Dramatic changes in avian influenza (AI) are posing an increasing threat to animal welfare, the global economy and human health. This was the key conclusion of a presentation by Marcelo Paniago to the world’s leading experts at the 3rd Global Risk Forum on public and animal health in Davos on Oct. 5. Paniago is the Director Global Veterinary Services Poultry at Ceva Santé Animale.
Paniago said, “Avian Influenza has changed dramatically in the last few years. To date, 2015 has seen 309 individual outbreaks of avian influenza reported to the World Organisation for Animal Health (OIE), which is a staggering 147% increase on outbreaks reported in 2014. Seventy five percent of emerging human infectious diseases, of which AI is one, come from animals.” 1
This increase in outbreaks has resulted in increasing costs for governments and industry as well as having a significant impact on animal welfare. In a major outbreak of the H5N7 strain in the Netherlands in 2003, some 255 separate incidents were managed, with 30 million poultry birds culled at a cost of 500 million euros. There were 86 cases of human infection with one fatality, a veterinarian that had visited an infected farm. The latest outbreak in the Netherlands in 2014, involving the H5N8 strain, saw 345,000 birds culled and a cost of 56 million euros. In the same year, outbreaks involving different strains occurred in multiple European countries as well as Japan, China and South Korea.
In the USA alone during the last six months, domestic poultry birds (layers and turkeys) have been destroyed due to AI, with the disease spreading across 15 states.2 It has been the worst epidemic of highly pathogenic avian influenza (HPAI) ever in the U.S. and despite the outbreak seemingly under control, there are fears that AI could reappear here this autumn following outbreaks across 31 countries already this year.3 The mass cull, which USDA estimated at more than $500 million, presented real challenges in terms of finding sufficient landfill sites to accommodate the huge volume of infected carcasses, presenting additional issues in working with local communities.
Data presented at the Summit showed that the disease being induced by more types of virus and it is being detected in more countries than ever before, but there is renewed hope for control of this disease.
“The more recent viruses are better adapted to wild waterfowl populations and can be carried over much longer distances as these birds follow their migratory patterns. The risk is much higher than ever, and this is the right time to forget old dogmas and adapt to this new situation. A new vector vaccine has been developed that overcomes most of the previous objections to using vaccination and means that vaccination can no longer be neglected but needs to be considered as an essential part of a One Health strategy to protect the poultry industry and wider communities against potentially enormous clinical and economic losses,” Paniago explained.
Work conducted in the Netherlands demonstrates how the spread of avian influenza between continents is increasingly being linked to migratory aquatic birds. Avian influenza affects wild waterfowl but strains such as H5N8 and H5N2, which was the source of the U.S. outbreak this year, take much longer to impact waterfowl, which means infected birds can carry the viruses for longer distances, and thus further into Europe and across to the USA. The H5N8 2014 outbreak in Holland is believed to have been started by the disease being transferred to native duck populations by Widgeons. Wild aquatic birds use migratory flyways that overlap extensively in “mixing zones” over Northern Eurasia during the breeding season, which sees the strains picked up by other birds that migrate south in Europe over autumn and winter.
Andre Steentjes, Ceva Poultry veterinarian and member of the EU Poultry Veterinary Study Group added, “The most important thing in terms of controlling AI is having an early warning system in place. Public opinion, which is increasingly in favor of poultry being kept outside to meet the desire for free range eggs and organic broilers, has meant that it is more difficult to control the spread of the disease. This is because you cannot always control poultry flocks mixing with infected wild birds. In this instance our preventative measures have to be renewed, of which vaccination is key.”
1 WHO information site, http://www.who.int/zoonoses/
2 USDA information site, http://tinyurl.com/l75hk53
3 OIE data, http://www.oie.int/en/animal-