Parasite Prevention
We’ve got the products, tools, and education to combat parasites in pets. Now comes the hard part – better pet owner compliance.
Have we been too soft on pet owners? When it comes to parasite prevention, perhaps the education used and sense of urgency communicated could use a stronger tone, at least according to several experts Vet-Advantage reached out to on the subject.
“People and the animal companions we love are locked in an eternal battle against parasites and pathogens,” said Jay Tischendorf, DVM, veterinary services manager for Ceva Animal Health, LLC – USA. “If we truly care for our pets and want to provide them the best health and safest life, strategic, aggressive parasite management is among the most critical things we can do.”
But how does the industry go about that as a collaborative effort? And how can veterinarians gain more compliance in the products and services they offer to today’s pet parents? Vet-Advantage asked several industry experts for insights into the dangers pets – and pet owners – face with parasites, as well as the veterinarian’s role in effective prevention. Participating are:
- Dr. Doug Carithers, director of applied research and publications at Boehringer Ingelheim
- Kevin Holcombe, product marketing manager, PRN Pharmacal
- Dr. Scott A. Krick, technical service veterinarian – Companion Animal, Norbrook, Inc.
- Dr. Jenifer Sheehy, medical lead, canine parasiticides for Zoetis’ U.S. Petcare business
- Dr. Jay Tischendorf, veterinary services manager for Ceva Animal Health, LLC – USA
Boehringer Ingelheim
Best practices for reducing parasite burdens and keeping parasite populations under control
Vet-Advantage: Have trends like recent hurricanes, other natural disasters and increased adoptions contributed to the spread of parasites? If so, can you explain why?
Dr. Doug Carithers, senior associate director of applied research and publications at Boehringer Ingelheim Animal Health: Hurricanes and natural disasters do contribute to the spread of parasites, and we’ve been seeing this for years. As an example, when Hurricane Katrina hit New Orleans in August of 2005, it set many wheels in motion. Louisiana has been an epicenter for heartworm disease and gastrointestinal parasites, which Katrina exacerbated. The immediate threat following Katrina was all the water. Standing water created extensive habitat for mosquitoes, the intermediate host of heartworms, which allowed a massive mosquito bloom, and increased heartworm exposure in unprotected dogs. The same water and flooding also interfered with everyday life, of course, causing people to forget medications for their pets. Local services, including mosquito abatement programs, were also disrupted. In short, Katrina caused people to have to reprioritize everything!
The flooding and strong winds also displaced people and pets. People left New Orleans and moved with their parasite-exposed pets to new cities and states, exposing new locales to parasites previously found in south Louisiana. Unclaimed dogs from New Orleans, often having parasites, were collected, then relocated to locales across the U.S. and into Canada. Studies demonstrated the relocated parasite-positive dogs infected the local mosquito populations in their new home with infective heartworm larvae and seeding intestinal parasite eggs and larvae in yards and dog parks. The results of this “seeding” from dogs moved post-Katrina are still being seen 17 years later in the most recent study.
VAM: How are parasites dynamic and ever-changing?
Dr. Carithers: Parasites have been around essentially as long as the parasite hosts have existed, and throughout that time, selection and refinement of the parasites has occurred due to host responses and environmental pressures. The most significant changes that we are currently seeing are due to the pressure that humans put on parasite populations via animal management practices and parasite control programs.
Many think of parasites as individuals; however, it is imperative that veterinarians consider that the parasites exist in populations. Populations can be altered by external pressures, including inappropriate use of anthelmintics, which could select resistance in parasite populations.
VAM: Why are broad-spectrum preventative recommendations important for vets to make?
Dr. Carithers: Practitioners should strategically utilize broad-spectrum anthelmintics, striving to keep animals healthy and reduce environmental contamination. Less environmental contamination reduces the potential for animals and humans to be exposed to parasites. It is a fallacy to expect that parasites can be eliminated in their entirety, as most of these parasites have faced bigger threats than humans over the years, yet they continue to thrive. The best that we can hope for as veterinarians and medical professionals is to strategically use antiparasitics to reduce parasite burdens and keep parasite populations under control. Humans have tried but have never been able to eradicate any parasites; however, when we are diligent, we can control them. Broad-spectrum preventatives are an essential tool as they provide broad coverage, making compliance more straightforward and more convenient.
VAM: Why has there been an emphasis by many in the industry to reframe this as a One Health discussion beyond pet health?
Dr. Carithers: The lives of animals and humans are pretty interconnected, and when animals are healthy, humans are healthier too. The One Health discussion is a concept that illustrates for the masses the intricacies and subtleties of human interaction with animals and the environment. As we already alluded to, the environment has a massive impact on parasite populations, as well as the potential for viral and bacterial survival when outside a host. Human and animal wellness are also affected by environmental conditions (as are parasites); other components to consider are population density, sanitation, the proximity of animals to humans … disease spread and transmission, including zoonotic diseases. All need to be considered when making decisions for One Health.
For the sake of understanding, One Health can be described as a movie with plots and sub-plots to consider, but the movie never ends! Not taking a One Health approach is akin to deciding based on a single photograph or one view of a radiograph rather than considering all of the possibilities or angles.
VAM: What are the biggest barriers to client compliance right now when it comes to the use of preventives?
Dr. Carithers: The most significant barrier to client compliance is understanding. Everyone has been conditioned to expect immediate gratification with little effort, consideration, or explanation. The other day, I ordered an item online, and it showed up at my door 12 hours later, at 9 a.m. I am certain that everyone involved in processing this order considered and understood the process (but to me, it was damn-near magic). Even practitioners fall victim to the concept of, ‘that’s easy to fix … give this …’ The problem is that clients need to understand the process. Why are the medications given? How do the medications work? What happens if I miss a dose? What happens if I give too many doses? What is going on when medications appear to fail? Some medications have become so effective that we feel that they don’t need explanation; however, this is not the case. As medications become more and more effective, it is imperative that we use them appropriately and that we educate pet owners on the importance of compliance so that medicines can benefit us now and far into the future. Education is key!
PRN Pharmacal
Parasite prevention should have a family focus
Vet-Advantage: Why do parasite prevention discussions with pet owners need to extend beyond standard products like chewables and topicals?
Kevin Holcombe, product marketing manager, PRN Pharmacal: The main reason is today’s veterinarian focus is on pets only. The focus should be on a family that owns a pet. Since the launch of the lufenuron, adulticides, and isoxazoline drug class, veterinarians have focused solely on chewables and topicals. The ease and effectiveness of these products have changed pet owners’ and veterinarians’ approaches to parasitic control. They call it “a game changer!” The belief is that the problem has been solved. If this is the case, why has the number of tick-borne diseases in humans tripled?
Instead of being proactive, pet owners are acting reactively. They see a flea, and then they go to their veterinarian. The problem is when pet owners stop seeing fleas and discontinue treatment. They only apply as needed and not as directed. Within the life cycle of a flea, only 5% are adult fleas. The rest of the cycle is another stage. When the pet owner stops seeing fleas, they think the problem is solved. They don’t consider the 95% of eggs, maggots, and pupae that are still active in their home and yard.
Almost every article, either in print or online, mentions knocking down the pyramid of fleas. This is done by using short-term adulticides and long-term fluralaners or isoxazolines. There is no mention of treating the yard and home – the environment where 95% of the flea life cycle inhabits. Pet owners need to know that treating the yard and home is just as crucial to overall protection as treating the pet.
The veterinarian is the expert in this environment and yet sends clients to Home Depot or a grocery store to purchase yard and home sprays. The vet only focuses on the topicals because that is what they have been taught.
VAM: Why has there been an emphasis by many in the industry to reframe this as a One Health discussion beyond pet health?
Holcombe: Because pets are seen as part of the family. The status of the pet has climbed in the hierarchy of the home in the last 20 years. Pets are now indoor pets compared to what they used to be. People within the home now see fleas on a more personal level, with sightings in carpets and couches. The problem affects everyone in the home and not just the pet. That is why chews and topicals only treat the pet and not the whole family. Again, vector-borne diseases have tripled in humans.
VAM: What are the biggest barriers to client compliance right now when it comes to the use of preventives?
Holcombe: Education! Veterinarians are being taught to use isoxazoline class drugs for fleas and that is it. When questioned at trade shows and one-on-ones regarding what they use, they all mention the leading isoxazoline drug as their primary prescription. When asked what they do regarding the home and yard, they seem confused.
Norbrook, Inc.
Veterinarians must help pet parents “see” the risk of parasites
Vet-Advantage: Have trends like recent hurricanes, other natural disasters, and increased adoptions contributed to the spread of parasites?
Dr. Scott A. Krick, technical service veterinarian – companion animal, Norbrook, Inc.: Yes! Natural disasters such as severe weather and wildfire events result in the displacement of local human populations along with their pets. As a result, particularly in the case of hurricanes, populations of pets from geographies where endemic heartworm disease and internal parasites are more prevalent are introduced to geographies where the prevalence may be lower. This is particularly true for heartworm disease following some of the Gulf Coast hurricanes in recent years, where families were displaced inland, either temporarily or permanently, bringing with them heartworm-positive dogs which served as reservoirs for infection of resident populations. (See American Heartworm Society maps for specifics on heartworm range increase over time)
Whether there was truly an increase in adoptions related to the COVID crisis is still debated. Indeed, animals that find their way to shelters and then adopted homes often have increased risk of parasite burdens. In general, though, animal welfare groups are very cognizant of parasites and screen and strategically manage prevention and control.
VAM: Are parasites dynamic and ever-changing?
Dr. Krick: Both endo and ectoparasites appear to be increasing their ranges. The increasing average annual temperatures that many geographies are experiencing has created favorable conditions for a far greater portion of the year for parasite reproduction and spread in many areas. (Reference CAPC for prevalence data for many parasites). Additionally, parasites continue to develop resistance to parasiticides with exposure over time. This is not a new phenomenon but is relevant to control programs.
VAM: Why are broad-spectrum preventive recommendations important for vets to make?
Dr. Krick: The human population is increasingly mobile, and their pets are increasingly included in their travels. It is no longer sufficient to use preventatives specific to a pet’s anticipated “home geography risk.” It is increasingly challenging to predict which parasites any given pet will be exposed to, and the distribution for many parasite species is expanding. As a result, effective broad-spectrum parasiticides provide the most significant opportunity to prevent or treat and control those parasites to which any given pet may be exposed to.
VAM: Why has there been an emphasis by many in the industry to reframe this as a One Health discussion beyond pet health?
Dr. Krick: Scientists recognize that human health, veterinary health, and ecosystems do not exist in a “bubble.” The COVID crisis provided a glaring example of how animal reservoirs of disease can significantly impact human health. Many of the parasites and diseases common to animals can have devastating impacts on human health as well. Because the relationship between people, animals, and their environment has become inextricably intertwined, it is prudent to take a One Health approach in order to protect all three.
VAM: What are the biggest barriers to client compliance right now when it comes to the use of preventives?
Dr. Krick: It seems that everyone wants to blame the cost of preventives and treatments. Cost is undoubtedly one of the most significant barriers to client compliance. By providing less costly options, we increase accessibility to pet owners who are financially stressed. Equally important, though, in my mind, is education. I believe that veterinarians are acutely aware of the risks of parasites and the need for treatment and control. In spite of that, the veterinary industry may not have done the best job of conveying the severity of the risks or the consequences of complacency. What pet owners don’t “see,” they may not take as seriously. As veterinarians, we are obligated to appropriately educate the public about the risks and benefits of appropriate parasite control so that they understand the consequences of inaction.
Zoetis
A ‘sense of urgency’ needed for protecting pets
Vet-Advantage: Have trends like recent hurricanes, other natural disasters, and increased adoptions contributed to the spread of parasites?
Dr. Jenifer Sheehy, medical lead, canine parasiticides for Zoetis’ U.S. Petcare business: Animal relocation has increased dramatically in recent years. According to the ASCPA, their relocations went from around 500 animals in 2014 to a high of 42,000 in 2019.
Using heartworm disease as an example, we know these dogs often come from heartworm-endemic areas, and once they arrive in their new homes, they can become reservoirs of disease living among neighboring, susceptible pets. A study from 2012 showed that over 70% of mosquitos collected from the backyards of heartworm-positive dogs contained heartworm larvae. 1
As these pets are transported into northern states with historically lower heartworm prevalence, where dog owners and even some veterinarians perceive an overall low risk, there may be less emphasis on testing and prevention during vet visits.
VAM: How are parasites dynamic and ever-changing?
Dr. Sheehy: We can look at this question in two ways:
We have a much better awareness of the recent emergence of resistant strains of heartworm and of some intestinal parasites…
But we are also seeing dynamic adaptation to changes in climate. For example, as we have seen warmer, wetter winters in the Northeast, Lone Star Ticks have significantly increased their territory, crowding out some of the species that were historically more common. 2
VAM: Why are broad-spectrum preventative recommendations important for vets to make?
Dr. Sheehy: Market research has taught us that many dog owners struggle to understand what coverage products provide – mistakenly believing that a flea and tick preventative is also a heartworm disease preventative, for example. In one study, 53% of dog owners chose a product that covered flea/tick or heartworm disease but not both. 3
VAM: Why has there been an emphasis by many in the industry to reframe this as a One Health discussion beyond pet health?
Dr. Sheehy: As veterinarians, we have always had an essential role in overall public health and education. Historically, this was in roles such as food inspectors, herd health managers, etc. We now know that among species, we can share several common illnesses and parasites, i.e., Lyme disease. We can learn greatly from sharing information with our physicians and public health colleagues.
VAM: What are the biggest barriers to client compliance right now when it comes to the use of preventives?
Dr. Sheehy: It would be hard to choose only one thing among the many challenges veterinarians face with compliance.
Pet owners often have difficulty understanding product attributes – especially since the market is crowded with various products sold in many different places. Veterinary appointment availability, as well as socioeconomic challenges, certainly play important roles as well.
But perhaps the biggest hurdle I would highlight is a lack of urgency when it comes to protecting pets from parasites. It is all too common in practice for us to see a patient who already has Lyme disease or heartworm disease before their family recognizes the importance of prevention. Zoetis works diligently to provide education and resources about year-round compliance, and we work to share this not only with veterinary healthcare teams, but also directly with pet owners, encouraging them to talk to their vet about prevention options.
1 Mckay T, Bianco T, Rhodes L, Barnett S. Prevalence of Dirofilaria immitis (Nematoda: Filarioidea) in mosquitoes from northeast Arkansas, the United States. J Med Entomol. 2013;50(4):871-878. doi:10.1603/me12197
2 Regions Where Ticks Live. Centers for Disease Control and Prevention. Updated December 5, 2022. Accessed May 17, 2023. cdc.gov/ticks/geographic_distribution.html
3 Zoetis Simparica Trio®, US Quantitative Research Findings Final Report, Foster Rosenblatt, April 2019
Ceva
Why parasites and vectors are ‘extremely adaptable’
Vet-Advantage: Have trends like recent hurricanes, other natural disasters, and increased adoptions contributed to the spread of parasites?
Dr. Jay Tischendorf, veterinary services manager, Ceva: The parasites and vectors which plague humans and pets tend to be highly adaptable, capitalizing on every opportunity to expand their numbers and range. Factors such as increasing human population, poverty, and strife, the mobile-global world in which we live, increased pet ownership, and increased translocation of animals both nationally and internationally – as well as our planet’s changing climate and natural disasters – all play in favor of parasites and the diseases they carry or help to spread.
At the same time, the more we look for parasites and vectors – and monitor for their diseases – the more we tend to find them. So, yes, while many parasites and vectors are increasingly abundant and/or expanding their range, at least some of them have long been in places we’ve never thought to look. Either way, the storyline is highly concerning, and I predict things will get worse well before they get better. It pains me to say this, but in short, it’s a terrific time to be a zoonotic disease or parasite such as heartworm!
VAM: If parasites are dynamic and ever-changing, how do we combat them effectively?
Dr. Tischendorf: Unfortunately for pets and people, being “dynamic and ever-changing” is pretty much a job requirement for the parasites and vectors against which we all struggle. These organisms are survivors. Consider the expanding ranges of native ticks and the many diseases they carry, the introduction of new tick species as well as the relatively recent North American arrival of zoonotic West Nile and Zika viruses, the occurrence of resistant heartworm strains, and the more recent emergence of resistant hookworms and tapeworms. Even individually, any one of these phenomena reflects the dynamic and dangerous world of parasites and pathogens we inhabit today. Taken together, the picture is even more compelling and grim.
Fortunately, bioscience and medicine are potent forces, and collectively we in these fields are continually seeking new approaches to outsmart our parasitic and microbial enemies.
VAM: Why are broad-spectrum preventive recommendations important for vets to make?
Dr. Tischendorf: People and the animal companions we love are locked in an eternal battle against parasites and pathogens. If we genuinely care for our pets and want to provide them with the best health and safest life, strategic, aggressive parasite management is among the most critical things we can do. Moreover, if we consider diseases like bartonellosis, or ocular or neural larval migrans, parasite prevention or management in a pet can help reduce human risk.
Animal health professionals are lucky today to have products ranging from those that repel and thus help prevent parasite bites to those that act systemically to kill the offending parasites. Increasingly, to maximize protection against deadly diseases, a combination or multimodal approach is warranted with our pets.
VAM: Why has there been an emphasis by many in the industry to reframe this as a One Health discussion beyond pet health?
Dr. Tischendorf: The foregoing discussion should make it clear that parasites, pets, people, and disease are inextricably intertwined. It’s a public and environmental health story. If there’s a poster child for the One Health movement, this is it.
VAM: What are the biggest barriers to client compliance right now when it comes to the use of preventives?
Dr. Tischendorf: Health care teams and pet parents both need to have conviction – the firm belief that parasite prevention is not merely an option or afterthought, but mandatory. Conviction comes from the heart, with a big boost from education. So, education and stories that better resonate with veterinary staff and clients both are a critical component to compliance, adherence, or what I like to refer to as “active participation.” Beyond that, any effort to make veterinary care, including parasite prevention, more affordable, accessible, and effective is worthwhile.
Image credit: istockphoto.com/Alexander Pytskiy
