Sanjay Kapoor • Kuldeep Dhama

2014

Influenza viruses are highly contagious, causing respiratory symptoms in humans,
animals, and birds. The flu viruses keep evolving in animals and poultry and
ultimately jump species to cause epidemics and even pandemics in humans. The
disease is highly contagious, zoonotic, and affects various systems of the body
with the potential to cross international borders. During the past 150 years,
various strains of influenza virus like Spanish flu, Asian flu, Hong Kong flu, Bird
flu, and Swine flu were responsible for high morbidity and mortality in both
human and animals.