Key facts
- On 11 June 2024, WHO reported one human infection with avian influenza A(H9N2) virus in India. This is the second detection of A(H9N2) in humans in the country.
- The case had exposure to poultry at home and household surroundings.
- No other cases of respiratory illness have been reported by family members, neighbours, or healthcare workers (HCWs) at health facilities attended by the case at the time of reporting.
- Since 1998, 137 human cases of A(H9N2) have been confirmed globally, including two deaths.
- Most of the cases reported to date have been in China (122 cases). No human cases have been reported in the EU/EEA.
- The risk to human health in the EU/EEA is currently considered very low.
Overview
Update
On 11 June 2024, WHO reported one human infection with avian influenza A(H9N2) virus in India. This is the second detection of A(H9N2) in humans in the country.
On 22 May 2024, WHO received a notification from the International Health Regulations National Focal Point (IHR NFP) regarding a child affected with avian influenza A(H9N2) in West Bengal state, India.
The case, previously diagnosed with hyperreactive airway disease, initially presented with fever and abdominal pain on 26 January 2024 and was taken to a paediatrician on 28 January. On 29 January, the case developed seizures and was again brought to the same paediatrician. On 1 February, the case was admitted to the paediatric intensive care unit of the local hospital due to the persistence of severe respiratory distress, recurrent high-grade fever and abdominal cramps. The patient was diagnosed with post-infectious bronchiolitis caused by viral pneumonia. On 2 February, the patient tested positive for influenza B and adenovirus at the Virus Research and Diagnostic Laboratory at the local government hospital.
On 3 March, with a recurrence of severe respiratory distress, the patient was referred to another government hospital and was admitted to the pediatric ICU and intubated. On 5 March, a nasopharyngeal swab was sent to the Kolkata Virus Research and Diagnostic Laboratory and tested positive for influenza A (not sub-typed) and rhinovirus. The same sample was sent to the National Influenza Centre at the National Institute of Virology in Pune for subtyping. On 26 April, the sample was sub-typed as influenza A(H9N2) through a real-time polymerase chain reaction. On 1 May, the patient was discharged from the hospital with oxygen support. Information on the vaccination status and details of antiviral treatment were not available at the time of reporting.
The case had exposure to poultry at home and the surroundings, as reported by family members. There is no known history of travel reported among family members living in the same household, or for any other individual visiting their house. There was no known case reporting symptoms of respiratory illness in the family, the neighbourhood, or among healthcare workers (HCWs) at health facilities attended by the case at the time of reporting.
Summary: As of 11 June 2024, and since 1998, a total of 137 laboratory-confirmed cases of human infection with avian influenza A(H9N2) viruses, including two deaths (both in patients with underlying conditions), have been reported in nine countries: China (122), Egypt (4), Bangladesh (3), Cambodia (2), Oman (1), Pakistan (1), India (2), Senegal (1), and Vietnam (1). Most of the cases were children with mild disease.
ECDC assessment
Sporadic human cases of avian influenza A (H9N2) have been observed outside the EU/EEA, mainly in young children. The source of infection of the current case is unknown. Direct contact with infected birds or contaminated environments is the most likely source of human infection with avian influenza viruses. The risk to human health in the EU/EEA is currently considered very low.
Actions
ECDC monitors avian influenza strains through its epidemic intelligence and disease network activities and collaborates with the European Food Safety Authority (EFSA) and the EU reference laboratory for avian influenza to identify significant changes in the epidemiology of the virus. ECDC also works with EFSA and the EU reference laboratory to produce a quarterly report on the avian influenza situation. The most recent report was published in March 2024.