What are fleas?
There are two types of flea that can affect dogs, though both are very similar in appearance. The most prevalent, rather ironically, is the cat flea: ctenocephalides felis. They measure between 1-2mm long, and are parasitic insects that will infest a dog's coat, feeding on their blood before quickly reproducing and laying eggs on their body.
Despite their lack of wings, the cat flea has long hind legs that allow them to jump high and move quickly. Coupled with the fact their incredibly tough shells prevent dogs from squashing them when they scratch, they can be tricky to get rid of.
The other type of flea known to affect dogs - though one that is less common - is ctenocephalides canis, also known as the dog flea. Dog-only households can be hit by these fleas, and unlike their cat flea cousins, they do not live on cats.
If your dog becomes affected by fleas, in can be very uncomfortable for them, and if untreated they can spread to other areas of your home too. While they don't live on people, dog fleas will feed on adults and children if given the chance.
Where they come from
Dogs pick up fleas from outside the home, and are especially susceptible if they visit the home of or - come in close contact with - another infected animal, or in long grass or woodland. This is because fleas can jump from one animal to another with ease, and begin laying eggs immediately.
Flea eggs can also be contracted from bedding, soil, carpets or floorboards. Flea eggs are extremely durable, and can lay dormant for months at a time. As a result, it's advisable to check for signs of fleas when buying an empty or neglected home. Barns attached to rural properties are also great breeding grounds for fleas.
Their life cycle
Fleas begin their lives as eggs, laid in batches of around 20 a time primarily on the body of a dog, though these can fall off onto bedding, carpets or a sofa. A period of between two days to two weeks will pass before a worm-like larvae will hatch, feeding on any organic material it can find nearby. While in this stage of their lifecycle, fleas will avoid brightly lit areas of your home and will seek out dark places to hide.
After one or two weeks have passed, the larvae will weave a cocoon similar to that of a butterfly, and spend a week pupating before hatching as an adult. They will immediately try to find a meal of blood and then the cycle begins again.
Fleas and your pet
Even if you are very vigilant with preventing your dog from coming into contact with other animals while out on walks, they can still pick up fleas from other sources. You can even bring them into your home on your shoes. Some dogs are good at hiding mild infestations, so carry out regular checks when possible.
Why do they pose a threat to your dog?
Other than the itching and irritation, fleas can also cause your dog other forms of discomfort. Flea larvae can feed on tapeworm eggs, thus making the flea a carrier of the parasite. As your dog grooms, it can ingest the parasite and become infected itself. The tapeworm will attach itself to the wall of the dog's intestine, before shedding eggs that pass through and out its body to be eaten by more larvae, thus continuing the cycle. Therefore any dog treated for fleas should also be checked for tapeworms.
Some dogs are allergic to flea's saliva, which can lead to skin diseases and painful itching. Instead of receiving small 'bug bites', they will develop dermatitis that cause severe discomfort and - when your dog itches and bites at the spot - can lead to infection. Severe infestation can also cause anaemia, which can cause lethargy and loss of appetite.As well as the risks to your pets, fleas will sometimes feed on human members of your household, including children. While dog fleas can't live on humans, they can still bite you and cause itching.