Tuesday, February 16, 2016

OIE: H5N1 In Dead Crows - Bangladesh


Between 2007 and 2013 Bangladesh was a hot spot for H5N1, with nearly 550 poultry outreaks reported and millions of birds killed by the virus or culled. Since 2013, however, Bangladesh has not reported any new poultry outbreaks to the OIE.

In January of this year, the WHO reported `A 60-year-old male from Mymensing District in Bangladesh was hospitalized on 12 October 2015 with severe acute respiratory infection (SARI)' who tested positive for H5N1. 

So while flying beneath the radar for a couple of years, it is apparent the H5N1 virus is  still floating around Bangladesh.

Today the OIE reports that 40 dead crows, collected earlier this month from Rajshahi city,  tested positive for the highly pathogenic H5N1 virus.  The epidemiological source of the outbreak is somewhat enigmatically stated as `Eating of City waste'. 

First some excerpts from the OIE report, then I'll be back with a bit more on previous murders of crows.

While waterfowl (ducks & geese) and gallinaceous birds (turkeys, grouse, chickens & quail) are most often associated with carriage of the H5N1 virus, terrestrial birds such as crows, starlings, pigeons, and sparrows are also known to carry, and shed, the virus as well (see 2007’s EID Journal  Role of Terrestrial Wild Birds in Ecology of Influenza A Virus (H5N1).
As far back as 2008, we saw reports out of India of crows dying from the H5N1 virus. In 2012, and again in 2014 India saw numerous wild bird die offs that were blamed on the avian flu virus (see Media Report: H5N1 Killing Crows In Jharkhand).

As crows are omnivorous, they can not only contract the virus through contact with infected birds or contaminated water sources, but through the consumption of infected carrion. This may explain why crow reports are fairly common.

Because of the low expectations of finding HPAI H5 in non-aquatic birds, until the arrival of HPAI H5N2/H5N8 a year ago, passerine birds were rarely routinely tested in North America (see Surveillance Plan for the Early Detection of H5N1 Highly Pathogenic Avian Influenza Virus in Migratory Birds: 2009).

The revised plan (see APHIS/USDA Announce Updated Fall Surveillance Programs For Avian Flu) released during the summer of 2015, calls for much broader testing. 

Although the incidence of terrestrial bird carriage of HPAI viruses is poorly understood and its significance remains hotly debated, recent studies and surveillance suggests their role may be greater than previously believed. 

With the emergence of new avian flu viruses around the globe nearly every year, research into their interactions with thousands of non-aquatic bird species has only just begun. 

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