November 8, 2013
China Reports Two New Cases Of H7N9 Bird Flu
Earlier this week, Chinese health officials notified the World Health Organization (WHO) of two new infections of H7N9 – a strain of the virus responsible for causing the bird flu. The Asian nation's Xinhua news agency reported on one of the cases Tuesday - that of a three-year-old boy living in south China's Guangdong Province. The boy tested positive for the virus by the provincial disease prevention and control center and is in stable condition at the People's Hospital of Dongguan City, according to the news agency.
Hong Kong's Centre for Health Protection (CHP) said the boy's seven close contacts had tested negative for the virus, but three of them had flu-like symptoms.
Officials from Zhejiang province, which sits about 800 miles northeast of Guangdong, reported two infections in October, a 35-year-old man and in a 67-year-old farmer, who also worked with live poultry. The Chinese province has reported the most H7N9 cases, with 49 infections and 11 deaths so far.
When Chinese officials identified the bird flu strain back in March, the number of cases jumped before falling off into May. Only two cases were reported over the summer. Experts have warned that flu viruses are erratic and there is a chance that the number of cases could start rising as the Northern Hemisphere moves into winter, a pattern followed by other avian influenza viruses.
The four Chinese infections reported this autumn are fueling worries of another wave of H7N9 infections, but some public health experts say it's too early to tell. Richard Webby, director of the WHO collaborating center for influenza studies at St. Jude Children's Research Hospital in Memphis, told CIDRAP News that it's too early to tell if the recent infections are due to cooling temperatures, "or if we are seeing an increase at all." Webby also pointed out, "chicken production is also likely getting ramped up soon for Chinese New Year."
Marion Koopmans, a virologist at the National Institute of Public Health and the Environment in the Netherlands, said the timing of the cases hints at seasonal factors, but there are too few of them to call it a trend just yet. She added that market surveys could be used to determine any trends.
"Whether or not we expect seasonality is related to the question where these viruses come from," Koopmans told CIDRAP, a health news service of the University of Minnesota. She also noted seasonality reports seem to focus on virality of the flu virus in wild birds. "If H7N9 is circulating in backyard farms, the picture may be quite different,” Koopmans said.
The WHO has said that since H7N9 causes only a mild infection in the birds, it could still be in the avian population of China. It has called for China and bordering countries to continue monitoring public health markers for the virus.