Source WHO Influenza At The Human-Animal Interface
Avian flu infections in humans, and outbreaks among poultry, generally reach their peak during the winter and spring months. This is a pattern we see nicely illustrated by the chart above.
So it is of little surprise that we have multiple reports of H5N1 and H7 avian flu activity from around the globe this weekend.
Rather than devote separate blogs to each of these reports, this morning we’ll roll them all up into one.
Since 16 January, Cambodia reported seven new human cases with influenza A(H5N1) virus infection
including six fatal cases. These cases come from four provinces all located in southern Cambodia. These cases do not seem to be linked epidemiologically, and most had contact with sick poultry in the village.
Enhanced surveillance has been put in place and did not detect additional cases linked to these cases.
Current evidence does not support human-to-human transmission. It has been suggested that the A(H5N1) virus is endemic in poultry in Cambodia1, and that there is more poultry and human movement around the Lunar New Year. As such, additional sporadic human cases might be expected.
Egypt has reported one new human case with influenza A(H5N1) virus infection in Behera Governorate. The A(H5N1) virus is also endemic in poultry in some areas of Egypt, and additional sporadic human cases are possible.
On 10 February 2013, China reported 2 new human cases of influenza A(H5N1) virus infection. Both
remain in critical condition. The cases come from the same province but do not seem to be
epidemiologically linked. Neither had documented contact with sick or dead poultry. Contact tracing and follow up is on-going but no additional cases have been identified. The last official report of A(H5N1) in poultry in mainland China was from Guangdong Province in September 2012
Since the return of H5N1 in 2003, there have been 620 lab confirmed human infections, of which 367 have proved fatal.
While these numbers suggest a mortality rate of 59%, the debate over the true number of cases, and the existence of `mild, undiagnosed’ infections, continues (see The Great CFR Divide).
This morning, some follow up stories, and reports of fresh outbreaks in poultry around the world.
First stop, a report from China indicating that more than 100 close contacts of the two cases reported above have been released from quarantine after developing no sign of infection.
February 17, 2013
A total of 110 people who had close contact with two patients contracted avian influenza H5N1 in southwest China's Guizhou Province earlier this month have been released from quarantine, local health authorities announced on Sunday.
Two residents of the provincial capital of Guiyang were reported to have contracted the H5N1 virus on Feb. 8. The health authority put 110 people who had close contact with the two patients under quarantine, according to the provincial government's emergency response office.
They were released as no abnormal symptoms were discovered.
One patient, a 21-year-old woman, died of multiple organ failure on Wednesday. The other patient, a 31-year-old man, is still receiving medical treatment.
Next stop Mexico, where authorities and poultry farmers have been engaged in a running battle with highly pathogenic H7N3 avian flu since early last summer (see Mexico Declares National H7N3 Animal Health Emergency).
While H7 is not considered as dangerous as H5N1, the OIE requires their notification (and containment steps taken) whenever H5 or H7 strains are identified because these strains have a history of evolving from LPAI into more pathogenic strains.
The original outbreak in Jalisco was quelled last fall (after culling 20 million birds), but the virus continues to pop up around the country (see Mexico: Fresh Outbreaks Of Avian H7N3).
This weekend, once again poultry farmers are faced with culling hundreds of thousands of birds, as reported from this New Zealand news story.
Sat, 16 Feb 2013 2:30p.m.
Mexico's animal health agency says a bird flu outbreak at seven farms in central Mexico has affected as many as 582,000 chickens.
Germany, too, is reporting an outbreak of avian flu in poultry, although there are conflicting reports on the test results. Assuming it is confirmed, this would make the first appearance of H5N1 in Germany in three years.
February 16 2013 at 04:08pm
Berlin - About 14 000 ducks at a German farm are being slaughtered following a bird flu outbreak.
Along with these outbreaks, we continue to see reports of multiple outbreaks in poultry from countries where the virus is well entrenched, particularly Egypt, Indonesia, Nepal, and Bangladesh.
We are now a decade since the H5N1 virus reappeared in Vietnam, and subsequently spread out of Asia to parts of Europe and the Middle East.
Despite many opportunities to do so, the virus has not managed to adapt well enough to humans to pose a pandemic threat. Nevertheless, the potential for this status quo to change exists, and so the WHO provides this risk assessment:
Any time influenza viruses are circulating in poultry, sporadic infections or small clusters of human cases are possible especially in people exposed to infected poultry kept in households.
However, currently, this H5N1 virus does not appear to transmit easily among people and therefore the risk of community level spread of this virus remains low. Therefore, the public health risk associated with this virus remains unchanged.