Cooke County — Virus-carrying mosquitoes are not a current Cooke County health issue, local officials said, but the resources to quell them remain at hand.

According to a state Associated Press story, more serious illnesses from West Nile virus have been reported so far this year than any since 2004, health officials said Wednesday.

Through the end of July, 241 human cases have been reported in 22 states, including four deaths. Texas, especially around the Dallas area, has seen the bulk of them.

But locally, the virus hasn’t taken any hold. City of Gainesville Community Manager John Noblitt said Friday that during the last 10 days, the city paid for a second round of “vector control” spraying through Express Services of McKinney.

The night session cost less than $1,000, Noblitt said and took only a few hours. He also explained that using a third party is much more effective for the city than any other option.

“When you’re dealing with public health safety, that cost is never an issue,” Noblitt said, but added that the expense would be three to four times higher if the City of Gainesville handled the spraying in-house. “We keep them on stand-by, and at this point we don’t need them. But if the need arises, we’re prepared to do it within 24 hours notice. We’ll continue that contract through the end of the year and if necessary, we’ll extend it.”

Noblitt added that the extreme heat may work in favor of mosquito control, and that city officials will stay in contact with the state health department to coordinate extra measures, if necessary.

One key factor in West Nile proliferation, he said, is stagnant water in hot weather, and that some city employees eliminate that where they see it in public.

“If we come across standing water that we have access to, we try to get that water dried up,” he said. “The best thing is to throw sand on it. We can’t do anything about places like the creeks. But that’s going to be your biggest solution, because if you don’t have standing water, then the mosquitoes can’t breed.”

Health officials believe the mild winter, early spring and very hot summer have fostered breeding of the mosquitoes that spread the virus to people.

Most West Nile infections are reported in August and September, so it’s not clear how bad this year will be. But it doesn’t look good.

“Unless the weather changes dramatically, we’ll see more cases (in 2012) than we have in the last couple of years,” said Roger Nasci of the Centers for Disease Control and Prevention. Nasci is chief of the CDC branch that tracks insect-borne diseases.

Mosquitoes pick up the virus from birds they bite and then spread it to people.

Only about one in five infected people get sick. One in 150 infected people will develop severe symptoms including neck stiffness, disorientation, coma and paralysis.

Of the 241 cases reported so far this year, 144 were severe cases in which the virus spread to the brain and nervous system and caused encephalitis or other problems. The last time so many serious cases were reported this early was 2004, when the number was 154.

West Nile virus was first reported in the United States in 1999 in New York, and then gradually spread across the country. Its peak occurred in 2002 and 2003, when severe illnesses numbered nearly 3,000 and deaths surpassed 260.

— The Associated Press contributed to this report.