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If it could happen in the direction of the pig then there is no reason to suppose that genetic segments from swine influenza and avian influenza viruses could not re-assort with human viruses and cause disease in the human population. This is believed to have been what happened in 1918 when the “Spanish flu” killed so many. It was probably an avian virus entering the pig and human population in the United States and then spreading to Europe. The threat of such a pandemic is what has concerned epidemiologists in the recent past.
In the last week of April there have been notifications of the outbreak of influenza in humans in Mexico to start with and then cases in the United States with subsequent spread by airline travellers to other countries.
As of the 28th April there are over 2500 cases in Mexico with over 150 deaths and in the USA there are reports from 6 states but as yet no deaths. The virus has been confirmed in 4 countries-Mexico, USA, Spain and Canada.
Epidemiologically, this is extremely interesting- why should it cause deaths in one country and yet following travel to a neighbouring country not. Perhaps it is attenuating as it travels?.
| This is not swine influenza as we know it. It is therefore best called North American influenza. It is a virus with genetic material from porcine, human and avian viruses which has shown the ability unusually for such a virus to transmit from human to human. The virus appears to have 2 of 8 gene segments that derive from eurasian swine viruses. The NA and matrix genes of the new virus have not been seen in humans or pigs before. It has not been found in pigs as yet and therefore cannot be found in pork or pig products So far certainly in the USA there is no evidence of any contact with pigs. All evidence so far suggests that it is only person to person transmitted. |
Control of this disease in the human population is virtually impossible as person to person contact is the method of transmission. Masks are unlikely to stop the passing of virions as they are so small. The only thing that will work is to keep away from sources of infection ie fellow human beings. (Remember that in the last 50 years there have only been 50 proven cases of swine influenza infection in humans in Europe). It will not be present in their pork but as in all cases effective cooking to 70 degrees will prevent any microbiological hazards in the meat.
Precautions to protect your unit
Protection of the pig unit may be important since we do not know at the moment whether pigs can become infected. Therefore, it is essential to carry out the usual precautions to protect your unit.
- High biosecurity especially with regard to incoming stock
- Quarantine in isolation for a significant proportion of time
- Discourage visitors
- Encourage high levels of cleaning and disinfection and personal hygiene
- Monitor all aspects of disease to detect any new manifestations of clinical disease
- The most likely source of any infection to a pig unit other than other pigs and humans are birds - keep out of the buildings
- Anybody becoming ill with suggestive respiratory signs should RING their doctor not infect his or her surgery.
