Influenza virus A is one type of flu virus that causes the seasonal flu in humans. The subtypes of influenza virus that are found in humans are influenza A H1N1 virus and influenza A H3N2 virus. In 2009, an H1N1 virus (swine flu) caused a pandemic. The flu virus found in pigs infected humans and caused widespread disease. Now, that same swine flu H1N1 virus is circulating in the human population, replacing the previous H1N1 virus. The reverse can happen as well, where the seasonal human flu virus can infect pigs. Once in the pigs, the flu virus surface proteins can mutate. This can eventually lead to new strains of swine flu which can then infect humans, continuing the infection cycle.
Researchers from the University of Cambridge have gathered a comprehensive dataset containing the protein variations of flu viruses from 1930 to 2013 in the U.S., Europe, and Asia. After reviewing their data, researchers discovered that the amount of surface protein diversity of swine flu virus was similar to the amount of diversity seen in human flu viruses. As a result, a flu vaccine for pigs would need to contain more than one flu virus strain. Additionally, the data collected by the researchers can be used to determine the pandemic potential of the viruses. The research has also shown that in order to assess the possibility of transmitting flu viruses between pigs and humans there needs to be an increase in surveillance.
When it comes to the swine flu, prevention is key. Wash your hands thoroughly and cover your mouth and nose when coughing and sneezing, respectively. If you do get swine flu: rest, drink plenty of fluids, contact your health provider and ask about antiviral medication.
The two most common types of influenza viruses as described by the CDC are:
- A/duck/Alberta/35/76 (H1N1) for a virus from duck origin
- A/Perth/16/2009 (H3N2) for a virus from human origin
A flu vaccine can protect you against flu viruses that are related to the viruses listed above. If you are experiencing flu-like symptoms it is best to see a doctor as soon as possible.
More information on this year’s vaccines can be found here.
Centers for Disease Control and Prevention