FLEASSS YUI

INTRODUCTION

Fleas are small, wingless bloodsucking insects (order Siphonaptera) with a characteristic

jumping movement. They feed mainly on mammals but also on birds. Of

the 3000 species only a dozen commonly attack humans. The most important

species are the rat flea, the human flea and the cat flea. Their bites can

cause irritation, serious discomfort and loss of blood. The rat flea is important as

a vector of bubonic plague and flea-borne typhus. Cat fleas incidentally transmit

tapeworms. The sand flea or jigger burrows into the skin of humans and may cause

infections. Fleas that bite people occur in most parts of the world.

LIFE CYCLE

The life cycle of fleas has four stages: egg, larva, pupa and adult . Adult

fleas are 1–4mm long and have a flat narrow body. They are wingless with well

developed legs adapted for jumping. They vary in colour from light to dark brown.

The larvae are 4–10mm long and white; they have no legs but are very mobile.

The cocoon (pupal stage) is well camouflaged because it is sticky and soon

becomes covered with dust, sand and other fine particles.

Both female and male fleas take blood-meals. Fleas breed close to the resting

and sleeping places of the host, in dust, dirt, rubbish, cracks in floors or walls,

carpets, animal burrows and birds’ nests. High humidity is required for development.

The larvae feed on organic matter such as the faeces of the host, small dead insects and undigested blood expelled by adult fleas. At the end of the larval period

the larva spins a loose whitish cocoon within which it develops into a pupa.

The adult fleas are fully developed within 1–2 weeks but only emerge from the

cocoons after receiving a stimulus, such as the vibrations caused by movement of

the host. In vacant houses they may survive in the cocoons for up to a year. People

moving into a vacant house can cause many fleas to emerge simultaneously from

the cocoons and attack people or animals in large numbers. Under optimal

conditions the development from egg to adult takes 2–3 weeks.

BEHAVIOR

Fleas avoid light and are mostly found among the hairs (Fig. 4.8) or feathers

of animals or in beds and in people’s clothing. If possible, a flea will feed several

times during the day or night. Heavy infestations with fleas are recognized by marks on clothing and bedding of undigested blood ejected by the fleas. Most flea

species feed on one or two host species, but in the absence of their normal host

they feed on humans or other animals. Adult fleas can survive several months

without food. Fleas move around by jumping; some species can jump as high as

30cm.

NUISANCE

Humans are most commonly bitten by the cat flea, Ctenocephalides felis and, less

commonly, the dog flea, C. canis. The so-called human flea (Pulex irritans) is, in

spite of its name, less important. Fleas jump up from the ground and most

frequently attack people on the ankles and legs, the easiest parts to reach, although

sleeping people can be attacked anywhere on the body. Flea bites cause irritation

and sometimes extreme discomfort. Heavy infestations may cause allergic reactions

and dermatitis.

Individual self-protection

An effective repellent, such as deet, applied to skin and clothing, prevents fleas

from attacking. A disadvantage is that repellents applied to the skin last only a

few hours (see Chapter 1). Longer-lasting protection is obtained by dusting

clothing with insecticide powder (see p. 262) or by using insecticide-impregnated

clothing.

Simple hygienic measures

Fleas and their eggs, larvae and cocoons can be effectively removed by keeping

houses well swept and floors washed. Removal with a vacuum cleaner is also

effective. When people enter an infested house that has been vacant for some time,

large numbers of newly emerged fleas may attack. The treatment of floors with

detergents, insecticides or a solution of naphthalene in benzene is recommended;

care should be taken to avoid inhaling benzene fumes.

Application of insecticides

Heavy infestations can be controlled by spraying or dusting insecticides into cracks

and crevices, corners of rooms and areas where fleas and their larvae are likely to

occur. Insecticides can also be applied to clothing and the fur of animals. Fumigant

canisters that produce aerosols of quick-acting insecticides (e.g. the pyrethroids,

propoxur and bendiocarb) kill fleas directly and are convenient to use . However, the insecticidal effect is brief and reinfestations

may appear quickly.

Cat and dog fleas

Fleas can be detected in the hair around the neck or on the belly of cats and dogs.

Treatment involves applying insecticidal dusts, sprays, dips or shampoos to the

fur. Dusts are safer to use than sprays because the insecticides are less likely to be

absorbed through the skin in the dry form. Dusts also produce less odour and do

not affect the skin as much as sprays. Carbaryl and malathion should not be used

on kittens and puppies under four weeks of age. Pets can be provided with plastic

flea collars impregnated with an insecticide. Flea collars are effective for 3–5

months, whereas other treatments give only short-term control.

Recently, lufenuron tablets have been used to control fleas in cats and dogs.

The tablets are administered once monthly at a dose of 30mg per kg of body

weight to cats and 10 mg per kg of body weight to dogs and are safe for use in

pregnant and nursing animals. Lufenuron is taken up by the female flea during

feeding and acts by inhibiting egg development .

Dusts must be rubbed thoroughly into the hair and can be applied by means of

a shaker . They must not be allowed to get into the eyes, nostrils and

mouths of animals. Heavy applications should not be made to the abdomen as the

material will be licked off. Application should begin above the eyes and all the

areas backward to the tail and haunches should be covered, ensuring thorough

treatment around the ears and underneath the forelegs. A small animal can be treated with one tablespoonful of dust, while 30 g may be required for a large dog.

Sprays must wet the hair completely and can be applied with a hand-compression

sprayer. It is also possible to spray with an insecticide aerosol from a pressurized

spray can.

Re-treatment may be necessary if reinfestation occurs. Important sources of

reinfestation are the places where animals or humans sleep or spend much time,

such as beds, bedding and kennels. Where possible, animal bedding should be

burned or laundered in hot soapy water. A vacuum cleaner may be used to remove

accumulations of dust that contain flea larvae and pupae, and infested premises

can then be treated with a residual insecticide. Treatment with insecticidal powders

or solutions is possible . Because flea cocoons are much less susceptible

to insecticides than the larvae and adults, treatments should be repeated every two

weeks over a period of six weeks to ensure that all emerging fleas are killed .

Human flea

This flea species does not usually remain on the person after feeding and by day it

rests in cracks, crevices, carpets and bedding. Regular cleaning of houses, and of

bedrooms in particular, should prevent large infestations.

More effective control is achieved by dusting or spraying insecticides on to

mattresses and cracks and crevices in floors and beds. Bedding left untreated

should be washed and cleaned during insecticide application. Fleas in many parts

of the world have developed resistance to DDT, lindane and dieldrin (13–15).

Suitable insecticides for spraying or dusting are indicated.

Disease transmission

Flea bites cause irritation and inflammation of the skin, usually on the lower legs and feet in humans.

Humans and animals often become sensitive to the bites. Diseases such as Murine typhus which is

mainly associated with rats and mice, can occasionally be transmitted to humans, although such

transmission in Australia is uncommon. Fleas can also carry tapeworms that affect dogs, cats and

rodents. Humans, particularly young children, can become infected with tapeworms by swallowing

fleas whilst playing with pets. The fur around the neck or belly of the dog or cat should be checked

regularly for fleas.

Prevention

Regular vacuuming of floors and any areas where animals rest will help to prevent infestation. Animal

bedding should be laundered in hot water, ironed or treated with appropriate insecticides. Checking

and treating animals for fleas and keeping them out of the house will also reduce the risk.

Control measures

If pets or other animals are infested with fleas, they should be treated with a suitable veterinary

insecticidal preparation. Their bedding and the rest of the premises must be treated at the same time to

completely eliminate fleas and so avoid animals being reinfested. Animals with fleas should also be

treated for tapeworm.

Animal bedding and other areas where they rest should be treated with insecticide to destroy adult

fleas and eliminate eggs and larvae. Where possible, low toxic pesticides such as pyrethroids should

be used in conjunction with an insect growth regulator such as methoprene, which prevents eggs

developing into reproductive adults.

Flea cocoons are not easy to kill with insecticide so treatment should be repeated every 2 weeks for 6

months to kill adult fleas as they leave their cocoons. Cleanliness is important for prevention and

control. Floors should be washed and floor coverings thoroughly vacuumed with insecticide powder

added to the dust bag of the vacuum cleaner and the contents emptied into a plastic bag, sealed and

placed in a garbage container. An effective alternative is to place the dust bag in the freezer for 24

hours prior to disposal.

Floors and floor coverings in infested areas should be treated with a residual insecticide and this

should only be cleaned off after the period recommended by the insecticide manufacturer. Attention

to sub-floor and outdoor areas is frequently required. It is advisable to wet outdoor areas with a hose

before applying insecticide. for examples of suitable insecticide preparations for

flea control. For persistent or extensive infestations it is advisable to consult a pest control operator.

Housekeeping and control measures - fleas

 Remove all bedding and seal in a water soluble bag.

 Send to laundry facility:-

• Place into a water soluble bag and secure

• Place into a laundry bag and secure

• Label "Infected clothes" and ward name

• Send to laundry facility

 For clothing, see Laundering and safe handling of linen and clothing.

 There is not specific treatment for the patient other than bathing and clean clothes.

 Contact Hotel Services on 01642 516851 to arrange for a Pest Control contractor to advise or carry out an eradication programme if environmental contamination is suspected.

 Vacuum floors, carpets, upholstery etc and treat with a residual insecticide if necessary.

 The Pest Control Contractor will arrange to treat inaccessible areas, i.e. ducting, under fixtures etc with residual insecticide if necessary.

 Members of the family or close contacts of the home environment should seek advice from their General Practitioner