The CDC's director, Tom Frieden, testified before a congressional subcommittee Wednesday regarding a recent anthrax incident and lab safety improvements he is instituting.
Sick with chikungunya, Karla Sepulveda, 5, waits in a public hospital with her grandmother in Boca Chica, Dominican Republic, on May 15. The Caribbean nation has reported more than 100,000 cases this year.
Ezequiel Abiu Lopez/AP
Dr. Lisa Sterman held a Truvada pill at her office in San Francisco in 2012. She prescribed Truvada to patients at high risk for HIV infection even before the Food and Drug Administration approved the medicine explicitly for that purpose.
The Centers for Disease Control and Prevention's PulseNet service monitors clusters of sickness linked to potentially dangerous strains of foodborne pathogens such as E.coli or salmonella.