How The Deadly New Bird Flu Is Spreading Across China
As of April 15, the World Health Organization (WHO) has reported 60 confirmed cases of patients infected with H7N9, 13 of whom have died. Another current report on ABC has the total deaths up to 14.
So far there is no evidence that the virus can spread from human to human. That's a good sign. Human-to-human transmission would give this outbreak legs to turn into a potentially devastating pandemic.
The Beginning
The first deaths from H7N9 were reported at the end of March in eastern China.
An 87-year-old man from Shanghai died on March 4 after becoming ill on Feb. 19, and a 27-year-old man died on March 10 after becoming ill on Feb. 27, Agence France Presse reported.
Both victims suffered from fever, coughs, and had trouble breathing.
The number of reported deaths and infections has increased since then.
Here's a curve of the confirmed cases reported to WHO. Red stands for confirmed deaths; green stands for confirmed cases.
The Source
Human H7N9 infections seem to be associated with infectious poultry.
Unlike H5N1, birds can be infected with the H7N9 virus and show no symptoms. Since officials don't know which birds and how many are infected, WHO warns that "further human cases of infection should be expected."
In response, officials have conducted mass slaughters at poultry markets throughout Shanghai, while inspectors check restaurants and supermarkets.
Geographic Distribution
The virus remained limited to Shanghai, or eastern China, until this week. There are now two confirmed cases of infected patients in Beijing.
A 7-year-old girl, whose parents are in the live poultry trade, was admitted to the hospital on April 11, AP reported.
According to CNN, on April 16, a 4-year-old boy, whose parents are involved in poultry and fish trading, was found to be infected with the virus, although he showed no symptoms.
Here's a chart from Flutrackers.com that shows the frequency of cases by week.
This chart, from April 9, shows the age distribution of bird flu patients. At that time, there were 28 reported infections, including 9 deaths.
According to WHO, cases are in either Eastern or Northern China. This includes three provinces — Anhui, Jiangsu and Zhejiang — and two municipalities — Beijing and Shanghai.
In comparison, the bird flu H5N1 never showed this wide of a distribution across provinces.
A Google map shows H7N9 cases in China. Red shows deaths; blue shows those who are infected.
View H7N9 map in a larger map