Fleas are small, dark brown or reddish brown, from 1 to 4 mm long, with flattened bodies. They are wingless and can jump up to 20 cm vertically and 41 cm horizontally.
Fleas have four stages of development: egg, larval, pupal and adult. It takes from 2 weeks to several months to go from egg to adult depending on the species, temperature, humidity and food availability. After each blood meal, females lay 4 to 8 smooth, round, light-coloured, sticky eggs. She can lay 25 eggs per day, and roughly 800 in her life. Eggs hatch into very small, hairy, worm-like larvae that are whitish with brownish heads. The larvae are from 1.5 mm to 5 mm long. They feed on organic debris, their own cast skins and dried blood in adult flea excrement. Larvae can survive up to 200 days even in unfavourable conditions and travel up to 30 cm per minute. They will spin silken cocoons covered with particles of dust, fibres, sand and organic debris and later emerge as an adult flea. Adult fleas may remain in the cocoon for several months until favourable conditions arise, such as a rise in temperature and carbon dioxide levels. Vibrations created by the presence of humans and pets will also stimulate their emergence and activity.
What can they do?
Unlike some pests that can be found around the home, fleas cause discomfort and irritation to both pets and people. Fleas are not just an annoyance, some people and animals suffer allergic reactions to flea saliva resulting in rashes. Flea bites create a small, hard, red, itchy spot, slightly-raised and swollen with a single puncture point at the center. The bites often appear in clusters or lines, and can remain itchy and inflamed for up to several weeks. Fleas can also lead to hair loss as a result of frequent scratching and biting by the animal, and can cause anemia in extreme cases.
Besides these problems, fleas can also transmit disease. For example, fleas transmitted the bubonic plague between rodents and humans by carrying bacteria. Endemic typhus fever, and in some cases tapeworm can also be transmitted by fleas.
Fleas usually feed several times a day, but can survive several weeks without a meal. Adult fleas usually leave the host after feeding; however, flea eggs, larvae or pupae may be found on pets. The peak season for flea infestations outdoors in most parts of Canada is from early August to early October. In excessively dry, hot summers fleas tend to dehydrate and die.