Influenza (seasonal)
Influenza (seasonal)

Influenza (seasonal) in China

Seasonal influenza is an acute respiratory infection caused by influenza viruses which circulate in all parts of the world. It is characterized by a sudden onset of fever, cough (usually dry), headache, muscle and joint pain, severe malaise (feeling unwell), sore throat and a runny nose. The cough can be severe and can last two or more weeks.

Most people recover from fever and other symptoms within a week without requiring medical attention. However, influenza can cause severe illness or death, particularly among high risk groups including the very young, the elderly, pregnant women, health workers and those with serious medical conditions.

In temperate climates, seasonal epidemics occur mainly during winter, while in tropical regions, influenza may occur throughout the year, causing outbreaks more irregularly

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Influenza (avian and other zoonotic)
© WHO/Yoshi Shimizu
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Influenza (avian and other zoonotic)

Influenza (avian and other zoonotic) in China

Animal influenza viruses are distinct from human seasonal influenza viruses and do not easily transmit between humans. However, zoonotic influenza viruses - animal influenza viruses that may occasionally infect humans through direct or indirect contact - can cause disease in humans ranging from a mild illness to death.

Birds are the natural hosts for avian influenza viruses. After an outbreak of A(H5N1) virus in 1997 in poultry in Hong Kong SAR, China, since 2003, this avian and other influenza viruses have spread from Asia to Europe and Africa. In 2013, human infections with the influenza A(H7N9) virus were reported in China.

Most swine influenza viruses do not cause disease in humans, but some countries have reported cases of human infection from certain swine influenza viruses. Close proximity to infected pigs or visiting locations where pigs are exhibited has been reported for most human cases, but some limited human-to-human transmission has occurred.

Just like birds and pigs, other animals such as horses and dogs, can be infected with their own influenza viruses (canine influenza viruses, equine influenza viruses, etc.).

WHO China/Beijing Fotolink Technology Development Co., Ltd
Woman handling poultry in China
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A(H7N9)

The first human case of influenza A(H7N9) was reported in China in 2013. Over 1,500 human cases have been reported since then. 

 

©WHO/Yikun Wang
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Other influenza subtypes

Human infections of other influenza subtypes (such as H5N1, H5N6, H7N4, H9N2, H10N8) have also been reported in China.

 

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