The Centers for Disease Control and Prevention confirmed a Colorado inmate tested positive for the highly contagious avian influenza A virus. The man had direct exposure to poultry and was involved in the culling of poultry with presumptive H5N1 bird flu. This is the first such recorded case.
The person, who is an inmate at a state correctional facility in Delta County in Colorado, was working with poultry at a commercial farm in Montrose County as part of a pre-release employment program where participants have the opportunity to work for private employers and be paid a prevailing wage. The affected flock has been euthanized and disposed of under the guidance of the the U.S. Department of Agriculture and the Colorado Department of Agriculture. All members of the response team, including other inmate workers, were provided personal protective equipment while working on the farm.
The adult male, who is reported to be younger than 40, is largely asymptomatic, reporting only fatigue. The patient is being isolated and treated with the influenza antiviral drug oseltamivir. While it is possible the detection of H5 bird flu in this specimen is a result of surface contamination of the nasal membrane, that can’t be determined at this point and the positive test result meets the criteria for an H5 case. The appropriate public health response at this time is to assume this is an infection and take actions to contain and treat.
The USDA confirmed the first case of highly pathogenic avian influenza (shortened to HPAI) in wild birds in South Carolina this January. One month later, the USDA announced the presence of HPAI in a commercial turkey flock in Dubois County, Indiana — the first commercial poultry case since 2020. Since then, the virus has been confirmed in 29 states, affecting more than 33 million domestic birds.
This case does not change the human risk assessment for the general public, which CDC considers to be low. However for those in agriculture, specifically people who have job-related or recreational exposures to infected birds, are at higher risk of infection should take appropriate precautions outlined in CDC guidance.
CDC has been monitoring for illness among people exposed to H5N1 virus-infected birds since these outbreaks were detected in U.S. wild birds and poultry in late 2021 and into 2022. To date, H5N1 viruses have been found in U.S. commercial and backyard birds in 29 states and in wild birds in 34 states. CDC has tracked the health of more than 2,500 people with exposures to H5N1 virus-infected birds and this is the only case that has been found to date. Other people involved in the culling operation in Colorado have tested negative for H5 virus infection, but they are being retested out of an abundance of caution.
This is the second human case associated with this specific group of H5 viruses that are currently predominant, and the first case in the United States. The first case internationally occurred in December 2021 in the United Kingdom in a person who did not have any symptoms and who raised birds that became infected with H5N1 virus. More than 880 human infections with earlier H5N1 viruses have been reported since 2003 worldwide, however, the predominant H5N1 viruses now circulating among birds globally are different from earlier H5N1 viruses.
Infected birds shed H5N1 viruses in their saliva, mucous, and feces. H5N1 virus infections among people are rare; however, human infections can happen when enough virus gets into a person’s eyes, nose, or mouth, or is inhaled. People with close or lengthy unprotected contact (not wearing respiratory or eye protection) with infected birds or places that sick birds or their mucous, saliva, or feces have touched, may be at greater risk of H5N1 virus infection. Illnesses in people from bird flu virus infections have ranged from mild (e.g., eye infection, upper respiratory symptoms) to severe illness (e.g., pneumonia) that can result in death.
