Developmental stages (eggs and larvae) of cat fleas (Ctenocephalides felis) and their importance for flea control

摘要

The wide distribution of fleas as well as their role as vectors for other pathogens, the source of flea allergy dermatitis and their public health impact, all make the successful control of these parasites using insecticides and insect growth regulators indispensable. The cat flea (Ctenocephalides felis) maintains its life cycle indoors feeding on pets. However, it must be emphasized that only about 1-5% of the flea population is on their hosts, the remaining 95-99% (eggs, larvae and pupae) are spread around the habitat. The eggs and dried blood faeces fall from the coat of the animal on its sleeping, resting or feeding sites. In the first study, three cats (2 [female], 1 [male]) were kept in a carpeted room and were infested four times with 50 cat fleas weekly. After five weeks, the spatial distribution of the developmental stages (eggs and larvae) in the carpet, and on the various resting sites was evaluated by vacuum cleaning. The hatched eggs were spread around the feeding and resting areas. A total of 565 eggs, the largest number of hatched eggs in a single sample were vacuumed from the male cat's resting box. The distribution of larvae was nearly the same as that of the hatched eggs. The appearance or absence of flea larvae in a certain area was related to several factors, including sunlight exposition (windows), temperature (heating) or activity areas of the cats. The concentrations of flea eggs and larvae on the carpeting were highest in the sleeping and resting areas. The second study was performed in order to evaluate the efficacy of vacuuming for removal of the developmental stages of cat fleas. The present data indicate that vacuuming can remove 40-80% of eggs that are located in the carpet pile, but vacuuming may remove only <5% of flea larvae in the carpet. The power of vacuum cleaners (1200, 1500 and 1800 W), and time of vacuuming after having infested the carpet with a defined number of eggs and larvae (1 and 6 hours) did not correlate with the number of removed eggs and larvae. However, the length of the carpet fibers was closely associated with the effectivity of removal of the developmental stages, with fewer eggs and larvae being taken up from carpets with longer piles. Vacuuming the household carpeting, especially in those areas where the pets spend their time, may remove only a small proportion of eggs and larvae. Vacuuming is thus limited as a control strategy for the elimination of flea eggs and larvae from carpeting. Consequently, integrated flea control has to include chemical control measures against adult fleas and their developmental stages.