#14,138
For the past six weeks we've been following the emergence and spread of a LPAI H3N1 virus - first in Belgium, and then showing up in France - that has demonstrated unusually morbidity and mortality in poultry (see Belgium: Non-Reportable LPAI H3N1 In Poultry).
Since H5 and H7 are the only LPAI viruses considered reportable by the OIE (see Terrestrial Animal Code Article 10.4.1.), these outbreaks have fallen into a regulatory grey area, which has made for a tentative response.It was only a week ago that an agreement in principle was finally hammered out on compensating farmers for their losses, at roughly the same time that Belgium's Federal Agency for the Safety of the Food Chain (ASFCA) released more stringent protocols for the control of H3N1.
Roughly 4 weeks ago France's ESA published their first update on LPAI H3N1 In Belgium, citing 36 outbreaks (as of May 13th). Today's report (published late yesterday) now shows that number has more than doubled.
First, some excerpts from the (translated) ESA report (bolding mine), then I'll return with a postscript.
H3N1 HOMES IN FRANCE (NORD) AND BELGIUM AS AT June 14, 2019
For the National Reference Laboratory (in alphabetical order) : François-Xavier Briand Martine Cherbonnel, Nicolas Eterradossi Beatrice Grasland Sophie Le Bouquin, Claire Martenot, Eric Niqueux Audrey Schmitz Axelle Scoizec
for the ESA platform (in alphabetical order) Didier Calavas (Anses), Julien Cauchard (Anses), Celine Dupuy (Anses), Sylvain Falala (INRA), Yves Lambert (EB), Alize Mercier (CIRAD)
corresponding author: julien.cauchard@anses.fr
Source: Communication ofauthoritiesveterinariansofBelgiumto theCommitteeStandingplants, theanimals, thefoodfoodand food foranimals(PAFF) of the CommissionEuropeanon 13May( link ) and of 12June2019 (ie link )alertPromedof 06.14.2019 ( link )
- Belgium: 71 low pathogenic avian influenza outbreaks (IA FP) non H5 / H7 were confirmed in Belgium in 2019 which 6 confirmed as H3N1. The first outbreak was confirmed in January 2019 in Flanders and Wallonia is also achieved with two fireplaces 14/06/19.
- France: Three H3 outbreaks were confirmed in the northern department of France since 05.22.2019. The epidemiological investigation revealed links between the first two homes and the Belgian poultry sector.
For the record, non-H5 LPAI viruses and non-H7 are not notifiable to the OIE and are not considered in France as a health hazard category 1.Belgium -release PAFF June 12( link)
A first case of AI FP H3N1 was confirmed in January 2019 in Flanders in the Belgian programmed monitoring program of AI in a free-range laying hens. Livestock was depopulated at the initiative of the operator.
The infection was again confirmed in this breeding April 6, 2019 and was confirmed in other farms since the last week of April.
On June 12, 71 outbreaks were confirmed as related to infection by influenza virus subtype H3, 6 H3N1 virus typed. Most of the infected farms are located in West Flanders, some are located in East Flanders, two farms in the province of Antwerp and 12 June 2019, two infected farms were discovered in the provinces of Liege and Luxembourg.
The H3N1 virus, characterized by low pathogenic like the method described in the manual of the OIE, is genetically linked to a strain isolated in 2017 in a wild bird in the Netherlands.
The clinical picture is characterized by a defect in the quality of eggs, a quick drop in egg (20% to 100%) and food intake. Mortality is increased (sometimes up to 50% or more) but the spread can be slow intra livestock and sometimes even asymptomatic.
France
A first non-notifiable avian influenza H3N1 has been confirmed by the NRL 22 May 2019 in a breeder farm, meat industry, located in the department Nord, 5 kilometers from the border with Belgium. The first signs suggestive had appeared May 17, namely a food drop in consumption, a drop in egg production and mortality per day of around 1 then 2 then 6%, the first three days to reach a cumulative mortality on 10 days 25%. Livestock was depopulated May 27, at the initiative of the hatchery integrator lot owner. The H3N1 virus identified FP is very similar to that found in Belgium.
A second suspect farm (located in the temporary control zone of 3 km around the 1 sthome), empty at the time of the visit was investigated 28 May 2019 and has been detected on H3 positive environmental samples. The lot in question was also a lot of breeders of meat industry. Mild respiratory symptoms and a mortality of 0.04% per day have been reported on this lot in the week before an episode of increased mortality (1.5% over two days) associated with food consumption decline and fall 5% oviposition. The lot had been shot (reform) from May 2, 2019 following a positive RT-PCR results in search of Mycoplasma gallisepticum .
The epidemiological investigation has shown that these two farms belonged to the same integrator hatchery and the same egg collection tour. They are located in a high density area of poultry farms. Beyond the geographical proximity to the outbreaks reported in Belgium, the survey also identified many epidemiological links in the chain broiler breeder chickens in the area with that country, particularly through the transport of live animals , intervention teams, provision of food and other livestock stakeholders (veterinary ...).
A third source of infection to H3 influenza virus also has been confirmed by the NRL June 14, 2019, in the same department about 20 km from the first outbreak. There is also a breeder farm, meat industry working for the same integrator hatchery. A notable increase in mortality was observed in this farm, totaling 2% on 2 consecutive days before depopulation June 12, at the initiative of the integrator.
The influenza virus H3
The virus type H3 influenza is typically a bird virus that is completely harmless to humans and the food chain. It has all the characteristics of a low pathogenic virus, which means that the virus itself can not be held responsible for the symptoms or mortality in poultry. Of course, it may, however, help to strengthen the symptoms caused by other pathogens ( point on the AFSCA site 06.12.2019 ).
Although originally native wild birds, it has meanwhile adapted to the hens, which explains its multiplication and increased transmission.
In addition, research has shown that this virus has a certain preference for laying device, which can contribute to the identified clinical problems and also explains why laying hens are mainly affected.
The virus is spread mainly by contact with contaminated materials and between animals, which makes the application of biosecurity more than strictly imperative.
The high mortality observed in the species Gallus [1]are typically not observed in the case of low pathogenic AI virus (with the notable exception of some infections AI FP H9N2 viruses characterized in recent years in the Middle East and North Africa). It is surprising that this virus alone can explain the signs observed in homes.
The question of another factor common to different farms concerned, that could explain the severity of the observed signs and dissemination of the phenomenon under investigation.
Pathogenicity of strains of influenza
The differentiation between highly viruses weakly pathogenic is based on the results of laboratory tests, defined in the Manual of Diagnostic Tests and Vaccines for animals land of the OIE .
This characterization is specific to poultry and other birds and does not concern other species likely to be infected by virus AI , including the human (link portal avian influenza OIE ).(Continue . . . )
The elevated morbidity and mortality produced by this LPAI H3 virus is both unusual and unexpected - but it is not unprecedented - as some strains of the LPAI H9N2 virus have shown similar impacts in poultry (see G1-lineage H9N2 virus Study).
The jury is still out as to whether the enhanced clinical symptoms being reported are due solely to the H3 virus having adapted to hens, or whether a co-infection or other exacerbating factor is at work.In any event, this is a reminder that viruses can sometimes learn new tricks, and that may require fine-tuning our responses going forward.
