What are hitchhiker fleas and where do they come from?

For us pet parents who flea-treat our pets regularly or who have an indoor-only cat, finding a random flea or two can be odd. How did they get there? What’s going on? We’ve asked the FRONTLINE® pet experts for the lowdown – and if there’s anything we need to do in this situation.

1. Fleas come from the environment, not directly from other pets

Some people think fleas jump from one animal to another. This isn’t true. A flea can happily live on one host for its whole life – why bother moving when it’s already got a seemingly endless source of its favourite food (that is, blood)? 

Instead, fleas are picked up from infested environments where flea life stages are scattered. Untreated animals (cats or dogs, or wildlife like hedgehogs, rabbits and birds) infested with fleas will be dropping flea eggs wherever they go. New fleas will eventually hatch out to find a blood meal. 

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2. Fleas can hitch a ride on pets as well as people

Fleas hatch out when they detect the movement, warmth and carbon dioxide of a new host. That can be a pet, another animal or a person. 

We or our outdoor pets can pick up these hitchhiker fleas from any infested environments we visit or walk through, such as gardens, parks and fields. Tiny flea eggs and pupae can also be brought into the home on our shoes or clothing.

3. Most fleas aren’t interested in us humans

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The good news is that fleas won’t live on us. They’ll give us a bite to check us out, but they won’t hang around for too long. 

The bad news is, they can hang around for long enough to come into our homes. If there’s not a suitable host at home (a pet), the flea will eventually die. But if they sense another animal…

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4. Fleas will find their way to a pet if they possibly can

Fleas will sense a pet’s presence and jump onto them, looking to have a feed, breed and complete their life cycle. And it only takes two fleas to start a much bigger problem – each female flea can lay up to 50 eggs a day. That’s how untreated pets get infested.

5. Flea-treating all pets puts a stop to hitchhiker fleas

Pet experts recommend all pets are regularly treated with a suitable flea treatment. Of course, indoor cats are less likely to get fleas than pets that go outside and directly pick up fleas from infested environments. However, as this information shows, it’s still possible.

With regular treatment, newly arriving hitchhiker fleas will be killed quickly – within 24 hours of jumping onto treated pets if you’re using FRONTLINE PLUS® or FRONTLINE® SPOT ON, or 6 hours when using FRONTLINE TRI-ACT®. This breaks the flea life cycle, helps prevent an infestation and gives pet parents real peace of mind.

So now you know how fleas can end up on pets whether they’ve been treated or not, and whether they go outside or not. Fleas will always be around in the environment, and they’ll always be looking to feed. It’s just part of life and it doesn’t mean our homes or pets are ‘dirty’. It just means us pet parents need to be aware of the problem and protect our cats and dogs so they can carry on enjoying their life.

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