Rabies Postexposure Prophylaxis Protocol Option for Unvaccinated Domestic Animals

Join the conversation with Pam Wilson on Veterinary Vertex where we unravel the complexities of rabies post-exposure prophylaxis (PEP). Pam shares Texas' successful PEP protocol. Over the course of ten years, 99.8% of unvaccinated domestic animals that were exposed to rabies did not develop the disease when they received this protocol. As we navigate the science behind immediate vaccination post-exposure, we also shed light on its significant influence on rabies management policies, stretching beyond the Lone Star State, with international echoes felt as far as Canada.

Full article: https://doi.org/10.2460/javma.23.11.0625

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Transcript

Speaker 1: 0:00

You're listening to Veterinary Vertex, a podcast of the AVMA journals. In this episode we chat about rabies post-exposure prophylaxis for unvaccinated domestic animals with Pam Wilson.

Speaker 2: 0:17

Welcome to Veterinary Vertex. I'm Editor-in-Chief Lisa Fortier, and I'm joined by Associate Editor Sarah Wright. Today, we have Pam joining us. Hey, pam, thanks so much for being here with us today.

Speaker 3: 0:29

Well, thank you, sarah and Lisa, for your interest and for the invitation to participate in Veterinary Vertex I am a fan of alliteration, too and also a thank you to your audience as well for taking the time to listen.

Speaker 1: 0:45

Pam, your JAVMA article discusses rabies post-exposure prophylaxis for unvaccinated domestic animals. Please share with our listeners the background on this study.

Speaker 3: 0:53

Okay, well, background. It's going to sound like I'm going way back and I am. I was interviewed for my job in Sonosis Control over 30 years ago by Dr Keith Clark, who became a mentor and I will be mentioning his name on and off during this podcast because of his rabies associations. And during the interview I was asked about handling rabies exposure scenarios and I mentioned that I'd noticed that the protocol in Texas state law differed from the national recommendations and Dr Clark at that time was listed as a committee member for the compendium recommendations it's they're in the compendium of animal rabies prevention and control, so he was associated with two different protocols, which was confusing to me. And he mentioned that, yes, texas had developed its own protocol for unvaccinated animals that were exposed to a rabid animal, including immediate vaccination against rabies instead of waiting five months into a six month quarantine to vaccinate, which at that time were the compendium recommendations.

Speaker 3: 2:13

And since this was a novel rabies post exposure prophylaxis and we'll refer to that as PEP from here on out protocol, we thought it would be a good idea to compile Texas data and get it published. We were hoping in a peer reviewed journal, we were hoping in Jafma, and it didn't get published in Jafma and since then we have had kind of a series of articles on the Texas PEP protocol and its data published in Jafma, and this most recent one was our fourth. And of course they're scanning different time periods and it actually kind of became my mission to keep publishing Texas data on this topic Because after that first article was published, dr Clark mentioned that by getting the data out there and published, many animals lives were saved. So in addition to really caring about public health, my passion for working in zoonosis control definitely includes animal health and safety. And, by the way, for purists out there, yes, realize that humans are animals too.

Speaker 3: 3:27

So purposes of our rabies discussions when we say animals, we're talking about non human mammals. I would like to mention that the compendium now does recommend immediate vaccination of unvaccinated animals that have been exposed to a rabid animal. In fact, they mentioned trying to do the vaccination within 96 hours of the exposure. And for clarity, I also want to mention that both the compendium and Texas state law do provide the option of euthanitizing the animal instead of administering PEP. And if I could do a side note, because I think that this would be of interest to clinicians to keep in mind that we are discussing in this study on vaccinated animals that have been exposed to rabies and got PEP. But both the compendium and Texas state law for currently vaccinated animals have the same protocol, which is to vaccinate immediately and do strict isolation for 45 days.

Speaker 1: 4:35

So, that being said, what were some of the important findings from this study?

Speaker 3: 4:38

Well, the current PEP protocol in Texas, again for vaccinated animals that have been exposed to a rabid animal, is to immediately vaccinate them against rabies, confine the animal for 90 days and administer boosters on the third and eighth weeks of the confinement period. For animals that are less than 3 months of age, additional vaccinations may need to be administered to ensure that the animal receives at least 2 vaccinations at or after the minimum age. Designate it by the USDA for the particular vaccine that was given. And, by the way, in our state law this is for animals for which the whole PEP protocols are, for animals for which USDA licensed vaccines are available. However, in all of our different study periods there have been animals that have gotten extra label vaccine administered, very frequently goats. We've had occasional pigs. This past study we even had a deer and a wolf dog hybrid. But in the law it mentions USDA licensed vaccine but extra label at the discretion of the veterinarian. So the main take home relevance, I think, of the study is that the current Texas PEP protocol, which was administered during the 10 year period of the study, remains a viable option for vaccinated animals that have been exposed to rabies. There were 1218 vaccinated animals that receive PEP and 98, 99.8% did not develop rabies. The three that developed rabies were less than 12 weeks of age when PEP was initiated. This was what was very rewarding to me, one of the parts of doing this whole study.

Speaker 3: 6:44

When the Canadian Council of Chief Veterinary Officers was developing their national recommendations, they heavily cited Texas's PEP and the articles that were published in Javma. Well, they came up with a modified protocol. They still include immediate vaccination, but they went in and this is for unvaccinated dogs, cats and ferrets but they went into just considering a booster at three weeks based on case by case investigation, and then no vaccination at the eighth week. Well, this to me, having just fantastic discussions and information sharing with Canadian public health veterinarians in Ontario, alberta, british Columbia. They all also have a recommendation for extra vaccination for the PEP that was started in very young animals.

Speaker 3: 7:45

And all the provinces you know they had special little tweaks to their national recommendations as well. But to me the importance is that, just as the Canadian Council and these provinces reviewed PEP articles from Texas and developed their modified recommendations, now Texas can consider their modifications when we start reviewing our state law for possible amendments. So it's been a really good learning activity, I think, all the way around. I also had a contact with a rabies expert who had an interest in researching the use of MABs for PEP in animals, which might inspire other researchers to pursue such studies. So all of this is also included in the discussion section of the article, but to me that is part of the significant impact of having data published in JAPMA.

Speaker 2: 8:49

Well, thank you for sharing it with us. Pam, I don't think we said this yet, but you have been a practicing veterinary technician for years and then went out and got your doctorate and community health. At what point? In clearly have a passion for rabies. What sparked your research interest along the way in rabies?

Speaker 3: 9:08

Well, my mentor, Dr Clark, was an internationally recognized rabies expert and he stimulated and nurtured my interest in rabies as soon as I began working at the health department. I worked on these novel rabies initiatives with him, like the creation of the oral rabies vaccination program in Texas for coyotes and great foxes and the Texas's PEP protocol which we're discussing now, and it has been an exciting ride to be involved with these very cutting edge projects.

Speaker 2: 9:50

Well, we're very pleased that you decided to share it with Javma. Why did you decide to submit this manuscript to Javma, Well?

Speaker 3: 9:56

again. When I started working at the health department, dr Clark tasked me with getting an article published on Texas's rabies episodic in domestic dogs and coyotes, which was very novel as well, and so Dr Clark and I both agreed let's submit this manuscript to Javma. And we went with Javma because it's peer reviewed, has an excellent reputation and we considered it the gold standard of veterinary publications. So I was so thrilled when that article got published, and it was after that we started collecting data on our PEP protocols and again turned to Javma for publication, and now we have had this is like I mentioned the fourth manuscript on PEP. With other co-workers we have had articles published in Javma on rabies and skunks and rabies and bats in Texas. It has always been a very positive experience working and interacting with Javma, staff present, company included, and if I could, I would like to do a shout out to Karen Dotson, the editorial manager. She is not only efficient and helpful but so nice with which to work.

Speaker 2: 11:29

Yeah, thank you. We have a fabulous culture. We love what we do and what you're doing, too. Right, you're impacting One Health. It's not just you're saving animals, you're helping veterinarians, you're helping the public health, and that's what we strive for too.

Speaker 3: 11:46

That's exactly right. On the One Health.

Speaker 2: 11:49

Pam, you talked about some of the interesting findings and significant findings from your manuscript. But what surprised you?

Speaker 3: 11:58

I think on this one, it was the first PEP manuscript in which we also include data on the number of on-vaccinated domestic animals that were exposed and were de-uthanatized instead of receiving PEP, and I was surprised that the number was as high as it was, since there is this PEP option.

Speaker 3: 12:23

It was like 925.

Speaker 3: 12:26

So we did a little closer look and in some of the more detailed reports it would describe the animal if they were kittens or puppies, and we found that about 45% involved kittens and puppies, and frequently this would be a litter that was attacked, usually by a rabbit skunk an occasional rabbit fox and I think skunks are great, you know, they're marvelous critters but when they have rabies they really practice some pretty insidious behavior, such as attacking litters and being found like chewing on the heads of kittens and puppies, and I know that's kind of a horrible mental image, but that is all part of it.

Speaker 3: 13:21

Plus, unfortunately, there are case scenarios in which cats were depopulated because they were on the premises where a rabbit animal was found and PEP could not be easily accomplished in these animals, and so, even if there was no direct exposure observed, they were euthanatized in an abundance of caution, since rabies is a fatal zoonotic disease. And, by the way I just wanted to mention, we wouldn't have data to publish if it wasn't for the dedicated zoonosis control staff statewide who prepare all of our zoonotic incident reports. And it is our zoonosis control staff out in our regional offices, along with local health departments, certainly local rabies control authorities and animal control officers across the state who do an amazing job of investigating the rabies cases. And I also want to mention and give kudos to the remarkable laboratory personnel who confirm if these are rabies cases and even very often what type of variant we're working with. So it couldn't be done without all of those folks.

Speaker 1: 14:52

Yeah, it's a really big undertaking. I participated in the Illinois State VMA's Power of 10 program last year and one of the modules was actually working with the state public health fat on like a rabies exposure scenario and just everything that goes into it. It's so much.

Speaker 3: 15:07

It is very involved and a lot of people that you depend on, like I said, not only our regional zoonosis control staff across the state, but all the animal control officers out there rabies control authorities that have to know what they're doing and take it seriously and do all the investigations and make sure that they're protecting the health of people and animals that are potentially exposed to a rabid animal.

Speaker 1: 15:39

Yeah, thank you To our listeners. Who's joining us? We're discussing rabies post-exposure prophylaxis for unvaccinated domestic animals with our guest Pam Wilson. Pam, as we discussed previously, you are a licensed veterinary technician and a doctor of community health. How did your advanced training prepare you to write this manuscripts?

Speaker 3: 16:00

Well, I'm going to go in the way back machine. To begin with, I had excellent English instructors before entering college and they taught me fundamental writing skills which really launched my whole interest in preparing manuscripts. I feel that they gave me all the basic skills for being able to do that. Kudos to all of them as well. My 14 years working in the private sector at an animal clinic I feel were very important because they gave me real life veterinary perspective, boots to the ground type experience and working with animals and with concerns about rabies and rabies exposures. I feel that that was very important when now working at the state health department dealing with public health and state laws.

Speaker 3: 17:08

There's a lot of I statements in what I'm saying, so I would also like to take this opportunity to thank my co-authors on the article, pat Hunt and Dr Eric Fonkin. We, to me, made a great team. We were very in sync with each other. Everybody in my office knows that I am not technology savvy at all. Pat Hunt can weave magic with databases. He was able to pull all of these rabies scenarios and compile them. He understands the very integral guts of the computer programs. Then he and Dr Fonkin or Eric and I we went through and reviewed all of these scenarios. We made sure that we were all in agreement with the post-exposure elements.

Speaker 3: 18:13

It was a very positive experience working with both of them. I don't know if they'll say the same thing about me, because I'm a little retentive, I get a little tense, but they put up with me really well. They would talk me down. I was like I think we should worry about this. They were great. I've got great co-authors. I just feel so fortunate, both my work at the clinic and with my work with all of my Zonus' control colleagues. For all of these years I have worked with the most amazing people who are dedicated to their jobs. All of this is possible because of them.

Speaker 1: 19:04

It's a very special field that we work in Now. This next set of questions is really important for our listeners. The first one is going to be relating more to the veterinarian. What are a few examples of key pieces of information the veterinarian should know before discussing rabies post-exposure prophylaxis with the clients.

Speaker 3: 19:24

Well, in speaking of people that make all of this work, veterinarians and veterinary technicians are right in the mix with all of that. They are such an integral part of dealing with post-exposure scenarios, counseling clients, understanding rabies and what constitutes exposures. So I would recommend that the veterinarian collect information pertaining to the exposure and then, of course, discuss with the owner. There are the options for PEP or for euthanitizing the animal, and some of the factors to consider are that animals' health, it's immunocompetence, status that's where some discussions start entering in with very young animals the location and severity of the exposure. If it's a direct exposure, probable, like reasonable to assume that there was an exposure or a low probability, you're dealing with rabies, so you're airing on the side of caution to go ahead and do PEP and now, for instance, example of the skunk chewing on a pup of your kitten's heads that's considered a direct exposure.

Speaker 1: 20:53

Yeah, the communication is so critical for these cases, so thank you for touching on that too. Now, on the other side of the relationship, what are some examples of important things clients should consider around rabies? Post-exposure prophylaxis?

Speaker 3: 21:08

Well, of course clients should consult with their veterinarian and to get from the veterinarian, for one thing, the very nature of rabies. It's a very elusive disease and a lot of times there aren't any concrete answers. A quote that I really like is in an article co-authored by Dr Rupert. It's in Lancet but it goes. Anyone seriously working in the field of rabies has been fascinated by its complexity and frustrated by its mysteries. There are so many unknowns on this disease that has been around for eons, even the elusiveness of the incubation period and how many variables. So to discuss with their veterinarian a bit about rabies that it is a deadly disease.

Speaker 3: 22:11

What constitutes an exposure? Typically it is infected saliva from an infected animal going through breaking the skin, frequently through the bite of an animal, a rabid animal. But it could be saliva contacting any break in the skin or mucus membrane, eyes, nose, mouth or neural tissue that's infected, contacting that, which might happen with a butcher or a hunter or something like that. But anyway, to discuss what might be an exposure, the degree of exposure their animal had, potential risks involved with PEP. Oh, to learn from their veterinarian some of the clinical signs An anal developing rabies may exhibit. Just a few of these clinical signs may exhibit a lot of them, and so to know that they should contact their veterinarian. And then, of course, the Department of State Health Services should be notified to if the animal starts to exhibit any of these potential clinical signs. You want to play it safe when it comes to rabies.

Speaker 2: 23:30

For sure that's a long time. Client compliance would be pretty tough for 90 days.

Speaker 3: 23:35

Yes, it can be, but you just have to really weigh in with the client that narrates. And actually the clients can contact their local or state health department as well for guidance. You always want to err on the side of caution with rabies, but you want to make things work for the animal too and for the people that are involved. But you want to keep it to a minimal amount of contact. Yeah, no messing around. Yeah, exactly. Very importantly, the veterinarian should stress to the owner the importance of pre-exposure rabies vaccination for animals. We don't want the owner feeling that, hey, pre-exposure isn't needed, because in the future, if an exposure happened, we have this post-exposure option and we don't want anybody reading our article or listening to this podcast to think that pre-exposure is not important. It is.

Speaker 3: 24:43

Not only are rabies vaccinations legally required for dogs and cats in Texas and most other states, they are important from a human health and safety perspective plus an animal health and safety perspective. I mean your animal could pick up a downed rabbit bat and you may never know about it until it is too late to administer PEP. I mean once the rabies virus is in the nervous system, it's too late. Once the animal is showing clinical signs of rabies, pep will not be effective. So then you've had an animal that's unnecessarily died of rabies and all the concerns about people and other animals that have been potentially exposed to rabies through that animal. So pre-exposure rabies vaccinations very important.

Speaker 2: 25:35

Yeah, great Thanks, pam. And to listeners who might not know this, most of us, as veterinarian and veterinary technicians who work with animals, are vaccinated as well, and we actually get our titers checked. So yeah, so thank you, pam, I learned a lot. And as we wind down, we like to ask this just slightly fun kind of question so what is the oldest or the most interesting item on your desk?

Speaker 3: 25:59

Well, a friend of mine who excavates for fossils gave me a rather impressive piece. It is an ammonite, it's this little snail looking thing. It's from the Crestaceous period I hope I'm pronouncing that correctly which I was informed runs anywhere from 65 to 140 million years ago, so it's certainly the oldest piece. But one other fossil that I have was when I was in college at SA Jung-Harvondale, so this was about 1978. My beloved dog, ripple, was out in the yard excavating as well and my very funky duplex, and he came in with this little rock and looking at it. You can't see it very well on here, but it has numerous little fern fossils in it. So here's just a smart.

Speaker 2: 26:55

That's very cool. Thank you for sharing.

Speaker 3: 26:58

Well, thank you so much for having me and for your interest in this article. I hope that your readers enjoy it and benefit from it, and so it's just been a fantastic experience to be included in Javma and to do this podcast.

Speaker 2: 27:19

Oh great. Thank you again, and to our listeners you can read Pam's article in print, Javma or on our journals website. I'm Lisa Fortier with Sarah Wright, and we'd like to thank each of you for joining us on this episode of Veterinary Vertex Podcast. We love sharing cutting edge research with you and we want to hear from you. Be sure to leave us a rating or review on Apple Podcast or whatever platform you listen to.