May 5, 2023
Sentinel chicken program enters phase two
MOBILE, Alabama — Since 1985, the Mobile County Health Department’s Vector Services has monitored sentinel chickens placed throughout the county to help detect the presence of viruses carried by mosquitoes. In April, MCHD received 100 newly hatched chicks that were placed in a cage heated by lamps located at Vector Services (a vector is any insect, rodent, or animal capable of harboring or transmitting diseases to humans).
The second step in the process took place this week. The chickens were moved into the larger hen house located on Vector Services grounds. It takes several more months for the chicks to mature enough to be placed in the field.
A video of the move can be found at this link — https://youtu.be/-C6Z_xzkvrg
Once mature, the chickens are vaccinated for fowl pox, and the initial blood draw is made to ensure they test negative for any diseases. At that point, the hens — roosters are not included in the study — are banded for identification and tracking purposes. The birds are dispersed to 13 coops located in various predetermined locations throughout Mobile County.
Blood samples are collected weekly from the wings of two hens at each location. MCHD processes the blood samples and sends them to a lab in Tampa, Fla. Test results are usually received within the submitted week and can reveal the presence of Eastern Equine Encephalitis, West Nile Virus, and St. Louis Encephalitis.
With the use of 13 coops, only 52 hens are used at one time. The rest are kept in reserve. If one tests positive for a disease, it is removed from the field and replaced with chicken from the reserve flock. If two birds from the coop test positive, all four birds are replaced.
MCHD began a project with the University of South Alabama in 2018 to test adult mosquito samples. This expanded disease detection to include Zika, Dengue, and Chikungunya using high-throughput molecular methods.
The program continues into the fall, usually ending in November. At that point, the hens are given away to the general public on a first-come, first-served basis. A new group of 100 chicks will start the program the following spring, as it did last week.