Birds are first line of viral defense
By Brian Joseph -- Bee Staff Writer
Published 2:15 am PDT Sunday, October 2, 2005
Story appeared in Elk grove laguna section, Page N8
Scattered about Sacramento and Yolo counties are 10 chicken coops the Sacramento-Yolo
Mosquito and Vector Control District maintains for research.
When bitten by a mosquito infected with West Nile virus, chickens develop antibodies and don't get sick or die.
That makes chickens the equivalent of a canary in a coal mine. Every season,
new birds are put in the coops, and blood is tested every other week for
West Nile virus. When a bird tests positive, district officials know where
the disease is traveling.
By mid-September, 46 of the district's 97 chickens had tested positive. The
sentinel chicken program usually stops in November and resumes in the spring.
But not this year.
District officials plan to keep chickens year-round to monitor the virus over the winter.
In other communities, West Nile virus infection rates have followed a bell
curve, said Dave Brown, district manager. Rates peak, usually the year following
the disease's discovery in a community; then they decrease. West Nile was
found in Sacramento County last year; district officials thought 2005 would
be the year it peaked.
But that's not necessarily how it will play out. Brown said there are several
theories. One is that aerial spraying could have suppressed the virus enough
so it hasn't burned itself out yet. Under that scenario, Sacramento could
be in for another high infection rate next year.
"I don't know if we've had it out here long enough to know how it's going to be," Brown said.
That means the district must prepare for another potentially rough summer.
Woody Schon, senior fish culturist, is gearing up to produce 6,000 pounds
of mosquitofish next year, the largest number ever by the district's fisheries
department. The fish eat mosquitoes.
"I don't know what next year's going to bring," he said, "so I want to be prepared."
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West Nile Virus