Douglas County's total of West Nile virus cases has risen to 10. In addition to the case of a 34-year-old woman reported in early August, at least two more residents older than 50 have contracted the critical neuroinvasive form of the virus in recent weeks.
Three of the cases here have been the milder form, without the neuroinvasive involvement that results in encephalitis or meningitis and at press time, the remainder of the cases had not been differentiated between the two forms of the disease that are reported.
The number of West Nile virus cases reported in Nevada has risen significantly in August, from 42 to 55 in the past week, according to Martha Framsted, spokeswoman for the Nevada Health Division.
The first serious case in Douglas County, in a woman under 50 years old, was reported Aug. 1, Framsted said.
Nationally, the number of cases of West Nile peak in August, according to the Centers for Disease Control.
Ed Foster, spokesman for the Nevada Department of Agriculture, said two wet winters followed by scorching summer temperatures have provided excellent breeding grounds for mosquitoes in Nevada.
"In a couple of counties, like Humboldt and Elko where they received above-normal precipitation, there is still standing water," he said. "That has increased the habitat. Everything is thriving, including the mosquitoes."
Elko County's total has risen by two cases for a total of 10 for the season and Humboldt County's total is now 13, another two cases from the previous count, according to Framsted.
Carson City's total has risen from two to four cases. Lyon County's total has risen from seven to four.
Three to five days of hard freezes will stop the mosquitoes, but mosquito season will probably extend into September. Every county in Nevada has reported West Nile Virus activity, but conditions in Douglas County with respect to fighting the spread of this disease are on a par with the best, he said.
Foster applauded the efforts of Douglas County's mosquito control officer Ron Lynch.
"It's impossible to cover every inch of a county," he said. "These people are putting their heart and soul into it."
Lynch said about 1,028 acres between Mottsville and Centerville lanes were sprayed Friday. Last week after the thunderstorms, he received 50 calls from the Johnson Lane and Fish Springs areas and spent six hours fogging those areas. Spraying under the right conditions, minimal wind and cooler temperatures, is critical and the ideal time is often between 10 p.m. to 3 a.m., Lynch said.
He expressed frustration over the lack of information from State Health officials, who he feels should tell him where people live who have contracted West Nile Virus so he can spray affected areas.
He heard of one of those cases through word of mouth and subsequently discovered positive mosquito pools after setting traps near that patient's home.
"The Health Department says I can't do anything about it anyway," he said. "But when I knew where the case was, I had something to go on."
Foster said for the most part, human beings are far too mobile to be good indicators of where the disease is being generated. Birds, horses and mosquitoes are much better indicators because they are more stationary. Positives in birds start dropping in four to five years after the disease is introduced to an area, as those susceptible to the infection die off and those who have survived are immune to the disease.
About one in 150 people infected with West Nile Virus will develop a severe form of the illness. Symptoms are high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis, and may last for several weeks, according to information from the Centers for Disease Control.
Standing water is critical to successful breeding for mosquitoes and should be eliminated. Screens should be installed or repaired if necessary. Mosquito repellent should be used, especially in the evenings or early morning and long sleeves and pants are recommended during those periods, to keep mosquitoes at bay.
Up to 20 percent of those infected will have fever, headache, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms can last just a few days, but even healthy people have been sick for several weeks.
The vast majority, about 80 percent of those contracting the disease, will experience no symptoms.
Susie Vasquez can be reached at svasquez@recordcourier.com or 782-5121, ext. 211.
