A bedbug is a tiny, flat insect about the size of an apple seed that feeds on human blood, usually while people are sleeping. These reddish-brown pests hide in mattresses, bed frames, and cracks in furniture during the day, then crawl out at night to bite exposed skin. Their bites leave itchy red welts that can be annoying but usually aren't dangerous.

Bedbugs were nearly eliminated in some countries by the 1950s but made a comeback in the 1990s, partly because they developed resistance to common pesticides. They spread easily by hitchhiking in luggage, used furniture, or clothing, which is why hotels and apartments sometimes struggle with bedbug infestations. Despite their name, bedbugs can live anywhere people spend time: couches, movie theaters, even backpacks.

Getting bedbugs has nothing to do with cleanliness. Even the fanciest hotel can have them. If you spot small dark spots on sheets (their droppings) or notice itchy bites in a line or cluster, tell an adult. Professional exterminators use heat treatment or special chemicals to eliminate them, but it takes persistence and follow-through.