By Lisa Schnirring
The Colorado Department of Public Health and Environment (CDPHE) has reported five human H5 avian influenza infections in workers who were part of the response to a recent large outbreak at a layer farm, four of which have been confirmed by the US Centers for Disease Control and Prevention (CDC).
Patients have eye, respiratory symptoms
The patients have mild illness, including conjunctivitis and common respiratory symptoms. None were hospitalized, according to statements from the CDPHE. Though officials haven't said if the virus on the poultry farm is the same as the B3.13 genotype infecting dairy cattle, conjunctivitis has also been reported in four dairy farm workers over the past few months.
Last week, the Colorado Department of Agriculture reported an outbreak at a large layer farm in Weld County, where the virus has also struck several dairy herds. The layer farm had 1.78 million birds, the state's second-largest outbreak since H5N1 first emerged in US birds in 2022. The Weld County poultry outbreak recently prompted an emergency declaration from the state's governor, a step that frees up more resources to help with the response.
Colorado has been one of the states hit hardest by the virus, with at least 36 H5N1 outbreaks in dairy cows, 23 of them from Weld County.
On July 12, the CDPHE reported three presumptive positive cases in poultry farm cullers working at a farm in the northeastern part of the state. It also added that state health officials had collected more samples from other symptomatic workers and that the investigation was ongoing with support from the CDC.
'"State epidemiologists suspect the poultry workers’ cases are a result of working directly with infected poultry," the CDPHE said.
Yesterday, the CDPHE upped its number of avian flu detections in poultry cullers to five, noting that the CDC has confirmed four of the infections and that results are pending for the fifth case, classified as a presumptive positive for now.
On July 3, the CDPHE reported H5 avian influenza in an adult male dairy farm worker exposed to infected cattle. He had mild symptoms, including conjunctivitis.
CDC field team on the ground in Colorado
The CDC yesterday also weighed in on the new Colorado cases, adding that it would confirm the fifth case when the samples arrive. Genetic sequencing of the virus is under way to determine the neuraminidase of the virus from the poultry workers.
It said a multidisciplinary, bilingual field team of nine people has been deployed to Colorado to assist state health officials.
The Colorado patients, the first poultry workers to test positive in the United States since 2022, had conjunctivitis, eye tearing, and typical flu symptoms, including fever, chills, cough, and sore throat. "Additional cases may be reported and subsequently confirmed, as monitoring and testing is ongoing," the CDC said.
Risk to the public is still considered low, but the spurt of new infections underscores the threat of exposure to infected animals, the CDC said.
Since the start of the H5N1 outbreaks in cattle in March, which are occurring alongside sporadic outbreaks in poultry, nine infections have been reported in farm workers, four in dairy workers and five in poultry workers. The most recent human case linked to sick dairy cows was reported from Colorado.
Source : umn.edu