Influenza A H7 viruses are a group of influenza viruses that normally circulate among birds. The influenza A (H7N9) virus is one subgroup of the larger group of H7 viruses. Although some H7 viruses (H7N2, H7N3 and H7N7) have occasionally been found to infect humans, no human infections of H7N9 viruses had been reported until recent events in China.

Bird flu has dominated the headlines in China after some cases of people infected with the H7N9 virus were confirmed in the country.

Some people have tried to link bird flu with SARS (severe acute respiratory syndrome), which caused Chinese people to panic a decade ago, but experts say that this strain of bird flu is far less threatening to people than SARS.

Sources from the National Health and Family Planning Commission say that, as of April 18, China has 87 confirmed cases of H7N9 infections, including 32 in Shanghai Municipality and 21 in Jiangsu Province.

Some of the infected individuals were in regular contact with animals or with an animal environment prior to infection. The virus was also found in a pigeon in a market in Shanghai. It is not yet known how the infection spread to humans. The possibility of animal-to-human transmission is being investigated, as is the possibility of person-to-person transmission.

Although both the source of infection and the mode of transmission are uncertain, it is prudent to follow basic hygiene practices to prevent infection. This includes hand and respiratory hygiene, as well as food safety measures.

Hand hygiene:

• Wash your hands before, while and after you prepare food; before you eat; after you use the toilet; after handling animals or animal waste; when your hands are dirty; and when caring for an ill family member. Hand hygiene will prevent the transmission of infections to yourself (from touching contaminated surfaces) and to others.

• Wash your hands with soap and running water when visibly dirty; if not visibly dirty, wash your hands with soap and water, or use an alcohol-based hand cleanser. 

Respiratory hygiene:

• Cover your mouth and nose with a medical mask, tissue, sleeve or flexed elbow when coughing or sneezing; immediately throw used tissues into a closed bin; wash your hands after coughing, sneezing or coming into contact with mucus.

Cooked meat:

• Influenza viruses are not transmitted through consuming well-cooked food. As they are inactivated by normal temperatures used for cooking (food must reach 70°C and be "piping" hot with no "pink" parts), it is safe to eat properly prepared and cooked meat, including poultry.

• Diseased animals and animals that have died of diseases should not be eaten.

Before visiting live market

• When visiting live markets, avoid direct contact with live animals and surfaces that have been touched by animals. If you live on a farm and raise animals for food, such as pigs and poultry, be sure to keep children away from sick or dead animals; keep animal species separated as much as possible; and immediately report any sick or dead animals to local authorities. Sick or dead animals should not be butchered or prepared for food.

Designated hospitals

A list of designated hospitals in Jiangsu Province has been announced:

» Jiangsu People's Hospital,

» Zhongda Hospital,

» The Second Hospital of Nanjing,

» Nanjing Drum Tower Hospital,

» Wuxi People's Hospital,

» The Affiliated Hospital of Xuzhou Medical College,

» The First People's Hospital of Changzhou,

» The First Affiliated Hospital of Soochow University,

» Affiliated Hospital of Nantong University,

» The First People's Hospital of Lianyungang,

» The First People's Hospital of Huai'an,

» The First People's Hospital of Yancheng,

» The First People's Hospital of Zhenjiang,

» The People's Hospital of Taizhou,

» The People's Hospital of Suqian,

» Northern Jiangsu People's Hospital.

(Sources: WHO and National Health and Family Planning Commission of China)

Symptoms

Thus far, most patients with this infection have had severe pneumonia. Symptoms include fever, cough and shortness of breath. However, information about the full spectrum of diseases that may be caused by infection with the influenza A (H7N9) virus is still limited.