ugg boots grey Update on Avian Influenza
December 20th 2016 Statement from the United Nations Environment Programme/Convention on Migratory Species (UNEP/CMS) and the Food and Agriculture Organization (FAO) Co Convened Scientific Task Force on Avian Influenza and Wild Birds, of which BirdLife International is a member.
This statement is released in response to the recent H5N8 highly pathogenic avian influenza (HPAI) developments (November 2016) to inform stakeholders in governments, the poultry sector, disease control, wildlife management, site management and conservation sectors about the potential interaction between wild birds and the H5N8 HPAI virus and appropriate ways of taking action.
1. Typically, highly pathogenic avian influenza (HPAI) outbreaks are associated with intensive domestic poultry production and associated trade and marketing systems with spread of HPAI virus via contaminated poultry, poultry products and inanimate objects.
2. Spread of HPAI viruses to wild birds has resulted in mortality and conservation issues for wild birds. The specific role of wild birds particularly in the long distance transmission of the virus, if existent, remains unclear.
3. Phylogenetic analyses indicate that wild birds acquired H5N8 HPAI from the pool of HPAI H5 viruses circulating in domestic Anseriformes (ducks and geese) in eastern Asia.
4. In 2014, H5N8 HPAI caused outbreaks in poultry in Asia, Europe and North America. Most detections were at relatively bio secure production facilities but with some detections in wild bird species with wild birds possibly being infected by poultry and vice versa.
5. In 2016, outbreaks of H5N8 HPAI were first reported from wild birds in the Republic of Korea, followed by detections in late spring in the Tyva Republic of the Russian Federation and subsequently from October in India, to date two countries in the Middle East, two in North Africa and 13 countries in Europe with outbreaks in wild birds, poultry, hunting bird decoys and a small number of zoological collections.
6. Based on the existing, contradictory evidence, the origin of the current H5N8 HPAI virus strains remains as yet unresolved. It cannot be concluded that sustained transmission and independent maintenance of the virus from 2014 to 2016 took place in wild bird populations.
7. Although the reported numbers of infected dead wild birds in Europe are higher in 2016 than in 2014, there is in the absence of systematic mortality assessments no evidence of a change in the mortality of wild birds possibly caused by changes in the virus since 2014. To date, there is no evidence of any particular species being capable of long distance asymptomatic carriage of the virus.
8. Although H5N1 HPAI has involved human infections, H5N8 HPAI remains a bird specific virus.
9. The Scientific Task Force on Avian Influenza and Wild Birds, urges countries, agencies and organizations to:
a. further extend surveillance and collaboration across sectors, and epidemiological
evaluation, to determine the true long distance, regional and local transmission routes of the virus, including possible transmission through national and international poultry trade and its by products, and mechanisms of transmission among domestic, captive and wild birds;
b. focus disease prevention on biosecurity at poultry holdings and in marketing systems, and focus disease control actions on affected farms and zoos, with the aim of minimizing the risk of disease spread to other poultry farms, zoos and/or wildlife by preventing poultry/captive bird wildlife contact;
c. In 2014, multiple outbreaks of H5N8 HPAI occurred in domestic ducks, chickens and geese and in wild birds in the Republic of Korea with subsequent outbreaks in Japan, China, Germany, the Netherlands, the United Kingdom and the USA. Only domestic but no wild birds were found positive for H5N8 HPAI in the United Kingdom, Italy and Hungary during those outbreaks1.
In 2016, H5N8 HPAI outbreaks were reported from wild birds in the Republic of Korea (in March), and subsequently detected in five wild bird species in Tyva Republic, Russian Federation (dead birds found on 25 May 2016, and hunter harvested birds in June). There were subsequent outbreaks in India (October), and from 26 October in 13 countries of Europe (in order of detection: Hungary,
Croatia, Poland, Switzerland, Germany, Austria, Denmark, Netherlands, Sweden, Finland, Romania, Ukraine and Serbia), two countries in the Middle East (Israel and Iran) and two countries in North Africa (Egypt and Tunisia).
More than 30 species of wild birds have been affected, usually waterfowl and fish or carrion feeding species, including mostly Tufted Duck (Aythya fuligula), and lower numbers of Common Pochard (Aythya ferina), Swans (Cygnus sp.), gulls (Laridae) including Black headed Gull (Chroicocephalus ridibundus), other wild duck species (Anatidae), Common Coot (Fulica atra), storks (Ciconiidae), Grey Heron (Ardea cinerea), Great crested Grebe (Podiceps cristatus), Common Tern (Sterna hirundo), Great Cormorant (Phalacrocorax carbo), Painted Stork (Mycteria leucocephala), Pelican (Pelecanus sp.), Crow (Corvus sp.), Munia Bird (Lonchura sp.), and recently some birds of prey (Common Buzzard Buteo buteo and White tailed Eagle Haliaeetus albicilla). Outbreaks in poultry (chickens, ducks, turkeys) and captive bird collections have been reported in India and in seven European countries (Hungary, Austria, Germany, Denmark, Sweden, the Netherlands and France), and in hunting decoy ducks in France. All outbreaks were associated with mortality events/die offs.
What is the role of wild birds in H5N8 HPAI?
In general, avian influenza viruses in wild birds can be transmitted to and from poultry, and potentially to and from some other domestic animals and people. Wild birds have been shown to be a reservoir for low pathogenic virus strains, with low prevalence though. Phylogenetic investigations of the current highly pathogenic H5N8 AI virus strains (within clade 18.104.22.168) and those strains circulating from 2014 to
2015 indicate that the virus evolved and returned1. However, virological and serological evidence, as well as results of field surveys in Central Eurasia between 2014 and 2016, indicate that sustained transmission and independent maintenance of the virus in wild bird populations during this period is unlikely.
There is no convincing evidence of any mechanism or wild bird species that is able to carry the H5N8
HPAI virus strains without causing the death of the carriers themselves during long distance migration.
The scientific community has not yet reached final conclusions regarding the relative likelihood of a significant role of wild birds in long distance spread, compared to that of origin and transmission of the current H5N8 HPAI virus strains by mechanisms involved in poultry production and trade. Considering the extensive poultry trade flows, including those between H5N8 affected regions (cf. UN Comtrade statistics), the risk of HPAI virus circulation by poultry production and trade remains significantly high.
H5N8 and human health
The EU/OIE/FAO Reference Laboratory for avian influenza has concluded that the virus is still predominantly a bird virus without any specific increased affinity for humans. However, as in previous outbreaks, appropriate personal hygiene measures should be taken.