Fleas are parasitic insects of the order Siphonaptera with more than 2,000 species recognised all over the world. Most household flea infestations are usually caused by dog fleas (Ctenocephalides felis), cat fleas (Ctenocephalides canis), and human or rat fleas. Cases of bad rodent infestations might also cause a flea infestation.

Table of Contents

  1. What Does a Flea Look Like?
  2. General Facts About Fleas
  3. What Do Fleas Eat?
  4. What are the Signs of Flea Infestation?
  5. Are Fleas a Health Hazard?
  6. Pets and Flea Infestation?
  7. Do Flea Collars Work?
  8. How Can I Prevent Flea Infestation?
  9. How Can I Get Rid of Fleas?
Fleas Control in London

Adult fleas are tiny (about 1 - 2.5 mm in length, depending on the species), and their bodies are thin and flat for better movement through an animal's fur. They have mouthparts which are used to extract the host's blood and depending on whether they have fed or not, they appear from yellowish to dark brown in colour.

Fleas are wingless, however, they can jump large distances - a hundred times their height, because of their six long legs. This is also the reason why it is so difficult to catch and kill fleas by hand and why typically they require some kind of chemical or professional pest treatment.


Fleas are parasites which survive solely on blood extracted from their host, typically a warm-blooded animal. They attach themselves to and live on their victim. With no host to provide food, a flea's life might be as short as a couple of days. How Do You Get Fleas? Flea infestations usually stem from pets, so in households, with animals, a flea infestation is a very probable occurrence because animals can get fleas from anywhere outdoors. However, it isn't impossible to have fleas if you do not own a pet. Other reasons might be:

  • the previous owner or tenant of the property had flea-infested animals;
  • the fleas are brought by another pest you might be harbouring, such as rats or mice;

The interesting thing about the lifespan of fleas is that it is heavily dependent on the conditions. A flea can live for one week to up to twelve months. Normally an adult flea lives for two to three months. If there is a huge lack of food supply a flea can only survive for a couple of days. The conditions needed for this pest to thrive are:

  • warmth
  • food source
  • humidity

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Checking your pet should be the first thing on your list to determine if you have a flea problem. Excessive scratching, reddened skin, loss of hair and the presence of live fleas on the head and neck areas, which are most targeted, are all signs of flea infestation. Sometimes you might not find an actual flea on your pet's coat, but you might find other signs of their presence like flea dirt or eggs. Flea larvae and pupae are found in and around areas where pets are spending time active or sleeping. Other signs of flea infestation include flea bites - most commonly on legs and arms resulting in red itchy spots - which occur in cases of large flea infestations.

Historically, fleas have posed a great threat to public health - spreading plagues and viruses. Today, fleas are mostly just annoying biting pests of both humans and animals. Severe cases of flea-infested animals often result in dermatitis. Catching a virus or disease because of cat, dog or human fleas is highly unlikely. However, there are species of fleas that are a risk to human health worldwide, such as the Oriental flea (Xenopyslla cheopis) which is a parasite of rats, but gladly feasts on humans. So if your infestation is not due to a flea-infested pet and you do suspect you are also harbouring a rat infestation - immediately contact a local pest controller.

If your animal companion becomes infected by fleas you should take immediate action. The fleas life cycle consists of rapid reproduction rates, which means your home can become heavily infested in no time. Fleas lay eggs on your pet (up to 50 eggs per day), then fall off to contaminate every part of your home. In addition, flea dermatitis occurs very often in companion animals such as cats and dogs as a result of ignoring and overlooking a flea problem.

Unfortunately most commercially sold flea collars are not effective with current flea infestations. Aggressive and professional flea treatments are necessary to combat an infestation due to their fast reproduction rate, small size and jumping abilities.

You can prevent flea infestation by regularly treating your companion animal for fleas. Your veterinarian can suggest a wide variety of treatments, with options for long-term effects for a full month.

Flea control can be difficult and complicated, especially if you have decided to do it yourself. Only treating the source of the infestation, such as an infected pest is not sufficient and an infestation will re-occur.

The same applies to "alternative" or natural flea treatments, which are not aggressive enough to actually repel these parasites plus they have no effect on flea larvae and pupa. Adult fleas comprise only 5% of the total flea population, which makes their eradication very tough. An adequate description of all the factors of carrying out flea control is beyond the scope of this section.

However, there are numerous control products ranging from different ingredients to different methods of application, so we recommend consulting with a veterinarian and a professional pest control company regarding which products and approach are suitable for your circumstances of flea infestation in the home, yard or barn. To completely get rid of fleas, combine a pet flea treatment with a professional pest flea treatment for your property.

Infestation Facts on Other Household Pests

  • Ant Infestation
  • Bed Bugs Infestation
  • Cockroaches Infestation
  • Mice Infestation
Ants are a common pest in our homes. If you want to learn more about this menace and how you can and should treat them. Read more on our ant infestation page.
The terror that is sleeping in your bed. This little blood sucking house pest could be in your mattress without you even noticing it. Learn more about the bed bugs and how to spot a bed bug infestation.
A pest that you don't want to spot in your kitchen. The cockroach can quickly take over your home, especially at night. Learn some interesting facts about the roaches, and how to spot the signs of cockroach infestation on time.
The house mouse is a small rodent coming inside of your home to steal your food and nest. The reproduction rate of this pest is quite impressive. Get to know mice and learn how to quickly spot mice infestation signs, before it is too late.

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