H9N2 avian influenza virus or bird flu: Causes, symptoms and preventive measures

H9N2 is a subtype of the Influenza A virus, belonging to the Orthomyxoviridae family. It primarily affects birds, with a high prevalence in poultry such as chickens and turkeys. The virus can undergo genetic reassortment, leading to the emergence of new strains. The transmission of H9N2 occurs through direct contact with infected birds, their respiratory secretions, or contaminated environments. The virus can persist in water and on surfaces, contributing to its spread within and between flocks. A human case of H9N2 virus infection in October 2023 in China was reported to WHO

In poultry, H9N2 infections can range from asymptomatic to severe, depending on various factors such as the bird species, age, and the presence of other pathogens. Common symptoms in birds include respiratory distress, reduced egg production, and a drop in feed consumption. In humans, symptoms are similar to those of other influenza viruses and may include fever, cough, sore throat, and difficulty breathing.

Implementing strict biosecurity measures is essential to prevent the introduction and spread of H9N2 in poultry farms. This includes controlling access to farms, regular disinfection of facilities, and ensuring that personnel and equipment are free from contamination. Regular surveillance of poultry populations is crucial for early detection of H9N2 infections. Monitoring bird health, conducting routine testing, and promptly reporting any unusual illness can help prevent the spread of the virus.

Practicing good hygiene is essential in both commercial and backyard poultry settings. This includes proper waste disposal, regular cleaning and disinfection of equipment and facilities, and the use of protective clothing by farm workers. Educating poultry farmers, workers, and the general public about the risks associated with H9N2 is important for prevention. Awareness campaigns can help disseminate information on proper hygiene practices, the importance of early detection, and the potential consequences of the virus. To avoid spreading to humans, those in contact with the infected animals should clean their hands regularly and disinfect their clothes and belongings if they are in direct contact with the birds.

"Union Health Ministry is closely monitoring the reported outbreak of H9N2 cases and clusters of respiratory illness in children in northern China. There is low risk to India from both the avian influenza case reported from China as well as the clusters of respiratory illness," as per an official statement made on November 24. The overall risk assessment by WHO indicates a low probability of human to human spread and low case fatality rate among human cases of H9N2 reported to WHO so far.

​China pneumonia outbreak in kids: Is it treatable?​