At a Los Angeles media briefing in 2010, Mariah Bianchi describes how her own case of whooping cough caused the death of her newborn son. Reed Saxon/AP hide caption

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Hospitals began testing blood for hepatitis in 1992, so anyone who received a blood transfusion before then is at an increased risk for contracting the disease. iStockphoto hide caption

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Each dot represents one case of mumps between late June 2009 and late June 2010. The New England Journal of Medicine hide caption

itoggle caption The New England Journal of Medicine

The use of multiple blood pressure medications may be helping some Americans bring their hypertension under control. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Federal agents investigate the offices of the New England Compounding Center in Framingham, Mass., on Tuesday. The company's steroid medication has been linked to a deadly meningitis outbreak. Barry Chin/AP hide caption

itoggle caption Barry Chin/AP

A label warns parents to keep Tide laundry detergent packets away from small children. Pat Sullivan/AP hide caption

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Technicians with the Contra Costa County Mosquito and Vector Control District spray insecticide in Brentwood, Calif., last month. Workers fogged areas of the county that had an increase in the numbers of mosquitoes carrying the West Nile virus. Justin Sullivan/Getty Images hide caption

itoggle caption Justin Sullivan/Getty Images

A man stands in a fountain in Washington Square Park on July 18, in New York City. Temperatures were expected in the upper 90's during another heat wave in the city. Mario Tama/Getty Images hide caption

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Two men from northwestern Missouri became ill after tick bites infected them with a previously unknown virus. iStockphoto.com hide caption

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A Beechcraft airplane sprays insecticide over Dallas early Monday morning to curb the spread of West Nile virus. LM Otero/AP hide caption

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People wait in line at the Durham County Health Department for the H1N1 flu vaccination in Durham, N.C., in November 2009. Gerry Broome/AP hide caption

itoggle caption Gerry Broome/AP