By Katie Nelson
Image credit Remko Tanis
Two more infections with H7N9 virus have been reported, one case being a 64 year old woman from Shaoyang in Hunan province. This brings the total number of people infected to 121 and the death toll to 23. Chinese citizens now fear that the virus will surface in Guangdong and Hong Kong.
Hunan’s health department reports that the woman had contact with poultry four days before she she began showing symptoms of the virus on April 15. She was diagnosed on Saturday and is currently being hospitalized and receiving antiviral therapy and respiratory support.
A 54 year old pork vendor in Jiangxi province was also confirmed to have contracted the virus yesterday. He developed a fever on April 15 and is currently being treated.
Close contacts of the two patients have been put on medical observation, but so far all appear to be healthy.
The virus has now shown cases in Hunan, Jiangxi and Fujian. Neighboring residents of Guangdong fear that it will soon break there as well.
Researchers are saying that poultry is the main cause of the virus’ spread across china. However, contraction through human-to-human contact is still a possibility.
“In the academic arena, a fast-tracked study, published in medical journal The Lancet, by University of Hong Kong microbiologist Professor Yuen Kwok-yung and Zhejiang University found that further adaptation of the virus could lead to less severe symptoms and more efficient person-to-person transmission,” reports the South China Morning Post.
Experts continue to research the strain in an attempt to find how exactly it is being contracted by humans, and from which mammalian host, as Foreign Policy reports:
According to the WHO’s Chinese Influenza Center, the new H7N9 is a recombinant of a type of influenza (H2N9) that has been spreading for a few years among wild aquatic birds in South Korea and China, an H7N3 found in wild Chinese ducks in 2011, and an H9N2 identified last year in Chinese brambling birds. The new virus is, therefore, a triple recombination.
When these three influenzas blended, the two “mammalian” mutations somehow occurred. One, dubbed ingloriously E627K, changed the virus’s temperature tolerance from 40 degrees Celsius — the normal temperature of a bird body — to 33 C, typical human body heat. The other mutation, Q226L, switched the virus’s hemaggluntinin protein from a form that latches onto a bird’s respiratory tract, which is rich in sialic acids, to a type that locks onto galactose-rich receptors found in the throats and lungs of human beings.
There is a missing link. For the new virus to have acquired these key mutations, it must be infecting a mammalian species of some kind, besides human beings. It had to have picked up those mutations inside a mammalian host. But to date no infected pigs or other mammals have been found, according to the Chinese CDC.
Foreign Policy’s Laure Garret also points out that the majority of cases have been adults over the age of 60.
“It is unlikely this is due to a unique vulnerability in the bodies of over-60 males. Rather, this may be another clue to the identity of the mysterious viral host — behaviorally, elderly Chinese urban men are engaged in some activity that puts them at greater contact with the unknown carrier creature.”