Warm Weather Triggers Early West Nile Season

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(Sacramento, CA)
Tuesday, April 24, 2007

Outside the Loaves and Fishes soup kitchen in Sacramento, vector control employees are handing out packets of individually wrapped towelettes containing insect repellent to a group of homeless people. 

Daniel Reynolds, a homeless man who sleeps outside at night, walks away with two of the packets.

"I’m right next to the river. That’s where your mosquitoes come. But yeah, I guess I’ll try this."

Jennifer Benito with the Sacramento-Yolo Mosquito and Vector Control District says the homeless are especially susceptible to mosquito bites.

"Well, they’re out more frequently than the average person would be so that’s why we’re out here making sure that they are protecting themselves."

Back in 2005, Sacramento County was the epicenter for the infection in California with 177 human cases. The high number of infections prompted vector control district manager David Brown to order aerial pesticide spraying. Last year, there were only 16 cases.

Brown says that’s because after the virus developed into an epidemic it started to recede. 

"We don’t anticipate it being at the high levels that we’ve seen the previous two years because viruses generally you’ll seen an amplification and then it’ll tend to drop off a little bit."

One reason it’s dropping off is that local bird populations are more immune to the virus. But experts say West Nile virus is still here to stay.

Gregory Lanzaro heads the University of California Mosquito Research Program at UC Davis. 

"It’s probably a permanent part of the California environment at this time. There’ll continue to be a cycle of transmission of this virus between mosquitoes and birds in the state with occasional outbreaks into human and equine populations as well."

Lanzaro says most people who contract the virus never even know it. Only a small portion actually get sick.  

"In perhaps 15% or so of cases people will develop a mild flu like illness and then in a very small percent of people will go on to develop an illness that involves the central nervous system and that’s the one that we’re most concerned about."

Even though the virus is subsiding and few people get sick from it, the vector control district is spending $450,000 this year on a “Fight the Bite” media campaign, about the same amount as last year.

Jennifer Benito with the district says they want residents to be prepared in case West Nile flares up again or another mosquito-borne illness develops.

"We want to make sure that people understand that they need to protect themselves from mosquitoes today, tomorrow and in the future because we don’t know what virus is going to be coming in the future so if they have those basic principles now and set then hopefully they’ll be able to protect themselves when the next virus comes." 

And that message seems to be getting through to the homeless men and women at Loaves and Fishes – including Donna Bradley who spends nights near the Sacramento River. 

"…and with all the rains and everything like that, of course we’re afraid of it. I don’t want West Nile virus. It’s scary, it’s scary." 

State health officials have not identified any human cases of West Nile virus so far this year. But 8 California counties have already reported infections in mosquitoes, chickens and horses.