Sentinel Chicken Tests Positive for Antibodies to West Nile Virus

Release date: 
Aug 9

Cotati, CA-The Marin/Sonoma Mosquito and Vector Control District (MSMVCD) announced the first sentinel chicken to test positive for antibodies to West Nile virus (WNV) in Marin County. The sentinel chicken that tested positive is from a flock that is located in the vicinity of Gage Lane in Novato. Additional West Nile virus activity was detected in three more dead birds in Sonoma County. The three birds were all collected from Santa Rosa.

The District currently maintains sentinel chicken flocks in Marin and Sonoma counties as part of an integrated vector management program. Blood samples are collected every other week and submitted to the California Department of Public Health Vector-Borne Disease Laboratory, where they are tested for the presence of antibodies to WNV and other vector-borne diseases.

 "Equine West Nile virus continues to be a risk for horses," stated Piper Kimball, Scientific Programs Director for the Marin/Sonoma Mosquito & Vector Control District. According to the California Department of Food and Agriculture, horses are most at risk for contracting WNV when mosquito activity is highest, typically during July through October.

"With the mortality rate in unvaccinated horses as high as 40%, we can't stress enough the importance of taking preventative measures against the virus. Horse owners, especially in the area where the positive chicken was found, are urged to contact their veterinarians to ensure their equine vaccinations are current," stated Kimball.

Horse owners should consult a veterinarian if their horse exhibits any of the following signs:

  • Fever
  • Incoordination, especially in rear limbs, causing stumbling and falling
  • Generalized weakness, muscle twitching, seizures or coma
  • Drooping lips and lip smacking, head drooping, grinding teeth
  • Hypersensitivity to touch or sound  
  • Recumbency (inability to rise)

Simple ways to protect your horses against West Nile virus:

  •  Maintain current vaccination status, including WNV.
  • Place fans inside barns and stalls to maintain air movement, as mosquitoes cannot fly well in wind.
  • Stock water troughs, ponds or other permanent water features with mosquitofish. The fish are free and can be delivered or simply picked up at the District office.
  • Use equine-approved mosquito repellents and/or protective horse gear such as fly sheets, masks, and leg wraps.
  • Check septic tank lids to ensure a tight seal and repair any visible cracks.
  • Screen septic tank vent pipes using a fine mesh screen.
  • Eliminate standing water in rain barrels, old tires, buckets, kiddie pools or any other item that can hold water for more than a week.
  • Call Marin/Sonoma Mosquito & Vector Control District if you have a mosquito-related problem that you cannot resolve on your own.

West Nile virus is a mosquito-borne disease that is spread by the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds. Infected mosquitoes can then spread the disease to humans and other animals.