Aedes aegypti mosquito. Photo via VectorBase.org
Aedes aegypti mosquito. Photo via VectorBase.org

County officials reminded San Diegans Friday to remain vigilant and remove standing water where mosquitoes can breed.

In past years, mosquito abatement was focused on stopping the spread of West Nile virus. But now, with the invasive Aedes mosquito taking hold in the region, tropical diseases like the Zika virus are also a concern, according to the county.

Supervisor Greg Cox said at a news conference that the fight against Zika will be waged “neighborhood by neighborhood, backyard by backyard,” and the public needs to be involved.

“Dumping out standing water inside and outside your homes is really important,” Cox said.

“Because if you don’t you could be growing invasive Aedes mosquitoes,” he said. “They can breed literally in a bucket, a discarded cup, in a toy left outside in the yard, even a bottle cap.”

The county does its share by making aerial drops of a granular larvicide that is harmless to people and pets, but kills mosquito larvae, on 48 waterways around the region. It treats another 1,400 potential breeding areas by hand, gives out free mosquito-eating fish, collects and tests dead birds for West Nile virus and tracks Zika cases.

The Aedes mosquitoes, which are black with white stripes, spread to San Diego County only a couple of years ago. The mosquito differs from the native variety by showing a preference for being in or around houses and biting during the day. Native mosquitoes feed outside at dusk and dawn.

County health officials said nearly all of the more than 80 San Diegans sickened with Zika contracted the illness while traveling overseas — with a couple of sexual transmissions from people who just returned to the area.

Zika has not been found in a local mosquito, according to the county. Nonetheless, when Aedes mosquitoes were discovered near the homes of 10 people with the disease last year, county officials sprayed the neighborhoods to keep the illness from spreading.

Most people infected with either the Zika or West Nile virus don’t experience symptoms. Deputy Public Health Officer Dr. Sayone Thihalolipavan said around 20 percent will feel like they have a mild case of the flu.

However, both illnesses have the potential for far worse impacts. Zika cases involving pregnant women have been blamed for causing microcephaly, which leaves infants with smaller brains and skulls. One San Diego child was recently born with the condition.

WNV is fatal in about one in 150 cases, with the risk increasing for patients over the age of 50, Thihalolipavan said.

The county Department of Environmental Health urged residents to report to them if they’re bitten by mosquitoes during daylight hours, or if insects that match the description of Aedes mosquitoes are spotted, by contacting the Vector Control Program at (858) 694-2888.

— City News Service