Chickens On Front Lines Against Disease In St. Johns County

With the Zika virus on many Floridians’ minds, it’s easy to forget the other mosquito-borne viruses present in the state.

However, troupes of chickens are standing guard throughout St. Johns County as the first line of defense against the blood-sucking parasites. Backyard chickens are a source of eggs for many Northeast Florida residents, but for the state’s mosquito prevention programs, they serve a very different purpose. 

Dubbed “sentinel chickens,” these birds act as an early warning system for diseases such as West Nile fever or eastern equine encephalitis, which are carried by the insects.

Anastasia Mosquito Control’s Christopher Bibbs said the system is a key part of preventing the spread of these diseases.

“You’re not looking at how to immediately rectify the problem, you’re looking at how to control it in the long term, which requires proper monitoring and surveillance,” he said. “There’s no point in blindfolding yourself before going out and trying to solve a problem — and that’s exactly what these things do, they give us eyes so we can go out and target things properly.”

Blood taken from the chickens on a weekly basis can give health departments throughout the state a clue about what diseases are making their way through local flocks. The sentinel chickens are checked for diseases that often affect birds first before a different type of mosquito allows it to cross into the human population.

Though the chickens can receive viruses that make people sick, they can’t pass them to people directly and don’t experience symptoms themselves. In fact, the chickens fight off the viruses so quickly that the blood tests can only detect traces of the chickens’ immune response. Otherwise, the chickens lead pretty normal lives in coops located throughout St. Johns County.

Last month, chickens in the northern part of the county tested positive for eastern equine encephalitis, which affects the brain of horses and can be fatal, prompting the Health Department to issue an advisory. No human cases have since been reported.

In the case of the Zika virus, sentinel chickens aren’t the best means of detection. The mosquitoes that carry the virus prefer human hosts, Bibbs said. For monitoring the Zika, mosquito control collaborates with the health department.