Spot-on parasiticides have transformed parasite control with a practical and easy way to protect pets against parasites, and they remain an essential part of prophylactic care and treatment for many dogs and cats.

However, recent research has highlighted that some of the active ingredients contained in these products can enter the wider environment. This has prompted veterinary organisations to review how these medicines are prescribed and used. Overall, the current guidelines are not to stop parasite prevention, but rather to use as little as possible but as much as necessary through a personalised, risk-based approach for each pet.

Here we look into what responsible use means and how owners can work together with their veterinary team to make informed decisions.

What are spot-on parasiticides?

Spot-ons are medicated liquid treatment for pets to protect against ectoparasites such as fleas, ticks, mites and lice and some cover for some internal parasites as well. Some of the most common active ingredients include:

• Fipronil

• Imidacloprid

• Selamectin

• Moxidectin

• Fluralaner
  

Why are spot-on parasite treatments important?

Responsible use does not mean avoiding parasite prevention. Parasites can cause serious health issues for pets. Flea infestations can cause not just itching but also anaemia and flea allergy dermatitis. Tick bites can become infected and also put your pet at risk of serious parasite-borne diseases, and mites can cause mange.

It is not just our pets that are protected, use of parasiticides can also protect people. Some parasites can affect both animals and people.  So stopping our pets from bringing them into the home protects vulnerable family members (like young children or people with weakened immune systems) from becoming the next host.

Parasiticide treatment as a preventative medicine is less intensive and more effective than treating established disease.

Why has responsible use become such an important topic?

Environmental contamination

Current evidence has found parasiticides in waterways, which may have a potential effect on aquatic invertebrates. These parasiticides have the potential to be transferred from treated pets into the environment. Possible pathways include:

• Swimming

• Bathing

• Wastewater

• Fur shedding

• Pet bedding
  

The One Health approach

Research is still evolving and is continuously being explored to get further insight into the exact causes and how best to adapt guidelines and practice to minimise risks.

The One Health approach brings together several disciplines, including areas in:

• Animal health

• Human health

• Environmental health

Together, they collaborate to achieve sustainable improvement for the health of all of them. With all disciplines working together, issues such as responsible parasiticide use can be navigated more thoroughly and effectively.

Appropriate prescribing of these medications protects these medicines for the future. There are concerns about the possibility of resistance developing against these active ingredients, so using only a risk-based approach in targeting treatment not only avoids unnecessary treatments but can also reduce the risk of resistance developing.

What does a risk-based approach mean?

Rather than recommending the same parasite treatment schedule for every dog and cat, veterinary professionals now take a risk-based approach. This means assessing each pet’s individual lifestyle, health and environment before deciding whether parasite prevention is needed, which parasites to target and how often the treatment should be given.

The aim is to use parasite treatment only when they are likely to provide a meaningful benefit, while continuing to protect animal welfare, public health and the environment.

Your pet’s lifestyle

How your pet spends their time can have a big impact on their parasite risk. Your vet may go through some questions such as:

• Are they indoors or outdoors

• Does your cat hunt

• Do they walk through woodland or long grass regularly

• Do they enjoy swimming

• Do they visit kennels, catteries or grooming salons

• Does your pet regularly mix with other animals

Pets that spend more time outdoors or have frequent contact with other animals are generally considered at higher risk of picking up parasites.

Location

Parasite risk can vary depending on where you live and travel. Your vet may consider:

• Local flea, tick and lungworm prevalence

• Urban or rural location

• Whether your pet travels within the UK or abroad

Household

Some parasites can affect people, so your household is also an important consideration. Talk to your vet about what is most appropriate if you have members in the household who are immunocompromised, elderly or very young and also if there are multiple pets within the home.

Your pet’s health

Your pet’s age and medical history can also influence the most appropriate treatment plan. Factors may include:

• Age and weight

• Existing health concerns, for example, history of seizures, allergies or kidney issues

• Current medications

• Pregnancy or nursing

• Previous parasite infestations or reactions to parasites or treatments

Finding the right balance

After considering all these factors, your veterinary team can recommend a parasite prevention plan tailored to your pet. Some pets may benefit from year-round protection, while others may only need seasonal or targeted treatments. The goal is to provide effective parasite control while avoiding unnecessary use of medicine, supporting both your pet’s health and the environment.

How can owners use spot-on treatments responsibly?

Here are some of the top ways to help use these medications responsibly at home:

• Use veterinary-recommended or prescribed products

• Apply exactly as instructed

• Dose accurately

• Never use dog products on cats

• Avoid unnecessary repeated treatment

• Store medicines safely

• Dispose of unused products correctly
  

Reducing environmental impact

The best ways to reduce the environmental impact of topical products are by reducing exposure to the waterways. Practical tips to help reduce this include:

• Avoid bathing soon after application

• Prevent swimming for the period recommended on the product label

• Allow the product to dry fully at the application site

• Prevent licking between pets after application

• Pick up your dogs poos

• Speak to your vet if your dog swims regularly, as other treatment options may be more appropriate
  

Are spot-on treatments the right choice for every pet?

While spot-on treatments are useful for their ease of application and effectiveness, there are alternative options if topical treatment is not suitable. Other options include oral tablets, chewable tablets, collars and even injectable treatments.

Treatment choice should always be made with your veterinary surgeon in order to find the best options for your individual pet's needs.

The bottom line

Spot-on parasiticides remain an important part of protecting many pets. Current veterinary advice focuses on using them only where they are likely to provide benefit. Following practical steps can reduce environmental contamination without compromising animal welfare.

The best parasite prevention plan is one tailored to your individual pet after discussion with your veterinary team. For further help and advice, please speak with one of our Joii vets who can give further guidance.