How did a new strain called swine flu originate?
The avian influenza virus and human influenza virus were both capable of infecting pigs. Pigs functioned as a grooming organism for the influenza viruses. Further the influenza viruses were able to form a new strain by mixing the proteins present in avian and human viruses. Thereby pigs served as mixing vessels for the influenza virus that led to the formation of the novel H1N1 influenza virus that is capable of infecting both humans and pigs.
