Wu Fan, director of the Shanghai Center for Disease Control and Prevention, took part in an online Q&A session on H7N9 bird flu yesterday after a young doctor with the virus died.
Zhang Xiaodong, 31, an emergency room doctor at the Pudong New Area People’s Hospital, stayed overnight at his parents’ home on January 4. A neighbor there kept pigeons.
There is a wet market selling live poultry opposite the hospital where he worked.
Tests are still being conducted to determine the source of infection in Zhang.
The doctor started to show symptoms on January 11 and gave himself medication before seeking treatment at the hospital on January 15.
His condition deteriorated and he was later admitted to intensive care and died last Saturday, just before 5am.
Zhang did not have direct contact with flu patients within the 10 days before he developed symptoms, nor take charge of respiratory disease treatment at the hospital, said officials.
Q: Why weren’t Zhang’s parents and the neighbor infected?
A: Like other flu viruses, the H7N9 virus is transmitted by contact or by air.
Contact with live poultry, both directly and indirectly, can lead to infection with the virus.
However, an individual’s health conditions can determine whether they become infected or ill. This means that even if someone has contact with the virus, they might not be infected. And even if infected, they might not develop symptoms.
Q: Why are most live poultry sellers not infected?
A: There are a variety of bird flu virus subtypes and these subtypes have cross-protection from each other.
Generally speaking, if someone has been in contact with a certain subtype for a long time, their immune system may develop to prevent them from being infected, not only from that virus subtype, but also from the H7N9 bird flu virus.
Q: How long is the incubation period? What are the symptoms?
A: The incubation period between infection with the H7N9 virus and the onset of symptoms can be up to seven days.
However, most patients begin to show symptoms within three to four days.
People who have been infected with the H7N9 virus will not have serious symptoms of an infection of the upper respiratory tract. And someone who is infected won’t have running nose, although they may well have a sore throat and a cough.
However, the H7N9 virus attacks deep into the infected person’s lungs, causing quick development of lung inflammation.
The use of anti-viral medication is effective in the early stage of infection.