Diseases and Conditions

Know how to prevent, treat and control the symptoms of various diseases and medical conditions. We explain what's happening in your body when disease strikes, and what you can do to feel better faster.

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The World Trade Center dust consisted of a dangerous mixture of particles, asbestos and a class of chemicals called persistent organic pollutants, and it's still causing health problems for survivors.

By Roberto Lucchini

We hear many reports of people vaccinated against COVID-19 getting the disease. How does that happen — and why should that not stop us from getting the vaccine?

By Alia Hoyt

New data released today from the U.S. Centers for Disease Control and Prevention is behind the agency's updated mask guidelines. What so alarmed the CDC that it's telling even the vaccinated to wear masks again?

By Joanna Thompson

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What in the world is monkeypox, and should Americans be worried about another contagious virus spreading across the country?

By Joanna Thompson

The wildly contagious delta coronavirus variant now accounts for more than 80 percent of cases in the United States. Does it pose a threat to eliminating COVID-19 across the globe?

By Jennifer Walker-Journey

Often you might hear someone say about their elderly relative "He died of old age." But what does that really mean? Can old age kill you?

By Alia Hoyt

How worried should you be about coronavirus variants? A virologist explains why we should pay attention to these five variants, some of which might be new to you.

By Paulo Verardi

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It's been a year since the World Health Organization officially declared the novel coronavirus a global pandemic. The last 12 months have been truly historic and life-changing in ways that we may not even yet recognize.

By John Donovan

We should know by now to wear a mask in public. But with more variants of coronavirus, should we wear two masks to stop the spread?

By John Donovan

Reopening schools is at the top of everyone's wish list, but does reopening them cause COVID-19 to spread? Well, it's complicated.

By Scott A Imberman, Dan Goldhaber & Katharine O. Strunk

You've probably heard of a tumor, but what about a neoplasm? How similar are they and are they always cancerous?

By Jesslyn Shields

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It might be OK for a Smurf to have blue fingers, but for the rest of us, it's something you don't want to see. Cyanosis is usually a sign of a bigger health problem.

By Alia Hoyt

The low FODMAP diet was created by a team of researchers in Australia to help those with digestive issues like IBS. This is one diet that's not about losing weight.

By Jennifer Walker-Journey

The symptoms for both are similar though there are a few differences. Treatment is also similar for mild cases of either. But severe cases of COVID are much more deadly, so how do you know what you have?

By Alia Hoyt

New parents — especially new moms — are prone to an ailment known as mommy thumb. It's painful and real, but what is it and how is your baby causing it?

By Kristen Hall-Geisler

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Sometimes you just can't avoid using a public bathroom. Is it safe with coronavirus raging? How can you be sure?

By Carrie Whitney, Ph.D.

Many health experts are gravely concerned about how the massive protest crowds, chanting and especially use of tear gas could accelerate the spread of coronavirus.

By Patty Rasmussen

Learn the steps of contact tracing, one critical way that public health officials stop viruses like COVID-19 from spreading, in this HowStuffWorks video.

Wearing some sort of face mask is more important than ever now to protect you and others from coronavirus. But how do clean and safely store it?

By Carrie Whitney, Ph.D.

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Despite strict closing and mask orders, San Francisco was hit hard by the 1918-1919 influenza pandemic. But some residents balked at the rules and that meant more people died.

By John Donovan

As COVID-19 rages around the world, distilleries quickly ramp up the switch from booze to hand sanitizer in an all-out effort to curb the spread.

By Jeremy Glass

When you were a kid, your mom probably told you not to go around barefoot because you could get worms. But are nematodes still a problem today?

By Alia Hoyt

Anosmia, or the loss of the ability to detect one or more smells, is a common symptom of upper respiratory viral infections. It might also be a way to tell if you have novel coronavirus.

By Jesslyn Shields

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The World Health Organization just declared the coronavirus a full-blown pandemic. What does that even mean, and how is that different from an epidemic?

By Sarah Gleim

You've probably heard the word "quarantine" a lot in relation to the coronavirus. But how is it different from patient isolation?

By Patty Rasmussen