Pepsi started to itch last week. He was using his hind leg to scratch the back of his neck, and he nibbled at his lower back with his teeth.
When Leona had a closer look, she could see fleas crawling around in his coat. Leona realised that the only answer was to get rid of the fleas, so she headed to a local pet shop.
She was sold three products: a shampoo, a flea collar and a spray for her house.
She was told to leave Pepsi outdoors for two weeks. Leona carried out the instructions as best she could: she gave Pepsi a shampoo, put on the flea collar, and sprayed his bed, but she didn't feel that it would be right to put him outside when he was used to being an indoor pet.
A day later, Pepsi was still itching as much as ever, and Leona could still see fleas moving around in his fur, so she decided to bring him to the vet.
The first thing I did was to check up on the details of what Leona had bought in the pet shop: I needed to work out why the fleas were still there.
I checked the small print on the various items, so that I could explain to Leona exactly what she had bought. The shampoo was just a coat cleaning shampoo, with no active ingredients that would kill fleas.
The flea collar, in contrast, contained a potent organophosphate that was originally developed as a nerve gas in the Second World War. Flea collars of this type were banned in France two years ago, after the authorities decided that the risk of human toxicity was too great.
The flea collars are still for sale in the UK and Ireland, but perhaps this is why Leona had been advised that Pepsi should sleep outside.
The spray for Leona's house contained a knock down flea killer, but crucially it didn't include a chemical to prevent flea eggs from hatching out: without this extra ingredient, Pepsi could be assaulted by a wave of newly-hatched fleas in a few months' time.
Flea eggs can incubate for up to nine months before hatching, so the best household flea sprays leave a residue that lasts for a year, preventing new fleas from appearing.
Now that Leona understood exactly what products she'd bought, she was curious: how come the powerful organophosphates had not eradicated the fleas? I was able to answer this: the pet shop assistant had not asked Leona about other animals in her household.
Leona also owns a cat called Molly who was probably harbouring fleas that were then hopping onto Pepsi.
Dog and cat fleas are equally happy to infest both species of animal. There's no point in just treating one animal in a multi-pet household: to eradicate fleas, all pets need to be treated at once.
Leona left my clinic with three new products. First, a safe and effective spot-on flea drop for Molly the cat. Second, a household flea spray that would stop flea eggs from hatching for a full year. And third, a new, safe, highly-effective flea treatment for Pepsi.
It's a tasty tablet that he took straight out of my hand, containing a long-lasting chemical that will continue to kill fleas and ticks for three months.
When I phoned Leona a couple of days later, she had good news for me: the fleas had finally been fully eradicated from her home and her pets.
Pepsi had stopped itching. And he hadn't even had to endure the cold and stress of being banished outdoors.
Owner: Leona Rowley from Bray
Animal: Pepsi, her two year old Jack Russell Terrier
Problem: Pepsi picked up fleas and they were not easy to eradicate
> Fleas are common in Ireland all year round in dogs and cats, with both species sharing them.
> A range of products is available to eradicate fleas from pets and houses
> Vets often stock the safest and most effective flea control methods