(New York Times) – A possible cluster of bird-flu infections in Missouri has grown to include eight people, in what may be the first examples of person-to-person transmission in the United States, the Centers for Disease Control and Prevention reported on Friday.

If confirmed, the cases in Missouri could indicate that the virus may have acquired the ability to infect people more easily. Worldwide, clusters of bird flu among people are extremely rare. Most cases have resulted from close contact with infected birds. (Read More)