Six Colorado workers have contracted the bird flu, more than any other state.

During a news release Tuesday, federal officials said temperatures above 104 degrees have made it difficult for workers to wear the full body suits, goggles and N95 masks required to protect against the virus.

“There is no doubt that the barns where the shutdowns occurred were warmer,” said Nirav Shah, director general of the Centers for Disease Control and Prevention. Large industrial fans were used to cool the barns, but they spread feathers around, which they said contained viruses. The culling method involves extensive interaction with infected birds and requires workers to place chickens in cages where they are gassed with carbon dioxide.

“The workers were having a hard time keeping a good seal or a good fit with the mask or the eye protection,” Shah said. “This combination of factors may play a role in explaining why, where and when this outbreak occurred.”

The operation at the Weld County poultry farm, which involves 160 workers, will continue for another 10 to 14 days to prevent further spread among the flock, said Eric Dibble, the USDA’s top bird flu response official. About 55 poultry workers with symptoms of the disease have been tested, Shah said. All but five workers were negative for bird flu. Four have been confirmed by the CDC; A presumptive positive case is pending confirmation.

An additional 16 symptomatic poultry workers were tested Monday and are awaiting results, Colorado health officials said.

While more cases may be detected, the risk to the public is low, officials said.

Human infection is rare. All are related to American humanitarian issues. Direct contact with infected cows or poultry – It has not been spread person-to-person, officials said.

H5N1 bird flu is spread by wild birds around the world and caused an outbreak in US dairy cows for the first time this spring. near 160 dairy herds The U.S. Department of Agriculture says 13 states have been infected. This highly pathogenic strain of avian influenza is deadly to domestic poultry and can wipe out entire flocks within days. But it causes less severe disease in cows.

Colorado is one of the states hardest hit by the virus and the outbreak has occurred. At least 37 dairy herds with poultry workers in Weld County Held. Genetic sampling of the virus from chickens at the farm showed the same type of virus found in nearby dairy herds, USDA’s Deeble said.

Earlier in July, a Colorado A dairy worker contracted bird flu after being exposed For infected cattle. Authorities are investigating the relationship between the milk worker and the five poultry workers.

Across the United States, a total of nine people, including three other dairy workers — in Michigan and one in Texas — have died of HIV this year.

Since birds shed flu viruses in their saliva, diarrhea and feces, direct exposure to infected birds increases the risk of contracting the disease. Dairy workers can contract the virus through contaminated milk or equipment.

A genetic sequence of the virus from one of the infected poultry workers may provide more clues about how the virus spreads, officials said. Part of the virus was the same as that in the Texas worker and the first Michigan worker, Shah said. One hypothesis is that infected dairy cows from Texas were transported to Michigan and Colorado.

“What’s happening in some limited cases has spread in those very tight regional or local areas,” Shah said. That explains why the virus we’ve seen is mostly the same, even though it’s popping up in different geographies, from Michigan to Colorado.

The CDC does not recommend that animal workers be vaccinated against bird flu because all infected workers report mild symptoms. The poultry workers experienced eye inflammation and watery eyes along with flu-like symptoms such as fever, chills, cough, sore throat and runny nose, the CDC said. None of them were hospitalized.

The CDC has not shown any unusual flu trends in lab data or emergency room visits at the national, state or local levels, Shah said.

Preliminary analysis of the genetic sequence of the virus from a poultry farm worker in Colorado shows no changes in the virus. This increases the severity of the disease, eases transmission from person to person or It reduces the effectiveness of Tamiflu treatment, Shah said.

Federal health and agriculture officials have repeatedly emphasized the importance of precautionary measures when working with infected animals. Federal and state officials have offered supplies to dairy farmers but have not required their use.

Federal officials on Tuesday praised Colorado for its planning and response to the outbreak. In May, the state requested 5,000 goggles, 300,000 pairs of gloves and 150,000 N95 masks from the federal stockpile when dairy herds in the state were infected with the virus. Over the weekend, the state ordered 500 courses of Tamiflu after testing confirmed the virus had infected five poultry workers. More than 150 workers at risk of exposure to infected poultry have received antiviral medication. State health officials immediately notified the CDC of worker infections, allowing the agency to send a 10-person bilingual team to help with the investigation.

Nahid Badelia, director of Boston University’s Center for Emerging Infectious Diseases and a former senior adviser to the Biden administration’s White House coronavirus response team, said infectious disease experts are worried about what could happen when the virus infects more people. Transmitting from person to person and mutating to cause a more severe disease.

“So far, yes, the pains haven’t been that bad,” she said. But it’s only a matter of time before a person with a medical condition finds the disease takes this serious course.

Colorado workers begin HIV testing in poultry workers for the first time since April 2022. Infected The same problem that caused bird flu among dairy cows. That worker reported fatigue as the only symptom, was treated with Tamiflu and recovered.