Canadian officials announced today that an Alberta resident who traveled to Beijing in December has died of H5N1 avian influenza, marking the first human H5N1 case reported in North America.
The victim, who was not identified, was admitted to an Alberta hospital on Jan 1 and died Jan 3, the government of Alberta said in a statement.
At an afternoon press conference, Canadian officials said the victim flew on Dec 27 from Beijing to Vancouver and then to Edmonton. They described the risk of transmission of the virus to fellow airline passengers or other contacts of the person as very low.
"This is a very rare and isolated case," Dr. James Talbot, Alberta's chief medical officer of health, said in the Alberta statement. "Avian influenza is not easily transmitted from person to person. It is not the same virus that is currently present in seasonal influenza in Alberta.
"Public health has followed up with all close contacts of this individual and offered Tamiflu [oseltamivir] as a precaution. None of them have symptoms and the risk of developing symptoms is extremely low. Precautions for health care staff were also taken as part of this individual's hospital treatment.
"I expect that with the rarity of transmission and the additional precautions taken, there will be no more cases in Alberta," Talbot said.
H5N1 infection is usually traced to contact with diseased poultry, but a few cases of probable human-to-human transmission have been reported in connection with prolonged close contact.
Officials said it was unclear how the person caught the virus, but there is no evidence of person-to-person transmission, according to a Canadian Press (CP) report.
Seeking to protect the victim's identity, the government gave no information on the patient's age, gender, or occupation, nor did it disclose where he or she was hospitalized.
The World Health Organization (WHO) lists a total of 648 human H5N1 cases as of Dec 20, 2013, including 384 deaths. China had two cases in 2013, both fatal, according to the WHO.
Officials at the press conference said the victim traveled with two companions, who are being monitored for signs of illness.
They said the person flew on Air Canada flight 030 from Beijing to Vancouver and, after a few hours' layover, on Air Canada flight 244 from Vancouver to Edmonton. Passengers on those flights will be contacted, mainly to reassure them that their risk is low, but also to advise them to contact local medical officials if they experience symptoms, health officials said.
The person's first symptoms developed during the trip from Beijing to Vancouver, CBC News reported.
Canadian officials described the person's symptoms as fever, malaise, and headache—an unusual presentation that suggested central nervous system involvement. One official said the signs were "more consistent with a subset of H5 cases which don't start with a primary respiratory presentation."
The patient was previously healthy, officials said. In investigating the case, they found that the person was co-infected with a common type of coronavirus—not the SARS (severe acute respiratory syndrome) coronavirus. (They didn't mention the Middle East respiratory syndrome coronavirus, which has been confined to the Middle East and to a few European and north African countries.)
One official said it was initially thought that the combination of two viruses might explain the severe illness, but because H5N1 infections are often severe, they concluded that that's not very likely.
Commenting on the case today, infectious disease expert Michael T. Osterholm, PhD, MPH, said he is surprised that more H5N1 cases have not been exported from areas where the virus is endemic to other parts of the world.
He voiced agreement that the risk of transmission to others is probably very low. "This doesn't fundamentally change the risk picture for H5N1 around the world," he said.
Osterholm is director of the University of Minnesota's Center for Infectious Disease Research and Policy, which publishes CIDRAP News.
Jan 8 Alberta government statement
WHO H5N1 case count
Jan 8 CBC News story
Jan 8 CP story