Human infections with the influenza A(H7N9) virus are on the rise again in China and the upcoming Chinese New Year festivities provide opportunity for further spread and human exposure, the UN Food and Agriculture Organisation has warned.
Millions of people and poultry are expected to be on the move, while many households will slaughter poultry at home to celebrate the New Year. The FAO has subsequently called on neighbouring countries to remain vigilant in the face of A(H7N9) and other avian influenza viruses, such as highly pathogenic avian influenza H5N1.
The number of human infections with H7N9 has considerably increased since late December in eastern and southeastern China, according to the World Health Organisation. The increase in cases was expected, as influenza viruses traditionally show increased activity during the winter months. So far, no other country has reported influenza A(H7N9) in humans, animals or in the market place.
Risks to humans remain
There is strong evidence that people are susceptible following close contact with infected live poultry, mostly in live bird markets or when slaughtering birds at home. According to the WHO, no sustained human-to-human transmission has occurred so far. Genetic analysis by FAO reference centres has revealed that the virus has not changed significantly since its emergence last year.
"Chinese authorities are enforcing important measures to reduce the risk of human exposure to the A(H7N9) virus," said FAO chief veterinary officer Juan Lubroth.
"This includes temporary closures of live bird markets, regular market rest days, improved hygiene in markets, heightened and ongoing surveillance in poultry and live bird market environment, and control of poultry movements."
"But countries need to stay alert, as the virus continues to circulate in poultry without showing any visible clinical signs. The risk to humans remains, especially over the next few months and particularly during the Chinese New Year's holiday period, " Lubroth said.
FAO is assisting a number of member countries, particularly those that are at high risk, in preventing and preparing for possible A(H7N9) introductions into their poultry populations, conducting risk assessment, contingency planning and expansion of diagnostic capabilities, and risk based surveillance.
In South and Southeast Asia, the FAO, with strong support from the United States Agency for International Development, has assisted countries with the implementation of animal and environmental surveillance at live bird markets and on farms since June last year.
FAO-supported projects are also underway to assist some countries in Africa to prevent and be prepared for facing threats from avian influenza viruses, including A(H7N9).
Focusing on good biosecurity standards on farms and markets, regular market cleaning and disinfection, and targeted surveillance in areas that have direct or indirect live poultry trade with infected areas, are essential.
If infection in animals is shown or suspected to be confined to a specific area, culling should be considered as long as it performed in a humane way with appropriate compensation paid to producers and marketers.