Epidemiological update: avian influenza A(H5N1)
09 Jan 2014
On 8 January 2014, Canada reported a fatal imported case of influenza A(H5N1) infection. This is the first confirmed human case of H5N1 in North America.
The onset of symptoms began on 27 December 2013 during a return flight from Beijing to Edmonton via Vancouver. The symptoms worsened during the travel and the patient was admitted to hospital on arrival in Edmonton, and passed away on 3 January 2014.
The clinical presentation, fever, malaise and headache, was consistent with meningo-encephalitis and did not involve the respiratory system which is unusual for A(H5N1) infection.
Tests at a reference laboratory confirmed influenza A(H5N1) infection on 7 January. The patient had not been outside of Beijing during the visit trip to China and had not visited live bird markets or farms.
The Public Health Agency of Canada is following up two family contacts who travelled together with the patient.
Risk of secondary cases considered very low
Worldwide since 2003, less than 650 human cases of A(H5N1), including 384 deaths, have been reported from 15 countries.
No autochthonous or imported cases of A(H5N1) infections have been reported in Europe since 1996, when this strain was first detected.
Most have been exposed to infected birds. In 2013, China reported 2 fatal cases of A(H5N1), and the last case was reported in February 2013.
The risk of secondary and co-primary cases among the close contacts of this case is considered to be very low for the following reasons:
- more than 10 days have passed since onset of the disease,
- transmission of A(H5N1) on board aircrafts has never been documented, and
- there is no evidence of sustained human-to-human transmission of A(H5N1) ever occurring.
The risk of health care associated transmission in Canada is considered very low for the same reasons.
The evidence points to an isolated case who was infected following exposure in China, although the source and mode of transmission has not yet been established.
A(H5N1) is a strain of avian influenza that occasionally crosses the species barrier and infects humans.
Sporadic cases originating in areas where A(H5N1) transmission has been documented in the recent past are therefore not unexpected.
Although the Canadian patient had an atypical clinical presentation and an exposure to potentially infected birds has not been established, the conclusions of the latest ECDC Risk Assessment of 12 January 2012 remain unchanged.
ECDC concurs with the recommendations made by the Canadian Public Health Agency which are in line with the ECDC recommendations that Europeans travelling to China and South-East Asia should avoid live poultry markets and any contact with chickens, ducks, wild birds, and their droppings. This reduces the risk of exposure not only to A(H5N1) but also to A(H7N9). Poultry meat and eggs should be well cooked.
Read more
- ECDC Rapid Risk Assessment: Human fatality from highly pathogenic avian influenza A(H5N1) virus infection in Guangdong province, China
- Avian influenza in humans - health topic
Other sources
- Areas with confirmed human cases for avian influenza A(H5N1) reported to WHO, 2013 to date
- Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2013
- Influenza at the human-animal interface Summary and assessment as of 20 December 2013
- H5N1 Technical Briefing Public Health Agency of Canada
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