The flea is dark brown in colour, wingless and possesses a laterally compressed chitineous abdomen (Soulsby, 1982). The glossy surface of the body allows easy movement through hair and feathers (Urquhart et al., 1987). Compound eyes are absent, but some species have large or small simple eyes.
The legs are long, strong and adapted for leaping (Soulsby, 1982). This can especially be seen in the third pair of legs which is much longer than the others (Urquhart et al., 1987) and muscular. In some species there are a number of large spines on the head and the thorax known as ‘combs’ or ctenidia. There may be a genal comb on the cheek (gena) and a pronotal comb on the posterior border of the first thoracic segment (Soulsby, 1982). These combs or ctenidia belong to one of the three sets of characteristics in morphological taxonomy for identifying fleas, the so-called chateotaxy. Thoracic and leg structures and the structure of the male segment IX, the female sternite VII and the sperm holding organ (spermatheca) are the other two characterising sets (Ménier and Beaucournu, 1998).
Restricted number of flea species
Concentrating on pets, particularly on cats and dogs, only a restricted number of flea species occur in large amounts with any regularity to be of importance as nuisance pests.
For the USA these are Ctenocephalides felis felis, the cat flea, Ctenocephalides canis, the dog flea, Pulex irritans, the human flea, and Echidnophaga gallinacea as well as Ceratophyllus gallinae, fleas found on poultry (Kalkofen and Greenburg, 1974; Amin, 1976; Harman et al., 1987; Dryden, 1988).
Similar situations are also found in Europe and other parts of the world with C. felis felis and C. canis mainly dominating and P. irritans and Archaeopsylla erinacei, the flea of the hedgehog, as species of possible high rates of infestations (24% (Baker and Hatch, 1972) and 8.3% (Kristensen et al., 1978)) (Fig. 1).
As can be seen in Origin and Distribution the species Ctenocephalides with its representatives C. felis felis and C. canis both have a worldwide distribution (Kalvelage and Münster, 1991) and are the most important flea species parasitising dogs and cats as man’s most wide-spread companions. Because of their genus similarities as well as their similar pattern of distribution and host spectrum, it is presumed that their biology does not show essential differences (Kalvelage and Münster, 1991).
- Amin OM: Host associations and seasonal occurrence of fleas from southeastern Wisconsin mammals, with observations on morphologic variations. J Med Entomol. 1976, 13, 179-92
- Baker KP, Hatch C: The species of fleas found on Dublin dogs. Vet Rec. 1972, 91, 151-2
- Dryden MW: Evaluation of certain parameters in the bionomics of Ctenocephalides felis felis (Bouché 1835). 1988, MS Thesis, Purdue University, West Lafayette
- Harman DA, Halliwell RE, Greiner EC: Flea species from dogs and cats in North-Central Florida. Vet Parasitol. 1987, 23, 135-40
- Kalkofen UP, Greenberg J: Public health implications of Pulex irritans infestations of dogs. Am Vet Med Assoc. 1974, 165, 903-5
- Kalvelage H, Münster M: [Ctenocephalides canis and Ctenocephalides felis infestation of dog and cat. Biology of the agent, epizootiology, pathogenesis, clinical signs, diagnosis and methods of control.] Tierärztl Praxis. 1991, 19, 200-6 [in German]
- Kristensen S, Haarløv N, Mourier H: A study of skin diseases in dogs and cats. IV. Patterns of flea infestation in dogs and cats in Denmark. Nord Vet Med. 1978, 30, 401-13
- Ménier K, Beaucournu JC: Taxonomic study of the genus Ctenocephalides Stiles & Collins, 1930 (Insecta: Siphonaptera: Pulicidae) by using aedegous characters. J Med Entomol. 1998, 35, 883-90
- Soulsby EJL (ed.): Helminths, arthropods and protozoa of domesticated animals, 7th edn., 1982, Lea & Febiger, Philadelphia
- Urquhart GM, Armour J, Duncan J, et al. (eds.): Order Siphonaptera. In: Veterinary parasitology. 1987, Longman Scientific & Technical, Essex, England, pp 171-5