Cat flea

The flea is a small parasitic insect that feeds on the blood of birds or mammals. There are about 2000 species of fleas worldwide but by far the most common is Ctenocephalides felis; known to millions of its long-suffering victims as the cat flea. Despite the name, the cat flea does not just infest just cats, though the unfortunate feline is indeed the fleaís diet of choice. But the cat flea will also happily dine on a domestic dog, raccoon, opossum, weasel, brown rat or domestic rabbit. And as the cat, dog and rabbit come regularly into contact with humans, so does the cat flea. Although cat fleas canít easily live on human blood, that does not stop them trying, especially if for some reason the usual hosts are not available. Many humans only discover that their cat has fleas when the cat goes away (for example for an extended stay at the vet) and the fleas in the carpet start looking for alternative meals.

A small number of fleas on a healthy cat generally cause little harm unless the cat becomes allergic to substances in the flea saliva. Flea Allergy Dermatitis (FAD) has symptoms which include redness, bumps, pustules (pas-filled bumps), scabs and in severe cases, hair loss in the affected area. Cats with FAD may also have secondary skin problems; for example feline eosinophilic granulome (skin lesions filled with infiltrating eosinophilis); miliary dermatitis (characterised by a widespread skin lesions) or self-inflicted alopcia (hair loss due to over-grooming). Or to put it bluntly, a cat with FAD will feel and look terrible, with bald patches and open sores on the skin.

How do cats get fleas?

Despite popular belief, fleas donít get around by direct animal to animal contact; or at least not often. Once a female flea finds a suitable host it settles in with the intention of staying there for life - which is generally several weeks. Once it meets with male fleas who hang around the same cat, the female flea starts laying eggs at an average rate of about one an hour (Though a female flea at peak production can reach 50 eggs per day.). The eggs are designed to be easily dislodged from the fur, and fall on on to where ever the cat is at that moment - a carpet, your bed, sofa or so on. These tiny eggs are too small to be seen by the naked eye.

The eggs will lie like little time bombs for about 21 days. Then they burst into larvae. Like true creatures of the night, flea larvae hate the light and seek out the dark, which is one reason why they love carpets and bedding. Depending on external conditions such as temperature, food availability and moisture the development of the larvae takes from between a few days and several months. During this time, the larvae feed on a variety of organic material, often adult adult flea frass (feces), which is shed with the eggs. This rather disgusting diet is in fact highly nutritious as it contains 90% of the protein from the blood of the cat it originally came from.

After maturing through several stages the larvae spin a cocoon for pupation. The creature which emerges from the cocoon is a mature flea determined to find a host as soon as possible. It homes in on body heat, and is ready to feed on blood within 48 hours. And so the cycle repeats.

As a general rule, mature cats seem to control flea infestations better than young animals. This may be related to better grooming habits, since an actively grooming cat can reduce her flea load by about 50%. (Which is not necessarily good news for other mammals in the immediate vicinity.)

Controlling flea infections

As usual, the best control is prevention. There are many ways to protect your cat from fleas. These range from flea collars and powders to spot-on products and more. There is also a large array of products available over the counter. But not all of these are suitable for cats. Be especially wary of formulas intended for dogs. These may well contain the insecticide permethrin, which is safe for dogs, but is highly toxic to cats, even at puppy-sized doses.

Flea collars are often used by people with outdoor cats. These may not always be the best option, as flea collars can cause skin irritation on the catís neck, or even hair loss. Also unlike normal cat collars, many flea collars are not elasticated and donít have a quick release mechanism. So if the collar gets caught on something like a tree branch, the cat might have great difficulty getting free. Do your research and pick a flea collar with care.

Flea powders also have issues. They are only effective when actually on the catís skin. Cats spend a lot of time licking and grooming that skin. They can easily swallow flea powder and enough of that can be toxic. One should look for better and safer methods to control fleas.

Spot-on treatments are medications in liquid form which are dabbed on the cats skin. The target zone of preference is the back of the catís neck. This is the hardest place for cats to groom, and since few cats appreciate the care their humans are giving them, they will certainly try to groom it away. From the scruff of the neck the medicines in the drop will slowly spread through the cat's skin, killing both fleas and their eggs in the process.

These drops are prescription medications, so you will need to get them from a vet. There are a number of formulas available, and they protect the cat not only from fleas, but also other parasites such as ticks. Although more expensive than most over-the-counter treatments, spot-ons are definitely the better choice in most circumstances, and are very easy to administer as well. Check with the vet whether a spot-on is right for your cat.

Other possible treatments are pills or injections. These are also by prescription and the cost will be similar to that of spot-on treatments. The pills have to be administered monthly. The injections are given every six months, generally at the vet's. This treatment doesn't directly kill the fleas, but rather prevents them from reproducing. Injection usually takes longer than other methods since it requires the fleas already on the cat to die from old age.

If your cat already has fleas, your house will have to be decontaminated, or reinfection from larvae is inevitable. Everything the cat had contact with has to be washed (and in the average house this usually means everything except - possibly - the light fittings). All carpets will have to be treated, for example with flea powders designed to be sprinkled onto the carpet prior to vacuuming. Other treatments are available from professional carpet cleaners and exterminators. These will generally destroy flea eggs as well as adult fleas.

Flea activity is most intense during summer months. A disadvantage of centrally-heated houses is that fleas can survive all year round. On the positive side, central heating helps to keep down damp, and larvae do not thrive in an arid environment.

Note: This information is for guidance only. It is not intended to replace consultation with a licensed practitioner.

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