Pet ownership and animal assisted therapy have become an increasingly common means to improve the physical health and wellbeing of people, including those with social and psychological conditions (Wells, 2009; Beetz et al, 2012). Like any other vertebrate animals, pets can be subjected to infection by a range of internal and external parasites, which can lead to adverse consequences on their health and welfare. The impact of parasites can extend to pet owners when their pets harbour zoonotic parasites. Individuals with compromised immunity are at high risk of infection and should avoid direct contact with infected animals. Preventative parasiticide treatment should therefore be used together with implementing environmental and hygienic measures to ensure the safety of pet owners. Rapid and hygienic disposal of dog faeces, covering sandpits and fencing off play areas, regular monitoring and safe removal of ticks, regular washing of pets' bedding and vacuuming of areas frequented by pets, as well as good hand hygiene and thorough washing of fruits and vegetables before consumption, are among the protective measures recommended by Wright (2017) to reduce the zoonotic risk of parasites.
Spectacular advances have been made during the past decade on the professional (improving knowledge and awareness) and industrial (providing many effective diagnostic and therapeutic products) levels to protect both animal and human health. However, there is a growing concern over the environmental impact of parasiticides, although a multitude of other sources contribute to the environmental contamination of the ecosystem. The role of veterinary professionals in ensuring the responsible use of parasiticides is often emphasised in any parasite prevention and treatment recommendations. However, pet owners and professional associations are also integral stakeholders of the responsible use of parasiticides. This article briefly summarises the important role of each of these stakeholders in supporting the responsible use of parasiticides in pets.
A multi-level approach to enforce responsible use of parasiticides
Pet owners
The high risk to pets and their owners of parasite infections does not seem to be paralleled by the appropriate level of knowledge of pet owners. For example, most pet owners are unaware of the risk of pet animals getting fleas from gardens and parks. Even indoor pets can be infested by fleas carried into the home on clothing or other materials, or from stray animals. Most pet owners do not realise that pets can pick up ticks while walking in long grass and vegetation where ticks wait to latch onto any passing by host. Better understanding of the veterinary and public health impacts of flea and tick infestation will help pet owners to recognise the importance of keeping their pets protected. Pet owners' knowledge of parasitic infections can also affect their perception of the efficacy of parasiticides and expectation of the success of antiparasitic treatment. In addition to good knowledge and awareness, pet owners' engagement and adherence to treatment recommendations provided by the veterinary team is required to achieve the desired treatment outcome and effective parasite control (Wong et al, 2021). This will ensure a rapid and successful treatment, which in turn reduces dosing frequency and unnecessary overuse of parasiticides. It is important for the veterinary practice staff to identify the causes of parasite treatment failure, particularly those attributed to poor or inadequate medication adherence, and to address those issues with pet owners. Recommendations have been proposed for maximising pet owner adherence to parasiticide treatment prescribed to their pets (Biggle, 2016; Elsheikha, 2016).
Veterinary professionals
The blanket treatment approach, and unawareness, inadequate knowledge, or inability of veterinarians to follow policies and guidelines recommended for the responsible use of parasiticides, are among the factors that exacerbate over-prescribing of parasiticides. Additionally, many parasiticide products are available over the counter (OTC) without prescription and pet owners can purchase them from supermarkets and pharmacies. The European OTC parasiticides market is calculated at USD 347.4 million in 2021 and is estimated to continue its growth with a projected revenue of USD 634.8 million by the end of 2031 (Research Nester, 2023). These are some of the challenges that require the involvement of veterinary professionals to promote the responsible use of parasiticides.
Professional organisations
Because most pets are at risk of acquiring parasite infections, using parasiticides to treat and prevent parasite infections is essential. However, it is important to know when the treatment is needed and would be beneficial for the pet, and whether the benefits outweigh any potential risks of adverse events (Copland and Elsheikha, 2021). The British Veterinary Association (BVA), British Small Animal Veterinary Association (BSAVA) and British Veterinary Zoological Society (BVZS) have voiced their concern regarding the parasite control practice involving ‘blanket-treatment’ and called for more responsible use of parasiticides to limit the risk of resistance developing and minimise the environmental impact (BVA/BSAVA/BVZS, 2023).
The European Scientific Counsel for Companion Animal Parasites (ESCCAP) UK and Ireland developed guidelines based on the understanding that the use of antiparasitics as preventatives differs based on the circumstances and needs of individual pets. These guidelines have been designed to arm veterinarians and pet owners with evidence-based advice to make an informed decision about the most appropriate use of parasiticides.
Despite the potential benefits of the individualised treatment approach, many barriers to its implementation have been identified in recent articles (Bagster and Elsheikha, 2022a; 2023a; 2023b). The recent analysis of the challenges associated with adopting a risk-assessment-based parasite control approach is undeniably important and highlights the need for investigation of the potential modifiability of the behaviour and perception of veterinarians to improve responsible use of parasiticides and achieve more effective parasite control. It is possible that veterinarians' opinion of risk-assessment-based parasite control will change as new data emerge.

The dual benefits of testing
The last few years have showed us that pets are more than ever susceptible to exotic parasitic diseases, which are emerging at a rapid pace (Bagster and Elsheikha, 2022b; Wright and Elsheikha, 2023). To protect pets from acquiring exotic parasite infections, the BVA and ESCCAP UK & Ireland recommended measures to be taken, including using more diagnostics to recognise and detect exotic infections in travelling pets before and after arrival in the UK. More use of diagnostics will not only help in limiting the risk of exotic parasites establishing in the UK but will also be important to guide treatment and minimise potential zoonotic exposure. Rationally, timely and correct diagnosis is the cornerstone of effective treatment and management of parasitic infections in pets. Routine testing can be used to monitor for product efficacy and verify if treatment frequency is sufficient (Wright, 2023). The economic benefits of routine testing have not been evaluated and ascertained yet. However, the utility of routine testing may gain popularity among small animal practices if future studies can demonstrate that the clinical benefits offset any added cost.
Conclusions
The burden of parasite infection can be considerable due to its adverse effects on animal health and welfare, and the associated socio-economic implications. Emerging parasites can impose additional risks to pet animals and public health. Therefore, effective parasite control is critically important for the health and welfare of companion pets and their owners. Although debate remains regarding the effectiveness of routine testing and risk-assessment-based parasite control, there is a growing sentiment that these approaches could bring a paradigm change in parasite management. The quest for optimal parasite control continues; however, it is fraught with challenges. Overcoming these challenges requires a multi-pronged approach to improve the quality of pet health care, while preserving the efficacy of the mainstay component of parasite control; the parasiticides. While concerns around the environmental impact of parasiticides require attention, questions remain unanswered regarding the real effect of parasiticide products on the ecosystem.
KEY POINTS
- Parasiticides are life-saving medications and a major contributor to better health and quality of life of pets.
- Improper use of parasiticides may lead to poor clinical outcomes and increase the risk of medication resistance.
- Responsible use of parasiticides can limit the risk of resistance developing and minimise environmental impact.
- Guidelines are available to veterinary professionals to improve parasite control.
- More work is needed to improve veterinarians' understanding of and attitudes towards risk-assessment based parasite control approach.
- Routine testing can reduce the risk of exotic parasites and monitor the efficacy of parasite control strategies.