First case of new bird flu H6N1 found in 20-year-old woman

Caged chickens are sold at a poultry market in Shanghai, China, April 5, 2013. Eugene Hoshiko/AP

A new bird flu strain called H6N1 has infected its first human.

Taiwanese researchers are reporting the new bird flu appeared in a 20-year-old woman from central Taiwan. The woman had been working in a delicatessen before she began experiencing flu-like symptoms and shortness of breath. She was then hospitalized in May 2013.

She has since fully recovered following treatment with antiviral drugs. The woman had not traveled abroad three months prior to the infection, and she said she had not been in close contact with poultry or wild birds. Interviews with 36 relatives and friends of the woman found no other cases of H6N1. Researchers say the source of her infection remains unknown.

The H6N1 strain is different from a new strain called H7N9 that has infected at least 139 people in China and Taiwan to date. That strain has been responsible for at least 45 deaths.

H6N1 has been circulating in chickens in Taiwan since the 1970s, according to the researchers, led by Dr. Ho-Sheng Wu, a scientist at the Centers for Disease Control in Taiwan. After sequencing the genome of the virus taken from a sample of the patient's upper airway, the researchers discovered the human virus closely resembled the chicken virus.

They found the strain in the woman had a mutation in a protein that's found on the surface of the virus that may have made it more able to infect humans. The mutation allowed the virus to evolve its ability to bind to a receptor found in the upper airway of people, called SAa-2,6. This may make the virus more infectious.

"As these viruses continue to evolve and accumulate changes, they increase the potential risk of human infection," Wu said in a statement.

His study of the new bird flu virus was published Nov. 13 in The Lancet Respiratory Medicine.

An accompanying commentary published in the same journal issue said the research raises familiar questions.

"What would it take for these viruses to evolve into a pandemic strain?" asked commentary author Dr. Marion Koopmans, head of virology at the National Institute for Public Health and the Environment in the Netherlands. "And an overriding question is if it is time to review our approaches to influenza surveillance at the human-animal interface? We surely can do better than to have human beings as sentinels."

The other new bird flu strain, H7N9, was first reported by authorities in March, with health officials suspecting many had been infected by being in contact with live poultry in animal markets. Then, human-to-human transmission was reported in August between a 60-year-old man and his 32-year-old daughter who had been taking care of him. Experts at the time said the transmission report "does provide a timely reminder of the need to remain extremely vigilant: the threat posed by H7N9 has by no means passed."

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