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Forum Post : H5N1 - Can we apply some of the lessons learned from FMD 2001 to other disease control contingency plans?

Message from Mary Marshall to Defra and others with regard to the UK response to H5N1.

Your responses and guidance on this would be most welcome.

UK response to risk of H5N1  protection of outdoor poultry

"....farm biosecurity and appropriate flock disease prevention/vaccination needs to be implemented. The former is a national/international responsibility; the latter is local." [ProMED-mail moderator MHJ, "Avian influenza, poultry vs migratory birds (02)", archive number 20060218.0536, 18 February 2006, http://www.promedmail.org ]

Measures should be implemented now to protect outdoor poultry and domestic waterfowl.

Poultry keepers should be given the option of protected outdoor management, including vaccination.

Currently, Defra is responding to lobbying from the commercial sector, but failing to address the concerns of small scale keepers (including the keepers of organic, rare breeds, and pet poultry) who have no coordinated voice. Yet protection of these flocks is a national human and animal health concern.

From Les Sims, Asia Pacific Veterinary Information Services, in this same important ProMED-mail posting, and also quoted below: The news articles reproduced in ProMED-mail posting 20060217.0516 highlight a number of misconceptions about avian influenza that need to be challenged before they become further entrenched in the minds of the public and policy makers.

FMD 2001 and H5N1 2006

Comparisons have been made between FMD 2001 and H5N1 2006. However the differences and similarities need to be more thoroughly analysed:

Similarities:

Mechanical transmission of the virus is significant with both diseases. Although FMD virus is initially spread as an aerosol, mechanical secondary transmission was probably widespread. Failure to control FMD in 2001, especially by the delay of three days in imposing a movement standstill and the risks associated with mass slaughter and carcass disposal, should not be mirrored in our response to H5N1. In particular, while it will be relatively easy for the commercial sector to put their flocks indoors at short notice under conditions of strict biosecurity, there is no such capability to protect outdoor flocks, and measures need to be taken now.

Decision making. Control decisions in 2001 were taken by government-appointed advisers, led mainly by modelers with no veterinary expertise. There was an absence of veterinary and local input into decision making. We require assurance that this will not be repeated in the response to H5N1 in 2006 and beyond.

Differences:

1 Silent carriers. Unlike FMD virus, H5N1 can be significantly spread by silent carriers, mainly migratory and domestic waterfowl, especially ducks, that spread the disease without showing any symptoms.

        Les Sims, Asia Pacific Veterinary Information Services, ProMED-mail 20060218.0536:
We have known since 1999 that domestic waterfowl can silently excrete highly pathogenic H5N1 viruses for a short period of time and pose a threat to terrestrial poultry. These results certainly provide further justification for segregating waterfowl from chickens but do not yet provide convincing evidence of widespread silent infection in chickens.

2 Risk to humans, especially children. FMD is not a direct risk to human health, and is sometimes characterized as a trade disease in terms of risk to animal health. While we are not at risk currently from pandemic human avian influenza because the virus has not (yet?) mutated, and if/when that does happens, it is likely to occur in Asia or Africa and more likely be brought to the UK by a human carrier, the current H5N1 strain is a risk to humans who are in direct and intimate contact with diseased birds, with the tragic example in Turkey of the death of children. While it must be emphasized that (Les Sims) This remains a rare zoonotic disease occurring in people living in households with infected poultry., it would be irresponsible to put these people at needless risk by leaving outdoor flocks unprotected. Equally irresponsible and dangerous, would be to allow the possibility of the need to keep poultry indoors to be interpreted as bringing poultry into the home/kitchen, as Peter Ainsworth has pointed out. At the same time, risk communication must provide clear information to consumers that, given proper handling and cooking of meat and eggs, avian influenza is not a food-borne illness.

Why do we need to act now?

1 Lack of adequate surveillance.

Surveillance should include testing waterfowl, both wild and domestic, since they can be silent carriers. Without such testing, the appropriateness of any risk assessment will be questionable. If H5N1 is detected in the UK, it will be highly unlikely that it is the index case, and much more likely that there will already be numerous cases. It would be prudent now to act as if we already have the disease.

2 Lack of preparedness

Les Sims: the vast majority of cases of H5N1 avian influenza are occurring in village and smallholder poultry. A key factor in emergence of avian influenza has been the expansion of the smallholder poultry sector without concurrent enhancements in biosecurity. This sector is where control measures are being focused at present [in Asia]. Few cases are seen in large intensive farms with properly implemented biosecurity programs.

What should we be doing?

The primary focus should be on preventing the spread of H5N1 to domestic poultry, regardless of how and whether the virus may have been introduced.

Poultry keepers should have a choice between putting their flock indoors or keeping them outdoors, safely.

Keeping poultry outdoors safely will involve: distribution of disinfectants and of netting and other supplies and measures to separate poultry from domestic waterfowl and both from wild birds; and vaccination.

Logistics to implement the distribution of materials (netting, disinfectants, vaccine) as a preventive measure should be assisted by the army, and should be provided to the farm gate, with entry onto the farm only when requested by the poultry keeper. To give full confidence that these measures will be implemented in the interest of promoting disease control, they should be directed by a committee from the independent veterinary authorities, such as the BVA and the British Poultry Veterinary Association, in conjunction with the SVS.

Vaccination:

Klaas Johan Osinga explained in todays Farming Today broadcast that the only alternative to vaccination is the permanent confinement of birds, since he believes that once introduced, the disease is likely to become endemic. He explains that the Netherlands will be vaccinating to protect against both H5 and H7 strains, and that it will be possible to distinguish between healthy vaccinated birds and vaccinated birds that carry the virus silently.

Albert Osterhaus stressed on radio 4s Today Programme that vaccination should begin immediately, or as soon as the vaccine can be made available, in order to protect domestic birds before the migration season begins.

Les Sims, ProMED-mail: In my view, in an emergency situation it is far better to have the high levels of flock immunity provided by vaccination than to risk uncontrolled infection and spread through movement of infected, non-immune flocks. Experience from Hong Kong where a vaccinated, biosecure compartment has been established shows that fears of silent infection are overblown. No cases of infection have been detected in vaccinated flocks, in dead birds in wholesale markets, or in cage swabs in retail markets since compulsory vaccination was introduced some 3 years ago, despite the presence of H5N1 viruses in the region.

It should also be noted that Hong Kong has also had a successful policy of separating poultry from domestic waterfowl (Robert Webster, personal communication, 2004).

To respond effectively to this risk beyond their control, the poultry industry is in need of financial and logistic support. Provision to the country of a safe and reliable food supply is a government responsibility. If government control measuresmake such food production unviable, the government is putting the country at risk, especially in the event of a disruption to international trade.

The Minister, Ben Bradshaw, continues to say that Defras decisions will depend on the advice they receive from their experts, and that he is content to wait until the disease arrives before taking action. Sadly, that is likely to be too late.

Mary Marshall

20 February 2006