You know the sound or feeling of a mosquito bite: A nasty itch, a red welt, and the risk of more serious symptoms. And it seems like more mosquitoes are biting than ever.
"This is a notable year. It started early. These are higher numbers than we've had in quite a while," said Cary Svoboda, Environmental Health Specialist with Ventura County’s Vector Control program.
There are concerns that there’s a significant uptick in the number of mosquitoes carrying West Nile Virus in the county. That’s not because more people have developed the disease, but because of another indicator of the virus: Dead birds.
"West Nile virus is naturally occurring in birds and mosquitoes," said Svoboda. "Its natural cycle is going from bird to mosquito, then from that mosquito to another bird, and on and on. And humans and other animals are dead-end hosts, but we can get sick from it."
"It seems counter-intuitive," said Svoboda of mosquitoes biting birds. "But they're very good at climbing their way up through the feathers. They can sense where the skin is closer to the surface, and when birds are roosting at night, they make good little feeding stations."
A bird collected in Camarillo and two birds in the city of Ventura tested positive for West Nile this month. That brings the total number of WNV-positive birds in Ventura County this year to six.
"That is a relatively high amount of West Nile activity. In addition to that, we also trap and test mosquitoes, and we've had one mosquito pool or batch of mosquitoes test positive this year," Svoboda said.
Statewide, the California Department of Public Health says we're at a five-year high of West Nile Virus activity.
The U.S. Centers for Disease Control and Prevention tracks U.S. cases of West Nile at the county level. The CDC also noted at the beginning of July that the disease was off to an unusually strong start this year, with 46 cases reported so far in California.
For about 80% of people infected by the virus, WNV won’t cause symptoms. About one in five will develop mild symptoms. But some people, about one in 150, can develop a serious infection of the central nervous system.
With current warm temperatures, Svoboda said it’s important to protect yourself from bites with clothing and insect repellent. Also, make sure mosquitoes don’t have standing water to breed in.
Ventura County health officials recommend taking the following precautions to minimize exposure to West Nile virus:
- Use an EPA-approved insect repellent containing Picaridin, DEET, Oil of Lemon Eucalyptus (or PMD), or IR3535
- When outdoors, wear long pants and long-sleeved shirts and limit activity, especially at dawn and dusk
- Ensure doors and windows have tight-fitting screens without holes
- Eliminate all standing water (i.e., potential mosquito breeding sources) from your property
"This year they got a real head start with our early heat, and they develop faster in high temperatures. The adults that are hatching out are really thriving in this warm, humid weather. And the virus is more transmissible in high temperatures as well," he said.
"It's really a helpful signal and reminder for people to take precautionary measures because there isn't any treatment for West Nile virus for humans at this time. There's no vaccine. There are preventative measures. You can eliminate mosquito breeding on your property. You could make sure your doors and window screens are in good shape and closed, and take particular care against West Niles virus at times when the mosquito species is active, between dusk and dawn."
WNV can affect humans, horses, and birds. For information on WNV in horses, the owners should contact their veterinarian.
To report mosquitoes or potential mosquito breeding sources in Ventura County, you can call the mosquito complaint hotline at 805-658-4310.
The Division also provides mosquito-eating fish to the public to use in non-maintained swimming pools, ornamental ponds, and similar water features. To request the fish, call 805-662-6582.
You can also report wild birds that have died recently at westnile.ca.gov, or at 877-968-2473.
