Fleas found they will normally be cat or dog fleas as human fleas are rare now except in third-world countries.

Pet fleas can be brought in by the pets, people, second-hand carpets etc. Adult fleas may feed on different animals but larvae require the sort of conditions offered by wall-to-wall carpeting (hiding places) and central heating (warmth all year). Flea eggs are laid on carpets or fabrics. The eggs hatch into larvae that then pupate. They can remain dormant before emerging as adults. If conditions are favourable e.g., vibration and warmth, they will hatch into adults. This takes about 2 weeks in mild weather. Eggs can lie dormant for up to 18 months, usually in empty properties.

House fleas

House fleas are tiny, wingless insects that feed on the blood of animals and sometimes humans. The most common flea found in homes is the Cat Flea, which can infest cats, dogs, carpets, furniture, and bedding