Should my horse get a strangles vaccine?

Most horse people are familiar with the dreaded “s- word”: strangles. But if there is a strangles vaccine available, why isn’t vaccination essential for all horses, like the rabies vaccine?

What is strangles?

Equine strangles is caused by infection with the bacteria Streptococcus equi var equi, causing mild to severe upper respiratory infection. Complications from infection can occasionally be fatal, but most horses fully recover. Strangles is a high morbidity disease, meaning it is extremely contagious in susceptible populations.  Proper biosecurity measures are crucial to limit the scope of an outbreak.

Pony with Strangles shows swelling from abscessed lymph nodes

Signs of strangles include fever, swelling of the lymph nodes (especially in the throat latch area), loss of appetite, cough, and significant mucoid yellow nasal discharge. The bacteria mobilize to the lymph nodes and causes intense immune response, so frequently these lymph nodes abscess open and drain. The term strangles originated from the harsh respiratory noise heard when severe swelling and lymph node abscesses can impair the horse’s ability to breathe.

Most infected horses respond well to supportive care. Supportive measures include anti-inflammatories, hot-packing of abscesses, and rest. More severe cases may benefit from hospitalization and antibiotics. To prevent the spread of strangles, hospitalized cases are managed in the isolation unit.

How does strangles spread?

Strangles is easily spread by horse-to-horse contact and via contaminated surfaces, such as handler clothing and hands, grooming equipment, and water troughs. Most horses will clear the infection within 3-6 weeks, but it is possible for some horses to recover fully and remain shedders of strangles. These horses appear healthy but will shed the bacteria and continue to infect other horses. Upon recovering from strangles, horses will be protected against reinfection for variable periods of time, sometimes even a few years.

Strangles vaccine options

Two types of strangles vaccines are available. One is a “killed” vaccine, meaning it contains dead/inactivated strangles. This vaccine is administered intramuscularly.  Killed vaccines produce a weaker immune response, so it is still possible for a horse vaccinated with this vaccine to develop strangles if exposed. Per the American Association of Equine Practitioners, the killed vaccine should not be expected to prevent disease. It may be effective in lessening the severity of infection. There is also an increased risk of vaccine site reaction with this product.

The second type of vaccine is called a “modified live” vaccine. This vaccine type uses a weakened form of strangles to stimulate a stronger immune response. In order to accomplish this, the vaccine is administered intranasally to target the same tissues as natural strangles infection. However, it is also possible for this modified live vaccine to cause lymph node abscesses, much like natural strangles infection. Horses that have natural immunity to strangles (those who have recovered from infection) have a higher risk of adverse reactions to strangles vaccination.

Should my horse have the strangles vaccine?

The take-home point is that we currently lack a perfect strangles vaccine. If your horse is in a high-risk population, discuss the pros and cons of strangles vaccination with your veterinarian to evaluate if strangles vaccination is worthwhile. It is important to remember that vaccination does not guarantee that your horse will not get strangles. Proper biosecurity is essential to prevent and limit strangles outbreaks.

Horse Show/Travel Biosecurity

The arrival of spring means long-awaited opportunities for trail riding, clinics, and horse shows. However, travel, new stabling, and the mixing of horse populations can also provide the perfect conditions for the spread of disease. With a little planning and biosecurity awareness, you can minimize potential risks to your horse.

What is Biosecurity?

Biosecurity refers to the preventative measures taken to minimize spread of disease. The most commonly encountered infectious diseases include influenza (flu), rhinopneumonitis (equine herpes virus), and strangles. While many horses are vaccinated against these diseases, vaccination does not guarantee 100% protection and does not negate the need for biosecurity.

How do I take effective biosecurity measures?

Some biosecurity measures are common sense – such as not allowing your horse to have nose-to-nose contact with other horses. Other measures are more complex.

First, consider your destination. Horse show venues and campgrounds may have specific requirements for incoming horses, such as a current Coggins test, health certificate, and proof of up-to-date vaccination. Remember to keep your veterinarian apprised of your summer travel plans so that you have all required documentation prior to your departure. While it can be frustrating to manage differing requirements, remember they are put in place for the health and safety of the horse.

When arriving at a campground or show stable, examine the housing for your horse prior to unloading. Look for overall cleanliness – an area free of manure and old bedding. It’s worth asking the venue how facilities are cleaned between horses prior to your arrival. Dirt floors and other porous surfaces are much harder to disinfect since organic debris can inactivate cleaners such as bleach.

Simple and easy biosecurity measures:

  • Prevent all direct contact between your horse and others (no nose-to-nose!)
  • Avoid sharing equipment with others, including; tack, grooming supplies, wheelbarrow, pitchfork, etc.
  • Avoid communal water sources/sharing hoses between horses. Dropping the end of the hose into multiple water buckets can transmit disease.
  • Wash your hands frequently and after touching any other horses.
  • Pack your horse’s thermometer. If your horse appears “off” a fever may be present before he is contagious to others.
  • Don’t forget to clean and disinfect your trailer regularly too!

Wishing you a safe, happy, and healthy riding season!

Is your horse current on his rabies vaccination?

Rabies is caused by a virus that infects mammals and is spread through the saliva/bites by infected animals. The virus exists in several wild animal reservoirs, most commonly bats, skunks, raccoons, and foxes. After the virus is transmitted via bite, it replicates in the muscle at the site of the bite, and then travels to the central nervous system (brain and spinal cord). The virus continues to replicate in the central nervous system and then spreads through the rest of the body, including the salivary glands, which then allows transmission to other susceptible animals.

Is rabies a problem in Colorado?

In 2019, there were 173 lab-confirmed cases of animal rabies in Colorado, including canine, feline, and camelid cases. So far in 2020, Colorado has seen 71 lab-confirmed cases of rabies, including in a dog, goat, sheep, and bull. It is important to remember that because rabies is endemic in bat, skunk, and raccoon populations, these numbers don’t accurately represent the true prevalence of this disease.

What does rabies look like in horses?

While mention of rabies conjures images of a frenzied animal frothing at the mouth, clinical signs in the horse can be extremely variable, so many people may be potentially exposed before a diagnosis is made. Non-specific signs of rabies in horses can range from colic and lameness to fever and depression. There is no available testing to diagnose rabies in the live horse. When examining an un-vaccinated horse exhibiting bizarre behavior or neurologic signs, your veterinarian must consider rabies as a potential diagnosis. Signs in an infected horse progress rapidly, usually leading to death within 5-7 days. Rabies is always fatal in an unvaccinated horse.

The rabies vaccine is a core vaccine for horses, according to the American Association of Equine Practitioners (AAEP). A core vaccine is one that is essential for every horse, regardless of the horse’s lifestyle. Rabies is a FATAL disease but it is preventable through annual vaccination by your veterinarian. Because human infection is also fatal, rabies vaccination in domestic animals is a matter of public health. Any person who may have potential exposure to rabies should immediately contact their health provider.

Protect your horse- and yourself! Be sure to keep your horse’s rabies vaccination current, and don’t forget to vaccinate your barn cats and dogs!

Core Vaccines

***This blog was originally written in January of 2020, and as of today, March 24th, 2020, times have changed significantly.  With Covid-19 causing the issues that it is, we feel it necessary to add the following statement.

Governor Polis on 3/20/2020, in Colorado Executive order 2020 009, made veterinarians part of the list of essential workforce to continue with “necessary procedures.”  For the safety and welfare of horses, the Mobile Veterinary Services vaccination schedule will continue as planned.  If delayed 3 or more months, depending on conditions, our horses will become susceptible to deadly diseases.  

As always, at MVS, we strive for clear client communication.  We will keep everyone informed to the best of our abilities as to the orders placed on us as veterinarians.  Please feel free to call with individual questions that you may have. ***

There is a long list of vaccines available to give our horses.  Owners and even veterinarians can get bogged down in the details, and that’s just based on the vaccines available. 

Then we start to talk about schedules for each group of horses.  Groups like Adult horses vaccinated in the past, Adult horses with no known or no history of vaccines, Foals (of vaccinated mares), Foals (of unvaccinated mares), oh yeah, and the broodmares!  Whew, I think that covers the horse population!!!

Really quickly a discussion of “just vaccines,” gets complicated.  Mobile Veterinary Services will always fall back on, “talk with your veterinarian to make a plan for YOUR herd and their individual needs.”  Here, we would like to discuss “core vaccines.”

What is a core vaccine? 

As defined by the AAEP (American Association of Equine Practitioners) a core vaccine “protects against diseases that are endemic to a region, are virulent/highly contagious, pose a risk of severe disease, those having potential public health significance, and/ or are required by law.  Core vaccines have clearly demonstrable efficacy and safety, with a high enough level of patient benefit and low enough level of risk to justify their use in ALL equids.”  It’s a mouthful, but what does it mean?  In the end, it means that they are safe, low risk, and designed and developed to protect horses and humans alike. 

These are the Core Vaccines recognized by the AAEP:

Tetanus:  Should be given annually.  If there is a question as to the status of a horse, they should receive a 2-dose series (4- 6 weeks apart).  Colts should receive a 3 shot series beginning around 6 months of age, second dose 1 month later, and another dose at 1 year old. 

EEE/WEE (Eastern Equine Encephalitis/ Western Equine Encephalitis):  Just like the Tetanus, it should be given annually, and they should go through an initial 3 dose series.  Conveniently, tetanus is often in a combination vaccine with these two. 

West Nile Virus:  As with the two above, West Nile should be given annually.  This is often in combination with WEE/EEE and Tetanus and can be given to colts and fillies in one shot on the same 3 dose schedule. 

Rabies:  Rabies is 100% fatal, in ALL species.  All youngsters should receive 2 vaccines starting around 6 months old (second one about 1 month later).  Then, every horse, every year should receive a booster. 

Every horse should receive at least these vaccines, every year.

It is important that these vaccines are handled correctly and managed at the appropriate temperature and environment to ensure that the vaccine is an effective and SAFE one.  This is the biggest reason that we recommend that you receive your vaccines from a licensed veterinarian.   If you ever have questions about your herd’s (no matter how big or small) vaccination protocol, please feel free to reach out to MVS!

Spring Time Tune Up For Horses

QUESTION: Is it time for spring shots?

ANSWER:

Warm days, green grass, tulips beginning to show, and the familiar buzz in the background are all signs that Spring is here.The first thought is, “it’s too early”, but sure enough, the bugs are here.Insects are powerful and efficient transmitters of disease.It is the threat of their annual appearance, which reminds us that is time to consider our horses and their “spring shots.”

The term “spring shots” can be a vague one.In general, we consider it the vaccinations which will cover insect borne diseases, as well as those communicable diseases that are passed from horse to horse as we start getting them out, and hitting the proverbial trail.

One of the more commonly administered vaccines for spring is often referred to as a 5-way shot.This label represents the 5 diseases that the vaccine is meant to prevent; Eastern Equine Encephalitis (EEE), Western Equine Encephalitis (WEE), Tetanus, Influenza (Flu), and Rhinopneumonitis (Rhino).This year you may also hear of a 6-way shot, which adds West Nile Virus (WNV) to the above vaccine.

EEE, WEE and WNV are all diseases that are transmitted by mosquitoes.These diseases most commonly cause a condition known as encephalitis, which is swelling and inflammation in the brain and spinal cord.Infection with these diseases can be life threatening and leave some horses with permanent nerve damage.

Flu and Rhino are diseases that we consider respiratory diseases most commonly.Like the flu and cold in humans, our equine companions can catch these viruses from other infected horses, sick or not.Also like humans, our horses can exhibit similar respiratory symptoms when affected by these viruses.Runny noses, coughing and fever are commonly seen when horses are sick from Flu or Rhino.

Horses as a species are also one of the most susceptible animals to Tetanus.Tetanus happens when the bacteria Clostridium tetani infects a closed wound.The disease can be fatal if not caught VERY early and is easily preventable with yearly booster vaccination.

Along with vaccines, there are a few other “house keeping” things to consider with your horses.Spring is a good time to remember to de-worm your horses.In the spring, we usually use a combination de-wormer.Combination de-wormers are an Ivermectin product, combined with another class of de-wormer called Praziquantel to provide coverage against any possible tapeworms.Having a routine dental examination to assess whether or not your horse is due for a dental float is also a good idea.

Spring is also a great time to clean up your pens (hopefully before mud season is here!) and consider how to best manage your horses to minimize exposure to insects.A good fly control program can improve the quality of your horses’ day to day life, as well as decreasing exposure to bacterial and viral diseases.Also making sure that there is no unnecessary standing water around to minimize the exposure to mosquitoes (for horses AND humans) can really decrease exposure of everyone to West Nile Virus.

By getting all of the preventative care and house-keeping tasks completed this Spring, you can focus on spending time with your horse, in the saddle or otherwise, and enjoy all of the nice weather that a Colorad

Horse Rabies In Colorado

rabies_shotQUESTION:
I have heard on the news over the last week or so about a couple of cases of Rabies in horses here in Colorado. Should we be vaccinating the horses for Rabies?

ANSWER:
The short answer is yes, here at MVS, we are currently recommending rabies vaccines for all of our equine patients.
There are many different “variants” of rabies, but here in Colorado we are concerned about only two. Bat rabies is carried in insectivorous bats (they eat only insects) here in Colorado and there is a low incidence of exposure and therefore transmission of the disease. Skunk (or terrestrial) rabies is carried by skunks and has a higher chance of exposing domestic pets and horses. Here in Colorado we have always had an incidence of bat rabies (though never reported in horses before 2009). Since 2008 there have been an increasing number of cases of skunk rabies reported. This has also led to a small increase in the number of domestic animals that have been exposed and tested positive for rabies, including a small number of horses. Since 2009, El Paso, Adams, and Douglas counties have each reported a case of rabies in a horse.

For a small cost each year, a horse can be protected from this 100% fatal disease. The vaccine is effective at protecting the horses, and is also quite safe. For a disease like rabies, where there are very serious public health ramifications to you and your family, the rabies vaccine is a great idea. Although the risk of exposure is still small, a properly vaccinated horse is the only horse that will survive infection with rabies.

As a note, we spoke with the state veterinarian today, and they confirmed that a horse has to be vaccinated by a licensed veterinarian to be considered protected from the disease. Therefore, in the event of a suspected rabies exposure, if your horse was not vaccinated by a veterinarian, they will be considered unvaccinated by the State of Colorado!