Eqine Encephalomyelitis Flashcards
What is the common name for equine encephalomyelitis?
Sleeping sickness
This disease is characterized by ____ _______ and moderate to high _______.
CNS dysfunction; mortality.
What family does equine encephalomyelitis belong to?
The Alphaviruses family
What are the types of equine encephalomyelitis?
- Eastern Equine Encephalomyelitis
- Western Equine Encephalomyelitis
- Venezuelan Equine Encephalomyelitis
Where do outbreaks of WEE typically occur?
In the west and midwest united states
The current morbidity of WEE is low due to ________.
Vaccines
EEE typically occur where?
Along the eastern seaboard and gulf coast (including LA)
VEE was isolated in _____ in Venezuela.
1938
In 1971, VEE spread into ____ _____ where _____ horses died.
Southwest Texas; 1500
In the 1930’s an outbreak of WEE in California resulted in more than ______ horse deaths.
180,000
What are the reservoir hosts for EE?
- Birds
- Rodents
- Reptiles
What is the transmission vector for the spread of this disease?
Mosquitos
This disease has been isolated from ____ different types of mosquitos in the U.S.
27
How do infections spread from reservoir hosts to horses?
By mosquitos carrying virus
Horses infected with WEE have a _____ viremia making them a “_____ ____ ____”
Low; Dead End Host
What does it mean when a horse has a low viremia?
Infection does not spread from an infected horse to other healthy horses
Horses infected with VEE have a ____ viremia.
High
What does viremia result in that allows the infection to pass from horse to horse?
viral shedding in body fluids
How can VEE spread to other horses?
Via aerosolized respiratory secretions or direct contact with body fluids
Horses infected with EEE have a ______ but ______ viremia.
Transient but significant
T or F: With EEE transmission from horse to horse is not possible.
False. This is possible
________ are seasonal in temperate region, occurring during warm months but not during cold months
Epizootics
In what state does transmission occur throughout the year with a peak in summer
Florida
Initially horses are _____ and ______ with clinical neurologic signs generally occurring ____ post-infection
Quiet and depressed; 5 days.
What are the clinical signs of this disease?
- Low grade fever
- Altered mentation
- Impaired vision
- Aimless wandering
- Head pressing
- Circling
- Inability to swallow
- Irregular ataxic gait
- Paresis and paralysis
- Terminally, convulsions and death
Most deaths occur within ______after onset of C.S.
2 - 3 days
What is the medical term for the inability to swallow?
Dysphagia
What are some examples of an altered mentation?
- Depression
- Moribund
- Comatose
Surviving horses may be “dummies” what does this mean?
They may have permanent neurologic damage
__________infections may occur with all of the sleeping sickness viruses
Asymptomatic
The mortality rate for WEE is __ to __ %
20 to 50%
The mortality rate for EEE is __ to __ %
50 to 90%
The mortality rate for VEE is __ to __ %
50 to 75%
Which type of EE has the highest mortality rate?
Eastern Equine Encephalomyelitis
What different ways can sleeping sickness be diagnosed?
- Presumptive diagnosis
- Serologic titers
- Virus isolation
What is a presumptive diagnosis of sleeping sickness based on?
- Clinical signs in endemic areas and vaccination history
How is a positive diagnosis with serologic titers made?
By a 4 fold increase between acute and convalescent samples
How are samples taken for a serologic titer?
- 2 samples 4 weeks apart
- 1st taken when clinical signs apparent and then sample and test again 4 weeks later.
How is virus isolation done for this disease?
The virus may be isolated from the CSF of horses with acute infection
T or F: There is an antiviral drug available for the treatment of EE.
False, there is no specific antiviral drug available.
What is the treatment protocol for sleeping sickness?
Supportive care including:
- I.V. fluids,
- Stomach tube feeding,
- Anti-inflammatory agents (MIGHT reduce severity of C.S.)
- anticonvulsants (For muscle spasm, tremors, seizures)
T or F: this disease is not zoonotic.
False. This disease is zoonotic.
How can humans contract this disease?
Not directly from the horse but from the vector.
What are clinical signs in man?
Range from mild flu-like symptoms to death
Who are the most susceptible humans to this disease?
Children, the elderly, and immunosuppressed individuals
In humans the mortality rate of EEE is up to ___ %
75%
In humans the mortality rate of WEE is ___ %
20%
In humans the mortality rate of VEE is ___ %
40%
For prevention you can use the ______ viral vaccine.
Inactivated
This vaccine is available in ____, _____, or ____ form.
mono-, bi-, or trivalent form
How is this vaccine given?
2 injections 30 days apart
How often are boosters given?
Annually or Biannually
How often must boosters be given in Louisiana?
Biannually
_______ _______ will interfere with vaccination.
Maternal antibodies
What is the vaccination protocol for foals?
At 3, 4, and 6 months of age
What is the vaccination protocol for mares?
Vaccinated 3-4 weeks before foaling
What is another important method of prevention?
Vector control –> controlling mosquito population (avoiding leaving stagnant water in yard, spraying pesticides, etc.)
