Learn more about the following conditions that could affect your horse.

Equine Gastric Ulcer Syndrome (EGUS)
Parasites of Horses
Viral Diseases of Horses

Equine Gastric Ulcer Syndrome (EGUS)

Horses' digestive systems are made for grazing. When horses can't graze, excess acid accumulates, which may result in the development of stomach ulcers, also known as Equine Gastric Ulcer Syndrome or EGUS.

More than 90% of race¹ and 60% of performance horses suffer with stomach ulcers² and these ulcers can develop in just 5 days³.

For your horse, the difference between this stomach and this stomach could be just five days.

Situations that may contribute to equine stomach ulcers:

¹Murray MJ, Schusser GF, Pipers FS, Gross SJ. Factors associated with gastric lesions in Thoroughbred racehorses. Equine Vet J. 1996; 28:368-374.
²Mitchell, RD. Prevalence of Gastric ulcers in hunter/jumper and dressage horses evaluated for poor performance. Association for Equine Sports Medicine, September 2001.
³McClure SR, Carithers DS, Gross, SJ, Murray MJ. Gastric ulcer development in horses in a simulated show or training environment. J Am Vet Med Assoc;2005;227;775-777.

Parasites of Horses
All horses should be included in a regular parasite control program. Foals should be treated initially at 6 to 8 weeks of age, and routine treatment repeated as appropriate.

Equine parasites:

• Bots (Gastrophilus spp)
  
• Equine intestinal threadworm (Strongyloides westeri)
  
• Equine Lungworm (Dictyocaulus arnfieldi)
  
• Horse roundworm (Parascaris equorum)
  
• Large-mouth stomach worm (Habronema muscae)
  
• Large strongyles (Strongylus vulgaris, S. equinus, S. edentatus)
  
• Neck Threadworm (Onchocerca cervicalis, aka nuchal ligament worm, neck threadworm; O. reticulata, aka ligament worm)
  
• Pinworm (Oxyuris equi)
  
• Small strongyles (Cyathostomum spp, Cylicocyclus spp, Cylicodontophorus spp, Cylicostephanus spp)
  
• Hair worm (Trichostrongylus axei)

Viral Diseases of Horses

West Nile Virus
Since equine West Nile Virus (WNV) first appeared in the United States in 1999, it has reached epidemic proportions. In 2001, the number of infected horses with clinical signs in the United States was greater than all prior reported clinical cases of West Nile encephalitis in horses worldwide. Variety of WNV-permissive native avian and mosquito hosts suggests few limitations for geographic spread, and the threat is expected to continue westward. Since late 2003, recurrence of cases in the same geographic location in sequential years has been a unique feature of the U.S. experience with this virus. Neurologic disease is a hallmark of WNV, which causes a polioencephalomyelitis. Lesions increase in number through the mid-brain, progress through the hind-brain, and frequently increase in severity distally throughout the spinal cord. Clinical signs can include increased body temperature, anorexia, weakness, ataxia, abnormal mentation, fasciculations, cranial nerve deficits, teeth grinding and ptyalism. Differential diagnosis includes alphaviruses, rabies, equine protozoal myeloencephalitis (EPM), equine herpes virus-1, botulism and verminous meningoencephalomyelitis.

Eastern and western encephalitis (encephalomyelitis)
These variations of equine encephalomyelitis are clinically similar syndromes characterized by signs of CNS dysfunction and moderate to high mortality. The causal arboviruses are transmitted by mosquitoes or ticks and infect a variety of vertebrate hosts, including man, in which they occasionally cause serious infections. Horses may be infected by alphaviruses including eastern (EEE), western (WEE), and Venezuelan (VEE) equine encephalomyelitis viruses. Clinical signs of an encephalomyelitis occur approximately 5 days after infection, and most deaths occur 2-3 days later. Signs can include fever, impaired vision, irregular gait, wandering, reduced reflexes, circling, incoordination, yawning, grinding of teeth, drowsiness, pendulous lower lip, inability to swallow, photophobia, head-pressing, inability to rise, paralysis, occasional convulsions, and death. Mildly affected animals may recover slowly in a few weeks but may have residual brain damage. Mortality in horses is 20-50% from WEE, 50-90% from EEE, and 50-70% from VEE.

Influenza
Equine influenza is an acute, highly contagious, febrile respiratory disease. The clinical outcome following viral exposure largely depends on immunological conditioning; in susceptible animals this may vary from a mild, inapparent infection to a severe disease that is rarely fatal except in young, old, or debilitated horses. Transmission occurs via the respiratory route through contact with infective respiratory secretions. Epidemics arise when one or more acutely infected horses are introduced into a susceptible group for show, sale, training, or racing.

Tetanus
Horses are the most sensitive species to this disease, with the possible exception of humans. Tetanus is a toxemia caused by a specific neurotoxin produced by Clostridium tetani in necrotic tissue. The incubation period varies from one to several weeks, but usually averages 10-14 days. Localized stiffness, often involving the masseter muscles and muscles of the neck, the hindlimbs, and the region of the infected wound is seen first; general stiffness becomes pronounced approximately 1 day later, and tonic spasms and hyperesthesia become evident. Mortality averages 80%.

Rabies
Rabies is an acute, viral encephalomyelitis that affects all warm-blooded animals. The mortality rate approaches 100%. The incubation period is prolonged and variable. Rabid animals of all species exhibit typical signs of CNS disturbance. Horses may show extreme agitation evidenced by rolling, as with colic. They may bite or strike viciously and, because of size and strength, become unmanageable in a few hours. Such animals frequently suffer self-inflicted wounds.

Potomac Horse Fever
Potomac horse fever (equine ehrlichial colitis, equine monocytic ehrlichiosis) is an acute diarrheal syndrome caused by Ehrlichia risticii. The disease is seasonal, with a high incidence during summer and autumn, and because it can be transmitted by blood inoculation, an arthropod vector is suspected. The first signs following a 9- to 12-day incubation period are depression, anorexia, fever, mucous membrane injection, and ileus. Diarrhea may be seen within 24 hours after the first signs. Severity varies considerably, but in the absence of treatment, mortality approaches 30%.