A mild winter and a forecast long hot summer will create perfect conditions for a massive flea outbreak this year, warns Bayer NZ vet Dr Kirstie Inglis.

"Pet owners need to start thinking about a flea control strategy now before numbers become out of control in the warmer weather," says Kirstie.

People and animals could be plagued by fleas this summer. Photo: Supplied.

If left unchecked, flea infestations could harm people, as well as cats and dogs. In rare cases there may be more serious repercussions such as bacterial infections or transmission of flea tapeworm, says Kirstie, and excessive scratching, nibbling or grooming by animals can often lead to bald spots.

Fleas feed by piercing the skin, injecting a substance that stops blood clotting and sucking up the resulting free flowing blood. Heavy infestations can produce life threatening anaemia in small kittens and puppies.

Flea saliva can also trigger severe reactions in allergic animals, says Kirstie.

"Few people realise that only about 5 per cent of the flea population lives as adults on a pet,” says Kirstie. "The remaining 95 per cent live in the environment as eggs, larvae and pupae which develop into adults.”

These concentrate around pets' sleeping areas and like hiding in carpets, cracks between floorboards and under debris in the garden.

Females lay up to 50 eggs per day, which then hatch into larvae that crawl into dark spaces, where they develop in cocoons.

"Adult fleas can then emerge from these cocoons in as little as eight days, usually in response to vibration from a pet walking past or by their body heat, and then jump onto a pet to start the cycle all over again.”

New adult fleas can take up to six months to leave their cocoons, so can spend a winter cycle indoors.

Flea populations boom when the weather favours a shortening of this life cycle. Temperatures between 21 degrees Celsius and 30C, and 70 per cent humidity can see the cycle shorten to just 12 days – rapidly building up an infestation thirsty for blood.

TIPS FOR TACKLING FLEAS

•Regularly clean pet blankets, beds, and throw rugs in a hot wash

•Vacuum furniture and car seats that can house pre-adult fleas, larvae and eggs

•Regularly vacuum the house, even wood flooring and tiles where eggs, larvae and pupae can be present. Dispose of the vacuum cleaner contents in a closed bag.