Is bird flu infecting humans? How would we know?

Bird flu, or avian influenza, is a strain of flu virus primarily affecting birds. The current strain of concern, H5N1, has been circulating since 2020, causing millions of bird deaths and spilling over to other species like dairy cows and marine mammals. In Australia, bird flu cases were first reported in June, initially in migratory birds and then in local wild birds.

While no humans in Australia have been diagnosed with the currently circulating strain, overseas evidence suggests that in rare cases, illness would generally be mild. The Australian Centre for Disease Control assesses the risk to humans as low, as the current strain does not spread efficiently between humans. However, public health authorities are monitoring the situation, particularly for groups at higher risk, such as wildlife caregivers and poultry workers.

Symptoms are typically mild, including a runny nose, cough, and fever, and sometimes nausea and diarrhea. More serious disease can develop, but it is more commonly associated with infections due to H5N1 strains other than the currently circulating one in Australia. Standard flu tests can detect bird flu, but they don't differentiate between seasonal and bird flu.

Doctors should be notified if a patient has had contact with potentially infected birds and requires specific testing. Public health authorities will assess potential exposures and infections. Prevention measures include specific antiviral medicine and surveillance systems to identify signals of bird flu in humans.