August rain, high heat create mosquito concerns in Northern California

SACRAMENTO — Until this past weekend, Sacramento had gone 3.5 months without a trace of rain, but those summer showers are now prompting some worries about mosquitoes.

"What we saw with the rains followed by the heat could be ideal to allow those eggs to hatch, develop into adults and then even adults to lay more eggs," said Joel Buettner, the general manager of the Placer Mosquito and Vector Control District.

Sacramento only saw a trace, but some neighborhoods in Roseville had more than two inches of rain.

The concern is over a specific type of invasive mosquito species that can transmit deadly diseases.

"Aedes aegypti, commonly known as the yellow fever mosquito, can carry yellow fever, zika, dengue, chikungunya," Buettner said.

Last year, they were detected in four Placer County neighborhoods. This year, they've spread to ten—mostly in the Roseville and Rocklin areas.

The good news is that West Nile Virus, which is transmitted by a different species, is way down this year, and Placer and Sacramento counties have not had any human cases reported yet.

That may be due to this summer's record-breaking stretch of triple-digit heat days.

"The severe early heat, I think, did a lot to kind of throw a wrench into the normal natural patterns of mosquitos," Buettner said.

However, the disease is still dangerous. Dr. Anthony Fauci announced that he was hospitalized for about a week and is now recovering.

"We see the peak of West Nile circulation about August through the very beginning of September," Buettner said.

Mosquito control districts are continuing to use drones and truck-mounted sprayers to help stop mosquitos from multiplying.

"In this case, prevention is the best policy and that's what we're out there trying to do," Buettner said.

Placer's mosquito control district is also doing additional trapping and door-to-door inspections in neighborhoods where the invasive insects have been detected.