Influenza is an infectious disease affecting birds and
mammals that is caused by RNA viruses of the family
Orthomyxoviridae (the influenza viruses, Flu). In the
past, influenza has spread around the world during seasonal
epidemics, resulting in the deaths of hundreds of
thousands annually – millions during pandemic years.
The management of influenza is given the highest priority
consideration in terms of public health in Japan. Vaccinations
against influenza are usually given to people as a
practical, protective method. However, a vaccine formulated
for a given year may be ineffective in the following
year as Flu evolves rapidly and different strains become
dominant year after year. Therefore, the enhancement of
natural defences by triggering nonspecific cell-mediated
immunity in a host animal might be a practical, effective
method for the management of Flu infections.