1. How did patients become infected with the influenza A(H7N9) virus? Is there any close contact dead or sick? Have the close contacts been placed under medical observation?
Influenza A(H7N9) virus evolved from avian viruses in biology. And Most of the previous influenza viruses of H7 subtype infecting human came from the poultry. However, it is still unknown what is the exact source of infection for these 3 confirmed cases so far.
In accordance with China's regulations of managing pneumonia cases of unknown origin, the health authorities of Shanghai Municipality, Anhui and Jiangsu provinces have placed all the close contacts of the confirmed patients under medical observation ( a confirmed patient from Anhui province is under treatment in Nanjing, Jiangsu province). Prior to the onset of illness of the confirmed case in Shanghai, two of his family members developed severe pneumonia and the cause is still under investigation. Whether 3 cases of this family are related remains to be investigated. And besides that, there is no infection cases found in close contacts of confirmed patients in Shanghai and Anhui.
2. What measures and investigations have been taken by National Health and Family Planning Commission and local health authorities?
The local health authorities have paid high attention to the case and taken several moves including clinical treatment, epidemiological investigation, specimen collection and testing, medical observation on close contacts and so on. The surveillance of pneumonia cases of unknown origin has also been strengthened.
National Health and Family Planning Commission has taken this issue very seriously and sent expert panels to Shanghai, Anhui and Jiangsu to guide the local treatment and investigation as soon as it was reported. Multi-department meeting was convened to discuss and judge the epidemic situation. The commission also deployed investigation, control and response preparations. After receiving the case report and specimen, China Center for Diseases Control (CDC) immediately carried out the epidemic risk analysis and laboratory testing to clarify the pathogenic diagnosis.
3. Two confirmed cases in Shanghai died in early March. Why hasn’t National Health and Family Planning Commission released the information until on March 31th?
Human infections of influenza A(H7N9) virus, a newly-reported subtype of influenza virus globally, has not been included in national notifiable disease reporting system.
Shanghai medical and health institutions have immediately conducted lab screening on the case and eliminated possible causes including seasonal H1N1 and H3N2, A(H1N1), H5N1, SARS and novel coronavirus. Shanghai public health clinical center found out that the patient might become infected by H7 flu through further testing. And the samples were sent to China CDC. China CDC managed to isolate 3 strains of H7N9 avian influenza virus in the afternoon of March 29. The experts organized by National Health and Family Planning Commission further confirmed that it was a new human case of infection with H7N9 avian influenza, according to composite analysis based on the results of lab testing, clinical manifestation and epidemiological data. Then National Health and Family Planning Commission released this information according to law on March 31.
4．It was reported that 3 persons of a family became infected with pneumonia of unknown origin in Shanghai, and 2 of them died in hospital. Is there any relation to the case reported this time?
On 20 to 25 February 2013, a hospital in Shanghai received Mr. LI and his two sons who were all suffering from severe pneumonia. Two of them died after emergency rescue efforts. Mr. LI was confirmed infection with influenza A(H7N9), and the other 2 patients are still under diagnosis.
5. How are the virulence and infectivity of influenza A(H7N9) virus comparing with influenza A(H1N1), A(H5N1) viruses and other seasonal influenza ?
As there are only 3 confirmed cases of human infections with influenza A(H7N9), research data of the virus and the diseases caused is very limited. Experts are further studying the virulence and person-to-person transmission capability.
6. Is it possible that infected people can be treated effectively if they seek medical advice for early symptoms?
The gene sequence analysis shows that the virus is sensitive to anti-influenza drugs knowns as neuraminidase inhibitors. Based upon past experience of antiviral treatment on influenza, it might be effective to use the antiviral neuraminidase inhibitors early in the course of illness. However, the specific treatment of the newly-found influenza virus(H7N9) still needs more investigation and research.
7. How can infection with influenza A(H7N9) virus be prevented? Is there anything else that we should pay particular attention to?
Flu is an acute respiratory infection. It benefits anyone to prevent the infection including flu by washing hands, ventilation, right nourishment and keeping fit. Cover your mouth and nose with a tissue or handkerchief when displaying respiratory infection symptoms such as coughing or sneezing. And avoid direct contact with dead or sick poultry and animals.
Health care workers are suggested to take necessary precaution since they have more opportunities to come into contact with patients with infectious diseases. Effective protection measures such as standard precautions, air transmission precaution, and contact transmission precaution should be taken when caring for confirmed or suspected influenza A(H7N9) cases.
No vaccine for the prevention of influenza A(H7N9) infections is currently available both in China or abroad.