By Jill Cowan
6:40 PM PST, December 1, 2012
Three Huntington Beach residents, a Newport Beach man and an Irvine woman were among 45 people who were reported to have tested positive for West Nile Virus in Orange County this year as of Nov. 20. None of those cases were fatal.
Of the 107 total avian cases countywide, four birds were found in Huntington, two in Costa Mesa, one in Newport, one in Laguna Beach and one in Irvine. No horses have tested positive this year.
Although 10 human cases were reported countywide over the same period last year, this year hasn't been unusual, said Matt Zahn, the county's medical director of epidemiology.
"We have seen cases every three to five years," he said. "The numbers seem to wax and wane since we started seeing cases in the beginning of the 2000s in the U.S. We've had as many as 79 and as few as one. What's interesting about this year is that it was quiet until September and October."
Since the beginning of November, he said, infections seem to have slowed again, but he added, "we're not at the point where we're done with the season."
In many cases, Zahn said, symptoms take several weeks to appear.
While 16 of the 45 human cases resulted in a fever, 23 resulted in significantly more dangerous neuroinvasive diseases. Six cases were "asymptomatic," meaning the virus was detected but the person did not become ill.
"Neuroinvasive disease generally means you have meningitis or encephalitis," he said. "It's less common, but it's by far the much more serious illness. West Nile neuroinvasive disease is the reason we're concerned."
While West Nile Fever is "unpleasant," he said, generally people recover in several days, but in the case of neuroinvasive disease, victims can suffer from long-term brain damage.
Zahn said the reason there may seem to be an uptick in diagnoses of West Nile neuroinvasive disease this year, compared with the fever, could be attributable to fewer people with fever symptoms being tested for the virus.
The last time Orange County residents died from the virus was 2008, when three succumbed to neuroinvasive disease.
Unfortunately, Zahn said, there are no specific treatments for the virus, meaning residents should focus on prevention.
"It's another reason we pay attention to [West Nile virus]," he said. "There are ways we can avoid it."
Tips for avoiding West Nile Virus:
•Stay away from pools of standing water. They're prime mosquito breeding grounds.
•Avoid having standing water on your property. No buckets sitting out or full swimming pools that haven't been attended to.
•Avoid being out at peak mosquito-bite times, which are dawn and dusk.
•If you're going to be outdoors, wear insect repellent and clothes that cover your body.
•Report dead birds if they have been dead for less than a day. Call Orange County Vector Control at (714) 971-2421 or state officials at (877) WNV-BIRD.