CDC reports early, strong start to West Nile virus season

ODESSA, Fla. - With the Fourth of July weekend approaching, health officials are urging Tampa Bay area residents to protect themselves against mosquito bites as the Centers for Disease Control and Prevention (CDC) tracks an early and strong start to the West Nile virus season.

CDC West Nile virus tracking

What we know:

The CDC reports 48 human cases of West Nile virus across the country so far this year. Normally, the average is about 10 cases by this point in the season.

Arizona currently leads the nation with 32 cases and four reported deaths. Florida has one reported human case in Alachua County.

"It's the highest number of cases of West Nile virus at this point in the year since 2004, which actually happened to be my first year in West Nile virus surveillance," Ryan Carney, an associate professor of digital science in USF’s Department of Integrative Biology, told FOX 13. 

Florida mosquito mitigation efforts

Local perspective:

In the Tampa Bay area, both Pinellas and Pasco counties have not reported human cases, but they have reported "non-human activity," according to the CDC case map. Pasco officials told FOX 13 a sentinel chicken tested positive for the virus in April.

"The chickens don't become sick from those viruses, but the mosquitoes will feed on them. And that serves as an early warning system for us. So a positive chicken tells us that there's an infected mosquito somewhere present in the area and that the virus is circulating in that local environment," Adriane Rogers, the executive director of the Pasco County Mosquito Control District, said.

Since that April case, the district has increased surveillance, conducted targeted mosquito control, trapped and tested mosquitoes, as well as sprayed. 

"We have gone out already for now nearly two months and performed additional mitigation efforts in that local area to ensure that we're doing everything that we can to reduce those mosquito populations so that disease transmission is not sustained and that it doesn't get out into the human population," Rogers added. 

What they're saying:

She said residents should not panic after hearing news about the positive chicken and the CDC’s warning. 

"It's not a reason for alarm. Mosquito-borne diseases like West Nile virus occur somewhere in the United States every year and that's exactly why local mosquito control programs exist. Our job is to detect virus activity early, reduce mosquito populations, and help prevent mosquito-borne illness before it occurs," Rogers explained. 

Understanding the bird disease spillover

The backstory:

West Nile virus is actually a bird disease, Carney points out. 

"So it's only through, what we call ‘spillover,’ where a mosquito will bite a bird, get infected, and then transmit it to a human after they bite the person," Carney said.

By the numbers:

According to the CDC, 80% of people infected with West Nile virus do not develop symptoms. However, some people infected can develop severe illness that affects the central nervous system, requires hospitalization, or results in death.

"The risk is highest in elderly and folks who have weakened immune systems," Carney said. 

What you can do:

Residents should take proper precautions while outdoors, especially during Fourth of July celebrations. Carney suggests remembering the three Ds, especially around dawn and dusk:

1. Drain — remove any standing water around your home
2. Dress — wear loose-fitting clothing and cover exposed skin when practical
3. Defend — wear EPA-registered repellent with DEET being the "gold standard," he said.

"You also want to reapply regularly," he added. "That's an important thing that most people miss is that they just spray, and they think that they're good for the day. But you want to reapply that regularly and follow the directions on the bottle."