Rabies and Horses: What’s the Risk?By Mark A. Yoder, DVM Student (Class <strong>of</strong> 2013)Edited by Dr. Stacy H. Tinkler, <strong>Purdue</strong> Equine Community PracticeIf you have ever wondered: “Can horses get rabies?”, “What arethe signs <strong>of</strong> rabies?”, “How is rabies spread between animals?”,or “Is my horse at risk and how can I prevent rabies?”, thenkeep reading!What is rabies?Rabies is a viral disease that can infect all mammals and resultsin neurologic disease—disease <strong>of</strong> the brain and spinalcord—that causes your horse to move or behave abnormally.There are a few different ways that rabies can be transmittedbetween animals and to humans, but the most common isthrough bite wounds <strong>of</strong> infected animals. Once an animal orhuman is exposed, the virus multiplies in the muscle aroundthe site <strong>of</strong> the bite wound. Eventually the virus travels up theperipheral nerves (outer nerves in extremities) and gets into thecentral nervous system (brain; spinal cord). Finally, the viruswill move from the central nervous system to various tissuesin the body; most importantly the salivary glands. This makesit possible for the virus to then be passed on to other animalsthrough the saliva via bite wounds.Top 7 Pointers for PreventingHyperthermia in Your Horse this SummerBy Dr. Janice Kritchevsky, Large Animal Internal Medicine Service, <strong>Purdue</strong> <strong>University</strong>IntroductionMany horse owners think summeris the best time <strong>of</strong> year. The showand fair season is in full swing, andit’s the best time for camping, trailriding, and many <strong>of</strong> the other activitiesthat make owning a horse sucha pleasure. Like humans, horses cool <strong>of</strong>f by producing sweat and byincreasing their respiratory rate. If the horse becomes so hot thatsweat and increased respiration cannot cool it down, hyperthermiaresults. Body temperatures above 105.8ºF can cause life threateningdamage to the body’s cells unless cooled <strong>of</strong>f quickly. Below are somethings to consider before hitting the trails this summer. If you have anyquestions about your own horse, be sure to contact your veterinarian.1. Know the difference between hyperthermia and a feverA fever is an increase in body temperature that occurs when the brainincreases the thermal set point, <strong>of</strong>ten in response to an infection orinflammation. Hyperthermia is an increase in body temperature thatoccurs because <strong>of</strong> an increase in heat from external sources. Usuallythe horse is otherwise healthy. While there is a maximal increase inits own temperature that a horse can reach due to fever, there is nomaximum with hyperthermia. This is why hyperthermia is so muchmore dangerous than fever.2. Know if your horse is at riskHorses that are older, debilitated, suffering from an illness,or have just moved to a hot climate from a cooler place areat increased risk <strong>of</strong> developing hyperthermia. Fans, shade, andfresh water should be available to horses at increased risk <strong>of</strong> hyperthermiaat all times.3. Access to fresh waterWhen a horse becomes dehydrated, blood supply to the skin is shutdown so that blood flow to vital organs is preserved. In addition, lesssweat can be produced. Both situations hinder a horse’s ability to coolitself <strong>of</strong>f. Horses will drink more water in the summer to compensatefor losses in the sweat; sometimes doubling their intake from that inthe winter. It is important that their increased water needs are metby having fresh, potable water available.4. Access to electrolytesIn addition to water, horse sweat has high concentrations <strong>of</strong> electrolytessuch as sodium, chloride, and calcium. Like water, it mustbe replaced for the horses to be able to cool <strong>of</strong>f. Electrolytes can be<strong>of</strong>fered to the horse in the form <strong>of</strong> a balanced complete diet, or assupplemental electrolytes that can be fed alone or added to water.If electrolyte water is <strong>of</strong>fered, always <strong>of</strong>fer fresh water as well.5. Trailers can become hot boxesLike a car with its windows rolled up, a closed up trailer becomesextremely hot when standing in the hot sun. If a horse must be keptin a trailer for any period <strong>of</strong> time, make sure that there is adequateventilation by opening windows and vents.6. Do not overworkMuscles generate heat when they are exercised, and a gallopinghorse must dissipate a large amount <strong>of</strong> muscle heat. This is moredifficult for a horse as the ambient temperature increases. Graduallyincrease the amount <strong>of</strong> exercise asked <strong>of</strong> a horse so that its body canadapt. During the very hottest days <strong>of</strong> summer, reserve hard trainingtimes to the cooler times <strong>of</strong> the day. Watch for signs <strong>of</strong> overheating,and do not continue with a horse that feels hot to the touch, stopssweating, or has an increased respiratory rate after stopping.7. Recognize anhydrosisAnhydrosis is the inability to sweat. A horse that cannot sweat has lostits best cooling mechanism, and is at very high risk <strong>of</strong> hyperthermia.A horse with anhydrosis will feel hot and dry to the touch, and willnot sweat when hot. To compensate, the respiratory rate increasesdramatically and <strong>of</strong>ten a horse with anhydrosis is believed to havepneumonia or some other respiratory disease. A horse that cannotsweat must be kept in a shaded, cool spot with good ventilation untila veterinarian has been able to examine the horse.