Monday, August 20, 2018

Brief ESA Report On HPAI H5N2 & H5Nx In Russia

78 Outbreaks of HPAI Since June 2018 - Credit OIE





















#13,466

We've been following Western Russia's summer of bird flu since early June, with dozens of reports of HPAI H5 spread across at least a dozen federal regions. Details have been scant, however, with most reports only identifying the virus as HPAI H5.
While recent history suggests most of these outbreaks are likely due to HPAI H5N8 - we are also aware of at least two outbreaks of HPAI H5N2 since last December  (see Russia Notifies OIE Of A Second HPAI H5N2 Outbreak In Kostroma Oblast).
Until last week, all we had was speculation on the origin of this HPAI H5N2 virus.  It was believed to be either a spontaneous LPAI-to-HPAI mutation of an LPAI H5N2 virus  OR  a newly reassorted HPAI virus from the currently circulating clade 2.3.4.4. HPAI H5N8 or HPAI H5N6 viruses.
Last week we learned that this latest HPAI H5N2 was indeed clade 2.3.4.4. - suggesting a recent reassortment event - although no details have been released regarding last December's virus.
The short history of clade 2.3.4.4. H5 viruses has been one of continual evolution, frequent successful reassortment (into H5N6, H5N2, H5N5, etc.), and rapid geographic expansion - primarily via wild and migratory birds. 
These viruses have sparked the largest avian epizootics on record in both Europe and North America, and have extended their reach all the way into the Southern Hemisphere.
With this fall's bird migration already underway in parts of the Northern Hemisphere, the introduction and possible spread of a new HPAI H5 subtype this fall is of considerable concern.  

 
Today France's ESA (Epidemiosurveillance Santé Animale) has released the following (translated) report on what little we know about this new subtype, along with some details on this summer's HPAI H5 activity in Russia.

As this report points out, the vague reporting from Russia this summer makes it impossible to gauge just how prevalent HPAI H5N2 has become, or how much of a threat it might pose to Europe this fall.  

Outbreak of H5 HPAI outbreaks in Russia and detection of H5N2
Keywords:

ALL IAHP H5N2 News health information 2018 avian influenza Russia

Submitted by Adler MOUKOUBOULOU on 20. August 2018 - 10:09.
For the VSI (in alphabetical order) : Anne Bronner (EB), Didier Calavas (Anses), Julien Cauchard (Anses), Sylvain Falala (INRA), Alize Mercier (CIRAD)
for the NRL Eric Niqueux
for ONCFS: Anne Van De Wiele
corresponding author: alize.mercier@cirad.fr


Source: OIE 17/08/2018
detection of a virus H5N2 hP in Russia
On 16 August, Russian authorities said the OIE of a highly pathogenic avian influenza (HPAI) found Aug. 9 in a poultry (species not identified) to Harino in Kostromskaya region (statement OIE of 16.08.2018) (Figure 1). Among the 498,485 birds breeding, 506 were infected and died (morbidity and mortality reported by 0.1%). The authorities control measures have been implemented such as culling, quarantine, disinfection, the establishment of containment areas and the protection around the fireplace and restricting poultry movements within the country (source: OIE).
The subtype H5N2 was confirmed by PCR and sequencing. Comparative analysis of nucleotide sequences of gene fragments H and N indicates that the isolate belongs to the Asian genetic lineage HPAI virus clade 2.3.4.4 which has spread in Russia as well as in several countries in Asia, Europe, Middle East and Africa in 2016-2018. The hemagglutinin cleavage site -REKRRKRGLF- has a sequence characteristic of a high potential virulence of the virus.
At this stage, no information is not available on the comparison between this virus and one that had been detected in Russia in December 2017 (see box).

DETECTION OF VIRUS H5N2 IN DECEMBER 2017

On 29 December 2017, Russia had declared an outbreak of HPAI H5N2 in a poultry farm of more than 660 000 birds in the Kostroma region, northwest of Moscow (OIE statement 12/29/2017 ). This home was originally notified as a H5N8 outbreak three days earlier.
This was the first statement of HPAI H5N2 in Russia, the last declared presence of H5N2 in Europe dating back to January 2016 three homes within farms in France. However, these two viruses may differ. In fact, regarding the origin of this virus, two assumptions are made:
- the transfer of an FP H5N2 virus present in animal husbandry, HP (virus as was the case in 2015 with the H7N7 virus in the UK and Germany, or H5N1, H5N2 and H5N9 in France )
- reassortment between H5N8 HP virus that circulated in 2016-2017 with a Eurasian strain FP, as with H5N6 in Europe. Indeed, the virus clade 2.3.4.4 have great potential for mutation, as was seen with the appearance of the H5N5 virus and H5N6 after H5N8 circulating in Europe during the 2016-2017 season.
Nevertheless, further analysis would be needed to better define the origin, the link between genetics and composition of these new viruses, and the evolution of the epidemiological situation in Europe is to follow with vigilance.
RESURGENCE of HPAI outbreaks in Russia h5
Since 20 June 2018, Russia declared 78 outbreaks of HPAI within ' poultry (unspecified types of birds) (Figure 2). The observation of these homes are spread dates from June 7 to August 5. Control measures implemented include poultry movement control inside the country, of surveillance measures in the areas of protection and containment and culling (source: OIE).

Of the reported outbreaks since June 13 (n = 79), the subtype H5N8 could be attributed to seventeen households reported July 18. For other H5 outbreaks (n = 62), it is impossible to attribute them to the H5N2 or H5N8 viruses reported during the same period.
It is important to note that bird migration has already begun, although they will be more important in September-October. The circulation of HPAI in Russia represents a significant risk to bird populations of France and Europe, and will be monitoring very closely with the intensification of the movements of birds.

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