Flea - Fact File

FleasSize: 2-3mm overall body length.
Markings: Adult fleas are dark mahogany in colour. Larval stages are white/straw coloured, small and hairy.
Location: Carpeting, bedding, under furniture, roof spaces (bird's nests). Any areas that pets frequent.
Detection: Visual sightings of adults. Bites, most often on the lower leg.

Fleas as adults are parasites on warm blooded animals, e.g. humans, cats, dogs, birds, etc. These are known as hosts. Those most commonly found in homes, hospitals and offices are cat fleas, but others (dog fleas, bird fleas, hedgehog fleas and occasionally human fleas) may also occur. The historical links with the Bubonic Plague, caused by a bacterium carried by the black rat flea, are widely known. What may be surprising is that plague has not been eradicated, and can still be caught in areas such as Madagascar and some areas of the Far East.


Female fleas lay eggs of about l mm in small batches on or near the host after a blood meal. After 2 or 3 days, the eggs develop into bristly, legless larvae. These feed on scraps of organic matter and specks of host blood passed by the adult fleas. After 3 moults and a period of typically about 3 weeks, the larvae pupate, turning into adults within days or laying dormant for many months.

Vibrations caused by the presence of a host triggers off the hatching process. Once hatched, the flea jumps towards any source of heat and vibration. They also 'taste' the air and detect the presence of carbon dioxide from the host's breathe, enabling them to home-in on their target. The complete lifecycle is temperature-dependent, but in favourable conditions one pair of breeding fleas can produce 6000 off spring in four weeks.

Reasons for Control:

It is important to control fleas for various medical and social reasons, i.e. fleas can be carriers of serious bacterial diseases and are vectors of tape worms to domestic animals and humans. In recent years flea infestations have increased due to a number of reasons, including central heating, fitted carpets (especially long pile) and increasing numbers of pets kept in homes (especially cats).


The normal way of treating a flea infestation in the home is by using a residual chemical. Complete eradication can only be achieved through a thorough treatment of the infested property, and unfortunately, the lack of thoroughness is one of the main reasons for a call-back. A thorough treatment includes the moving of all pieces of furniture to spray underneath, as well as careful attention to areas such as the three-piece suite and any areas where the pet frequents Removal of bird nesting material from lofts and attics and infested pipe lagging may also be required. Dead bird or rodent carcasses may be a source of infestation.

Where no pets are present, such as in an office environment, then further investigation is needed. This should involve examining the bites to ensure that they are indeed caused by fleas. Where on the body are the bites? Who is being bitten, and where in the room(s)? Does anyone own a pet? Does anyone visit friends with pets? Only by the use of such questions will the source of the problem be identified.

Spraying carpets and furnishings with an insecticide with some residual qualities is necessary - wettable powders are often thought best for these more porous surfaces. Care should be taken to avoid staining fabrics etc. with the insecticide. Aerosol applications to furniture are acceptable, but treatment of fabrics that'come into contact with human skin or pets is best avoided. If you do not gain the control you expect, then change to an insecticide from a different group of active ingredients, rather than hitting them again with the same product.

It is wise to use a space spray, such as an ultra low volume (ULV) application, to supplement the insecticidal treatment, as this has the advantage of getting into all the nooks and crannies.

For long-term control, the use of an insect growth-regulating (IGR) chemical is advised. Although this does not give instant results, as it works over the lifecycle of the insect, when it is tied in with an adulticide, a far greater success rate will result. IGRs are available in concentrate form, ready mixed with an insecticide or even in an aerosol format. A can of the aerosol will treat a typical 3-bed semi-detached house when used in conjunction with a normal 'coarse' spray application.

Treatment of pets should be carried out on a veterinary surgeon's advice by using one of the proprietary treatments as either an insecticide or as an insect growth regulator.

There has been some suggestion that a degree of insecticide resistance is building up amongst flea populations, particularly with the more commonly used chemicals (which may have been applied on several occasions). Whilst this is possible, it is unlikely to affect your control programme, as by changing insecticides and using a growth regulator, any resistance that may be present will be negated.

Do not be tempted to spray the bases of your trousers / overalls with the insecticide you have just prepared, because although it will undoubtedly kill some fleas, it is illegal, as the product is not approved for this use. Only an approved repelling chemical may be applied in this way.

If you need a fast, effective and reliable pest controller in the Bishops Stortford area
contact Cross Pest Control on:
Hertfordshire: 01920 822897
Mobile: 0777 5673088 or 0777 5673089