New cases of an unusual bird flu virus strain infection that is affecting humans is baffling experts. Chinese health authorities stepped up monitoring after four more confirmed cases of H7N9 bird flu were reported today, bringing the total so far to seven.

The four new human infections have been reported in the Jiangsu Province, eastern China. In Shanghai, where two people died of H7N9 avian influenza earlier this month, the municipal government announced in a press briefing that statistics on unexplainable pneumonia cases will be reported on a daily basis.

The four new bird flu infections include 3 women and 1 man, all from different cities. They are all in a critical condition and receiving emergency treatment, according to the Jiangsu provincial health bureau.

None of the 167 people that the four infected patients came into contact with had symptoms of fever or flu.

Below are details about the four new cases of human infection with the H7N9 avian flu virus strain (Source: Shanghai Daily):

  • A woman, a poultry culler, surnamed Xu, aged 45 years, from Nanjing. She became sick with flu-like symptoms on March19th, was transferred to an ICU in a Nanjing hospital on March 27th. H7N9 avian influenza virus infection was confirmed on April 2nd.
  • A woman, aged 48 years, from Sugian City. She became ill with flu-like symptoms on March 19th and was hospitalized in Nanjing on March 30th. She is also in an intensive care unit (ICU). H7N9 avian influenza virus infection was confirmed on April 2nd.
  • A woman, aged 32 years, from Wuxi City. She became ill on March 20th and was hospitalized locally on March 28th. H7N9 virus strain infection was confirmed on March 31st.
  • A man, aged 83 years, from Suzhou City. He became sick on March 20th and was hospitalized locally on March 29th. H7N9 avian influenza virus infection was confirmed on April 1st.

The Shanghai city government says it is setting aside funds to set up a team of experts to evaluate the risk of H7N9 infection, as well as to determine how severe this bird flu virus strain might be.

Before last week, the H7N9 avian flu virus strain had never infected humans; this is a new development which is worrying virologists.

The Shanghai Animal Disease Prevention and Control Center took 34 samples of pig carcasses and tested them. Thousands of dead pigs have been found floating in the Huangpu River this month. The Huangpu River flows through the city of Shanghai and is its main source of drinking water. The Control Center emphasized that no bird flu viruses were found in any of the 34 carcasses.

In Jiangsu, the local government announced that its top 16 hospitals have been designated to accept new cases of suspected bird flu infection. Officials said it is imperative to offer the best treatment possible and to keep mortality rates down to a minimum.

Hospital staff in relevant parts of China, and then the rest of the country, will be trained on how to treat unexplained pneumonia, the Beijing Health Bureau informed today. It has told hospitals to test for H7N9 bird flu as a part of its routine monitoring.

Schools, nurseries and poultry farms in Shandong Province will receive regular visits from health officials for morning tests of cough, fever and other respiratory signs and symptoms.

Last week, the Chinese Health Department informed that two men in Shanghai died after becoming infected with the H7N9 avian influenza virus strain. A woman from Chuzhou became ill and is critically ill. According to Chinese authorities and the World Health organization, H7N9 has never infected humans before.


A 27-year-old man became ill on February 19th and died on March 4th. The other patient, aged 87, became ill on February 27th and died on March 10th. One of the patients’ two sons, both adults, became ill with flu and were admitted to hospital – one of them died of severe pneumonia while the other was discharged after making a full recovery. Neither of the sons had been infected with H7N9, Chinese authorities emphasized.


Authorities last week also informed about a woman, aged 35, who became infected in Chuzhou, in the eastern province of Anhui. She became ill on March 10th and is still in a critical condition in a hospital in Nanjing.

Chinese experts are trying to find out how the H7N9 bird flu virus strain spreads among humans. They are certain that, so far, there has been no case of human-to-human transmission. Tests on 255 people who were in contact with the 7 infected patients have found no signs of flu symptoms, or bird flu infection.

Most likely, people are becoming infected through contact with sick birds.

According to WHO (World Health Organization), there is no vaccine to protect people from H7N9 infection.

WHO and the Chinese CDC (Center for Disease Control and Prevention) say there is no evidence pointing to a human-to-human transmission of H7N9. They are sure it is not highly human transmissible.

In an interview with Shanghai Daily, Jiang Qingwu, dean of Public Health School of Fudan University, said “So far, it is still an animal virus not a human virus”.

In an interview with the Associated Press, Timothy O’Leary, of WHO, said “There is apparently no evidence of human-to-human transmission, and transmission of the virus appears to be inefficient, therefore the risk to public health would appear to be low.”

Chinese citizens have been told by health authorities to see their doctors immediately if they have a fever, are coughing, and/or have breathing problems.

Bird flu, avian flu or avian influenza is a type of flu caused by a virus that infects wild birds, pet birds and farmed poultry, and makes them sick.

Avian influenza is a highly infectious disease among birds; some strains are highly infectious among humans. HPAI (highly pathogenic avian influenza) is the more aggressive one.

The avian influenza virus does not only infect birds and humans (some strains). Pigs in China were found to be infected with the avian influenza virus in December 2012.

Avian flu can be transmitted from farmed livestock to wild birds, from livestock to pet birds, from pet birds to wild birds, from wild birds to pet birds, and from pet birds to livestock. The infection spreads through the nasal secretions, feces and saliva of the infected animal.

Millions of birds have either died of infection or have been culled since December 2003 because of bird flu outbreaks in Asia, Africa and Europe.

Experts say there are at least 16 different types of avian influenza viruses. The H5N1 strain kills 60% of infected people. Fortunately, H5N1 does not infect a human easily.

Most human cases of bird flu were caused by close contact with infected birds or objects/surfaces contaminated with their feces or secretions.

Approximately 359 people have been killed by H5N1 bird flu infection since 2003, according to WHO.

Last year, a novel bird flu virus infected harbor seals, according to a report published in MBio.

Written by Christian Nordqvist