There are over 2000 species of flea in the world. Thankfully, only the cat flea and the dog flea (Ctenocephalides felis, Ctenocephalides canis ) are important to dogs and cats. Despite the name, cat fleas infest dogs just as much as they infest cats.
The problem is that fleas breed in stupendous numbers. Female fleas can lay from 20 to 50 eggs a day and up to 2000 eggs during their lifetime, which immediately fall off the animal, all around your home.This is why, even today with very effective products to treat adult fleas, it may become necessary to practice Integrated Flea control where a combination of an Insect Growth Regulator, an adulticide and environmental cleaning (vacuum etc) are being used to tackle the problem from all sides.
The degree to which you need to control fleas will vary from person to person, and from pet to pet.
Where do fleas come from?
You might think that a pet kept entirely indoors would be at no risk of
catching fleas. But don't forget that it only takes a visit from one untreated
animal to trigger an infestation in your home, so even housebound pets may
require flea control.Pets that routinely go outdoors will likely come into contact with fleas from time to time, and require regular treatment.
 |
Finally, some pets are allergic to relatively small numbers of fleas, and may need particularly stringent flea control.
Discuss the most appropriate level of flea control with your veterinarian. Before you do, though, it is important that you have a basic understanding about fleas.
Cat flea life cycle
The most prevalent species of flea to infest pets around the globe is the cat flea. In order to understand how flea infestations occur, it is important to have a basic understanding of the flea life cycle.
Please click on the tabs above to learn more about the different stages of the flea life cycle.
The cat flea life cycle has four main stages:
The adult fleas you see on your pet are only 5% of any flea infestation, the remaining 95% are living as immature stages in your home.
Stage 1: Flea Eggs
Once on a host, adult cat fleas take a blood meal and mate. Within 36 to 48 hours, the female begins laying eggs. Flea eggs are pearly white, oval with rounded ends and approximately 0.5 mm long. Eggs typically make up 50% of an infestation in the home. The female flea lays her eggs in the haircoat of the host. Since the eggs are not sticky, they fall off the host into the environment. Thus, flea eggs may be deposited in all those places to which the dog or cat has access. Female fleas can lay from 20 to 50 eggs a day and up to 2000 eggs during their lifetime. Eggs usually hatch in 1 to 10 days, depending on temperature and humidity. Humidities below 50% and over 92% kill flea eggs.
Stage 2: Cat Flea Larvae
Newly hatched flea larvae are slender, white, segmented and worm-like. They
are sparsely covered with short hairs and are 1 to 2 mm in length. They have an
egg-tooth, similar to that of a bird, that they use to cut their way out of the
egg. Larvae are free moving, and survive by feeding on organic debris found in
their environment and on adult flea feces, which is essential for successful
development. Once the larvae have ingested adult flea feces or other material
they become darker in color. They have been observed to crawl as far as 6 meter
(20 feet) while in this stage of their life cycle.
Since larvae are negatively phototactic (avoid light) and positively geotropic (prefer to move downward), they are found deep in carpet fibers, mattress or couch stuffing materials or organic debris (branches, leaves, etc.). They accumulate in areas where the animal spends a great amount of time. These "hotspots" are typically in pet resting areas. They are not usually found in open lawn. Flea larvae are extremely susceptible to heat and desiccation. Moisture in the larval environment is essential for development; relative humidities below 50% cause dessication. Flea larvae undergo two molts before developing into the Pupal stage. While the first larval instar is no more than 2 mm long, the fully developed larvae can be 4 to 5 mm in length. The larval stage usually lasts 5 to 11 days, depending upon the availability of food and the climatic conditions, and will account for about 35% of an infestation in a home.
The transition from egg to larva, between molts and from larva to pupa, is controlled by juvenile hormone. When the juvenile hormone level drops, the larva molts to the next stage. The actual molting process is triggered by another hormone, ecdyson.
Stage 3: Cat Flea Pupae
Since larvae are negatively phototactic (avoid light) and positively geotropic (prefer to move downward), they are found deep in carpet fibers, mattress or couch stuffing materials or organic debris (branches, leaves, etc.). They accumulate in areas where the animal spends a great amount of time. These "hotspots" are typically in pet resting areas. They are not usually found in open lawn. Flea larvae are extremely susceptible to heat and desiccation. Moisture in the larval environment is essential for development; relative humidities below 50% cause dessication. Flea larvae undergo two molts before developing into the Pupal stage. While the first larval instar is no more than 2 mm long, the fully developed larvae can be 4 to 5 mm in length. The larval stage usually lasts 5 to 11 days, depending upon the availability of food and the climatic conditions, and will account for about 35% of an infestation in a home.
The transition from egg to larva, between molts and from larva to pupa, is controlled by juvenile hormone. When the juvenile hormone level drops, the larva molts to the next stage. The actual molting process is triggered by another hormone, ecdyson.
Stage 3: Cat Flea Pupae
Upon completion of development, the mature larva produces a silk-like cocoon
in which it pupates. The cocoon is ovoid, whitish, and loosely spun. Because the
cocoon is sticky, it quickly becomes coated with debris from the environment
which helps camouflage it. In most homes, the pupation can be completed within 5
to 14 days in ideal conditions. Once the pupa has fully developed, the adult
flea (pre-emerged adult) will remain inside the cocoon for several days to
several weeks until stimulated to emerge from the cocoon. Physical pressure
(being stepped on), carbon dioxide (that mammals exhale), vibration (from
walking, or vacuuming) and heat (generated by potential hosts or heated homes)
can all stimulate emergence. It is interesting to note that flea pupae do not
hatch all at once regardless of the stimuli. It is believed there is some type
of communication involved (Pheromonal?, Genetic?) that causes flea pupae to
stagger there hatching over a varied period of time. This effect is sometimes
mistakenly perceived as a flea control product failure when it is in fact a
normal mechanism of the flea to increase the likelihood of survival.
The fully formed adult flea residing in the cocoon (pre-emerged adult) is the stage that can extend the longevity of the flea, and makes it the most troublesome from a control standpoint. If the pre-emerged adult does not receive the proper stimulus to emerge, it can remain dormant in the cocoon for several weeks and possibly as long as one year in rare conditions, until a suitable host arrives. Added to this is the fact that there are no chemical sprays available on the market today that can penetrate the pupael cocoon. House sprays will kill exposed eggs and larvae, but pupae will remain unaffected and will hatch at some point long after the residual effect of most sprays has expired. Successful treatment of pupae must usually wait until it has hatched into an adult where it may then be killed with an adulticide. Cocoon's are typically spun around the base of carpet fibers or bedding material which make them impossible to remove with regular vacuuming. Vacuuming is recommended though as the vibration from the vacuum may stimulate the flea to the point of emergence.
Pupae commonly make up 10% of the infestation in a home. Depending upon temperature and humidity, the entire life cycle of the cat flea can be completed in as little as 12 to 14 days under ideal conditions, or be prolonged to 6 months and possibly as long as a year in rare instances. However, under average household conditions, cat fleas will complete their life cycle within 3 to 4 weeks.
Pupal Window Effect
Once adult fleas begin to emerge from cocoons, they are vulnerable to insecticides. However, after treatment with an adulticide pupae will continue to emerge for at least 2 to 4 weeks. In fact, small numbers of fleas may continue to emerge for periods up to one year; a phenomenon called "delayed emergence." Or "Delayed Pupal Hatching" This continued emergence of fleas following treatment is called the Pupal Window.
The pitfalls of the Pupal Window Effect are:
The fully formed adult flea residing in the cocoon (pre-emerged adult) is the stage that can extend the longevity of the flea, and makes it the most troublesome from a control standpoint. If the pre-emerged adult does not receive the proper stimulus to emerge, it can remain dormant in the cocoon for several weeks and possibly as long as one year in rare conditions, until a suitable host arrives. Added to this is the fact that there are no chemical sprays available on the market today that can penetrate the pupael cocoon. House sprays will kill exposed eggs and larvae, but pupae will remain unaffected and will hatch at some point long after the residual effect of most sprays has expired. Successful treatment of pupae must usually wait until it has hatched into an adult where it may then be killed with an adulticide. Cocoon's are typically spun around the base of carpet fibers or bedding material which make them impossible to remove with regular vacuuming. Vacuuming is recommended though as the vibration from the vacuum may stimulate the flea to the point of emergence.
Pupae commonly make up 10% of the infestation in a home. Depending upon temperature and humidity, the entire life cycle of the cat flea can be completed in as little as 12 to 14 days under ideal conditions, or be prolonged to 6 months and possibly as long as a year in rare instances. However, under average household conditions, cat fleas will complete their life cycle within 3 to 4 weeks.
Pupal Window Effect
Once adult fleas begin to emerge from cocoons, they are vulnerable to insecticides. However, after treatment with an adulticide pupae will continue to emerge for at least 2 to 4 weeks. In fact, small numbers of fleas may continue to emerge for periods up to one year; a phenomenon called "delayed emergence." Or "Delayed Pupal Hatching" This continued emergence of fleas following treatment is called the Pupal Window.
The pitfalls of the Pupal Window Effect are:
- Re-treatment with adulticides on the pet is needed to control the emerging fleas; and
- Pet owners unaware of the effect may believe the control measures used aren't working and either discontinue them or switch to other, perhaps less effective methods.
Stage 4: Cat Flea Adult
Once the flea emerges form the cocoon, it immediately begins seeking a host. A flea that emerges from the pupael cocoon due to the pressure of the pet stepping on it, can hatch, jump on the pet as it is walking by, and begin feeding in as little as 7 seconds. There is nothing currently available that is able to prevent the flea from jumping on the pet and feeding due to the short time frame involved. There are no repellents for fleas. Contrary to some myths, fleas are not repelled or killed by such items as garlic or brewers yeast. In laboratory experiments fleas were fed brewers yeast in order to sustain them until a blood meal could be introduced. There is also no clinical data to support theory of sonic flea control devices. Owners that experience success with these types of treatments are usually the lucky few that would not suffer from fleas regardless of what the pet is on. Newly emerged fleas are attracted to pets by various stimuli produced by these hosts: body heat, movement and exhaled carbon dioxide. In contrast to larvae, adult cat fleas will orient and move towards light. The adult is negatively geotactic (prefers to move upward). These behaviors enhance the cat flea's success in finding a host because newly emerged fleas move directly to the top of the carpet pile where they are more likely to encounter a passing host. The presence of fleas is not an indication of a "dirty" home. Regardless of sanitary conditions a flea is able to survive in a home as long as there is a host on which to feed.
If the newly emerged cat flea does not find a host, it can survive for 1 to 3 weeks before requiring a blood meal, but once they initiate feeding the flea must be able to feed again within 4 days or it will die.
Adult fleas are dark reddish-brown and 2 to 5 mm long. They have thin, flattened bodies and backward-directing spines on their legs and bodies that facilitate forward movement through fur, hair or feathers and prevent them from being easily dislodged.
Adults make up only about 5% of a population. Fleas are wingless, but have strongly developed legs that permit them to jump up to 100 times their own body length (8 inches vertically and 15 inches horizontally). That's the equivalent of a human jumping the length of three football fields. The g forces (gravity pull) on the flea measure about 150g's as it jumps. Compare that to the g force of 3 that astronauts experience as the space shuttle takes off. Fleas are very resilient in their environment due to their strong insect exoskeletons made up of a substance called chitin (KITE-IN). It is this shell that helps the flea survive on the pet. Once on a host, the cat flea initiates feeding within seconds and egg production begins within 48 hours. Contrary to what has been commonly reported, the adult cat flea is actually a permanent ectoparasite. It does not leave the host unless it is forced off.
Therefore, once on a suitable host, fleas do not leave their host voluntarily. They remain until removed by ingestion, grooming behavior, dying a natural death, or dying from chemical induced death (insecticide application). The drawback with any adulticide only treatment is the 85% of the pre-adults waiting to develop in the environment. The adult cat flea can survive on the host and maintain some reproduction for 2-4 weeks under most natural conditions, but if not killed prematurely an adult flea may live as long as 4 months.
Flea-Related Problems in Cats: Threats
Biting or scratching is usually the first reaction of an animal with fleas. Some animals may begin excessive grooming to try to rid themselves of the irritation, eating many of the fleas in the process. Light-haired dogs or cats who do this may develop an orange-brown discoloration due to salivary staining. These general symptoms are usually referred to as pruritus.
Pruritus (itching) is caused by reactions to flea saliva. During feeding, the
flea releases saliva to stop blood from coagulating. The saliva contains
chemicals that cause an irritant reaction in the host:
-
histamine-like substances (compounds that cause allergic responses)
-
proteolytic enzymes (substances that initiate the breakdown of protein)
-
a hapten (an incomplete antigen that becomes complete when combined with dermal collagen)
Dogs and cats that are hypersensitive to flea saliva have intense reactions,
often out of proportion to the number of fleas on the pet. Recent research
indicates that FAD may be caused by intermittent exposure to large numbers of
fleas. Animals sensitized in this way may subsequently become intensely reactive
even when only a small number of fleas are present. This is significant as it
suggests the way to prevent FAD may be to prevent the repeated exposure to flea
infestation.
The initial reaction is usually a reddened wheal, which forms a papule or swollen nodule and crusts over. After that, several secondary changes are possible:
-
superficial pyoderma (skin infections affecting the skin surface)
-
seborrhea (scaling, crusting, yellowish patches on the skin)
-
diffuse erythema (reddening of the skin over various parts of the body)
-
hair loss
-
"hot spots" - bare, eroded, oozing patches (a severe localized skin infection or pyoderma)
This particular species of tapeworm must use the flea as an intermediate host
in its own life cycle. Egg packets deposited by the adult tapeworm are shed into
the environment where they are consumed by the flea larvae. If a pet ingests an
adult flea that consumed the tapeworm egg pack as a larvae, the tapeworm
parasite is passed on. Although tapeworm in pets usually doesn't cause serious
disease, it is particularly annoying to pet owners. Tapeworms are easily
detected by the pet owner. Small rice-like objects are seen clinging to the hind
end of the animal near the base of the tail, and their presence usually evokes a
feeling of disgust in most owners. In addition, people can become infested if
they inadvertently ingest infected fleas.
Being blood-sucking insects, fleas can produce parasitic anemia in heavy
infestations, particularly in young animals. Fleas in the genus
Ctenocephalides have been reported to produce anemia in dogs, cats,
goats, cattle and sheep. Severe flea infestations in young pups can cause anemia
to the point of death.
Fleas are able to reproduce on any mammalian blood supply, including humans.
However, a female flea must feed for a prolonged period of time in order to
begin egg production. Fleas may spend 2-3 hours sucking on one spot and most
humans will scratch or perform some other action to interrupt this feeding
process. As such, the flea is not able to feed for the required length of time
to produce eggs.
Disease transmission due to fleas in man is not a common occurrence, but
any suspected reactions should be discussed with a human doctor.
How to check your pet for fleas
A trained eye isn't usually needed to spot a heavy flea infestation. You'll
probably notice your pet scratching, biting its coat, or showing other signs of
discomfort. If you then run a fine metal comb through your pet's coat, you might
see them crawling around on the comb afterwards.
Often though, you'll notice symptoms of a flea infestation without being able to find the culprit. That's because pets, especially cats, will groom fleas out of their coats long before you've had a chance to try and find out what's making them itch.
If you're in any doubt, carry out a simple flea check. First sit your cat or dog on a large piece of white paper. Then rub its back vigorously for a minute or so. As you rub, any flea faeces will fall onto the paper. You may need to hold the animal's tail between its legs in order to prevent it moving whilst you do this. Next pick up the piece of paper, remove any hair, and transfer the 'rubbings' onto some damp cotton wool. Leave to stand for a minute.
Flea faeces are made up of dried blood from the host they have bitten. When dry, they are dark brown flecks that can be easily confused with dirt or dead skin. But once transferred onto the moist cotton wool, they'll dissolve and turn a lighter shade of red. So, if you can now see red spots on the cotton wool, you can be certain that your pet has been in recent contact with fleas. Treatment is required.
Flea-Related Problems in Cats: Flea TreatmentOften though, you'll notice symptoms of a flea infestation without being able to find the culprit. That's because pets, especially cats, will groom fleas out of their coats long before you've had a chance to try and find out what's making them itch.
If you're in any doubt, carry out a simple flea check. First sit your cat or dog on a large piece of white paper. Then rub its back vigorously for a minute or so. As you rub, any flea faeces will fall onto the paper. You may need to hold the animal's tail between its legs in order to prevent it moving whilst you do this. Next pick up the piece of paper, remove any hair, and transfer the 'rubbings' onto some damp cotton wool. Leave to stand for a minute.
Flea faeces are made up of dried blood from the host they have bitten. When dry, they are dark brown flecks that can be easily confused with dirt or dead skin. But once transferred onto the moist cotton wool, they'll dissolve and turn a lighter shade of red. So, if you can now see red spots on the cotton wool, you can be certain that your pet has been in recent contact with fleas. Treatment is required.
There are essentially 2 different types of insecticide used to prevent or
eliminate flea infestations:
 |
Adulticides To remove adult fleas from your pet | ||||
Adulticides are designed to kill adult fleas on your pet. Most work within 24 hours. However it can not be ruled out completely that freshly caught fleas may have the chance to lay eggs. This is why scientists the world over agree that the most effective way to prevent or eliminate fleas is to use adulticides in combination with Insect Growth Regulators (see below). This is known as Integrated Flea Control.
Type of Products:There are different ways of practicing Integrated Flea Control, depending on the level of control required for the pet, its 'natural' exposure to fleas, the level of control that you want to achieve, and the type of product you want to use.
Source: Novartis Animal Health
| |||||
