Despite the discovery of bird flu among five workers at a Colorado egg farm, there is no reason to vaccinate livestock workers against the viral disease, said a top CDC official on Tuesday. Nirav Shah, CDC principal deputy director, said a heat wave, with temperatures above 100 degrees, may have discouraged workers from wearing a full set of protective gear.
“We understand PPE [personal protective equipment] use was not optimal” as workers culled a flock of 1.8 million egg-laying hens infected with the H5N1 avian flu virus, said Shah during a teleconference. USDA official Julie Gauthier said the recommended outfit of water-resistant coveralls, goggles, mask, gloves, and boots can be taxing to wear during manual labor at high temperatures.
The risk to the general public from bird flu remains low, and the CDC does not recommend vaccination of farmworkers, said Shah. Infections continue to be mild and responsive to antiviral medications — two key considerations. For weeks, the agency has recommended farmworkers, meat plant workers, veterinarians, and other people working with infected or potentially infected animals should wear protective equipment.
Five farmworkers tested positive for bird flu over the weekend while employed at the egg farm in Weld County, about 60 miles northeast of Denver, said Colorado public health officials. An additional 55 workers developed flu-like symptoms but tested negative for bird flu, said the CDC. Producers were dealing with avian flu outbreaks on both poultry and dairy farms in the county.
“PPE use in these situations…is always a balance,” said Shah when asked about the role of hot weather in responding to bird flu. Large industrial fans were used in the poultry barns to provide ventilation for workers, but they also blew feathers and dust into the air.
The CDC constantly evaluates a number of factors to determine the need for vaccinations, said Shah, including whether the H5N1 virus is evolving to become more contagious, the severity of symptoms among infected people, and the efficacy of antiviral medications. “Fundamentally, the virus remains an avian virus,” he said.
It may take an additional 10 days to two weeks to kill all of the hens at the egg farm, said Eric Deeble, USDA bird flu adviser. “Right now, the USDA considers it important…to prevent spread and amplification of the virus.”
About 160 people are part of the depopulation effort, said Gauthier. Contract laborers capture a group of hens, place them in a cart to be euthanized by carbon dioxide gas, and then dispose of the carcasses.
The USDA strategy to eradicate the H5N1 virus among dairy cows is to isolate infected herds and let the disease burn out, said Deeble. “We do believe we can eliminate this within the [U.S.] dairy herd.”
To date, bird flu has been confirmed in 158 herds in 13 states since late March.