Health Care

Yellow-fever mosquito found in 2 new areas of Madera County

The yellow-fever mosquito has been found in two new areas of Madera County, the Madera Mosquito and Vector Control District said Friday.

Abatement crews have been looking for the mosquito ever since it was discovered last month breeding in a neighborhood near the Arbor Vitae Cemetery in Madera, west of Highway 99, and in a neighborhood near Temperance and Shaw avenues in Clovis.

Friday, the district said abatement workers have discovered the insect breeding in the Madera Ranchos area near Avenue 12 and in the Parkwood area near Avenue 13 and Road 27.

The Madera Ranchos and Parkwood areas are halfway between the cities of Madera and Clovis.

Experts say the yellow-fever mosquito, known as Aedes aegypti, is an aggressive day-biting mosquito that is not native to California. It is common in hot, humid tropical areas, like the southeastern United States, Mexico, and Central and South America.

Since finding the mosquito on June 9 near the Madera cemetery, mosquito abatement crews and local health officials have worked to determine the extent of the infestation.

“Our goal is to eradicate this population” Leonard Irby, manager of the Madera County Mosquito and Vector Control District, said Friday.

“We definitely do not want this mosquito to become established in our communities,” he said. Irby said the district continues to expand its search for the mosquito by going door-to-door in the neighborhoods surrounding the infested areas. Abatement crews also are spraying larvacide and insecticide.

The Aedes aegypti is dark brown or black and has distinctive white markings.

Unlike common mosquitoes that like stagnant swimming pools, a female Aedes aegypti can lay eggs in any open container — a planter, a bucket, a bird bath, an unused dog dish or an empty beer bottle — as long as it has water.

The female mosquito also lays up to 200 eggs several times a season, and prefer to lay eggs just above the water line of the containers. The eggs then survive for months, even if the container dries out. Once the eggs are flooded, they hatch into larvae and within a week develop into adult mosquitoes. These mosquitoes can then lay more eggs.

Though it is an aggressive day-biter, the insect also is active around dusk and dawn, and is known to transfer diseases such as dengue, yellow fever, chikungunya, and several viruses that cause encephalitis, Irby said.

Although testing results on the sample of Aedes aegypti found in traps are negative for dengue and chikungunya, authorities on Friday urged the public to take precaution to prevent mosquito bites, especially since other mosquitoes can transfer serious diseases such as the West Nile virus, which is endemic to the San Joaquin Valley.

“At this time, there is no need to consider vaccination for yellow fever, unless you plan to travel in an endemic area,” said Dr. Thomas Cole, Madera County’s health officer.

Residents who experience mosquito bites during the day or detect unusual numbers of mosquitoes in one area are urged to report them to the Mosquito and Vector Control District at (559) 662-8880.

“We need the public’s help on this one,” Irby said.

Tips to control mosquitoes and avoid bites:

Check your yard weekly for water-filled containers.

Throw away or recycle water-holding containers that are not needed.

Empty containers or large objects, such as boats or old appliances, should be covered, turned over or placed under a roof so they don’t fill with water.

Clean and scrub bird baths and pet-watering dishes weekly and dump the water from overflow dishes for potted plants and flower pots.

Check that gutters are not holding water and cover rain barrels with tight screening so mosquitoes cannot enter.

Fill tree holes and other cavities in plants with sand or soil.

Check for hidden bodies of water such as wells, septic tanks, manholes, clogged drains.

To avoid mosquito bites wear long-sleeved shirts, long pants, socks and shoes. Also userepellents such as DEET, picaridin, oil of lemon eucalyptus, or IR3535 (as directed on the product label). Do not use repellents under clothing.

Also use mosquito netting over infant carriers, cribs and strollers, and install or repair window and door screens to keep out mosquitoes.

Information about control measures can be found on the district’s website: