Summary of Brussels working paper

We must be careful not to over-react if and when pigs in the European Union catch new variant flu, says a working paper by the health and consumer affairs directorate in Brussels. Assuming the pandemic virus remains mild to moderate, only a limited number of actions will be necessary. Anything else would be disproportionate, it says.

PROPOSED MEASURES

Farmers should improve biosecurity to avoid further virus spread within the affected farm and to other farms.

People at risk because of their close contact with the suspected or affected pigs should be recommended for human vaccine, when available.

Sustainable quarantine/movement restrictions until one week after the last clinical case.

Recovered pigs and healthy pigs can be routinely sent for slaughter for human consumption.

See also notes at foot of this article.

SYMPTOMS

Flu in pigs is a mild respiratory disease characterised by coughing, sneezing, nasal discharge, fever. Mortality is low and recovery is usually quick and uncomplicated (within 10-14 days).

AH1N1 in pigs is a mild infection of the respiratory tract, with some morbidity but generally leading to uneventful recovery.

HOW IT SPREADS

Flu virus can be spread by direct contact and by short-distance aerosol transmission. Even in high pig farm density areas it does not spread very far or very rapidly by air.

Pre-existing immunity due to a previous swine flu infection or following conventional flu vaccination may not protect pigs against the pandemic influenza virus, but may, possibly, provide some partial protection.

VACCINATION

Vaccines currently available against swine flu may not be effective against the pandemic influenza virus.

Once an AH1N1 vaccine is available, vaccination against the pandemic virus should be considered on all units within a hypothetical control zone or on at-risk units as soon as possible.

The vaccine will be an inactivated vaccine. Two doses (two shots) with at least two weeks interval are needed and therefore it will last several weeks before the immunity is fully established.

It should be considered that vaccine alone will not be sufficient to eradicate the virus.

Emergency vaccination in an infected farm is in general not recommended since the spread of the virus within the holding will be much faster than the immune response to the vaccine.

CONSUMER SAFETY

Swine flu is not a food-borne zoonosis. There is no evidence the pandemic virus can be spread to humans by meat or meat products.

SURVEILLANCE

Brussels hopes surveillance by member countries will lead to early/timely detection of the introduction/circulation of the pandemic virus in the European Union pig population (assuming that currently there is no circulation of this virus in this population).

Surveillance should be primarily targeted to farms where an epidemiological link to human cases has been clearly established and where an identified risk of human-to-pig transmission exists. It should also be assumed there is a risk of transmission between pigs and humans.

DIAGNOSTIC

Nasal swabs from pigs collected two-three days after the onset of the clinical signs are the sample of choice.

NOTES

Defra's guidance, when available, is likely to reflect the above Brussels working paper. Any movement controls will be voluntary.

The working paper’s advice that farmers do what they can to restrict virus spread within the unit may not find favour with all pig-keepers. Realiostically, some may prefer to let new variant flu rip through the pigs in order to speed up clearance.

The working paper is clear that member countries must not go over the top in the way they react to new variant flu in pigs.

For instance it stresses movement restrictions should only be put in place if there is a clear exit strategy and even then limited movements of pigs to other farms might be allowed, following a risk assessment.

Culling is specifically not recommended.

Swine flu is not a notifiable disease. Although it is not the officially recommended course of action, realistically, some pig-keepers, if they see swine flu in their pigs, may decide to say nothing (because of the fear of unhelpful publicity) and let it quickly spread through the herd, and then send the finished pigs for slaughter as usual when they have fully recovered.