What are the transmission routes of the H7N9 avian influenza virus?

The primary transmission routes of H7N9 avian influenza are horizontal transmission—namely, direct contact with infected birds or indirect contact with virus-contaminated materials (e.g., contaminated drinking water, cages, egg trays, or other objects). The virus may enter the body via the digestive tract, respiratory tract, or conjunctiva through natural exposure.

What are the transmission routes of the H7N9 avian influenza virus?

Avian influenza viruses can be shed via the respiratory and digestive tracts. Thus, potential modes of infection include mechanical transmission—for instance, contamination of vehicles, tools, clothing, or footwear of poultry handlers by respiratory secretions from infected sources. To date, however, no evidence supports such mechanical transmission.

H7N9 avian influenza is an acute respiratory infectious disease primarily caused by infection with the H7N9 avian influenza virus. The disease is mainly transmitted via the respiratory route; close contact with birds infected with avian influenza virus—or with their secretions and feces—may lead to infection. Ingestion of water contaminated with the avian influenza virus may also result in infection. Wild birds—including pigeons—play a significant role in the natural transmission of avian influenza; therefore, contact with such birds should be minimized. When unavoidable, individuals should wear masks and gloves and perform disinfection as needed. Additionally, some patients may become infected by consuming poultry (e.g., chickens, geese, or ducks) affected by avian influenza or by drinking water contaminated with the virus, leading to gastrointestinal infection. Individuals at high risk—such as those who frequently handle birds—may develop avian influenza if they have open wounds or skin breaks.

Currently, there is no confirmed evidence of sustained human-to-human transmission. The primary reservoir of infection remains avian influenza-infected birds. Respiratory isolation is the main preventive measure. Individuals exhibiting relevant symptoms should seek further evaluation and management at fever clinics.