Scientists are racing to gain a better understanding of the A/H1N1 strain of swine flu that has triggered an epidemic in Mexico and a public health emergency in the United States. Of particular concern are signs that this virus intermingled human, swine and bird viruses in an apparently novel combination.
It's not unusual for an animal virus to make a leap to a person who's had close contact with an infected animal. That's primarily the way swine flu has infected people in the past and the way in which bird flu has claimed most of its victims. This virus, however, has apparently gone through an antigenic shift, explains the Wall Street Journal, exchanging genes from different viruses and making it possible for the virus to spread from person-to-person.
Pigs make the perfect host animal for new viruses, epidemiologists explain, as they can be infected by viruses that infect birds and humans as well as swine. And this novel mix of genes has laid the groundwork for earlier pandemics in 1957 and 1968.
- read the report in the Wall Street Journal