Fleas can be monitored in several ways. The simplest is to count and collect fleas landing or crawling on an observer's lower legs for one minute. In making surveys, trousers should be tucked into white socks to prevent bites and make collecting easier (socks can be put on over shoes). Light-colored trousers are preferred to provide greater contrast and facilitate counting and collection. A variation on the above is to wrap fly paper (sticky side out) around the lower legs and count fleas adhering after a predetermined interval.
Fleas may also be combed off animals for an index of animal infestation. Do this over a white surface so fleas can be easily observed.
Pet bedding should be periodically checked for flea eggs and dried-blood feces (frass) of adult fleas. This has been described as "salt and pepper" because it looks like small flecks of black and white debris. The frass is generally cylindrical, twisted, and about 1/16" long. It is dark in color. Larvae and pupae can be found at the edge of pet bedding or animal nests.
Indoors, five or more fleas on the legs of observers in less than one minute is indicative of severe infestation.
Flea populations in animal burrows or dens can be sampled by using a flannel cloth that is run through the burrow on the end of a plumber's snake. The number of fleas on the cloth is then counted.
Several studies have indicated that fleas spend the majority of their life either on the host or in the host's bedding or nest, so flea management should focus on these. In outdoor settings, the emphasis should be on spot treatment of nests with an insecticide. Exclusion of the host animal from an area may be desirable as well, but the feasibility of this strategy will vary with the animal and the location of its nest. In the case of domestic animals, sanitation should be the focus of a flea management program. Regular cleaning of bedding and other areas where the animal spends the majority of its time should reduce flea populations to non-irritating levels.
In areas where plague is endemic (e.g. the southwestern United States), efforts should be made to keep humans and fleas (and their wildlife hosts) separate. Prairie dog towns should not be allowed to expand into campgrounds and other developed areas. Camping and other outdoor activities should be restricted during an outbreak when fleas seek other hosts. Prairie dog burrows can be dusted with insecticide. Check with Public Health Service officials if your area is affected.
In most other cases, fleas are considered pests due to the nuisance caused by their bites. In these situations, management decisions should be made on a case-by- case basis.
Sanitation Fleas require warm-blooded hosts for development and for egg maturation. Elimination of suitable habitat for wild rodents and other animals near structures will often reduce flea population levels. Screened vents prevent animals from resting inside or underneath structures. Eliminating vegetation close to structures and raising woodpiles off the ground reduces rodent harborage.
Indoors, wash or vacuum all pet bedding and sleeping areas on a regular basis. Cracks and crevices should be vacuumed and sealed, especially the area between the baseboard and floor. Dispose of vacuum cleaner bags to prevent reinfestation. Pets should be washed regularly and treated with insecticides if necessary.
Ultrasound The ultrasonic collar is sometimes for the control of fleas on domestic animals. A recent study showed that ultrasound devices are ineffective.
Insect Growth Regulators A newer technology in the management of fleas is the use of insect growth regulators (IGRs). These substances are similar to chemicals produced by the flea to regulate the shedding of its skin during molting. They work by interfering with the molting process, thus preventing the immature flea from developing into an adult. This method of control is a long-term process, since it will only kill larvae as they molt. A recent study using pyriproxyfen (sold as Nylar ), an insect growth regulator reported to be effective against several insects, examined its effectiveness against the cat flea. One problem with insect growth regulators is that they break down when exposed to light, limiting their outdoor use. In this study, Nylar was determined to be stable when exposed to light. It was found to persist in home yards for three weeks after application and to prevent development of 90% of the fleas in treated areas. Another effective IGR for flea management indoors is methoprene (trade
name Precor). It is important to combine the use of a material such as this with observations of the infested animal's movement so that only areas where it spends the majority of its time are treated.
Conventional Insecticides These are applied to areas where fleas are most likely to breed, including animal bedding, cracks in floors, and baseboards. Many veterinarians also recommend the use of indoor foggers to
apply pesticides to rooms where domestic animals spend the bulk of their time. Flea collars are not considered to be effective. When insecticides are used, it should be in conjunction with sanitation. One difficulty with the use of insecticides as part of a flea management program is the ability of the adult flea to remain in its cocoon as a preemerged adult. This means that the adult flea can remain in the cocoon in which it pupates until it encounters a suitable host. Insecticides have been found to be ineffective against these preemerged adults. This highlights the
importance of sanitation as the key element in a flea management program.