Adult fleas are no larger than 1/8 inch long, so it is difficult to see a number of the characteristics used to describe them. These reddish-brown, wingless insects are laterally compressed, so they look as if they are walking on edge. Cat fleas have both pronotal and genal combs. They have piercing-sucking mouthparts through which they obtain blood meals from their hosts.
Adult cat fleas remain on the host where feeding, mating, and egg laying occur. Females lay about 20 to 50 eggs per day. Cat flea eggs are pearly white, oval, and about 1/32 inch long (Figure 3). The eggs are smooth and readily fall from the pet and land on surfaces such as bedding and carpeting in the animal’s environment. They hatch in about 2 to 5 days.
Flea larvae are no larger than 3/16 inch long, hairy, and wormlike with a distinct, brownish head but no eyes or legs (Figure 4). The larvae feed on dried blood and excrement adult fleas produce while feeding on the pet. Larval development is restricted to protected places where there is at least 75% relative humidity. The larvae feed and crawl around for 8 to 15 days before building small, silken cocoons in which they pupate and develop into adults. Debris, such as pet hair or skin or carpet fibers, usually covers the pupae, providing visual camouflage.
Flea larvae develop more quickly at higher temperatures, preferring areas that are 70° to 90°F. At cool temperatures, fully formed fleas can remain in their cocoons for up to 12 months. Warm temperatures and mechanical pressure caused by walking on or vacuuming carpet stimulate emergence from the cocoon. At normal room temperatures, the entire life cycle can occur in about 18 days.
An adult cat flea generally lives about 30 to 40 days on the host. When normal grooming activity is restricted, 85% of adult females survived for 50 days. You can find fleas on pets throughout the year, but numbers tend to increase dramatically during spring and early summer when conditions favor larval development.
cat fleas are capable of transmitting a murinelike typhus disease in humans, cat flea rickettsiosis. The symptoms are similar to murine typhus but less severe, including headaches, chills, fever, vomiting, and rash. This rickettsial agent is widely found in cats and cat fleas worldwide. It is likely that many previously diagnosed cases of murine typhus actually might have been cat flea rickettsiosis.
Fleabites consist of a small, central, red spot surrounded by a red halo, usually without excessive swelling. They usually cause minor itching but can become increasingly irritating to people with sensitive or reactive skin. Some people and pets suffer from fleabite allergic dermatitis, characterized by intense itching, hair loss, reddening of the skin, and secondary infection. Just one bite can initiate an allergic reaction, and itching can persist up to 5 days after the bite.
Cat fleas serve as intermediary hosts of dog and cat tapeworms. Cats or dogs can acquire this intestinal parasite while grooming themselves if they ingest adult fleas that contain a cyst of the tapeworm. Children occasionally can acquire these tapeworms too.