Equine Diseases 1

Question 1

Salmonellosis

Answer 1

o Horses may have Salmonella spp. As normal gut flora
o Can be very contagious to other horses
o Can be zoonotic!
o Can be very contagious to other horses.
o Easily spread by fomites

Question 2

Causes of Salmonellosis

Answer 2

o	Stressful situations
o	Sudden changes in feed.
o	Antibiotic use. 
o	Illness.
o	Surgery
o	Immunosuppression.
o	Nosocomial origin.

Question 3

Clinical Signs of Salmonellosis

Answer 3

	Signs similar to colitis.
	Acute, profuse, watery, foul-smelling diarrhea.
	Fever
	Anorexia
	Often neutropenia

Question 4

o Management of Salmonellosis

Answer 4

 Isolation is very important!!!!!
 Horse should be assigned to one tech.
 Protective clothing: gown, gloves, boots.
 Disinfect feet and wash well after handling the horse.
 I.V. fluid therapy: balanced electrolyte solutions such as LRS
Maybe a probiotic
Maybe fecal transfers
 Plasma transfusion if hypoprotienemia is present.
 Monitor vital signs.
 Antibiotics will make it worse!

Question 5

Vaccine

Answer 5

Preparations of killed or attenuated microbes administered to activate the immune system against those microbes

Question 6

Toxoid

Answer 6

A toxin that has been treated to destroy it’s toxic properties but allow an immune response to form antibodies against the toxin.

Question 7

Titers

Answer 7

o a measurement of the amount of antibodies produced from antigenic stimulation, such as a vaccination
o Initial vaccinations may not produced sufficient titers to protect the patient, so more, or “booster” vaccination are needle for adequate titers

Question 8

Core vaccines

Answer 8

o Vaccines to protect against the most prevalent equine diseases
o AAEP recommends
 Tetanus
 Easter/Western Equine Encephalitis
 West Nile
 Rabies- not as common/ don’t always give

Question 9

Common Equine Vaccines

Answer 9

	Equine 5 way
•	Encephalomyelitis:  Eastern, Western, Venezualan 
•	Influenza
•	Rhinopneumonitis 
	TetanusToxoid 
	Tetanus Antitoxin
	West Nile Virus
	Rabies 
	Equine Influenza

Question 10

Spread of Equine Influenza

Answer 10

o Direct contact between horses.

o Air borne particles (aerosols)

Question 11

Management of Equine Influenza

Answer 11

o Isolate infected animals.
o Keep horse warm in well ventilated stall.
o Avoid stressful situations.
o Rest until full recovery is important to prevent relapses.
Will recover, it just takes awhile

Question 12

Clinical Signs of Influenza:

Answer 12

o	Lethargy and depression.
o	Fever.
o	Severe, dry cough.
o	Increased lung sounds (in some cases).
o	Watery nasal discharge.
o	Anorexia.
Constipation. Constipation- flowed by colic laminitis
o	Some muscle soreness.

Question 13

Infection of Equine Influenza is more frequent in the winter and spring because of:

Answer 13

o Low temperatures
o High humidity
o It can occur year – round

Question 14

Equine Influenza virus

Answer 14

o Respiratory disease
o Most common in horses age 1-3
o Found most common where there is a high movement of horses
o Passed through direct contact (air borne)
o All normal flu symptoms
o Need to re vaccinate in high risk horses
Seen at stables and horse shows
Viral strains

Question 15

Equine Influenza Vaccines

Answer 15

o Viral Strains in U.S. are A/1 & A/2.
o Vaccines are available in both injections and intranasal forms.
o Intranasal vaccines provides immunity at the point of infection.
o Immunity is short-lived, revaccination required every 2 to 3 months for horses at risk for infection.
Have an intranasal version for horse- short lived

Question 16

Equine Encephalomyelitis or Sleeping sickness

Answer 16

• Carried by biting insects such as mosquitos.
• Birds are the natural host of the virus- intermediate host
• Horse and people are “dead-end” hosts.
• Causes severe disease and death in horses and people.
• Can’t spread from the birds- Humans and horses can’t spread the disease- dead end
• Not transmissible horse to horse, or people to people, or horse to people.

Question 17

Clinical Signs of Equine Encephalomyelitis or Sleeping sickness

Answer 17

o Severe depression – “sleeping”.
o Anorexia.
o Convulsions.
o Death: death rate is 19% to 90%.

Question 18

Three strains of Equine Encephalomyelitis or Sleeping sickness cause disease in horse

Answer 18

o Eastern Equine Encephalomyelitis (EEE)
o Western Equine Encephalomyelitis (WEE)
o Venezuelan Equine Encephalomyelitis (VEE)
o EEE and WEE are in the U.S., but not VEE due to vaccination (vaccines have all 3).

Question 19

Rhinopneumonitis or Equine Herpes Virus (EHV)

Answer 19

• Pregnant mares are vaccinated at the 5th, 7th and 9th month of gestation.
• It’s a good idea to vaccinate all the horses if there are breeding mares on the farm.
• Common vaccination is called Flu/Rhino.
• Can cause abortion storms and /or respiratory signs depending on the strain
• Vaccinate pregnant mares at 5th, 7th, and 9th month
• Isolate

Question 20

Management of EHV-4

Answer 20

o Isolate infect animals
Can’t kills a virus- only support
o Avoid stressful situations (ie. trailering)
o Exercise for brief periods to keep blood and lymph circulation
o Keep warm in well ventilated stall.

Question 21

Clinical signs of EVH-4:

Answer 21

o Usual signs of respiratory disease as well as:
 Increased lung sounds.
 Possibly swollen lymph nodes.

Question 22

Four strains of EVHcause disease in horses, two are important and contained in the vaccine:

Answer 22

o EHV-1 : Causes abortion storms in mares and neurologic disease.
o EHV-4: Causes respiratory disease in young horses and rarely abortion.

Question 23

West Nile Virus

Answer 23

• Clinical signs variable: usually neurologic (weakness, tremors).
• Mortality rate in horses 30% to 40%.
o Carried by biting insects
o Birds are the natural host- kills birds
• Foreign disease before 1999.
• Prevalent throughout the U.S.
• Caused by a virus that infects some birds and mosquitos and Culicoides flies.
• Crows, Jays, Humans and Horses are dead end hosts.

Question 24

West Nile Virus Vaccine

Answer 24

• Vaccinate before mosquito season.
• Requires two vaccines 30 days apart, then given once yearly.
• Vaccinate before mosquito season- if they are not year round
• New vaccine may require booster even in previously vaccinated horses- because they are that different

Question 25

Rabies

Answer 25

• Very low incidence in Washington state.
• Horses in states with Rabies in wildlife should be vaccinated.
• Always fatal.

Question 26

Rabies signs in horses

Answer 26

o Dumb Rabies: depression, anorexia.

o Rage: Aggressive behavior, very rare.