Colorado H5 Bird Flu: 3 Human Cases Confirmed, CDC Investigates | July 2024
Colorado Poultry Workers Test Presumptive Positive for H5 Bird Flu
Colorado health officials have announced three presumptive positive cases of highly pathogenic avian influenza (HPAI) A(H5) – commonly known as H5 bird flu – in individuals working at a poultry facility experiencing an outbreak. Specimens have been sent to the Centers for Disease Control and Prevention (CDC) for confirmatory testing. All three individuals experienced mild symptoms, and the CDC is dispatching a team to Colorado to support the ongoing investigation. This development underscores the potential for human exposure when working closely with infected birds, though public health officials currently assess the risk to the general public as low.
What is H5 Bird Flu?
H5 bird flu is a strain of influenza virus that primarily affects birds, but can, on rare occasions, infect humans. The current outbreak is caused by a specific variant, H5N1, which has been circulating in wild birds and has recently caused outbreaks in both dairy cows and poultry across multiple states. The CDC defines HPAI as a strain of avian influenza that causes severe disease in poultry.
Who is Affected?
Currently, the confirmed and presumptive cases are limited to workers involved in the depopulation process – the culling of infected birds – at the affected poultry facility in Colorado. The CDC notes that most human cases of bird flu occur in people who have not been using recommended personal protective equipment (PPE) while working with potentially infected animals. While the risk to the general public remains low, those in close contact with poultry or other potentially infected animals are considered to be at moderate to high risk. The Colorado Department of Public Health and Environment is supporting the Colorado Department of Agriculture in responding to the outbreak.
Mild Symptoms Reported, Pandemic Potential Monitored
According to the CDC, the three individuals who tested presumptive positive for the H5 virus reported experiencing mild illness. Symptoms included flu-like symptoms such as fever, chills, coughing, and a sore throat or runny nose. The CDC is also monitoring the situation for any signs of genetic changes in the virus that could increase its transmissibility between humans. While the current virus does not appear to spread easily from person to person, the potential for a pandemic remains a concern, as with any novel influenza virus. The CDC explains that human infections are concerning as of their potential to cause severe disease and their pandemic potential.
What Does This Mean in Plain English?
The detection of H5 bird flu in poultry workers in Colorado is a reminder that close contact with infected animals carries a risk of infection. The fact that the reported cases have been mild is reassuring, but it’s crucial to remember that even mild illness can be a sign of a potentially serious virus. The CDC’s ongoing investigation will help determine if any changes to public health recommendations are needed. It’s vital to understand that the virus is constantly evolving, and continued surveillance is essential to track its spread and identify any potential changes in its behavior.
Risk Context: Low Public Risk, Higher Risk for Workers
The CDC currently assesses the risk to the general public as low. This assessment is based on the fact that the virus has not demonstrated the ability to spread easily between people. Still, the risk is considered moderate to high for those who have direct contact with infected animals or contaminated materials. It’s important to distinguish between absolute and relative risk. While the absolute risk of infection for the general public is currently low, the relative risk is higher for those working with poultry or dairy cows. This means that while the overall chance of getting infected is little, the chance is significantly greater for those with occupational exposure.
Public Health Recommendations and Worker Protection
The CDC recommends that people avoid close, long, or unprotected exposure to sick or dead animals, including wild birds, poultry, and other domesticated animals. It also advises avoiding unprotected exposure to animal waste, unpasteurized milk, and materials that may have been contaminated by infected animals. For workers in the poultry and dairy industries, the CDC has specific recommendations for the employ of personal protective equipment (PPE), including respirators, eye protection, and gloves. These recommendations are central to reducing a person’s risk and containing the overall public health risk.
What Comes Next: Investigation and Surveillance
The CDC team sent to Colorado will support the state’s investigation by assessing the outbreak, monitoring the health of potentially exposed individuals, and analyzing virus samples. The investigation will also focus on determining whether workers were following recommended PPE guidelines. The CDC will continue to monitor the situation closely and provide updates as new information becomes available. Ongoing surveillance of both animal and human populations is crucial for detecting any changes in the virus and assessing the effectiveness of public health measures. The CDC’s flu surveillance systems are being used to monitor for H5 bird flu activity in people, and data on human monitoring and testing are reported monthly. Further updates can be found on the CDC website.