said.

This is why it is important for the public to know what to do to help stop the spread of the mosquitos in the area.

“Many mosquito repellents are available to prevent bites, but they do not all work equally well. The Centers for Disease Control recommends products with the active ingredients DEET, Picaridin, IR3535, or oil of lemon eucalyptus as being safe and effective against mosquitoes that can transmit disease when used according to the labels. Wearing loose-fitting long sleeves and pants can also help deter bites,” according to the GLACVCD website.

In addition to repellents to help protect from being bitten there are actions that can be taken to reduce the mosquitoes’ breeding area. Any water left standing for more than one week in containers such as flowerpots, fountains and pet dishes provides an ideal breeding habitat for mosquitoes. GLACVCD reminds residents that even the smallest water source can contribute to a large public health problem.

There are some simple steps that can help reduce the threat of West Nile virus, and the spread of the mosquito population: Eliminate standing water in clogged rain gutters, rain barrels, discarded tires, buckets, watering troughs or anything that holds water for more than a week. Ensure that swimming pools, spas and ponds are properly maintained. Change the water weekly in pet dishes, birdbaths and other small containers. Request mosquitofish from your local vector control district for placement in ornamental ponds. Wear insect repellent when outdoors where mosquitoes may be present. Report neglected [green] swimming pools in the neighborhood to the vector control district.

For more information or questions/concerns, contact GLACVCD at (562) 944-9656 or online at www.glacvcd.org.