Well

H5N1, an avian flu virus, has killed tens of thousands of marine mammals, and infiltrated American livestock for the first time. Scientists are working quickly to assess how it is evolving and how much of a risk it poses to humans.

Officials have shared little information, saying the outbreak was limited. But asymptomatic cows in North Carolina have changed the assessment.

Among those with substance use disorders who have been referred to child welfare, less than half received medication or counseling.

The “car key conversation” can be painful for families to navigate. Experts say there are ways to have it with empathy and care.

Mammography can miss tumors in women with dense breasts, so their doctors often include ultrasound or M.R.I. scans. Patients often wind up paying the bill.

The change followed a sweeping review by England’s National Health Service that found “remarkably weak” evidence for youth gender treatments.

After a drawn-out global controversy over the coronavirus, the W.H.O. has updated its classification of how pathogens spread through the air.

In a first, a Colorado law extends privacy rights to the neural data increasingly coveted by technology companies.

The company reported results of clinical trials involving Zepbound, an obesity drug in the same class as Novo Nordisk’s Wegovy.

For the actor, compatibility comes down to food. You need to be able to share.