If you hear a low-flying plane, it’s most likely an effort to combat mosquitos.

The Turlock Mosquito Abatement District has been conducting aerial spraying in Ceres, Turlock, Denair and Newman.

So far this year in the TMAD, 16 mosquito samples have tested positive for West Nile Virus — up from seven in the last report, according to vector biologist Monica Patterson. Three birds have tested positive for West Nile Virus in Ceres, including Ceres River Bluff Regional Park as recently as July 6; Smyrna Park on June 20 and in the Morgan and Kinser area on June 6.

Also, 51 birds have tested positive for the virus statewide — none in the Turlock district, but one in neighboring Modesto. So far, there have been no cases reported in horses or humans, and no recordings of the St. Louis encephalitis virus.

“Usually, West Nile is more predominant than St. Louis,” said Patterson, who’s been with TMAD for 15 years. “Seven is a bit low. In light of the updated results I would say we are moving into average territory. We anticipate more as the weather heats up. And we know those numbers tend to escalate in Stanislaus County in July, August and September.”

According to Weather.com, the 10-day forecast for Ceres shows triple digits arriving Friday and reaching 111 by Sunday.

While the number of West Nile Virus samples may be below average for this time of year, overall mosquito activity is up.

“We place traps every week, and collections have been above average,” said Patterson, who pointed out that the excessive rain in the early part of the year, which led to flooding in parts of the region, has been a contributing factor.

“We encourage residents to use repellents and wear long sleeves and pants, if possible,” said Patterson. “And limit outdoor activities at dusk and dawn, when mosquitos are most active.”

Lise Talbott, public health administrative operations manager for the county’s Health Services Agency, advises everybody to be cautious this time of year.

“Human infection is less likely, but certainly a risk,” said Talbott. “Eighty percent of people infected don’t get any symptoms. The 20 percent that do, will get a fever, headache, nausea. Most recover quickly, while some might continue having symptoms for a couple of weeks.”

Less than one percent of human cases will affect the brain and central nervous system, and even fewer result in fatalities.

“We want to encourage residents dump and drain any standing water,” said Talbott. “Pet dishes, flower pots, kiddie pools — even a capful of water is enough for mosquitos to breed.”

Visit turlockmosquito.org and click on the “Treatment Notification and Treatment Maps” sector (then hover over the shaded polygons) for further information.

Local residents who live in the Eastside Mosquito Abatement District,  can call 209-522-4098 or visit eastsidemosquito.com for updates.

To report a dead bird, call 1-877-WNV-BIRD (968-2473).

“One thing your readers might find interesting is the reason we track sick birds,” said Talbott. “They’re a good indicator of when West Nile Virus is really active in a community.”