Australia registers first case of H5N1 bird flu infection

On May 17, 2024, the WHO Collaborating Centre (WHO CC) for Reference and Research on Influenza in Australia notified the NFP of Australia of a suspected case of human A(H5N1) avian influenza (HPAI) in Melbourne, Victoria.

The state Victorian Department of Health confirmed this case on 18 May 2024. Under Article 44, the NFP of Australia advised the NFP of India of the confirmed case on 21 May 2024. Under Article 8, the IHR NFP of Australia notified WHO of the case on 22 May 2024, Caliber.Az reports, citing the WHO press service.

The case is a 2.5-year-old-female child with no underlying conditions. She had a history of travel to Kolkata, India from 12 to 29 February 2024. She returned to Australia on 1 March 2024.

Upon returning to Australia, the child presented at a hospital in Victoria on 2 March 2024, where she received medical care and was admitted on the same day. On 4 March, the patient was transferred to the intensive care unit at a referral hospital in Melbourne, Victoria, due to worsening symptoms, for a period of one week. The patient was discharged from hospital after a 2.5-week admission. The case is now reported to be clinically well.

The Victorian Department of Health reported on 23 May 2024 that the family advised that the child started to feel unwell on 25 February 2024, with loss of appetite, irritability and fever, and was taken to a doctor on the evening of 28 February 2024 in India. She was febrile, coughing and vomiting and was given paracetamol. It was not reported to an Australian airport biosecurity officer that the child was unwell when she arrived in Australia on 1 March 2024.

Additional information provided by the family indicates that the case did not travel outside of Kolkata, India, and did not have any known exposure to sick persons or animals while in India. It is understood that no close family contacts of the case in Australia or India developed symptoms, as of 22 May 2024.

A nasopharyngeal swab and endotracheal aspirate taken on 6 and 7 March respectively tested positive for influenza A at the referral hospital. The samples were sent to the WHO CC for further characterisation on 3 April as part of a batch, as there was insufficient knowledge from the referring practitioners at the hospital to connect the case to the H5N1 virus. Virus genetic sequence obtained from the samples confirmed the subtype A(H5N1) and indicated that the haemagglutinin (HA) gene belonged to clade 2.3.2.1a, which circulates in South-East Asia and has been detected in previous human infections and in poultry.