Yellow fever mosquitoes found in Fresno, Fowler

Mosquitoes capable of transmitting deadly yellow fever, dengue and other diseases have been found in metropolitan Fresno and Fowler, the Fresno County health department announced Wednesday.

The two new finds bring the total to four in the central San Joaquin Valley. In June, Aedes aegypti mosquitoes were found in Madera County and in Clovis. Yellow fever mosquitoes have also been reported in San Mateo County this year.

The brown mosquitoes with white markings bite during the day, prefer humans and need only a teaspoon of water to lay eggs to reproduce.

So far none of the mosquitoes that have been trapped has carried diseases.

Dengue is a virus that can cause headache, body pains and a rash similar to measles. Extreme cases can be deadly. Yellow fever is a virus that causes severe flulike symptoms and sometimes jaundice. It also can kill.

The mosquitoes acquire yellow fever and dengue from infected humans and then transfer them to other people. In southern Florida, dozens of residents have been infected by dengue.

The mosquito also has been detected in Texas and Arizona.

Scientists at the University of California, Davis, and at Yale University are performing genetic testing on the yellow fever mosquitoes to determine their country of origin. Preliminary results show they could be from Central America.

Tim Phillips, manager of the Fresno Mosquito and Vector Control District, said the new finds are alarming and that authorities need the public’s help in prompt reporting to help the district eradicate the pest before it gets a foothold. Residents are asked to report mosquito bites received during the day, and report any mosquitoes that match the description: brown with white markings.

The Fresno detection came after a resident saw a vector control display last week at the Big Fresno Fair and reported daytime attacks. Likewise in Clovis, a resident complained about unusually aggressive mosquitoes.

The mosquitoes have been trapped at about 100 sites in Clovis, where vector control agents are going door-to-door warning residents to empty all standing water. Officials working along with the California Department of Public Health are spraying the insecticide promethean in and around thousands of infested homes.

“It’s very difficult to control because of its biology,” said Steve Mulligan, who is working on the Clovis outbreak. “They like humans and will come inside the house. We’re trying hard to eliminate it.”

Residents can call the Fresno Mosquito and Vector Control District at (559) 268-6565.

Protect yourself

The Fresno Mosquito and Vector Control District offers tips for staying safe:

• Apply insect repellents that contain DEET, picaridin, oil of lemon eucalyptus or IR 3535 according to label instructions.

• Use repellent, especially in the early morning and in the evening.

• Make sure that doors and windows have tightfitting screens to keep out mosquitoes. Repair or replace screens that have holes.

• Use mosquito netting over infant cribs, carriers and strollers.

• Eliminate standing water and containers that can hold water from around the home. Yellow fever mosquitoes lay eggs in water-holding containers.

• Get free mosquito fish for backyard ponds or water features from mosquito abatement districts.

• Go to the Fresno County Department of Public Health website to download a flier with information about, and images of, the Aedes aegypti mosquito.

• Call (800) 821-1577 to speak to a mosquito abatement district representative or go to


for details.