On Aug. 26, a 3-year-old Standardbred gelding in Carroll County, Maryland, tested positive for West Nile virus (WNV). The gelding, who is unvaccinated, developed neurologic deficits on Aug. 20. He is still alive. 

EDCC Health Watch is an Equine Network marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. The EDCC is an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.

WNV 101

West Nile virus is transmitted to horses via bites from infected mosquitoes. Not all infected horses show clinical signs, but those that do can exhibit:

• Flulike signs, where the horse seems mildly anorexic and depressed;
• Fine and coarse muscle and skin fasciculation (involuntary twitching);
• Hyperesthesia (hypersensitivity to touch and sound);
• Changes in mentation (mental activity), when horses look like they’re daydreaming or “just not with it”;
• Occasional drowsiness;
• Propulsive walking (driving or pushing forward, often without control); and
• Spinal signs, including asymmetrical weakness; and
• Asymmetrical or symmetrical ataxia.

West Nile virus has no cure. However, some horses can recover with supportive care. Equine mortality rates can reach 30-40%.

Studies have shown that vaccines can be effective WNV prevention tools. Horses vaccinated in past years need an annual booster shot, but veterinarians might recommend two boosters annually—one in the spring and another in the fall—in areas with prolonged mosquito seasons. In contrast, previously unvaccinated horses require a two-shot vaccination series in a three- to six-week period. It takes several weeks for horses to develop protection against the disease following complete vaccination or booster administration.

In addition to vaccinations, owners should work to reduce mosquito population and breeding areas and limit horses’ mosquito exposure by:

• Removing stagnant water sources;
• Dumping, cleaning, and refilling water buckets and troughs regularly;
• Keeping animals inside during insect feeding times (typically early in the morning and evening); and
• Applying mosquito repellents approved for equine use.

A 7-year-old Quarter Horse gelding in Cache County, Utah, recently tested positive for West Nile virus (WNV). The horse developed clinical signs on Aug. 20, including weakness, muscle fasciculations, and neurologic behavior. He is now recovering. 

EDCC Health Watch is an Equine Network marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. The EDCC is an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.

WNV 101

West Nile virus is transmitted to horses via bites from infected mosquitoes. Not all infected horses show clinical signs, but those that do can exhibit:

• Flulike signs, where the horse seems mildly anorexic and depressed;
• Fine and coarse muscle and skin fasciculation (involuntary twitching);
• Hyperesthesia (hypersensitivity to touch and sound);
• Changes in mentation (mental activity), when horses look like they’re daydreaming or “just not with it”;
• Occasional drowsiness;
• Propulsive walking (driving or pushing forward, often without control); and
• Spinal signs, including asymmetrical weakness; and
• Asymmetrical or symmetrical ataxia.

West Nile virus has no cure. However, some horses can recover with supportive care. Equine mortality rates can reach 30-40%.

Studies have shown that vaccines can be effective WNV prevention tools. Horses vaccinated in past years need an annual booster shot, but veterinarians might recommend two boosters annually—one in the spring and another in the fall—in areas with prolonged mosquito seasons. In contrast, previously unvaccinated horses require a two-shot vaccination series in a three- to six-week period. It takes several weeks for horses to develop protection against the disease following complete vaccination or booster administration.

In addition to vaccinations, owners should work to reduce mosquito population and breeding areas and limit horses’ mosquito exposure by:

• Removing stagnant water sources;
• Dumping, cleaning, and refilling water buckets and troughs regularly;
• Keeping animals inside during insect feeding times (typically early in the morning and evening); and
• Applying mosquito repellents approved for equine use.

Two horses in Clarke County, Virginia, recently tested positive for strangles. 

One of the affected horses is a suckling Tennessee Walking Horse colt. The colt initially lived at a facility in Tennessee with an ongoing strangles outbreak. He was shipped from Tennessee to Virginia in early August and developed a fever and throatlatch swelling on Aug. 19. He was subsequently referred to an equine hospital, where he tested positive for strangles on Aug. 26. He has improved with medical management. 

The second horse is a 12-year-old Tennessee Walking Horse mare. She does not have clinical signs. 

EDCC Health Watch is an Equine Network marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. The EDCC is an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.

About Strangles

Strangles in horses is an infection caused by Streptococcus equi subspecies equi and spread through direct contact with other equids or contaminated surfaces. Horses that aren’t showing clinical signs can harbor and spread the bacteria, and recovered horses remain contagious for at least six weeks, with the potential to cause outbreaks long-term.

Infected horses can exhibit a variety of clinical signs:

• Fever
• Swollen and/or abscessed lymph nodes
• Nasal discharge
• Coughing or wheezing
• Muscle swelling
• Difficulty swallowing

Veterinarians diagnose horses using polymerase chain reaction (PCR) testing with either a nasal swab, wash, or an abscess sample, and they treat most cases based on clinical signs, implementing antibiotics for severe cases. Overuse of antibiotics can prevent an infected horse from developing immunity. Most horses make a full recovery in three to four weeks.

A vaccine is available but not always effective. Biosecurity measures of quarantining new horses at a facility and maintaining high standards of hygiene and disinfecting surfaces can help lower the risk of outbreak or contain one when it occurs.

Working With a Strong but Willing Mare

“The walk feels quite good so that is when I will go to the trot. If I feel that she gets a bit resistant, I will go back to the walk.

“It’s all about learning.”

“Can you see when I take the left rein? I’m not just holding it. I play a little bit with it. So taking, giving, taking, playing a little bit with it and giving.”

Listening to the Rider’s Aids

“We are looking for a shortened frame, not just a shortened neck. We want her frame a little shorter from her tail to her ears. A great way to do that is a little lengthening in the canter then bringing her back.”

“You want to hold the half-halt a little bit longer to finish the half-halt. I don’t want to do a little lengthening in canter, give one half-halt, then let go because she wouldn’t get it. You want to really finish the half-halt where you can say, ‘Right here I feel quite comfortable releasing and she stays with me and collected a few strides on her own.’”

“Within the trot, do a few transitions. Start with posting trot. Do a gentle lengthening and allow her to go. For her, you don’t need to push much. Then, sitting trot to bring her back. Even if you get a walk step that is still much better than her running through the bridle.”

“Expect lightness.”

Improving Responsiveness

“When you lengthen the canter, do just about 10-15 meters of lengthening along the rail—no longer. Then, bring her back to a collected canter. Build it up daily to go longer in the lengthening but not faster.”

“For collecting, it is a holding leg—not a pushing forward, driving leg—with support from the seat.”

“When going from trot to halt, see if you can eliminate the walk steps before she halts.”

Watch & Learn on E+

• You can watch Steffen Peters’ entire series on managing a strong mare here on EQUESTRIAN+.
• For additional videos featuring Peters’ top tips and training strategies, click here.
• From short training tips to how-to videos and insider-access to private clinics and lessons, learn more from top dressage experts on EQUESTRIAN+.

About Steffen Peters

Born in Wesel, Germany, Steffen Peters gained a solid dressage foundation in his birth country before moving to San Diego in 1985. He struck out on his own as a trainer in 1991 and become a U.S. citizen in 1992. Peters worked his way to the top level with the support of special horses and sponsors, achieving impressive results. He is a six-time Olympian who earned team silver (2021) and team bronze (1996, 2016) medals. Peters collected team silver (2018), team bronze (2006) and individual bronze (2010) at the FEI World Equestrian Games, team and individual gold at the 2011 and 2015 Pan American Games and the 2009 FEI Dressage World Cup Final title. He and his wife, Shannon, run SPeters Dressage in San Diego, California.

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On Aug. 22, a 3-year-old Quarter Horse stallion in Polk County, Iowa, tested positive for West Nile virus (WNV). The horse, who is unvaccinated, developed clinical signs on Aug. 16, including ataxia, facial nerve paralysis, fever, and lethargy. He is now recovering. 

EDCC Health Watch is an Equine Network marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. The EDCC is an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.

WNV 101

West Nile virus is transmitted to horses via bites from infected mosquitoes. Not all infected horses show clinical signs, but those that do can exhibit:

• Flulike signs, where the horse seems mildly anorexic and depressed;
• Fine and coarse muscle and skin fasciculation (involuntary twitching);
• Hyperesthesia (hypersensitivity to touch and sound);
• Changes in mentation (mental activity), when horses look like they’re daydreaming or “just not with it”;
• Occasional drowsiness;
• Propulsive walking (driving or pushing forward, often without control); and
• Spinal signs, including asymmetrical weakness; and
• Asymmetrical or symmetrical ataxia.

West Nile virus has no cure. However, some horses can recover with supportive care. Equine mortality rates can reach 30-40%.

Studies have shown that vaccines can be effective WNV prevention tools. Horses vaccinated in past years need an annual booster shot, but veterinarians might recommend two boosters annually—one in the spring and another in the fall—in areas with prolonged mosquito seasons. In contrast, previously unvaccinated horses require a two-shot vaccination series in a three- to six-week period. It takes several weeks for horses to develop protection against the disease following complete vaccination or booster administration.

In addition to vaccinations, owners should work to reduce mosquito population and breeding areas and limit horses’ mosquito exposure by:

• Removing stagnant water sources;
• Dumping, cleaning, and refilling water buckets and troughs regularly;
• Keeping animals inside during insect feeding times (typically early in the morning and evening); and
• Applying mosquito repellents approved for equine use.

Two horses in Sacramento County, California, recently tested positive for the respiratory form of equine herpesvirus (EHV). Two additional horses are suspected to be positive, and 10 horses have been exposed. 

EDCC Health Watch is an Equine Network marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. The EDCC is an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.

EHV 101

Herpesvirus is highly contagious among horses and can cause a variety of ailments in equids, including rhinopneumonitis (a respiratory disease usually found in young horses), abortion in broodmares, and EHM.

In many horses, the first or only sign of EHV-1 infection is fever, which can go undetected. In addition to fever, other common signs of EHV-1 infection in young horses include cough, decreased appetite, depression, and a nasal discharge. Pregnant mares typically show no signs of infection before they abort, and abortions usually occur late in gestation (around eight months) but can be earlier. Abortions can occur anywhere from two weeks to several months following infection with EHV-1.

Horses with EHM usually have a fever at the onset of the disease and might show signs of a respiratory infection. A few days later, neurologic signs such as ataxia (incoordination), weakness or paralysis of the fore- and hind limbs, urine retention and dribbling, loss of tail tone, and recumbency (inability to rise) develop.

Herpesvirus is easily spread by nose-to-nose or close contact with an infectious horse; sharing contaminated equipment including bits, buckets, and towels; or clothing, hands, or equipment of people who have recently had contact with an infectious horse. Routine biosecurity measures, including hygiene and basic cleaning and disinfection practices, should be in place at all times to help prevent disease spread.

Current EHV-1 vaccines might reduce viral shedding but are not protective against the neurologic form of the disease. Implementing routine biosecurity practices is the best way to minimize viral spread, and the best method of disease control is disease prevention.

According to the state veterinarian, one horse in Johnson County, Wyoming, has tested positive for West Nile virus (WNV). 

EDCC Health Watch is an Equine Network marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. The EDCC is an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.

WNV 101

West Nile virus is transmitted to horses via bites from infected mosquitoes. Not all infected horses show clinical signs, but those that do can exhibit:

• Flulike signs, where the horse seems mildly anorexic and depressed;
• Fine and coarse muscle and skin fasciculation (involuntary twitching);
• Hyperesthesia (hypersensitivity to touch and sound);
• Changes in mentation (mental activity), when horses look like they’re daydreaming or “just not with it”;
• Occasional drowsiness;
• Propulsive walking (driving or pushing forward, often without control); and
• Spinal signs, including asymmetrical weakness; and
• Asymmetrical or symmetrical ataxia.

West Nile virus has no cure. However, some horses can recover with supportive care. Equine mortality rates can reach 30-40%.

Studies have shown that vaccines can be effective WNV prevention tools. Horses vaccinated in past years need an annual booster shot, but veterinarians might recommend two boosters annually—one in the spring and another in the fall—in areas with prolonged mosquito seasons. In contrast, previously unvaccinated horses require a two-shot vaccination series in a three- to six-week period. It takes several weeks for horses to develop protection against the disease following complete vaccination or booster administration.

In addition to vaccinations, owners should work to reduce mosquito population and breeding areas and limit horses’ mosquito exposure by:

• Removing stagnant water sources;
• Dumping, cleaning, and refilling water buckets and troughs regularly;
• Keeping animals inside during insect feeding times (typically early in the morning and evening); and
• Applying mosquito repellents approved for equine use.

Four horses in Utah recently tested positive for West Nile virus (WNV). The horses live in Utah, Weber, and Cache counties.

In Utah County, an under-vaccinated, 6-year-old Quarter Horse mare tested positive after developing clinical signs on Aug. 15, including inappetence and facial fasciculations. She is recovering. 

In Weber County, a vaccinated, 2-year-old filly tested positive after developing clinical signs on Aug. 17, including wobbliness and facial fasciculations. She was treated in an equine hospital and is now recovering.

Also in Weber County, a 15-year-old gelding tested positive after developing clinical signs on Aug. 14, including inappetence and weakness in the hind end. He was hospitalized and is now recovering. 

In Cache County, an unvaccinated yearling filly tested positive after developing clinical signs on Aug. 22, including slight ataxia and mild drooping lip. She was treated on the farm and is recovering. 

EDCC Health Watch is an Equine Network marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. The EDCC is an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.

WNV 101

West Nile virus is transmitted to horses via bites from infected mosquitoes. Not all infected horses show clinical signs, but those that do can exhibit:

• Flulike signs, where the horse seems mildly anorexic and depressed;
• Fine and coarse muscle and skin fasciculation (involuntary twitching);
• Hyperesthesia (hypersensitivity to touch and sound);
• Changes in mentation (mental activity), when horses look like they’re daydreaming or “just not with it”;
• Occasional drowsiness;
• Propulsive walking (driving or pushing forward, often without control); and
• Spinal signs, including asymmetrical weakness; and
• Asymmetrical or symmetrical ataxia.

West Nile virus has no cure. However, some horses can recover with supportive care. Equine mortality rates can reach 30-40%.

Studies have shown that vaccines can be effective WNV prevention tools. Horses vaccinated in past years need an annual booster shot, but veterinarians might recommend two boosters annually—one in the spring and another in the fall—in areas with prolonged mosquito seasons. In contrast, previously unvaccinated horses require a two-shot vaccination series in a three- to six-week period. It takes several weeks for horses to develop protection against the disease following complete vaccination or booster administration.

In addition to vaccinations, owners should work to reduce mosquito population and breeding areas and limit horses’ mosquito exposure by:

• Removing stagnant water sources;
• Dumping, cleaning, and refilling water buckets and troughs regularly;
• Keeping animals inside during insect feeding times (typically early in the morning and evening); and
• Applying mosquito repellents approved for equine use.

On Aug. 25, a 6-year-old Belgian mare in Allen County, Indiana, tested positive for West Nile virus (WNV). The mare, who was unvaccinated, developed clinical signs on Aug. 21, including muscle fasciculations and hind limb ataxia, which progressed to recumbency. She was euthanized. 

EDCC Health Watch is an Equine Network marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. The EDCC is an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.

WNV 101

West Nile virus is transmitted to horses via bites from infected mosquitoes. Not all infected horses show clinical signs, but those that do can exhibit:

• Flulike signs, where the horse seems mildly anorexic and depressed;
• Fine and coarse muscle and skin fasciculation (involuntary twitching);
• Hyperesthesia (hypersensitivity to touch and sound);
• Changes in mentation (mental activity), when horses look like they’re daydreaming or “just not with it”;
• Occasional drowsiness;
• Propulsive walking (driving or pushing forward, often without control); and
• Spinal signs, including asymmetrical weakness; and
• Asymmetrical or symmetrical ataxia.

West Nile virus has no cure. However, some horses can recover with supportive care. Equine mortality rates can reach 30-40%.

Studies have shown that vaccines can be effective WNV prevention tools. Horses vaccinated in past years need an annual booster shot, but veterinarians might recommend two boosters annually—one in the spring and another in the fall—in areas with prolonged mosquito seasons. In contrast, previously unvaccinated horses require a two-shot vaccination series in a three- to six-week period. It takes several weeks for horses to develop protection against the disease following complete vaccination or booster administration.

In addition to vaccinations, owners should work to reduce mosquito population and breeding areas and limit horses’ mosquito exposure by:

• Removing stagnant water sources;
• Dumping, cleaning, and refilling water buckets and troughs regularly;
• Keeping animals inside during insect feeding times (typically early in the morning and evening); and
• Applying mosquito repellents approved for equine use.