The number of people who die from HIV-related causes each year in the U.S. is now down to about 12,700—from a peak of more than 50,000 in the mid-1990s—thanks to condom education and distribution campaigns, increased testing and improved treatments. But now a different infectious disease is quietly killing even more people than HIV is: [...]

A killer cancer that is threatening to wipe Tasmanian devils off the map for good has been spreading—from an original infected female 15 years ago—via live cancer cells, according to evidence from genome sequences of the cancer and the animal, published online Thursday in Cell. Finding out how this happened could help save this species [...]

The white powder that arrived in envelopes addressed to lawmakers and journalists in 2001 proved to be a deadly delivery for several people. The lethal substance—spores commonly known as Anthrax (from the bacterium Bactillus anthracis)—can cause a toxic reaction in a host’s blood stream, killing cells and leading to tissue damage,  bleeding and death. But [...]

Lyme disease is notoriously tough to diagnose. The symptoms often don’t appear for one or two weeks after a bite and can vary from feeling flu-ish to longer-term neurological damage. And ticks seem to lie in wait throughout much of the U.S., prepared to pounce and infect a passerby. Part of the difficulty in confirming [...]

A controversy over whether the U.S. government should allow details of a deadly new flu strain to be published in scientific journals has recently caught fire in the media. But I first heard the news of the mutated virus months ago in Malta at the European Scientific Working group on Influenza (ESWI) meeting. The morning [...]

Smart phone apps can help you check your vision, keep tabs on your blood-glucose levels and track your blood pressure. Earlier this year the U.S. Food and Drug Administration even approved an app that allows doctors to view scans on an iPhone or iPad to help them make diagnoses on the go. But fancy apps [...]

Bacteria easily elude human detection—even those that can make us sick—quietly spreading from person to person, country to country. A recent global spike in bugs that are resistant to common antibiotics, however, has caused many scientists and policymakers to pay closer attention to when and where these infections are occurring. A new collection of updated [...]

NEW YORK—Just as a true outbreak might, the new viral thriller Contagion, opening this weekend, begins unremarkably enough. A simple cough, heard against a black screen. This is no ordinary hack, of course. Aside from coming from the lovely, if peaked, Beth Emhoff (Gwyneth Paltrow) passing time at a Chicago O’Hare airport bar, this cough [...]

MIAMI—Before a government reports a disease outbreak, cases must usually be counted, verified and assessed—a process that can take days, weeks or months. This delay creates a tension, however, as faster responses are the best hope for keeping a local outbreak from becoming an epidemic or even a pandemic. Overall, bureaucratic diligence and even political [...]