Particles of H5N1 virus — a particularly dangerous type of bird flu that can infect people — attack lung cells. Chris Bjornberg/Science Source hide caption

toggle caption Chris Bjornberg/Science Source
Feds Tighten Lab Security After Anthrax, Bird Flu Blunders
  • Download
  • <iframe src="https://www.npr.org/player/embed/330725773/330760949" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript

Human immunodeficiency virus Type 1 inserts its genetic material into the DNA of human cells, turning them into little HIV factories. Eye of Science/Science Source hide caption

toggle caption Eye of Science/Science Source
Mississippi Child Thought Cured Of HIV Shows Signs Of Infection
  • Download
  • <iframe src="https://www.npr.org/player/embed/330538734/330631774" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript
HIV Returns In Infected Toddler, Dashing Hopes Of Imminent Cure
  • Download
  • <iframe src="https://www.npr.org/player/embed/330496171/330496172" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript
Daniel Horowitz for NPR
Like All Animals, We Need Stress. Just Not Too Much
  • Download
  • <iframe src="https://www.npr.org/player/embed/325216030/330038165" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript

Doctors used a rapid DNA test to identify a Wisconsin teen's unusual infection with Leptospira bacteria (yellow), which are common in the tropics. CDC/Rob Weyant hide caption

toggle caption CDC/Rob Weyant
Quick DNA Tests Crack Medical Mysteries Otherwise Missed
  • Download
  • <iframe src="https://www.npr.org/player/embed/319210230/319222889" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript

Red blood cells infected with the Plasmodium falciparum parasite. Plasmodium is the parasite that triggers malaria in people. Gary D. Gaugler/Science Source hide caption

toggle caption Gary D. Gaugler/Science Source
Experimental Malaria Vaccine Blocks The Bad Guy's Exit
  • Download
  • <iframe src="https://www.npr.org/player/embed/314884348/314925157" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript

False-color transmission electron micrograph of a field of whooping cough bacteria, Bordetella pertussis. A. Barry Dowsett/Science Source hide caption

toggle caption A. Barry Dowsett/Science Source
Family Tree Of Pertussis Traced, Could Lead To Better Vaccine
  • Download
  • <iframe src="https://www.npr.org/player/embed/306845814/306918632" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript

This mouse egg (top) is being injected with genetic material from an adult cell to ultimately create an embryo — and, eventually, embryonic stem cells. The process has been difficult to do with human cells. James King-Holmes/Science Source hide caption

toggle caption James King-Holmes/Science Source
First Embryonic Stem Cells Cloned From A Man's Skin
  • Download
  • <iframe src="https://www.npr.org/player/embed/303658757/304186978" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript

In this colored transmission electron micrograph, an infected cell (reddish brown) releases a single Ebola virus (the blue hook). As it exits, the virus takes along part of the host cell's membrane (pink, center), too. That deters the host's immune defenses from recognizing the virus as foreign. London School of Hygiene & Tropical Medicine/Science Source hide caption

toggle caption London School of Hygiene & Tropical Medicine/Science Source
Ebola Drug Could Be Ready For Human Testing Next Year
  • Download
  • <iframe src="https://www.npr.org/player/embed/301418627/301882848" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript