By Sean Rabé
The positive test result came after the infected person donated blood. Health officials would not release the name of the individual or where the person lived due to confidentiality issues.
“This person made a blood donation and our screening process picked up the positive test result,” health department nursing director Angel LeSage said Wednesday. “The person has shown no symptoms of the disease, however. This will probably be one of those cases where there are no symptoms shown, which happens in a lot of cases.”
“The appearance of West Nile Virus in Amador County is not a surprise,” said Dr. Bob Hartmann, county health officer. “WNV has been detected in eight birds and two horses in the last six weeks. As the virus has moved across California, we have been preparing for its arrival in our county. It is important that people be aware of WNV and know that there are measures they can take to minimize exposure to mosquitoes and reduce the chance of becoming infected.”
LeSage said that because those who are infected with the disease are often asymptomatic, it is “absolutely possible that others in the county who are infected haven´t been sick enough to show symptoms.”
Despite the recent spraying of pesticides to control the mosquito population in Sacramento and San Joaquin counties, LeSage said she doesn´t think Amador County will take such measures.
“There has been discussion about spraying with the county´s West Nile Virus Task Force, but I don´t think it will happen,” she said. “There has been more virus activity in the Ione and Camanche areas and the task force has been evaluating if spraying would be necessary. It´s not a public health department call, however; it´s an agriculture department call. If something were to happen we would certainly let residents know well in advance.”
As always, prevention is the best defense against contracting West Nile Virus, LeSage said. She referred specifically to the use of mosquito repellents containing DEET, picaridin and lemon oil of eucalyptus.
“The No. 1 thing people can do is to work on prevention,” LeSage said. “The mosquito season is still strong until we reach daytime temperatures topping out at 60 degrees.”
As of Tuesday morning, a total of 416 human West Nile Virus infections have been reported statewide. The largest concentration of human cases has been Sacramento County, which has seen 97 cases reported. Riverside County is the next closest county in terms of human cases with 51 reported.
Like the positive human case in Amador County, most individuals who are infected with WNV will not experience any illness, the county´s health department reported.
The disease is a form of encephalitis transmitted by mosquitoes and causes an inflammation and infection of the brain. Before 1999, it had not been documented in the Western Hemisphere.
Though the vast majority of infections still occur only in birds and horses, the insects then can transmit the disease to mammals while biting to feed. There have been cases of infection in cats, bats, skunks, squirrels and domestic rabbits.
Not all mosquitoes are infected with the disease. Even in areas where the virus is circulating, very few of the insects carry the virus. And even if a mosquito is infected, less than 1 percent of people who get bitten and become infected become severely ill.
Among humans, those infected with the disease and suffering from severe symptoms have a case-fatality rate range from 3 to 15 percent. The elderly and children seem to be most at risk for illness.
When symptoms do occur they can include fever, headache, nausea, body aches, a rash, swollen lymph nodes and encephalitis. However, most people infected with the virus have no symptoms. There is no treatment for the disease other than supportive care.
The county has embarked on an ongoing public education campaign since early spring, reminding people to eliminate mosquito breeding grounds and to avoid mosquito bites.
The disease is generally transmitted to humans and animals through a mosquito bite. Mosquitoes become infected when they feed on infected birds. Individuals can reduce their risk of mosquito-borne diseases by taking these precautions:
• Avoid spending time outside when mosquitoes are most active, especially at dawn and the first two hours after sunset.
• When outdoors, wear long pants and long-sleeved shirts.
• Apply insect repellent containing DEET according to label instructions.
• Make sure that doors and windows have tight-fitting screens. Repair or replace screens that have tears or holes.
• Eliminate all sources of standing water, which can support mosquito breeding.
Reprinted with permission from Amador Ledger Dispatch
This post was last modified on 01/31/2009 2:31 pm