Q&A: Why parasite risk looks different than it did 15 years ago

Ticks and other parasites are on the move. Christopher Lee, DVM, MPH, DACVPM, DACVM (Parasitology), discusses the role of climate change and animal movement in expanding parasite ranges and explains practical steps clinicians can use to protect pets and people. He also makes the case for year-round use of isoxazolines and for keeping parasites on the differential list even for indoor pets.

RELATED: Why year-round isoxazolines are important for flea and tick protection

Editor’s note: This dvm360 Q&A has been lightly edited and consolidated from a verbal interview to better fit a written format while retaining the substance of the original conversation.

Are ticks expanding their territory and should clinicians be worried?

Lee: Yes, ticks are expanding. They are remarkably well designed and have not changed much over millions of years. Their range was limited by ice ages in the past, but climate change is opening up new areas for them. Movement of wildlife and birds also carries ticks long distances. Many ticks do not move far in their lifetime, so who they attach to determines where they end up. As deer populations expand, we see Lyme territory expand too. We even have millions of foreign ticks being introduced into the U.S. every year.

What about all the pathogens beyond Lyme?

Lee: Lyme is on a lot of people’s radar because humans know the name, but other veterinary pathogens are less recognized. Ticks in their nymph or larval stages are tiny and easy to miss. A lot of owners do not realize their pet is hosting ticks until someone finds one in a surprising place. Clinicians should be talking to clients about year-round protection, especially with products that reliably kill ticks. If you are in the US, putting patients on an effective product year-round makes detection and prevention much easier.

You mentioned fleas in houses and human risk. How do you approach that with clients who are used to seasonal protection?

Lee: Flea infestations are often driven by juvenile stages in the home. Once established, it can take weeks or months to control. I explain to clients that prevention is not only for the pet but also for them. In Southern California we have had human outbreaks like typhus linked to fleas. I know somebody who developed severe disease after a single flea bite and was hospitalized. If pets are on year-round isoxazolines and a flea exposure occurs, those fleas are killed quickly and the risk to people falls dramatically. Waiting until there is a visible problem often means months of household exposure.

Are isoxazolines also helpful for ticks and mosquitoes?

Lee: Isoxazolines have strong activity against fleas and ticks. Many clients use over the counter repellents thinking that is enough. Some repellents can stun or knock ticks down only for them to recover later and then seek a new host, including people. For mosquitoes, keeping dogs and cats on isoxazolines reduces the number of biting insects that survive contact with the pet. That lowers the chance of mosquito borne disease, and it also reduces nuisance biting.

What about indoor pets that never go outside? Do they need parasite protection?

Lee: Yes. The world is smaller than we think and nature brings pests to our door. Cockroaches, flies, rodents and other vectors carry parasites and pathogens into homes. Indoor pets can still be exposed via those routes. I treat indoor animals as candidates for prevention and keep parasites on the differential list when they have compatible signs.

Any memorable messages you use to get clients to comply?

Lee: I use simple, sticky messages. One that resonates is calling pets “indoor bug zappers” when they are on isoxazolines. That image helps clients understand the personal and household protection they gain. Short, memorable phrases often drive better adherence than long lectures.To read more news and view expert insights from Fetch Long Beach, visit dvm360’s dedicated site for conference coverage at https://www.dvm360.com/conference/fetch-long-beach