Dog Fleas are minute insects that do not have wings and feed on the blood of animals. Apart from being annoying pests, they also spread diseases, cause anaemia and allergies. The numbers of species of flea that exist worldwide are over 2200, with only a few actually infesting house pets in North America. The cat flea (Ctenocephalides felis) and the dog flea (Ctenocephalides canis) are the two most common flea species, although majority of fleas on both animals tend to be cat fleas. They bring about extreme irritation in both humans and animals, while also spreading diseases like tapeworm infections and typhus-like rickettsiae.
Life Cycle and Spread
The reproductive cycle of dog fleas typically starts a day or two after feeding on the blood of a host. The female flea will lay her eggs as she moves and feeds on the skin of the host, and is capable of laying 50 eggs in one day and almost 2000 during her lifespan. The eggs tend to be small, oval and pearly white in colour. When a dog scratches itself, it flicks the eggs off and drops them onto carpets, soil and beddings. Within 1 to 6 days, the eggs hatch into larvae that are mobile and feed on adult flea faeces and organic matter. The newly hatched larvae stay away from direct light and hide deeper in carpet fibres or below organic waste, e.g. leaves, branches or soil.
Larvae are vulnerable to dry environments, and humidity levels that fall under 50% are fatal to them. They are able to move as much as 3 feet just to ensure that they get an appropriate location to survive. When inside the house, the larvae protect themselves by hiding under carpet fibres, floor board cracks, and on damp concrete floors in the basement. The outdoor environment is where fleas grow, as long as the ground is wet and dark. The availability of food and suitable environmental conditions determine the duration of the larval stage of fleas (5 to 11 days), but which may stretch to 2 to 3 weeks.
As soon as its development is over, the mature larva pupates in a silk-like cocoon. In around 1 to 2 weeks, the pupa is completely developed, though the mature flea may stay within the cocoon for a couple of weeks until an appropriate host comes along. It can survive for at least 2 weeks without food after it leaves the cocoon. The fleas that have just emerged from the cocoon are the ones that tend to latch onto pets and bite humans. It is quite rare for fleas to vacate their host’s bodies except in situations where the dog is groomed or insecticides are used. Cold weather is completely unsuitable for the lifecycle of cat fleas. If the environmental temperature gets below 37°F (3°C) for more than a few days, the fleas will not survive.
If the humidity and temperature conditions are suitable, the lifecycle of the flea can be over within 2 weeks. If conditions are not conducive, it can take up to 350 days. In most cases, fleas undergo their whole life cycle in about 3 to 6 weeks. Mating is done only after feeding, with the females producing eggs 1 to 2 days after ingesting the first blood meal.
A dog or cat that is infested with fleas can easily bring them into the house, where they drop the flea eggs. The eggs then mature resulting in more infested pets and bitten humans.
Flea Allergy Dermatitis
As the flea feeds on the host’s blood, it injects saliva into its body, causing an allergic reaction. Both allergic (dogs and cats) and non-allergic animals will begin scratching themselves due to the irritation from the bites. Signs of an allergic response in dogs include severe itching, restlessness, excessive scratching, rubbing, licking, and nibbling on the affected area. The consequences often include scabbing, loss of hair, and secondary infections. In cases of extreme infestation or in young puppies, the blood loss could lead to anaemia.
Majority of flea allergy dermatitis cases take place during late summer, which is when flea populations are at their highest. Animals that have not yet reached the age of 1 year rarely suffer from flea allergy dermatitis. The common mode of diagnosis is by observing the animal visually. Moving the hair aside will often expose fast moving fleas and flea droppings. The droppings tend to be reddish-black in colour, pellet or comma-shaped, and dissolve easily in water. Its dissolution turns the water reddish brown. It is also important to check the dog’s beddings for the presence of flea eggs, droppings or larvae.
The fact that fleas are present does not mean that another disease can’t be responsible for the itching and scratching. Skin tests may be done to confirm the flea allergy dermatitis, while eliminating other potential causes of the itching. Such alternative conditions that might resemble flea allergy dermatitis include infections of the food allergies, hair follicles, mange, respiratory allergies, and skin parasites.
There have been major developments in flea control measures. In the past, constant application of insecticides on the animal and surroundings was necessary. Nowadays, new insect growth regulators and insecticides have been formulated. These new products don’t need constant applications and ensure residual control. Insect growth regulators inhibit the reproduction of fleas. The treatments consist of oral and injected drugs, ‘’fogger sprays’’, and topically applied liquids. Flea control products should be discussed with your veterinarian in order to establish the most appropriate treatment for your pet and the surrounding environment.
The main aim of treatment is to eliminate all fleas on the animal’s body and in the environment, irrespective of the life stage of the flea. The first thing is to get rid of fleas presently living on your dog. It usually takes 12 – 36 hours for topical spot-on treatments to spread adequately to eradicate all the fleas. Eradicating all fleas in the pet’s surroundings is the next step. Studies done inside the home have shown that the newly developed oral and topical flea control products are effective in controlling flea populations, negating the need to treat the environment. These products make it easier to kill all fleas in a household, though there might be a variation in the time taken to achieve flea control. This is due to the life cycle and environmental conditions. The time frame for controlling an infestation is typically 6 weeks to 3 months. If there is a severe infestation or flea allergy, it may be necessary to treat the environment around the house. Using residual-acting insecticides or repeatedly applying short-acting products are some of the control measures. It is important not to forget to treat places such as carpets, bedding, furniture, closets, and behind baseboards, and gaps in hardwood flooring where eggs and larvae collect.
When treating the environment, it is unnecessary to spray flea control products all over the yard. Focus on shaded areas like garages, dog houses, below porches, and beneath shrubs. Alternative hiding spots for fleas include under the decks, beneath steps, tiny gaps in sheltered or damp brick walks, and patios.
It might be almost impossible to completely eradicate fleas quickly enough to avoid flea allergy dermatitis from infecting your dog, regardless of your best efforts. It may be necessary to find treatment in order to control itching and secondary skin infections in animals that are hypersensitive. Your veterinarian can recommend medication that will manage the affected dog’s skin condition and ensure that your pet is more at ease.