Ventura County's water recycling plant in Fillmore has some unusual residents: A flock of chickens.
"The reason that chickens are at a water treatment facility is that it's a protected location," explained Steve Solomon from the county's Vector Control Program. The chickens are on watch duty, acting as sentinels looking out for signs of viruses carried by mosquitoes, including West Nile.
"Sentinel chickens have been used for decades as a surveillance method for mosquito-borne diseases," said Solomon.
Why chickens?
"Chickens are a dead-end host," Solomon explained. "If they're bitten by a mosquito carrying West Nile virus or encephalitis, it ends there. It can't be transferred back from the chicken to the mosquito. Also, chickens don't typically die from it, as some wild birds do."
Once every two weeks, Solomon is tasked with taking a small blood sample from the chickens in this flock.
"Sentinel means that they're being used to detect something in the environment, in a way, like the old cliché would be a canary in the coal mine," he said. "These chickens are just sitting here stationary. If one of these chickens tests positive for antibodies that show they've been exposed to West Nile virus or encephalitis, we know that there are mosquitoes in this area carrying that."
One by one, he gently catches and cradles the chickens between his knees. They don’t seem to like the chase, but once he’s holding them, they relax, and he makes a small prick in their comb.
"It is a poke, so it probably doesn't feel good to get poked, but it's very quick and not very painful, and we're just taking blood samples. We're not doing experiments on the animals," he said.
"There's an art to handling the chickens," Solomon explained. "You want to be gentle, but you also need to be firm with them because if you're too gentle, they're going to flap and flail and squawk because they don't know what you're trying to do. Holding them kind of firmly but gently at the same time makes them feel relaxed and calm."
The blood samples are sent to the state for testing. The program has been going for more than 40 years, with two sentinel flocks: this one and another in Simi Valley. It’s a hands-on way to monitor public health risks.
West Nile virus can cause a small percentage of infected people to experience serious symptoms, such as vision loss, numbness, and paralysis. It can also be fatal.
Older people or those with weakened immune systems or diabetes are at a greater risk. Officials recommend preventing mosquito bites by using repellent and removing standing water.
"The native Culex mosquitoes are the species that can spread West Nile virus and are the concern," said Solomon. "We still have those throughout the county. There's one that breeds in containers, one that breeds in flooded fields, one that breeds in the creeks and the more natural waterways that we're constantly trying to control and reduce the risk of West Nile transmission."
And for the chickens? They earned a treat: Salad leaves!
