What are fleas? - briefly
Fleas are tiny, wingless ectoparasites of the order Siphonaptera, distinguished by laterally compressed bodies and strong jumping legs. They feed on the blood of mammals and birds, often transmitting disease‑causing agents.
What are fleas? - in detail
Fleas are small, wingless insects belonging to the order Siphonaptera, comprising roughly 2,500 described species. Their bodies are laterally compressed, facilitating movement through the fur or feathers of hosts. A hardened exoskeleton, powerful hind legs, and a siphon-shaped mouthpart enable rapid jumping and blood feeding. Adult size ranges from 1 to 4 mm, and coloration varies from reddish‑brown to dark brown.
The life cycle includes egg, larva, pupa, and adult stages. Females deposit eggs on the host or in the surrounding environment; each can lay 20–50 eggs per day. Eggs hatch within 2–5 days, releasing larvae that feed on organic debris, including adult flea feces rich in blood proteins. Larvae undergo three molts before spinning a silken cocoon; pupation may last from a few days to several months, depending on temperature and host availability. Emergence of the adult is triggered by vibrations, carbon dioxide, or heat from a potential host.
Fleas are obligate ectoparasites of mammals and birds. They attach to the host’s skin, pierce capillaries with their stylet, and ingest blood. Saliva contains anticoagulants and anesthetic compounds that prevent clotting and reduce host awareness of the bite. Feeding frequency varies among species; for example, the cat flea (Ctenocephalides felis) may feed every 24–48 hours, while the human flea (Pulex irritans) feeds less often.
Disease transmission represents a significant health concern. Fleas act as vectors for bacterial pathogens such as Yersinia pestis (plague) and Rickettsia typhi (murine typhus). They also transmit the protozoan Dipylidium caninum and serve as intermediate hosts for tapeworms in dogs and cats. Pathogen acquisition occurs during blood meals from infected hosts; subsequent transmission occurs when the flea bites a new host or through contaminated feces.
Control strategies target multiple stages of the flea’s development. Mechanical removal includes regular grooming, vacuuming, and washing bedding at temperatures above 60 °C. Chemical interventions involve insecticide‑treated collars, spot‑on formulations, oral systemic agents, and environmental sprays containing insect growth regulators (IGRs) that disrupt larval development. Integrated pest management combines host treatment, environmental sanitation, and monitoring of flea populations to achieve sustained reduction.
Ecologically, fleas contribute to nutrient cycling by processing host debris and supporting predatory arthropods that feed on their larvae. Their presence influences host behavior, grooming patterns, and social interactions, thereby affecting broader ecosystem dynamics.