External Parasite Prevention for Pets and Livestock

So settle in, and enjoy today’s episode.

Kenny Coogan: Good day, everyone. I am Kenny Coogan, and joining me today is Dr. Caroline Sobotyk, Assistant Professor of Clinical Parasitology at the University of Pennsylvania School of Veterinarian Medicine. We’re going to be discussing ways to keep your pets and livestock [00:01:00] healthy. Welcome to the podcast, Carol.

Caroline Sobotyk: Thank you. Thank you for the invitation. And thank you for having me. Let’s have fun and talk about parasites.

Kenny Coogan: Yes. Hopefully we can have fun talking about them.

Caroline Sobotyk: I can have fun for sure.

[00:01:17] Threat of Fleas, Ticks, and Parasites on Pets and Livestock

Kenny Coogan: Oh, good. So it’s winter. And how concerned should caregivers of livestock and pets be? Or is it, are we more concerned about what’s going to happen in the springtime and the summer?

Caroline Sobotyk: It’s an excellent question and very common as well. So, wow, like flea, ticks, and other ectoparasites or external parasites can present different health risks to humans and animals, right? So it’s important to take preventive measures year round. This is the first and most important thing. Of course their prevalence and [00:02:00] activity will increase during like spring and summer periods, because you have like a warmer temperature. We have more environment factors that contribute for the reproduction of those populations.

However, and of course, the dogs, for example, are gonna be more, gonna be outdoor, like, more, have more, like, outdoor activities, more frequently than during the winter. This is another very important factor. However it’s not because they are not, like very, very activity. They are not around like the parasite. And they are just looking for a host. I don’t remember to have like a very specific or season since like a long time ago. So we are seeing like more and more warmer days during the winter and the fall. And we just need like a couple hours to increase this population. So we just need a little bit more like a [00:03:00] warmer temperature to have this parasites increase and reproduce like very fast.

So everyone, like dogs, cats, and humans and any other animal, are exposed to ectoparasite infestations any time of the year.

Kenny Coogan: And what are the real dangers of ectoparasites? They’re so tiny. And their hosts are so large. Are we actually concerned about these tiny creatures, or are we more concerned that parasites are vectors for more harmful things? I was just looking, and they said, the most dangerous animal to a human is a mosquito.

Caroline Sobotyk: It’s another good question, and maybe it’s the reason why I’ve become a parasitologist. I’m a vet, but I’m first a parasitologist, and after a vet, I think, because I love them. [00:04:00] I think parasites are so interesting because even like this small little guys can kill like a dog or even a large animal like an elephant, for example, or us.

So they are so amazing, but of course I’m biased. So. Their presence seems like irrelevant because of the small size, their small size in comparison like to the host, of course, but can cause like significant, significant health issues and discomfort to the host. Of course, the transmissions of vector borne disease, so bacterial virus and parasites, is the most important health issues related with this populations, with these parasites, but ectoparasites can also cause like anemia, especially ticks and fleas.

Fleas can cause like allergic reaction, ticks as well, but it’s, it’s [00:05:00] very portent in fleas’ population. So some people with animals can have allergy because of the ectoparasite bite. In the case of the fleas, it’s very common here in U.S. and other countries as well, especially on companion animals. Because there is like a condition called “flea allergy dermatitis” that is like a hypersensitivity reaction to some proteins in the flea saliva. So the dogs, so even like a very, very small numbers of flea or even with one or two bites can cause like this severe allergic reaction. Secondary infections is another concern. Ectoparasites bites can cause irritations and create this open sores on the skins, right? And this scratching, these bites can lead to secondary bacterial infections with it, can [00:06:00] cause very severe dermatological condition.

So again, like vector borne disease is our first concern for sure, but we have like other health issues also related with ectoparasite infestations.

[00:06:16] Fleas vs Ticks

Kenny Coogan: So I can envision a little flea hopping around or like a nasty tick attaching to myself or to an animal. And you said that these parasites are fascinating and you think they’re amazing. Is there like a big difference in flea and tick behavior or treatment, or is there something that makes them really special compared to the other one?

Caroline Sobotyk: Yes and no. Let’s talk about what they have in common.

So they are ectoparasites. So we are going to find them outside of the body, right? We have endoparasites that we can find inside of the body of the host, and ectoparasites. [00:07:00] So ticks and fleas are considered like ectoparasites. They are arthropods. They feed on blood. So this is another thing they have in common. They can transmit like a different disease. So again, virus, bacteria, and other parasites as well. So they can be vectors of different disease, right?

But they are, in terms of biology, they are a little bit different. For example, ticks, they have like a different, a different life cycle. So ticks, we are going to have like larval forms, nymphs, and adults. For fleas, we are going to have adults let’s follow the same order, eggs, pupae, and larvae, and adults.

What is the difference, main difference between them? Ticks, all the larval or immature states of ticks, all needs to feed on the host [00:08:00] as well. So they need to find a host to survive and molt to the next stage. Fleas don’t need. Only the adult, you are only gonna find the adult stage on the host. So this is the main difference.

But another difference in terms of biology and epidemiology and life cycle of these parasites is like flea infestations is very difficult to control, and usually we are gonna find inside of our house. With ticks, they are in the environment. So it’s basically impossible to control the environmental infestation of those parasites.

With fleas, it’s very complicated, but at least we have extra tools to control because everything is concentrated inside of the house. But it’s very difficult, don’t get me wrong, and take very, very long time to [00:09:00] control like a, a flea infestation in your house. Months. It’s not easy. It’s not fast. But this is, I think it’s the main difference. So basically we can find like a major stage of ticks on us or our pets and, related with fleas, only the adult is gonna feed on you.

[00:09:21] How to Spot Signs of External Parasites

Kenny Coogan: How would you, or how would a listener know if their animal has a parasite? Like, I have indoor cats, and it’s very easy to see on the, on the counter, if they’re scratching. You have that, like, flea dust. But what happens if somebody has a livestock guardian dog that lives outside with the sheep? Or you have a cow, and it’s, and they’re on hay? How would you know if they were covered in ectoparasites?

Caroline Sobotyk: It’s a very good question. With ticks, the first recommendation is check your dog every time. So after, like, any walk or any outdoor [00:10:00] activity, you should check your dogs and look for ticks or fleas or any ectoparasite.

There is no specific diagnostic test for ectoparasites, unfortunately, besides the visualization. So you see and you collect that specimen, and you can send to a lab for morphological identification, of course. But we do not have like a specific diagnostic test like for endoparasites. If you have like a GI parasite, you can collect poop, and we can check in the lab and look for eggs. For ectoparasites, it’s more related with clinical signs and visualization itself of the parasite. As you said, like sometimes it’s very difficult to detect or find these little guys on your pet, but animals also present like changes in behavior, so you can pay attention of this. So they might become restless, [00:11:00] agitated, or engage in like excessive scratching or grooming. And you are gonna see like a different behavior. So pay attention on those signs as well.

Kenny Coogan: Let’s say your cow or dog has just like a couple of ticks, and the owner doesn’t notice it. Will they eventually go away on their own? Or is it gonna just get worse and worse if there’s no treatment?

Caroline Sobotyk: It’s a very tricky question. My natural answer is no, they are not never going to go away on their own. Fleas, for example, are going to bite your pet and or you, or your pet and you, replicate, lay eggs, contaminate the environment. And, and the new flea generation are going to bite the animal again and start another cycle, right? Not all parasites are the same, right? So the [00:12:00] answer for these questions is largely depends on different factors, like type and species of parasites, animals’ immune system, environment conditions, severity of infestation, et cetera.

So we need like an appropriate diagnostic test. Most of the case, we are going to need some intervention, so we are gonna need to provide a medication to control and treat these parasite population infestation. But some parasites, not very related with ectoparasites, but for some endoparasites, for example, we can have a natural cure from the host. So, largely depends on the species that we’re talking about. Some lice usually are very host specific, so sometimes they are going to bite you by accident, like, because they are looking for a new host, but they know, well, [00:13:00] this is not the guy that I’m looking for, and they go away. So it depends on the species. So this is a talk that you need to have with your vet, for sure, based on the diagnostic test.

So when you have, like, a confirmation of the parasites involved in the infestation, we can have, like, a better perspective, like, if we need or not a treatment or any kind of intervention.

[00:13:27] How Can Parasites Affect Animals?

Kenny Coogan: That makes me think, like, I know the difference between a cat and a cow is hundreds of pounds, but if each of them have, like, 1 percent parasite coverage on their fur. I don’t know how we measure it. But do dogs and cats and livestock, are they all affected the same way if they get 1 percent of fleas? Or are there some species or breeds that are more resistant to parasites? Even like goats and sheep are so [00:14:00] similar, but they’re, they’re very different. Their world is so different.

Caroline Sobotyk: Yes, very, very different. So, again, my answer is “yes” and “no” at the same time. So, both livestock and companion animals can all be affected by ectoparasites, right? But the impact and severity of infestations can vary among these populations, and even among like the same individuals from the same population.

So even like dogs in the same breed can have like a different reaction or present a different situation related with the ectoparasites’ infestation. For example, ectoparasites infestation in dogs and cats can cause, like, irritation, itching, allergic reactions, and many other skin disease and health issues, right? In addition to all these dermatologic issues, [00:15:00] ectoparasites infestations in large animals can also lead to significant economic impact, for example, loss of productivity, mortality, or even secondary disease. So with large animals, we have like another factor that is the economic factor involved.

So in large animals, this is in general, like not only ectoparasites. Infection doesn’t mean disease. We will not like treat all the time. We are going to treat if we have a disease and we have like an impact in the production. It’s different for small animals. For small animals, we are going to treat if they are positive, because they are very close to us. They are like inside of our house. There is no economic impact factor involved on this. So it’s a different approach. This is my natural answer for, partially answered.

But as I [00:16:00] said before, not all animals are going to present severe clinical signs. So some individuals may show like minimal clinical signs or tolerate the parasites without any significant health issues. And other individuals, the infestation or the infection is going to be really severe. So this tolerance can be influenced by different factors, like breed, environmental adaptions, uh, individual immunity. For example, some dog breeds might have like thicker coats that make it harder for fleas to establish an infestation. Same with cattle. So some animals, we know there is some breeds that it’s more resistant to tick infestations due to a skin characteristic.

Again, although some animals are more resistant to parasites, it’s important to remember they can also be infested. So [00:17:00] not, not because they are like more genetically resistant to ticks or fleas, they are immune to a tick or flea infestation. So we need to provide preventives. It doesn’t matter the reason, right, or the dog breed.

[00:17:19] Best Ways to Prevent Parasites

Kenny Coogan: So I just inherited my third cat. And the cat came with the flea collar. I’m not too sure how long flea collars last, but it was like a brand -new flea collar. And I saw this little flea right on her whisker, and I was wondering, do pills, flea collars, and sprays, do they work equally well, or is there one better than the other? Maybe not even sprays, but there’s like that liquid that you put on the back of your animals?

Caroline Sobotyk: Topical solutions. Yeah. Yeah, sprays is a little bit different, but in general, oral medications or topical products or collars, they [00:18:00] are effective in treating and preventing ectoparasite infestation.

What matters is the active ingredient, and they own those products. So it’s these that determines their effectiveness. So we have some reports of resistance in fleas. So could be the case of your cat. So it depends on the compound on those products. In general, like, oral products and collar are typically effective in repelling and killing fleas and ticks.

These products can be very convenient, but the choice between those methods is more related to personal preference of the pet owner, much more than like if they are efficient or not, you know what I mean?

Sprays is a little bit different. They can be effective in killing parasites on contact, but their efficacy [00:19:00] duration might be shorter compared to oral or topical or collars products. But sprays can be a good option for spot treatment. So for some pets with specific needs, could be a very good option.

Kenny Coogan: And how frequently should topical or pills be given? And I know, and I’m not meaning the instructions say “every six weeks” or “every four weeks.” Are these year round things or are these more seasonal?

Caroline Sobotyk: Yeah, no, it’s, year round.

Kenny Coogan: Year round. Okay.

Caroline Sobotyk: With flea, mainly with the flea and ticks, because as I said before, we never know when we are gonna find, they are just there waiting for us. They can survive the winter. I’m from Brazil, so in Brazil it’s a big issue because it’s a tropical country. So we have fleas and ticks all the time. Here, I’m now in Philly. So in Philly, it’s a little bit better, because we have a very strong winter. [00:20:00] Yes. I’m still trying to adapt to the winter. For a Brazilian person, it’s a little complicated, but it’s good for, for us in relation to parasites.

So this population decrease, significantly decrease, during the winter, but they are there. So they are around, and they are just waiting for the right time to get a new host, right? We need to keep the preventive protocol, unfortunately, year round, like there is no other option. Of course, the, how you are gonna, give this product. Some products, some products are effective for a month, other for three months or several months and et cetera. So it depends on the product, right?

[00:20:48] Ectoparasites to Watch Out For in Livestock and Poultry

Kenny Coogan: Now, lots of listeners have poultry and livestock, and it’s winter now. What types of ectoparasites, [00:21:00] parasites on the outside, should livestock and poultry owners be concerned with this time of year?

Caroline Sobotyk: I think the most significant ectoparasite infestation in poultry during this time of year is, for sure, mites and lice. We have some s pecific species of mite and lice that is very important. Like the most common economically important mite species in birds in general, not only poultry, are the red mites.

So the scientific name is Dermanyssus gallinae. It’s a beautiful name. Dermanyssus can be like very problematic during the colder months because it can survive in poultry house even during the winter. They can hide in like cracks or crevice and coming out at night and feed on birds.

Regarding lice infestation, there is like a number of [00:22:00] species as well, like mites as well, we have a number of species. So we have like different, different species have been described in chicken and turkeys. Uh, but the chicken body louse is the most important one for sure. It’s Menacanthus stramineus, another very beautiful name. This parasite can also cause, like, severe irritation on those animals, can reduce egg production, so we are going to have, like, an impact on production. Keep an eye on this and be aware of those guys, little guys.

Kenny Coogan: And listeners would know that they have lice or mites because of some feather damage?

Caroline Sobotyk: Yes, also, yeah. It depends on the species, right, we have like some that is more aggressive than others. They are located like in different place in the poultry, but you are gonna notice like, you are gonna notice dermatological difference, like skin [00:23:00] disease on those animals for sure, like dogs and cats.

Kenny Coogan: Should we be concerned for our livestock and our pets regarding mosquitoes?

Caroline Sobotyk: Yes, and flies. I should say flies is more important than mosquitoes. But for sure, they can transmit like a different, they are vector for different disease. And they can also can cause a huge discomfort on this, on those animals for sure.

Kenny Coogan: Is there a preventative for flies?

Caroline Sobotyk: Yes, we have a number of products.

Kenny Coogan: From the feed store, probably.

Caroline Sobotyk: Yeah.

[00:23:41] Does Natural Heartworm Protection Work?

Kenny Coogan: We posted the questions on our social media pages, and we have several questions. The first one is from @cosmochristina, and she asks, “Do you know of any natural heart worm prevention that works?” Because we love [00:24:00] natural remedies and cures, but they need to work. It’s not good enough that they’re natural. But Carol, before you answer that, can you tell us where the heartworm comes from?

Caroline Sobotyk: So, heartworm disease, it’s a vector borne disease. So, mosquitoes transmit heartworm disease. So, Dirofilaria immitis is the name of this worm from one dog to another. So, there is no direct transmission, direct contact. We need the mosquito. So, the mosquito is the vector, or intermediate host, we call intermediate host. This parasite is located in the pulmonary artery of dogs. So basically they are going to cause damage to the cardiorespiratory system of the dog. It’s a very severe disease, can also infect cats and wild canids.

And I love natural things as well, I would, I should say. And I wish that we could have a [00:25:00] natural heartworm preventive, but we do not, unfortunately. And heartworm disease is a little bit more challenging than other endoparasites, because the drugs that we have available that we call preventive drugs, so macrocyclic lactone, it’s the drug class, they are effective against immature stages of heartworm.

What this means, they are effective only against larval stage. They do not kill the adult worm. We do not understand very well why this happens. But filarial nematodes, like Dirofilaria immitis, they, the macrocyclic lactones do not work on those worms, specific group of worms. So what is the problem of this?

Like, the treatment is very restrictive to one single class of drug called arsenicals. So melarsomine is the only drug available to [00:26:00] kill adult worm. And it’s very, have a very narrow safe margin. So it’s a very aggressive treatment, but we do not have any other option. And to not have a treatment, it’s worse than have a treatment in those cases. So prevention is the key for heartworm disease, because we are going to keep our pets safe and are going to avoid cardiorespiratory damage to our dogs.

[00:26:31] Do Natural Flea and Tick Repellents Work?

Kenny Coogan: Jane asks, “Do you know of any natural flea and tick repellents? Because the internet says, or offers, baking soda, lemon juice, salt, rosemary.” Do any of these work? Or work well enough to be implemented?

Caroline Sobotyk: So my, my answer is going to be no. I’m a scientist, right? So I can say that we do not have any evidence that those products work.[00:27:00] This doesn’t mean that doesn’t work at all. So maybe they can contribute to the, to our preventive protocol. So they can contribute like repelling fleas and ticks, but for sure they are not 100 percent effective. We need more research on this for sure. And we have like most of a number of drugs like that we actually buy and use on our dogs and cats and companion animals came from natural compounds. So we first found like they have some activity, natural activity, against like specific parasites. And after this, after a lot of research, we develop like a well established compound that is 100 percent effective or close to this, effective to some parasite population. So, so far, we do not have, like, any evidence. Maybe in the future I could [00:28:00] have, like, good news and we can discuss this again.

[00:28:03] Flea and Tick Medicine for Indoor Pets

Kenny Coogan: Very good. Demi Stearns, who’s been a subscriber to Mother Earth News since the 80s, asks, “Do indoor only cats need flea and tick medicine if you don’t have any other animals outside?”

Caroline Sobotyk: Even indoor only cats can be at risk of flea and tick infestation for sure. And I saw a number of times here in U.S., in Brazil, and different states. While the risk, of course, is lower compared to outdoor cats or dogs, flea and ticks can be carried into the house by other animals, like other pets, other dogs and cats. But also rodents or other small mammals that we do not have, like, totally control. Or even us, we can bring fleas and ticks into our house by accident, in our body [00:29:00] or in our clothes. So there is a number of options. So because of this, preventive measures are recommended to avoid infestation and potential health issues, even to indoor cats. So I would recommend those medications for any companion animals, dogs and cats, with access or without access to outdoor areas.

[00:29:30] Effectiveness of Flea and Tick Medicine

Kenny Coogan: The last question is from Bertha Vazquez, and she’s the director of the Teacher Institute for Evolutionary Science, and she asks, “does the active ingredient in flea and tick medicine need to be rotated due to the parasites building an immunity?”

Caroline Sobotyk: Yeah, no, for sure, no. This is not a good decision. We have like different reports of [00:30:00] resistance in ecto and endoparasites as well. And this is natural, like this, it’s some adaption from the parasite to the compound, that it’s gonna happen at some point. So it’s basically impossible to avoid, but we can delay.

This is the key. So in the moment that you rotate different medication, you are exposing these, those parasites. So this population, this parasite population, to different compounds and given them the opportunity to adapt to different compounds. So the best option here is to stay with one single product as long as possible. If it’s working for you, if it’s effective, if it’s convenient, if your dog do not present any adverse reactions, keep the same. There is no reason to change or rotate like monthly or annually. You can keep the same for sure.

[00:31:00] And we have like different products as well with the same compound, but just with a different presentation. So sometimes oral medication is not like very convenient, or it’s not convenient anymore. You can change to a topical product with the same compound. So since the compound is working, keep the same, and talk with your vet. I’m sure they are going to provide like the best option for you.

Kenny Coogan: So we shouldn’t be concerned if the active compound says it kills 99 percent of the fleas. Like that 1 percent we’re not really worried about. We’re, we’re happy that it’s killing 99%.

Caroline Sobotyk: Okay. Now I’m going to say like a researcher again. We do not have like 100 percent effective compound or 100 percent diagnostic test, like that is 100 percent sensitive or specific. Same with drugs, like it’s virtually impossible. And the flea population and tick population [00:32:00] is huge. Like, there is a chance that we are going to find a resistant tick or a resistant flea, right? So the 1%, it’s totally fine. It’s totally okay.

Kenny Coogan: It might even say 99. 9 percent. So I might be exaggerating. So it might even be a tenth of a percent.

Caroline Sobotyk: Yeah, it’s very very small, because we have like a bunch of research on this, on those compounds, right? So it’s not easy if you have like a product approved, FDA approved, in the U.S. It’s because we have like a history of years and years of research. So we, if we got this number, it’s because it’s very accurate and we should believe, but it’s virtually impossible to find like a product like 100 percent effective against any parasite.

Kenny Coogan: So what I hear you saying is that if it, if it allows a 10th of a percent or 1 [00:33:00] percent to live a year after we use this active ingredient, there’s no need to swap it out for a different one.

Caroline Sobotyk: There is no need, yeah. If you’re not seeing like a significant infestation on, on your dog or cat, there is no need to change the product for sure. We have like, not for ectoparasites for, for endoparasites, for example, we have like some diagnostic tests that we can measure the effectiveness of a specific compound against specific parasites, endoparasites. So we usually say like compounds over 95 percent of efficacy, it’s, it’s a efficient product. So we should keep using the same if it’s 95% or more of efficacy against that specific target parasites. So any number over 95 percent, it’s totally fine.

Kenny Coogan: Thank you so much, Dr. Sobotyk, for being our [00:34:00] guest on the podcast. We really appreciate it.

Caroline Sobotyk: Thank you for having me.

Jessica Mitchell: Thanks for joining us for this episode of Mother Earth News and Friends. To listen to more podcasts and get connected on our social media, visit our website, www.MotherEarthNews.com/P odcast. You can also email us at Podcast@OgdenPubs.com with any questions or suggestions.

Our podcast production team includes Jessica Mitchell, Kenny Coogan, John Moore, Carla Tilghman, and Alyssa Warner.

Music for this episode is “Travel Light” by Jason Shaw. The Mother Earth News and Friends podcast is a production of Ogden Publications.

Until next time, don’t forget to love your mother.

Meet Dr. Caroline Sobotyk

Caroline Sobotyk is an Assistant Professor of Clinical Parasitology in the Department of Pathobiology at the University of Pennsylvania. Her research focuses on the improvement and development of detecting parasitic infections with the aim to improve the general health and well-being of domestic and wild animals and better understand treatment and prevention strategies.

Our Podcast Team:

Jessica Anderson, John Moore, Kenny Coogan, and Alyssa Warner
Music: “Travel Light” by Jason Shaw

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