(CNN)As the Northern Hemisphere heads into winter, whether a fever and cough mean the flu or Covid-19 is a nerve-racking guessing game. There is, however, a silent killer that causes similar symptoms and could be lurking in your home.
Carbon monoxide poisoning or Covid-19? Here's how you can tell
Carbon monoxide is a colorless, odorless gas that's produced when a fossil fuel — coal, crude oil or natural gas — is burned by furnaces, portable heaters, vehicles, stoves, grills, gas ranges or fireplaces.
Breathing in too much of it can poison you, leading to symptoms including headache, upset stomach, dizziness, weakness, vomiting, chest pain and confusion, according to the US Centers for Disease Control and Prevention — mimicking the symptoms of the flu or Covid-19.
Inhaling high concentrations can make you pass out or kill you, especially if you are sleeping, drunk or belong to a group that's at high-risk for serious illness and death from different diseases and exposures. Carbon monoxide can also poison your pets.
"Influenza and (Covid-19) hijack the cells, mostly in lungs, where they reproduce and that's where the main damage is often done" and where symptoms stem from, said Dr. Jeremy Brown, an emergency care physician and author of "Influenza: The Hundred-Year Hunt to Cure the Deadliest Disease in History."