Taipei, April 29 (CNA) Health authorities maintained Monday that there is no evidence to suggest that the H7N9 avian flu virus has spread between humans, despite an additional family cluster case reported in China a day earlier.
The son of a man who was Shandong Province's first case of H7N9 avian flu was confirmed to have contracted the disease, according to Chinese health authorities. The case marked the third so-called "family cluster" case in China.
Centers for Disease Control official Chuang Jen-hsiang said 60 percent of the H7N9 cases in China had prior contact with poultry, although the remaining 40 percent had reported no such contact.
There is no evidence of sustained human-to-human transmission of the virus, he said, adding that the number of cases reported in China has slowed.
Huang Li-min, director of the Department of Pediatrics at National Taiwan University Hospital, said analysis of the point of mutation of H7N9 shows that the virus has not yet adapted to human transmission.
But he added that it is not yet known how long it will take the virus to mutate to a point where person-to-person transmission is possible.
Meanwhile, Ho Mei-shang, a research fellow at Academia Sinica's Institute of Biomedical Sciences, said China's order for all live poultry markets in Shanghai to close down has had some effect, indicating that such a move is effective in confining the disease.
Ho noted that after Shanghai closed down all live poultry markets April 6, there have been no additional cases reported in the city since April 16.
Taiwan is scheduled to close down all its live poultry markets May 17.
She also said that as summer gradually approaches, the high temperatures are likely to slow the spread of the disease, adding that the government and the pharmaceutical companies should step up efforts to develop a vaccine to prepare for next winter.
(By Chen Ching-fang and Ann Chen)