3 more Colorado poultry workers test positive for bird flu, bringing total to 10

DENVER — Three additional workers culling poultry at a second commercial egg-laying facility in Weld County affected by an outbreak of highly pathogenic avian influenza have tested positive for bird flu, state health officials said Thursday, bringing the total number of confirmed human cases in Colorado so far this year to 10.

At least one of the three cases confirmed Thursday by the U.S. Centers for Disease Control and Prevention (CDC) had been announced as a presumptive positive case by the state over the weekend. Testing on other symptomatic workers that was later sent to the CDC for confirmation found the other two cases.

The update from the Colorado Department of Public Health and Environment (CDPHE) means 10 workers have been infected with H5N1 at poultry farms — nine of them just within the past two weeks — since the outbreak of avian influenza was first detected in the state in March of 2022 .

A dairy worker was infected with the virus earlier this month after coming into contact with sick cattle, the first instance in which the virus was likely transmitted from a mammal to a human since the unprecedented spillover of the virus into the country’s dairy cattle herds earlier this year.

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The announcement from the CDPHE did not say what clinical symptoms the three additional poultry workers presented, nor did it say if any had to be hospitalized or what type of antiviral treatment they had received. Denver7 followed up with the CDPHE for additional details, which said the three workers all had mild illness, only reporting conjunctivitis, or pink eye, and none were hospitalized. A news release from the CDC states they had been offered oseltamivir for treatment of their symptoms.

These three additional cases now bring the total number of humans infected with H5N1 since the virus was first detected in the U.S. in 2022 to 14, according to the CDC.

"There are no signs of unexpected increases in flu activity otherwise in Colorado, or in other states affected by H5 bird flu outbreaks in cows and poultry," a CDC spokesperson said in a statement, adding that these infections are concerning "because of the potential to cause severe, widespread disease."

CDC officials said to date, they have not seen any genetic changes in the virus that would make it more likely to transmit between humans.

An analysis done by the CDC on a sample from one of the Colorado poultry workers recently infected with H5N1 found the version of the virus that infected that worker was most similar to the one that infected one of the Michigan dairy workers. It also found that the version of H5N1 that infected the Colorado poultry worker still has characteristics that favor birds and "lacks changes that would make the virus better adapted to infect or spread among humans."

Further, the analysis also showed that despite having a characteristic that would make it better at infecting mammals, it had no markers that would make it more resistant to antiviral medication. Even better news? That version of the virus is closely related to two bird flu samples available to manufacturers which could be used to make an H5N1 vaccine, if needed, the analysis found.

Additionally, a recent study out of Michigan showed workers exposed to sick cattle at two separate dairy farms experiencing outbreaks of H5N1 found no signs of antibodies from the virus in their blood, providing some preliminary evidence that asymptomatic spread isn't happening as the workers were not infected.

Still, CDC officials said they are "closely monitoring" the evolving situation as earlier versions of the same virus have been deadly to people.

A CDC multidisciplinary, bilingual field team is currently deployed to support Colorado’s response to ongoing poultry outbreaks of H5 bird flu in the state, the CDC spokesperson said.

Colorado leads the nation in both the number of outbreaks among dairy cattle as well as the number of people infected with the virus, effectively becoming the current epicenter of the outbreak .

CDPHE launches human bird flu tracker as cases in people continue to rise

After the largest cluster of human cases in the country to date, state health department officials said in a news release Thursday they would be launching a human bird flu data tracker that will be updated on their website by 4 p.m. every Tuesday and Thursday.

"The biweekly update will include the number of presumptive positive human cases, number of confirmed human cases, approximate number of people tested, and a link to the Colorado Department of Agriculture for the number of impacted dairy and poultry farms," the release states.

Colorado Department of Public Health and Environment (CDPHE)

Federal and state health officials maintain that the risk of catching bird flu for the general public is low, though people who come into contact with sick poultry or cattle are at greater risk of becoming infected with the virus.

"So far, we have not seen evidence of person-to-person transmission," CDPHE officials said Thursday. "Epidemiologists both here in Colorado and at CDC are monitoring for genetic variations in the virus and changes in transmission patterns."

How you can protect yourself against bird flu

The nation's top public health agency recommends that farm workers who come into contact with cattle suspected or confirmed to be infected with H5N1 wear disposable fluid-resistant coveralls, disposable gloves, boots or boot covers, vented safety goggles or a face shield, as well as an N95 respirator.

The CDPHE is providing personal protective equipment (PPE) to dairies and poultry farms who request it, including face shields and/or goggles, gloves and masks (N95 respirators and/or surgical masks).

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The general public should avoid contact with sick birds or other animals to reduce their chances of becoming infected with bird flu, state epidemiologist Dr. Rachel Herlihy has said in the past. If you must handle sick or dead birds or animals, be sure to wear gloves, a high-quality mask such as a KN95 or N95 respirator, and eye protection. After handling the animal, double bag it and throw it away in your municipal trash can before thoroughly washing your hands with soap and warm water. If soap and water are not available, use an alcohol-based hand rub, the CDC recommends.

People should also avoid unprotected exposures to animal poop, bedding (litter), unpasteurized milk, or materials that have been touched by, or close to, birds or other animals with suspected or confirmed H5N1 infection, CDC officials said.

The CDPHE is advising anyone who works with dairy cows or poultry who may have flu-like symptoms, to call the state health department at 303-692-2700 (after normal business hours: 303-370-9395). Officials said the department can help those potentially exposed get a flu test and medicine if needed.

Can I catch bird flu from drinking milk or eating meat?

FDA officials have said the likelihood that eggs will contain H5N1 is low “due to the safeguards in place, which include testing of flocks and federal inspection programs,” that call for the disposal of eggs and meat from infected poultry. Proper egg storage and preparation “further reduce the risk,” they said.

Though the agency “does not know at this time if the HPAI H5N1 virus can be transmitted to humans through consumption of raw milk and products made from raw milk from infected cows,” scientists are advising people to avoid raw milk and dairy products made from raw milk, as it does not go through the process of pasteurization, which inactivates harmful viruses and bacteria.

Though Colorado isn't testing swine and beef cattle for bird flu, ground beef appears to be safe for consumption after USDA researchers found no live virus in retail meat samples from states with ongoing outbreaks. The agency said it was confident that the meat supply was safe after at least three different safety studies found no viral particles in beef cattle, including one in which the meat was cooked to varying degrees of preparedness.

As of Wednesday, the CDPHE was monitoring more than 1,600 workers at dairy and poultry facilities for possible exposure to H5N1. Approximately 100 poultry workers and 14 dairy workers have been tested for avian influenza to date, a CDPHE spokesperson said.

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