_900.png "What is Influenza?")
Influenza or the flu, is an acute respiratory infection caused by influenza viruses. It spreads easily between people through respiratory droplets when they cough or sneeze. Vaccination is the best way to prevent the disease. There are four types of influenza viruses: A, B, C, and D. Influenza A and B viruses cause seasonal epidemics, with influenza A being the only type known to cause pandemics. Influenza A viruses are further classified into subtypes, such as H1N1 and H3N2, while influenza B viruses are categorized into B/Yamagata and B/Victoria lineages. Influenza C usually causes mild infections and has little public health impact, while influenza D primarily affects cattle and does not infect humans.
