Fleas

Fleas are a type of wingless parasite found worldwide. They feed off the blood of humans and animals such as dogs and cats. Because fleas use a wide range of hosts, diseases can be passed from one host to another.

Fleas are known to transmit tapeworm larvae and, uncommonly, the disease murine typhus. They are most notorious for transmitting bubonic plague from wild rodents to humans in certain parts of the world.

The three main species that bite humans are the cat flea, the dog flea (Ctenocephalides canis) and the human flea (Pulex irritans). The cat and dog flea are the most common.

Symptoms of a flea bite#

A flea bite is intensely itchy, and secondary infections caused by scratching are common. Typical features include:

• It is extremely itchy.
• A red, swollen weal develops within about half an hour of the bite.
• After a day or so, the weal (lump) may develop into a blister or small wound.
• The legs and feet are often targeted.
• Secondary infections caused by scratching are common.

Some people may become hypersensitive (very sensitive) to bites.

Physical characteristics of the flea#

A flea:

• Is wingless, oval shaped and around 2 to 8 mm long.
• Is light to deep brown in colour.
• Has a disproportionately small head.
• Has six legs, including large hind legs that let it jump long distances.

Adult fleas can survive for some months without feeding.

How fleas feed and breed#

The flea uses its saw-like mandibles (jaws) to cut through skin, usually on accessible parts of the body such as the legs or feet. Its saliva contains anticoagulants that keep the blood flowing.

Female fleas are prompted to lay their eggs after feeding. The eggs are light coloured and oval shaped, and the larvae cocoon themselves within weeks of hatching.

Vibration, such as footsteps, prompts adult fleas to emerge from their cocoons. This is why you may be bitten after entering a house that has been unoccupied for some time.

Household pets and fleas#

Dogs and cats are common “reservoirs” for fleas. Your pet may be irritated by flea bites and scratch often.

Check for fleas by parting the fur, particularly around the ears and rump, and look for the fleas themselves or for flea faeces. Flea faeces look like minuscule dark specks. For a positive identification, place a few specks on a piece of lightly moistened white tissue - flea faeces will leach a ring of blood into the tissue.

Treatment for flea bites#

Suggestions to treat flea bites include:

• Resist the urge to scratch.
• Wash the bites with antiseptic soap to reduce the risk of infection.
• Apply an icepack frequently to help relieve swelling.
• Use calamine lotion, anaesthetic creams or similar to ease the itching.
• Ask your pharmacist for advice on suitable antihistamine medication to reduce swelling.
• Seek treatment for possible tapeworm infection, since fleas can transmit this parasite through their bite.

See your doctor if symptoms worsen or if a secondary infection develops (shown by a discharge of pus from wounds).

Treating your pet for fleas#

Infested animals should be treated every two weeks for several weeks. Suggestions include:

• See your veterinarian for a range of suitable flea-killing products. Options include tablets the animal swallows, and solutions or powders applied to the fur.
• Treat your pet for tapeworm, since fleas can transmit this parasite through their bite.

Treating your house for fleas#

Some general suggestions for eliminating fleas yourself include:

• Clean animal bedding and the general surroundings thoroughly.
• Vacuum the carpets. Throw away the vacuum cleaner bag, since it will contain fleas and eggs, or spray a surface spray into the bag.
• Use a suitable spray or “flea bomb” in your house, taking care to follow the label directions carefully.
• Treat outdoor areas your pet uses often, such as kennels, with suitable insecticides. Wear gloves and long-sleeved protective clothing as instructed on the label.
• Repeat the procedure once or twice, since flea eggs can survive for some weeks.
• Maintain good hygiene practices, such as regular vacuuming and keeping pets free of fleas, to prevent another infestation.

Professional flea control#

A persistent infestation may need to be treated by a qualified pest control operator. A licensed operator can determine the type, source and extent of the infestation, then use registered insecticides to control the fleas. Good hygiene practices, such as frequent house cleaning, should reduce the risk of further infestations.

Key points#

• Fleas are known to transmit tapeworm larvae and, uncommonly, the disease murine typhus.
• The three main species that bite humans are the cat flea, the dog flea and the human flea (Pulex irritans).
• The cat and dog flea are the most common.
• A flea bite is intensely itchy, and secondary infections caused by scratching are common.

Where to get help#