Friday, April 1, 2011

Vaccines Debunked, Part I

Disclaimer: I am not a veterinarian and while I hope you find my advice helpful, you need to always check with your vet before changing/adding something that could in anyway affect your horse’s health.

As some of you may have already been able to tell by the giant mud holes that used to be your horse’s pasture, spring is here! Cue winter blankets being stored away, horse hair coming off in tuffs (and going everywhere), show schedules being sent out, and a general sense of relief that winter is finally… FINALLY… over. Spring also means something else for many horse owners and barn managers around the world: time to call the vet out for spring shots.

When you get right down to it, vaccines are pretty complicated. Every horse owner has a different opinion on what to give their horse and when to give it. Some states require certain vaccines, while others could care less. Some vaccines are given in the nose, some in the neck. Some cause big reactions and come cause bigger reactions. So how the heck do you know what your horse should get and what they shouldn’t? And it’s not as if the vaccines themselves are helpful in understanding what they do. Here are the generic names of four different vaccines I pulled from www.unitedvetequine.com

V + WNV, EWT + WNV, TEK + EWT, Encevac TC-4 VEE.

Huh? Is this some complicated algebraic equation I never learned how to solve in high school?

Many of us solve the dilemma of what vaccines to give our horse by simply handing the problem over to our vet. “My horse is due for his vaccines. What does he need? Uh huh, uh huh… Again so soon? Didn’t he get that six months ago? OK, well if you’re sure… See you in a week!” Sound familiar? I thought so.

Does your horse need a tetanus shot every year? What about rabies? Coggins? Eastern and Western Encephalomyelitis? Rhinopneumonitis (EHV-1 and EHV-4)? Influenza (A2 and KY97)? West Nile Virus? Yikes, when it’s spelled out like that it does seem overwhelming. With technology these days seven of those vaccines can be given in ONE SHOT that’s simply called Fluvac Innovator 7-Way. What the heck are those vaccines protecting our horses against? I originally intended to only write one post on the subject of vaccines, but decided to break it into two parts because of that very reason. Before you even start thinking about what vaccines to give your horse, you should have a good understanding of what the vaccines are intended to protect your horse from in the first place.

WEST NILE VIRUS. The only known way a horse can be infected by the WNV is if they are bitten by an infected mosquito. WNV cannot be transmitted from horse to horse. Signs that a horse has been infected with WNV include stumbling, weakness in hind limbs, circling, ataxia, inability to stand, listlessness and head shaking. The rate of full recovery from WNV is very high. WNV has been found in nearly every state. This map shows the number of detected cases (note that these are NOT deaths) in 2010.



EASTERN ENCEPHALITIS. EEE (sleeping sickness) is a viral disease that is spread by infected mosquitoes. EEE cannot be transmitted from horse to horse. It effects the central nervous system and has a very high mortality rate. Symptoms include unsteadiness, erratic behavior, lethargy, and loss of coordination. There is no effective treatment and seizures resulting in death usually occur 48-72 hours after neurological symptoms have set in. The fatality rate is 90%. In 2010 there were 230 EEE cases reported in the United States.

WESTERN ENCEPHALITIS. WEE is transmitted via mosquitoes and is also commonly referred to as sleeping sickness. An infected horse will exhibit the same symptoms as EEE, but to a lesser degree. According to the US Department of the Interior’s website (which tracks diseases for human, animal, and mosquito) there were no reported WEE infections of horse or human in 2010 in the entire United States and there has not been a serious outbreak of the virus in twenty years.

EQUINE INFECTIOUS ANEMIA. Ever wonder why your horse needs to have a coggins? This virus is why. EIA is a highly infectious viral disease that has no treatment, vaccine, or cure. Symptoms include fever, weight loss, anemia, swelling in the limbs, and overall weakness. Because there is no treatment or vaccine for EIA, horses who become infected are often put down or forced into complete isolation for the rest of their lives. While EIA is not common (in 2009 only thirty one horses were infected across the entire United States) the Coggins test is. Most boarding barns and horse shows require a horse to have a negative Coggins (showing they do not have EIA) before letting them on the property. If you are crossing state lines you also need a Coggins. Most Coggins expire after two years, but it isn’t a bad idea to have your horse tested every year. It is a simple blood test and very inexpensive.

TETANUS. Tetanus is a bacterial disease that can affect animals and people. It is caused by the bacterium Clostridium tetanii which can be found in soil and fecal matter just about everywhere. It enters the body through wounds, especially puncture wounds. Symptoms include muscular stiffness and spasms which become increasingly worse. Left untreated, tetanus is lethal and even when it is caught early it has a high mortality rate.

BOTULISM. Like tetanus, botulism is a bacterial disease caused by the bacterium Clostridium botulism. Botulism is similar to tetanus, but is even more lethal. Horses can become infected through an open wound (again, like tetanus) or by ingesting feed that has been contaminated with the bacteria (dead/decaying things such as a rat in a hay bale can carry it). Symptoms include muscle tremors, extreme weakness, tongue control loss (may hang from mouth), drooling, and walking stiffly. Botulism has a 90% mortality rate.

RHINOPNEUMONITIS. EHV 1 & EHV 4 is a respiratory disease caused by the herpes virus 1 and herpes virus 4. Because it can be passed from horse to horse, it is highly contagious and outbreaks need to be taken very seriously (any horse that is even suspected of having Rhino needs to be immediately quarantined and everything it came into contact with over the past seven days disinfected). Symptoms include fever, congestion, coughing, loss of appetite, swollen lymph nodes, and nasal/eye discharge. EHV 1 can also cause abortion and stillbirths in pregnant mares. Recovery in healthy adult horses is usually good, but complications can occasionally develop.

EQUINE INFLUENZA. Commonly known as the horse flu, EI is a common respiratory disease that is most often found in young horses (age one to five). It is highly contagious and is most often passed by coughing. Symptoms include a dry hacking cough, fever, runny nose, lethargy, and reluctance to eat/drink. Horses who get EI almost always recover after two to three weeks of rest and antibiotic support.



STRANGLES. Strangles is a highly contagious disease that spreads from horse to horse via direct contact. Once a horse is exposed the strangles bacteria they will normally begin to show symptoms within one to five days. Those symptoms include abscessed lymph nodes (which, if left untreated, will rupture and drain), fever, low appetite, and a thin, watery nasal discharge that will turn thick and yellow as the disease progresses. Strangles is most often found in young horses (age one to five) and while it does not have a high mortality rate, it is very dangerous because of how contagious it is.

RABIES. In horses, rabies is 100% fatal. A horse who tests positive for rabies will be (and should be) immediately euthanized. Rabies is passed through the saliva of an infected animal. Rabies is transferable to humans.

There you have it. The main diseases/infections/viruses your horse can be vaccinated against (or, in the case of EIA, tested for). What are you planning to vaccinate your horse for this spring?