Four times in the past century, a new strain of flu has emerged that can spread quickly in humans. One of those strains, which emerged in 1918, killed an estimated 50 million people.

All human flu strains evolved from flu viruses that live in birds. To understand how these transitions happen, scientists have recently been tinkering with a strain of bird flu to see how many mutations it takes until its spreads from mammal to mammal.

When news of their efforts emerged last fall, a fierce debate broke out about the wisdom of publishing the experiments in full.

Continue reading “Flu That Leapt From Birds to Seals Is Studied for Human Threat” →

On May 20, a 10-year-old girl in rural Cambodia got a fever. Five days later, she was admitted to a hospital, and after two days of intensive care she was dead.

The girl was the most recent documented victim of the influenza virus H5N1, a strain that has caused 606 known human cases and 357 deaths since it re-emerged in 2003 after a six-year absence.

H5N1 can race through bird populations, and the World Health Organization suspects the girl was infected while preparing chicken for a meal.

Continue reading “The Evolution of Bird Flu, and the Race to Keep Up” →

For a century, doctors have waged war against bacteria, using antibiotics as their weapons. But that relationship is changing as scientists become more familiar with the 100 trillion microbes that call us home — collectively known as the microbiome.

“I would like to lose the language of warfare,” said Julie Segre, a senior investigator at the National Human Genome Research Institute. “It does a disservice to all the bacteria that have co-evolved with us and are maintaining the health of our bodies.”

Continue reading “Tending the Body’s Microbial Garden” →