| dc.description.abstract | - Influenza, sometimes known as the flu, is a highly infectious
respiratory infection caused by flu viruses that infect the nose,
throat, and lungs.
- Influenza is challenging for scientists to study because there are
hundreds of strains that are classified into four main categories:
1. Type A: is the most prevalent cause of human sickness and has
been the source of all significant influenza pandemics in modern
history.
2. Type B: cause seasonal epidemics.
3. Type C: cause mild respiratory illness
4. Type D: not known to cause disease. | en_US |
