- What is the avian influenza A(H7N9) virus?
- What are the main symptoms of human infection with avian influenza A(H7N9)?
- Why is this virus infecting humans now?
- What is known about previous human infections with H7 influenza viruses globally?
- Is the avian influenza A(H7N9) virus different from influenza A(H1N1) and A(H5N1) viruses?
- How did people become infected with the avian influenza A(H7N9) virus?
- How can infection with avian influenza A(H7N9) virus be prevented?
- Is it safe to eat meat, i.e. poultry and pork products?
- Is it safe to visit wet market with live poultry?
- Is there a vaccine for the avian influenza A(H7N9) virus?
- Does treatment exist for avian influenza A(H7N9) infection?
- Is the general population at risk from the avian influenza A(H7N9) virus?
- Are health care workers at risk from the avian influenza A(H7N9) influenza virus?
- Does this influenza virus pose a pandemic threat?
1. What is the avian influenza A(H7N9) virus?
Influenza A H7 viruses are a group of influenza viruses that normally circulate among birds. The avian influenza A(H7N9) virus is one subgroup among the larger group of H7 viruses. Although some H7 influenza viruses (H7N2, H7N3 and H7N7) have occasionally been found to infect humans, no human infections with avian influenza A.
2. What are the main symptoms of human infection with avian influenza A(H7N9)?
Thus far, patients with this infection have had severe pneumonia. Symptoms include fever, cough and shortness of breath. However, information is still limited about the full spectrum of disease that infection with avian influenza A(H7N9) virus might cause.
3. Why is this virus infecting humans now?
At present, the source of exposure for these human infections remains unknown. However, analysis of the genes of these viruses suggests that although they have evolved from avian (bird) viruses, they show signs of adaption to growth in mammalian species. These adaptations include an ability to bind to mammalian cells, and to grow at temperatures close to the normal body temperature of mammals (which is lower than that of birds).
4. What is known about previous human infections with H7 influenza viruses globally?
From 1996 to 2012, human infections with H7 influenza viruses (H7N2, H7N3, and H7N7) were reported in the Netherlands, Italy, Canada, the United States of America, Mexico and the United Kingdom. Most of these infections occurred in association with poultry outbreaks. The infections mainly resulted in conjunctivitis and mild upper respiratory symptoms, with the exception of one death, which occurred in the Netherlands. According to the Chinese Center for Disease Control and Prevention, no human infections with other H7 influenza viruses have been reported in Mainland China. (Access on 5 April 2013:
5. Is the avian influenza A(H7N9) virus different from influenza A(H1N1) and A(H5N1) viruses?
Yes. All three viruses are influenza A viruses but they are distinct from each other. H7N9 and H5N1 viruses are considered animal influenza viruses that sometimes infect people. H1N1 viruses can be divided into those that normally infect people and those that normally infect animals.
6. How did people become infected with the avian influenza A(H7N9) virus?
Some of the confirmed cases had contact with animals or with an animal environment but it is not yet known how these persons became infected. The possibility of animal-to-human transmission is being investigated, as is the possibility of person-to-person transmission.
7. How can infection with avian influenza A(H7N9) virus be prevented?
Members of the public are reminded to take heed of the following preventive advice against avian influenza:
- Keep hands clean. Wash hands frequently with liquid soap, especially before eating, touching the mouth, nose, or eyes, handling food or eating, and after going to toilet, touching public installations or equipment such as escalator handrails, elevator control panels or door knobs, or when hands are dirtied by respiratory secretion after coughing or sneezing
- Avoid casually touching eyes, nose and mouth
- Avoid direct contact with poultry and birds or their droppings; if contacts have been made, they should wash hands thoroughly with soap and water
- Build up good body resistance and have a healthy lifestyle. This can be achieved through a balanced diet, regular exercise, adequate rest, reducing stress and no smoking
- Poultry and eggs should be thoroughly cooked before eating
- Cover the nose and mouth while sneezing or coughing, hold the spit with tissue and put it into covered dustbins
- Maintain good environmental hygiene
- Maintain good indoor ventilation
- Avoid crowded places and contact with fever patients
- Wear a mask when respiratory symptoms develop or you need to take care of fever patients; and
- When you have fever and influenza-like illnesses during a trip or returning to Hong Kong, promptly consult doctors and reveal your travel history
8. Is it safe to eat meat, i.e. poultry and pork products?
It is safe to eat properly prepared and cooked meat because influenza viruses are inactivated by sufficient heating, normal temperatures used for cooking (such that food reaches 70°C in all parts) will kill the virus.
On the other hand, the consumption of raw meat and uncooked blood-based dishes is a high-risk practice and is discouraged. Sick animals should not be eaten. Always keep raw meat separate from cooked or ready-to-eat foods to avoid cross contamination. Do not use the same chopping board or the same knife for raw meat and other foods. Do not handle both raw and cooked foods without washing your hands in between and do not place cooked meat back on the same plate or surface it was on before cooking. Do not use raw or soft-boiled eggs in food preparations that will not be heat treated or cooked. After handling raw meat, wash your hands thoroughly with soap and water. Wash and disinfect all surfaces and utensils that have been in contact with raw meat.
9. Is it safe to visit wet market with live poultry?
According to the risk assessment by the National Health and Family Planning Commission, the avian influenza A (H7N9) virus is of avian origin and people are mainly infected through exposure to infected poultry or its contaminated environment. Hence, members of the public should avoid contact with infected poultry or visiting wet markets with live poultry as these are important risk factors of human infection of avian influenza.
10. Is there a vaccine for the avian influenza A(H7N9) virus?
No vaccine for the prevention of avian influenza A(H7N9) infections is currently available.
11. Does treatment exist for avian influenza A(H7N9) infection?
Laboratory testing conducted in China has shown that the avian influenza A(H7N9) viruses are sensitive to the anti-influenza drugs known as neuraminidase inhibitors (oseltamivir and zanamivir). When these drugs are given early in the course of illness, they have been found to be effective against seasonal influenza virus and avian influenza A(H5N1) virus infection. However, at this time, there is no experience with the use of these drugs for the treatment of avian influenza A (H7N9) infection.
12. Is the general population at risk from the avian influenza A(H7N9) virus?
At present, it is not known enough about these infections to determine whether there is a significant risk of community spread. This possibility is the subject of epidemiological investigations that are now taking place.
13. Are health care workers at risk from the avian influenza A(H7N9) influenza virus?
As health care workers often come into contact with patients with infectious diseases, appropriate infection prevention and control measures be consistently applied in health care settings, and that the health status of health care workers be closely monitored. Please refer to the relevant guidelines for health professionals at
14. Does this influenza virus pose a pandemic threat?
Any animal influenza virus that develops the ability to infect people is a theoretical risk to cause a pandemic. However, whether the avian influenza A(H7N9) virus could actually cause a pandemic is unknown. Other animal influenza viruses that have been found to occasionally infect people have not gone on to cause a pandemic.