Bird Flu Mutating: Are We On The Brink Of A Deadly Pandemic?
A new strain of bird flu in China has adapted in a way that allows the virus to thrive in human cells, scientists said last week. Reports from China indicate that at least 60 people have become ill with this recent strain of bird flu virus, and that 13 of those infected with it have died.
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The Chinese Center for Disease Control and Prevention reported the first human cases of the evolved H7N9 avian flu virus on March 31. Until the recent outbreak, which started in the Yangtze River delta region of eastern China but has spread to Beijing and Shanghai, the H7N9 virus was not thought to cause illness in humans, a fact that raises concerns over the ability of the bird flu virus to adapt to human hosts.
Reuters reports that investigators are working to ascertain the threat of the virus causing a global pandemic - much like the Severe Acute Respiratory Syndrome, or SARS, oubtbreak of 2003 which killed one in ten of the 8,000 people infected worldwide.
With the new bird flu virus able to thrive in human hosts, could we be on the brink of a deadly pandemic?
The latest iteration of the bird flu virus, H7N9, is a mutation of the avian influenza virus, a virus that normally affects birds.
Some strains of the avian influenza virus, however, can also infect humans, like the H5N1, which first spread to people in 1997 in Hong Kong. Initially, 18 people were diagnosed with the H5N1 virus; 6 of them died. One-and-a-half million chickens were butchered to stop the oubreak. Since then, more than 380 people worldwide have become ill with this strain of avian influenza virus, over 60 percent of who have died.
Researchers led by Masato Tashiro of the Influenza Virus Research Center and Yoshihiro Kawaoka of the University of Wisconsin-Madison and the University of Tokyo studied the adapting avian flu virus over the past few weeks. They found that the H7N9 virus has a protein mutation that allows it to multiply at temperatures that correspond to the human upper respiratory tract.
"These viruses possess several characteristic features of mammalian influenza viruses, which likely contribute to their ability to infect humans and raise concerns regarding their pandemic potential," Kawaoka and his colleagues conclude. Their findings appear in the April 11 edition of the journal Eurosurveillance.
Kawaoka said that indications that the virus is adapting to human hosts are "unmistakable," According to Science Daily.
A pandemic is an infectious disease that occurs on mulitple continents and which spreads at an unexpectedly high rate. The 20th century has seen three influenza pandemics: The Spanish flu at the end of World War I; the Asian flu of the late 1950s; and the Hong Kong flu of the late 1960s.
The likelihood of the bird flu virus becoming a pandemic depends on its ability to replicate and take over the living cells of its host. Reuters reports that there is still no indication that the virus is spread through human-to-human contact. Rather, it is believed to be the result of direct contact with infected poultry.
"Health officials believe people are contracting the H7N9 virus through direct contact with infected fowl and say there is no evidence the virus is spreading easily among people," AP reports.
Chinese authorities slaughtered poulty in markets where the H7N9 virus was detected and suspended sales of live poulty in Shanghai - where 21 cases, including seven fatal ones, have been reported - in an effort to curb any more infections in those areas.
The World Health Organization, or WHO, reports that when outbreaks of bird flu occur, they have a devestating impact on the livelihoods, economy and international trade in the affected countries.
Symptoms of bird flu in humans include a high fever, diarrhea, vomiting and abdominal and chest pain - similar to those of the common flu virus. However, the fatality rate for bird flu virus infections is much higher than that of seasonal flu infections.
According to WHO there is currently no vaccine to prevent the H7N9 virus.
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