New research suggests that Americans' risk for developing dementia over a lifetime may be higher than previously thought. A study found that after age 55, people have up to a 4 in 10 chance of eventually developing dementia — if they live long enough. The risk is highest after age 75, but doctors say there are ways to reduce that risk. Controlling blood pressure, diabetes and cholesterol is good for both your brain and your heart. They also urge staying physically and socially active. The study was published Monday in Nature Medicine.

Five years after the virus that causes COVID emerged in China it still holds some mysteries. The disease has killed an estimated 20 million people globally, according to the World Health Organization, and thousands are still dying every year. But scientists still aren't clear where it came from, and they are still trying to understand what causes long-term symptoms called long COVID. And while vaccines have helped dramatically reduce severe disease and death from COVID, the virus mutates so quickly researchers have struggled to find a vaccine that stops the spread.

The death of an Oregon house cat from bird flu and a pet food recall are raising questions about how people can protect their pets. Oregon health officials have traced the cat's illness to frozen cat food that contained raw turkey. Some pet owners feed their animals raw meat, but that can be dangerous, even fatal for the animals. Cooking destroys the bird flu virus and other disease-causing germs. Cats seem more susceptible than dogs to the bird flu virus. But the best advice for pet owners is to avoid feeding animals raw protein.