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 United Nations Food and Agriculture Organisation (FAO) has warned.

Millions of people and poultry are expected to be on the move and many households will slaughter poultry at home to celebrate the New Year. FAO has called upon 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 increased considerably since late December 2013 in East and Southeast China, according to the World Health Organisation (WHO). 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.

FAO said there was strong evidence that people became infected following close contact with infected live poultry, mostly in live bird markets or when slaughtering birds at home. According to 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 in 2013.

“Chinese authorities are enforcing important measures to reduce the risk of human exposure to the A(H7N9) virus,” said Juan Lubroth, FAO Chief Veterinary Officer. “This includes temporary closure 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,” he said.

Risk to humans remains

But countries need to stay alert, as the virus continues to circulate in poultry without showing any visible clinical signs, according to FAO.

“The risk to humans remains, especially over the next few months and particularly during the Chinese New Year’s holiday period,” Mr Lubroth said.

FAO said it was 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.

In South and Southeast Asia, FAO, with strong support from the US Agency for International Development (USAID), has assisted countries with the implementation of animal and environmental surveillance at live bird markets and on farms since June 2013. 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).

FAO said 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, were essential. If infection in animals is shown or suspected to be confined to a specific area, culling should be considered “as long as it was performed in a humane way with appropriate compensation paid to producers and marketers”, the FAO said.

Recent ‘bird flu’ outbreaks in Australia

Australia faced its own, less widespread, outbreak of H7 avian influenza in late 2013. Two poultry farms in the Young district in New South Wales (NSW) were found to have layer hens infected with a strain of avian influenza. The quarantine of the two farms between October 2013 and December 2013 was predicted to mean an egg shortage in NSW in the lead up to Christmas.

The NSW Department of Primary Industries announced on 10 January 2014 that the outbreak had been successfully eradicated. Results of final clearance testing on restocker birds on the two affected properties returned negative for the virus and restrictions on operations at the two farms were lifted.

Australia has previously had a small number of outbreaks of avian influenza viruses, which were all quickly and successfully eradicated.

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