Fleas are parasitic insects that feed on the blood of humans and animals. While they're commonly associated with pets, fleas can infest homes even without pets present, as they can be brought in on clothing or by other wildlife.
A single female flea can lay up to 50 eggs per day, with eggs developing into adults within 2-3 weeks under ideal conditions. This rapid reproduction rate means small problems can quickly escalate into major infestations.