BERGEN COUNTY, N.J. — The mosquitoes are biting, and Bergen County officials are warning residents to fight back before the pests become a bigger public health threat.

“We are doing a lot of control operations right now around the county to prevent human infection,” said Matt Bickerton, Bergen County’s entomologist.

The warning comes as mosquito season hits its peak and testing shows Bergen County has some of the highest levels of West Nile virus in its mosquito population.

“Right now is when the virus starts to really pick up,” Bickerton said. “Our mosquito population in Bergen County has some of the highest numbers of the West Nile virus. It’s really a hot spot right now.”

So far, no human cases have been confirmed in Bergen County this season. But Bickerton said this is typically the point in the summer when human infections begin appearing.

West Nile can cause flu-like symptoms including fever, headache, body aches and sometimes a rash. More serious cases can involve high fever, stiff neck and swelling of the brain, according to the New Jersey Health Department.

And residents have plenty of work to do.

Mosquitoes can breed in less than a half-inch of water, with the invasive Asian tiger mosquito currently the county’s “biggest nuisance.”

“They’re kind of small, black-and-white and real pesky little mosquitoes,” Bickerton said. “They are producing and laying eggs in anything that has just a little water in it.”

That means checking children’s toys, gardening equipment, tarps and anything else sitting outside that can collect rainwater. Bickerton recommends residents inspect their yards several times a week, particularly after rain.

He also warned against the viral “bucket of doom” mosquito-control trend, in which residents leave water in a bucket containing a mosquito-killing “dunk.” The tablets typically last about 30 days, meaning a forgotten bucket can quickly become a breeding ground.

“If you forget to replace the dunk in so many days, you’re now going to have a mosquito habitat that can produce thousands and thousands of mosquitoes in weeks,” Bickerton said.

The county operates roughly 5,000 inspection and trap sites and uses surveillance, testing and spraying to track mosquito populations and diseases. Bergen is also among the few counties in New Jersey able to test its own samples and receive real-time data.

Residents can request a free mosquito inspection through the county’s Office of Mosquito & Vector Control.

Meanwhile, Bergen is turning to technology. The county has begun using a large drone as it looks to replace helicopter treatments used to reach inaccessible bodies of water, including areas around the Meadowlands near MetLife Stadium.

The goal is simple: stop the mosquitoes before they reach people.

And this summer, officials say, that starts in every backyard.