Colorado Farmworkers Hit by H5N1 Virus

OMAHA (DTN) -- With a growing outbreak of highly pathogenic H5N1 in Colorado, the Centers for Disease Control and Prevention (CDC) is stressing livestock workers need to get vaccinations for seasonal flu to reduce the risk that H5N1 and the seasonal flu could "reassort" to become a more dangerous virus.

Colorado has seen nine human cases among poultry workers, including three last week. USDA now has confirmed 50 dairies with H5N1 infections in the state, including 24 dairy farms in the past 30 days. Another 3.4 million chickens have been depopulated in Colorado this month because of outbreaks mainly on two large commercial egg-laying operations.

Nationally, there have been 172 dairies with confirmed infections by USDA across 13 states since March.

In poultry, USDA has depopulated nearly 101 million birds, mainly in commercial operations, going back to February 2022.

Among the reasons Colorado is seeing a concentration of cases is the "geography of Weld County," said Eric Deeble, deputy undersecretary for Marketing and Regulatory Programs at USDA. There are 106 dairies in Colorado, and nearly all of them are located in Weld County in the northern part of the state surrounding Greeley, Colorado.

"And they are all in very close proximity to one another," Deeble said of the dairies. "There is a lot of sharing of equipment and personnel, and a lot of movement on and off farms to adjacent farms. This is just a quirk of history and geography that contributed to this unique set of circumstances."

Deeble credited the state veterinarian and dairy farmers in Colorado. "They have come together in what I will just say is a remarkable spirit of cooperation."

Colorado last week ordered mandatory testing for the virus at every commercial dairy farm in the state.

As far as human cases, those have mainly come from poultry workers on the infected egg-laying farms, which are also in Weld County. Each of the human cases in Colorado is considered "mild" with conjunctivitis, or pink eye, as the main symptom. The infection of farmworkers does not change CDC's overall assessment that the risk to the general population remains low at this time. "That said, these cases highlight that certain groups -- here poultry workers -- who focus on depopulating (birds) are at heightened risk of infection," said Nirav Shah, principal deputy director of CDC.

VACCINATING FARMWORKERS

With those human cases, the CDC will provide $5 million to the National Center for Farmworker Health, which will then partner with community organizations in states with H5N1 livestock and poultry cases to provide training and educate farmworkers on the risks. They will also work to increase access to testing, personal protection equipment (PPE) and treatment.

CDC also will spend a separate $5 million for "seasonal influenza vaccines" to encourage livestock workers to get voluntary vaccinations starting in the fall. The CDC will focus its vaccine push on farm workers with states that have bovine outbreaks. The seasonal flu vaccines will reduce the risk livestock workers are affected with those viruses.

"When livestock workers are vaccinated against seasonal flu. they themselves are protected as well as their coworkers and family members," Shah said. "This is critical, since many livestock workers live communally in rural areas where access to healthcare may be limited."

The seasonal vaccine will not protect farmworkers from contracting the H5N1 virus, officials emphasized.

The key reason CDC is encouraging the seasonal flu vaccines is to reduce the risk of "co-infection" of seasonal flu viruses with the H5N1 virus. Livestock workers are at risk of infection from seasonal flu just like anyone else, but they are also at risk of exposure to H5N1 from infected livestock. Such dual infections are rare but could potentially lead to an exchange of genetic material between the two viruses.

"This is a process that's known as reassortment," Shah said, "and in theory reassortment could lead to a new influenza virus that could pose a significant public health concern, a virus that has the transmissibility of seasonal influenza and the severity of H5N1. We want to do everything we can to reduce the risk that the virus may change because of this co-infection."

Shah stressed the CDC is encouraging voluntary vaccinations for livestock workers, but also emphasized vaccinations are the best way to protect families and communities from spreading the seasonal flu virus as well.

STOPPING H5N1

Deeble said, "There is a lot about this disease that makes us feel we can arrest its progress. And we've actually seen some success demonstrated to date."

H5N1 so far, "does not appear to move by respiratory transmission," meaning it's not moving by air. H5N1 instead produced "high viral loads in milk," and principally moves through contaminated equipment or clothes on a person or machinery moving from farm to farm.

"Given that we have seen a real increase in awareness of producers and an increase in biosecurity, we believe that we can arrest the spread of this disease and ultimately eradicate it in dairy cattle on the farm."

FAIRS AND OTHER SHOWS

Deeble said USDA has been "in constant dialogue" with state officials about biosecurity measures and other restrictions at state fairs or other exhibition shows. "We've seen changes to the types of animals that will be exhibited in some states."

Some states have put in requirements to test lactating cattle before shows. Others have banned lactating cows for now.

"In some places we've seen the display of lactating cattle removed entirely from the program," Deeble said.

Also see, "Biosecurity Plan Can Help Protect Dairy, Beef Cattle Herds From H5N1," https://www.dtnpf.com/…

Chris Clayton can be reached at Chris.Clayton@dtn.com

Follow him on social platform X @ChrisClaytonDTN

(c) Copyright 2024 DTN, LLC. All rights reserved.