September 24, 2009 Equine Rabies: What Every Horse Owner Should Know Guest: Hello, I recently purchased a TB Broodmare and would like to vaccinate her against Rabies. She is in foal on a April 06 2009 cover. Could you recommend a good time to begin to administer the vaccines? Any other advice on Rabies Vaccinations and the Broodmare would be very helpful. Dr. Steve Reed: Vaccination of broodmares is best done during the last trimester of gestation. At that time the foal is developed and now only growing. This will also allow time for antibody levels to increase during the end of gestation and to be at a high in colostrums to provide best protection for the foal. Guest: I am veterinarian from India. My question is which laboratory method is simplest and quickest to diagnose RABIES ante mortem? Dr. Amanda House: As far as I am aware, there are no definitive ante-mortem diagnostic tests for rabies in the horse. Guest: What is your opinion concerning pre-vaccination of handlers for rabies? Dr. Amanda House: All veterinarians and generally veterinary technicians are vaccinated for rabies. Equine owners and farm handlers are typically not vaccinated. Guest: My horse has been diagnosed with EPM and has been on 7 rounds of Marquis. I heard that horses under treatment for EPM shouldn t vaccinate for rabies nor get ivermectin. Is this true? Dr. Amanda House: I have not heard that, I would still vaccinate. Guest: How come you can give your horse shots but here in NY you can t Dr. Steve Reed: The responsibility for storage, handling and administration of the vaccine needs to be in the hands of a veterinarian especially in light of this being such a dangerous and an always fatal disease Guest: How long can the virus live outside the host? Dr. Amanda House: A very limited time. Typically once saliva is dry, it is not infectious. Heat inactivates the virus. Strong soaps, detergents, acids, and alkalis all inactivate the virus. Guest: I give all my horse s shot s in the spring each year, including rabies. How often should the rabies be re given? I have heard that the shot only last for several months. Dr. Amanda House: It lasts one year. All horses should be vaccinated annually. EquiRab is labeled for every 14 months. For more information on equine health, care and management, visit TheHorse.com 1
Guest: My horses receive a rabies vaccination from the veterinarian each year, along with VEWT and West Nile. Is there something else I need to do to help protect them? Dr. Amanda House: The vaccination is generally very effective in protecting against the rabies virus. Limiting environmental exposure to wildlife may be helpful as well. Guest: As a veterinary student early in my training, I plan on practicing in an area with lots of annual rabies cases (in horses, cattle, goats, as well as the more normal cat, dogs, raccoons etc.) and in a very economically depressed area. Is there any way to help with cost of post-exposure (confirmed disease) cost on the clients property? Dr. Steve Reed: this is a very good question. Post exposure for a vaccinated horse costs would be the cost of re-vaccination and then maintaining the horse in quarantine and in the case of a non vaccinated horse vaccinate all horses on the farm and observe while in isolation Guest: How long is the vaccine effective for? Our veterinarian doesn t recommend vaccination. He says if we want to vaccinate that it should be done in the winter when horses are more likely to contact common rabies carriers such as skunks & raccoons who might be in the horse s barn for shelter. He also said that the vaccine is not effective for a full year after administration. We used to have the vaccination done in the spring with other inoculations, but don t relish the idea of having the vet come here for 2 barn calls in one year. We have 4 older gelding quarter horses ranging in age from 16.5 to 26.5 yrs. Dr. Steve Reed: The vaccine is licensed to be effective for one year. Guest: Do we need to vaccinate for rabies every year or can it be done like cats and dogs every three years? Dr. Steve Reed: At this time all available vaccines for horses carry only one-year protection label to my knowledge. Guest: Do you know the percentage of horses who have an adverse reaction to the rabies vaccine? In the 18 years I have had my horse, he has had many inoculations and never an adverse reaction UNTIL he had a strong adverse reaction to the rabies vaccine. Dr. Steve Reed: I do not know the answer to this, however there is always the possibility of an adverse reaction. Since many horses are vaccinated and the vaccines remain on the market without problem, my guess is the number is quite low Guest: I would like to know how effective the vaccine is in preventing rabies if an animal is exposed to a rabid animal and is a follow up vaccine required. Dr. Steve Reed: The vaccine is likely very effective, however as a reportable disease it is my understanding that no horse would be allowed to be vaccinated after a known exposure. Although the horse could have time to build a protective immunity, the risk of exposing naive people to the disease is great enough that you would most likely only be able to quarantine the animal and watch for signs of disease. I do not know the regulations in every state, however my understanding is as stated above. Guest: I would really like the experts to address off-label use of the vaccine in late-term broodmares. (I live in Virginia.) My therio vet won t give it because it s off-label usage. So I arrange for another vet For more information on equine health, care and management, visit TheHorse.com 2
in her practice to vaccinate my late-term mares. I cannot imagine my foals not having that protection from his or her first moments. There is nothing more curious than a foal -- and investigating that skunk or raccoon in their pasture is nearly a given. Waiting until 3 months to give that protection just seems incredibly reckless. It also seems to me that giving a vaccine off-cycle and in such a narrow window between breed-backs opens the door for the vaccine getting missed. Dr. Amanda House: Rabies vaccination can be administered in the last trimester of pregnancy prior to delivery to protect the foals, although your veterinarian is correct, it is off-label use. Mares that are vaccinated prior to breeding are generally considered to pass adequate antibodies to foals in their colostrum as well. Foals have excellent maternal antibodies to protect them from this disease if the mare has been vaccinated and they have consumed adequate colostrum. Actually, studies have shown that foals of vaccinated mares will not mount an adequate response to vaccination if they are immunized before 6 months of age, due to maternal antibody interference. Guest: Would you recommend vaccinating more than once a year? Dr. Amanda House: No, it should not be necessary for adults unless it is the initial series. Guest: How effective is rabies vaccine? Is one manufacturer better than the others? Are there different strains of rabies like there are for flu? Dr. Amanda House: The rabies vaccine is extremely effective, although no vaccines absolutely guarantee protection. All of the products on the market are excellent. There are different variants of rabies, but the vaccine is generally protective Guest: If a horse is up to date on the rabies vaccine but comes into contact with a rabid animal, can he pass it on unknowingly to his caretakers, although he himself shouldn t get rabies? Dr. Steve Reed: Transmission of rabies from a non-infected but in contact animal would be very unlikely but not impossible. Basically this horse would be acting as a fomite. For example, you come upon your horse having an encounter with a strangely acting wild animal which bites the horse on its nose. The horse immediately backs away and turns to you and buries its head and face in your chest and arms seeking protection; theoretically this could be an exposure for the owner. Guest: I recently moved to the Eastern Plains of Colorado, having previously lived in Western Colorado for 30+ years. Two weeks ago, I had my older gelding and mare vaccinated for Rabies following information that there had been at least six confirmed cases of Rabies in skunks in El Paso County, Colorado. Last week there was a confirmed Rabies and resulting death in a horse in the same area. Following the vaccination, my gelding became quite listless, refused to eat or drink, and spent quite some time lying down in the pasture. I phone my veterinarian and picked up a dose of injectible Banamine for him. Provided that I wish to continue to vaccinate him for this disease, what can I do prophylactically so that he does not again have this type of reaction? Dr. Steve Reed: I cannot answer why your horse had a reaction to this vaccine. However some horses react differently to various products. Since all vaccines appear to be effective options might be to try a different product the next year. Trying to pre-administer Banamine as you did post-vaccine this year might also be an effective treatment Guest: Are there disadvantages to administering the rabies vaccine? Is there any reason not to vaccinate? Dr. Amanda House: I would recommend vaccinating all horses for rabies vaccination, since the disease is For more information on equine health, care and management, visit TheHorse.com 3
always fatal. Adverse reactions can occur but fortunately are rare. Guest: Should I worry about an open water tub in my pasture in terms of contamination from an infected raccoon, etc. drinking from the same source? If the rabies pathogen is on the surface on an outside object- like a feed pan on the ground, what kind of temperatures or environment would kill the pathogen to render it non-infectious? Dr. Amanda House: Rabies does not survive for a long time in the environment, it is not even considered infectious in dried saliva. The chance of infection from a water or feed trough is very small. However, I recommend vaccination of all horses for rabies. Heat inactivates the virus. Strong soaps, detergents, acids, and alkalis all inactivate the virus. Guest: I have my rabies certificate and i noticed that the vet has the wrong age on there will this cause any problems Dr. Steve Reed: Whenever there is an error on a certificate of vaccination it is best to correct this. It is especially important since this will be what you are using to assure yourself and others your animal has been vaccinated. Guest: Do minis get the same dose? Dr. Amanda House: Yes. Guest: Can rats be infected with rabies too Dr. Amanda House: Yes, all mammals can become infected with rabies. Guest: So to correct it, I need to have the vet redo it Dr. Steve Reed: Yes Guest: How long can the virus live outside the host? Are there other ways the horse can contract the virus other than a direct bite, such as drinking water after an infected animal might have drooled in it as in a pond or eating grass where the animal has been? Can someone contract rabies from a vaccinated horse which has had a fresh exposure? Dr. Amanda House: Typically, horses are infected by the bite of infected animals. However, horses that contact the mouth, eyes, or central nervous tissues of infected animals with open wounds or their mouth can become infected. Horses that have been vaccinated will typically not transmit the virus to people or other animals. Guest: If one notices a bite/scratch on a horse would there be some type of post-exposure prophylaxis available for the horse? If so, is there some type of series similar to the human series? Dr. Steve Reed: If one sees a scratch or bite on their horse and was aware of a rabid animal identified in the local environment this still may not constitute an exposure. For a vaccinated horse re-vaccinate and observe; for a non-vaccinated horse isolate and observe Guest: Is the vaccine as effective for older horses (+25 years)? For more information on equine health, care and management, visit TheHorse.com 4
Dr. Amanda House: Yes, the vaccine is as effective for older horses as far as I am aware. Guest: Can they still get the rabies even if they have been vaccinated? Also, is it still deadly? Dr. Steve Reed: The vaccines appear very effective but as has been stated none are 100% effective if an animal developed the disease it will be fatal Is the vaccine as effective if given at same time as a couple of other vaccines? Dr. Steve Reed: it should be.however, to our knowledge there are no evidence based studies on safety and efficacy on the concurrent administration of vaccines.certainly administering a killed and a modified live vaccine at the same site should not be done as this may inactivate the modified live vaccine I know this is about horses but we have cows and goats as well. Should they be vaccinated just like the horses or is there a vaccine for cattle and goats? Thank you! Dr. Amanda House: Yes, there is a vaccine available for cows and goats, and they can also develop the disease. It is recommended to vaccinate all pet goats and cows or other livestock in contact with people. Guest: So would you recommend giving the rabies vaccine at a different time than other vaccines? Dr. Steve Reed: I would not worry about giving this vaccine at a different time but at least at a different site. For more information on equine health, care and management, visit TheHorse.com 5