Fleas on cats and dogs

Ctenocephalides felis

This parasite is the most common flea on dogs but it is also found on cats and is often called the cat flea. It is an ectoparasite, meaning it lives on the exterior or surface of its host. 

The adult fleas feed on the blood of the host and in extreme cases can cause anaemia, but more commonly they cause flea allergy dermatitis and secondary skin irritations.

This flea is also the intermediate host of the dog tapeworm Dipylidium caninum. This is known as hyperparasitism, where one parasite is carried by another. Both cats and dogs can become infected with the tapeworm by swallowing infected fleas.

Fleas require a warm damp environment. They can live on cats or dogs for a few months but only survive a few days if not on their host.

The females can produce a few thousand eggs during their life. The eggs are laid on the skin of the host and fall off within a few hours. Those that fall into the host’s bedding stand the best chance of developing into adults. The bedding provides a suitable environment with low fluctuations of temperature and humidity. For the larvae that hatch it also provides a ready supply of food, such as dead skin from the host and faecal blood from adult fleas. 

Under good conditions the larvae can hatch from the eggs within 2 to 21 days. After pupation, adults emerge to find new hosts. 

If no dogs or cats are available, fleas are well known to vary their diet by sampling humans.

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