Just whisper the word fleas or mention a flea circus, and most people immediately start feeling itchy and begin to scratch.

The real question is – what effect do fleas have on humans, dogs, and cats as their primary hosts and/or on their secondary hosts? The answer is simple – the hosts feel the urge to itch and scratch endlessly, which increases the chances of transmitting diseases. Fleabites basically damage the skin by causing lesions. Hosts who are hypersensitive to the flea’s saliva get what is called flea allergy dermatitis, which can be extremely painful. These fleas are parasites that serve as vectors for the plague and typhus, and as hosts for tapeworms.

If we wish to combat this problem, we first need to understand more about the types, habitat, and way of life of fleas. Although roughly 1,500 kinds of fleas are found around the world, I would like to concentrate on just the following types:

The human or common flea called Pulex irritans is about 2 to 4 mm in size, and dark brown to black.

Primary hosts: humans, dogs, cats

The canine or dog flea called Ctenocephalidis canis is 1.5 to 3.2 mm in size, and brown to chestnut.

Primary hosts: dogs

Secondary hosts: humans at times, hosts for tapeworms

The feline or cat flea called Ctenocephalidis felis is about 1.5 to 2.7 mm in size, and brown to chestnut.

Primary hosts: cats

Secondary hosts: humans are preferred; this type represents 80% of the European flea population.

The rat flea called Xenopsylla cheopsis is about 1.4 to 2.0 mm in size, and brown to chestnut. As opposed to human, dog, and cat fleas, rat fleas do not have genal or pronotal combs on their heads.

Primary hosts: rodents

Secondary hosts: humans, vector for the plague and typhus

Found in tropical regions of Africa, Asia, and America

Well, how do our dogs get fleas? They are passed on in several ways:

· Humans to dogs

· Dogs to dogs

· Cats to dogs

· Hedgehogs to dogs

In most cases, fleas thrive in the coats of dogs and cats and end up in the living sphere of humans. Fleas stay close to their secondary hosts, humans, at places where dogs and cats sleep, in floor cracks, carpets, furniture upholstery, wall joints, garbage, and in the animal owner’s beds.

If they are not completely exterminated, re-infestations will keep occurring. Then the only solution is to wish you “happy scratching”!

A flea is a temporary parasite, since it seeks a host only when it needs to feed on blood. These pests have adapted their lifestyles to their hosts. Interestingly, they have strong legs made for jumping – and they can manage up to 30 cm hops in case of danger (flea circus). Their exoskeleton is made of a hard, brownish horny substance called chitin. It is almost impossible to crush them with your fingernail. They have a lifespan of about 18 months, during which time the female lays several hundred eggs – preferably where the host typically sleeps. Within ten days, these grey-white, oval, and smooth eggs turn into hairy, legless larvae at an ambient temperature of 18 °C. They nourish themselves from the feces of adults and from organic garbage. The flea larvae pupate two weeks after eclosion. Vibrations in wooden floors, for instance, help the fleas to emerge from their cocoons. Depending on the ambient temperature, the pupae stage lasts about a week to several months. The hatched flea waits patiently for months in its pupal case until a potential host comes within striking distance. Fleas typically sting several times in adjacent spots that look somewhat like the rungs of a ladder.


My dogs wear a flea/tick collar.

I regularly check their coats for fleas.

I also inspect the areas where my dogs sleep for fleas, their eggs, and excrement.

Helpful tips:

To identify flea feces, moisten a piece of blotting paper, and place the suspected substance on it. If the paper turns red (from undigested blood), it is excrement.

Keep your dog’s basket, cushions, and surrounding area extremely clean. Vacuum these daily and wipe clean with a wet cloth.

If your dog is infested, take it to a vet for an examination. The vet will apply a compound like drops. He/she could also use the opportunity to do a stool analysis and deworm the dog, if necessary.

If a person is infested, it is important to wash the whole body thoroughly, launder the clothes and bedding using a disinfectant. Also get a powder or spray from a pharmacy to kill the fleas.

If the dog’s fleabites get infected, take it to a vet immediately!

Hanspeter Kobold

Ibiza: 2002

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