Influenza

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Slide 10

Antigenic shift and antigenic drift

Mutations which produce small changes in antigens are referred to as antigenic drift and these occur in the same strain

Mutations which result in a major change and produce new strains are referred to as antigenic shifts

Slide 11

Life cycle of the ‘flu virus

Slide 12

Transmission

The virus is spread by inhalation or by direct contact.

Reservoirs of infection are primarily humans, but birds and pigs can act as reservoirs.

The multiple host status makes for mixing of flu types.

Slide 13

Prevention

Public education campaigns are used to reduce infection rates

Isolation of infected people is desirable but not always practical

Immunisation

Slide 14

Immunisation

Vaccines are offered to people aged 65 or over (Note: Currently this group has some immunity and are not being targeted)

Clinically at risk groups – asthatics, immuno-compromised patients, diabetics, people with chronic respiratory disease.

Health care workers

Vaccine effectiveness varies between 40 – 60%

Slide 15

Chemotherapy

Tamiflu (oseltamivir) – inhibits the neuraminidase and thus prevents the spread of the virus in the body

Tamiflu can therefore be used to reduce the length of illness and its transmission within a household

Resistance of H1N1 strain to oseltamivir has been reported at 25%

Slide 16

Conclusion

Flu can be a bit of a swine!

Prevention is better than cure!

Avoid contact with infected people.

Read how the population of Eyam avoided spreading the plague!

Eyam - Plague Village - Derbyshire