Carbon monoxide poisoning is sometimes mistakenly identified as what?

When we breathe red blood cells bond to the oxygen but when we inhale carbon monoxide (CO), it sticks to red blood cells and block the oxygen and suffocation occurs. It is also known as "Silent Killer".

Headaches, nausea and fatigue are some of early symptoms of carbon monoxide poisoning. It is sometimes mistakenly identified as "Flu". Because this gas cannot be detected at home. It is produced by common household appliances, if not proper ventilated, such as water heaters, generators, cars etc.