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Is avian flu advice only scratching the surface?

01 March 2017, at 12:00am

Avian influenza is a highly infectious disease that can affect all species of bird. We spoke with avian specialist Neil Forbes about the potential effects of the disease on birds of prey and waterfowl as well as poultry, and how this risk should be managed.

Having affected birds in all corners of the world, the latest strain of avian influenza reached the United Kingdom in December last year. The disease poses a threat to all birds – from passerines to peregrine falcons – not just those that are farmed. Neil Forbes, a specialist in avian medicine, discusses the current bird flu outbreak with us, with a particular focus on non-poultry birds in the UK.

It is understandable that most of the advice and restrictions provided by the Animal & Plant Health Agency (APHA) to date have been devised with poultry farmers in mind. Poultry are said to be particularly susceptible to this strain and its spread amongst farms could have devastating consequences for the poultry industry. Strict restrictions have been put in place to ensure that biosecurity is of utmost importance to keepers of poultry throughout the outbreak.

Dr Neil Forbes, an RCVS Specialist in avian medicine based in Swindon, UK, believes that the initial information provided by the authorities to OVs and keepers of large flocks was “incredibly sensible”. He does note, however, that keepers of small, backyard collections of poultry must also be kept in the loop. Whilst DEFRA has contact details for everyone with a flock of 50 or more poultry, Neil explains that during this outbreak, “it took quite a long time for information to get out to individual owners of small groups”. He goes on to say that this is an area where veterinary practices and OVs have an official role to play; they may well be coming face to face with small-scale poultry farmers and owners and can offer advice on the importance of biosecurity.

Birds of prey have also received little attention. Neil states that keepers of birds of prey have been given mixed messages by the authorities: “There are people out there flying and hunting waterfowl, letting birds eat waterfowl and believing that there’s not a risk.” That, he says, is wrong; “It is misleading and could lead to problems with controlling the disease.”

“Poultry in higher-risk areas have to be housed or kept within an enclosed aviary,” Neil explains. “In parts of the information it says that it includes captive birds, but it doesn’t specifically say ‘excluding birds of prey and pigeons’. In an area that’s not higher risk, they can have their range areas – the ground has to be cleaned and disinfected, the birds must be under supervision the whole time, so it seems strange that you have that degree of control for those species, and yet others that are susceptible to the disease are not being controlled.”

Many falconers are looking for advice on the problem – should they be flying their birds of prey? Neil suggests that “if the restrictions are there from a disease-control point of view, people should not be flying birds of prey in higher-risk areas”. This issue also extends to wildlife casualty cases: should centres take in injured wild birds during the outbreak? Neil explains that many falconry centres take in injured wildlife simply because they think it’s a good thing to do and to support the public, “but every time they take in an injured bird, particularly if they are in a higher risk area, they are putting the whole of their collection at risk”. He feels very strongly about this issue from a risk-assessment point of view; owners and management of falconry centres and wildlife rescue centres may listen to the advice of APHA over that of their local vet – “particularly if it’s a question of them trying to keep business coming in”.

Moreover, the symptoms of avian influenza are not the same from one species to the next. Neil believes that this is something that vets need to be very clued up on. Poultry infected with avian influenza display a range of different symptoms. If a bird of prey is infected, on the other hand, it will not display any symptoms at all. The disease is only identifiable in post-mortem, and even then, Neil tells me, sometimes only by a pin-head sized area of inflammation in the pancreas.

Some of the most endangered bird species in Britain belong to the category of waterfowl. In fact, arguably the most endangered avian species in the world at present, the Madagascan pochard, is a lake-dwelling bird. Avian influenza could have a devastating impact on these species, but can anything be done to help protect them from the disease? Neil explains that necessarily, wildfowl are wild birds; they are free-living and (even if a reliable vaccine were available) it would not be possible to catch up with all the birds in the wild population and vaccinate them.

The issue has, however, been considered by organisations like the Wildfowl and Wetlands Trust. The WWT has an avian influenza contingency plan in place, which, says Neil, “basically means that they have polytunnels which are kept clean and biosecure, so that in the event of an outbreak, they can ark (in other words put into care) the most important species”. At least if you’ve got a captive population, Neil reasons, then we have the species elsewhere on other continents that can be kept as a secure population to breed from so the species can eventually be released back into the wild. “At least we are making provision to save that species,” he says.

This is no mean feat. Creating accommodation that is welfare friendly and biosecure is a challenge – particularly for waterfowl. Zoos often have tropical houses and similar environmentally controlled exhibits – “you can have temperate houses as well, so they get rained on, they have running water, they can bath, they have ultraviolet light provided,” says Neil. It is expensive, but is perhaps the direction that we should be moving in to try to conserve those species at high risk, he explains.

Though not of immediate concern, it is important that vets remember that this disease can affect all bird species. Neil confirms that it can affect passerines at bird feeders as well as poultry on farms. “We do know that infection is in the wildlife population and though it is more of an issue near water, ponds, marshy areas, rivers, canals and so on, it can be anywhere.”

Avian Specialist at Vets Now Referrals

Neil leads the team at Great Western Exotics, part of Vets Now Referrals. Neil graduated from the Royal Veterinary College in 1983 with a First Class Honours degree.

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