L7: Infectious Disease Prevention Programs (Mallicote)

Question 1

considerations for infectious disease program

Answer 1

-risk/cost of contracting disease, and vaccination

Question 2

considerations when choosing site of IM injection

Answer 2

neck, chest, or back end

-anaphylactic reaction and local tissue reaction may affect performance if in neck

Question 3

vaccine efficacy depends on:**

Answer 3

type of vaccine and route of administration

Question 4

individual response to vax may be affected by:

Answer 4

stress
illness
nutrition
concurrent meds
presence of colostral Ab

Question 5

Vax in foals

Answer 5

3 rounds, starting at 6mo.

• some exceptions
• caution: maternal interference

Question 6

vaccine titers

Answer 6

• no research to establish protective titers or challenge the duration of immunity!
• prolonging intervals may inc. risk of dz
• tetanus titers should be done yearly

Question 7

2 types of vaccines

Answer 7

core

risk-based

Question 8

risk-based vaccine goal

Answer 8

minimize or eliminate diseases that affect performance or herd health

Question 9

core vaccines

Answer 9

tetanus
encephalidities (EEE, WEE, WNV)
Rabies

Question 10

cause of tetanus

Answer 10

spores from Clostridium tetani

• present in intestines, manure, soil
• enter horse through wounds, lacerations, umbilicus

Question 11

CS of tetanus

Answer 11

• stiff gait
• facial m. spasm
• third eyelid prolapse
• “Sawhorse” stance
• excessive response to external stimulation
• recumbency
• m. stiffness

Question 12

prevention of tetanus

Answer 12

• vaccinate ALL horses annually with tetanus toxoid vacine
• use tetanus antitoxin for previously unvaccinated horses or neonates (beginning at 6mo. with 2 boosters)
• booster if open wound or sx procedure >6 mos. since vaccine

Question 13

tetanus contagious b/w horses?

Answer 13

no

Question 14

mortality rate of tetanus

Answer 14

> 80%

Question 15

types of viral encephalomyelitis

Answer 15

EEE
WEE
WNV
Venezuelan Equine Encephalomyelitis

Question 16

seasonal difference in WNV activity

Answer 16

:)

Question 17

seasonality of EEE

Answer 17

higher incidence in summer months

Question 18

lifecycle of EEE

Answer 18

birds are reservoirs, transmitted by mosquito. Horses and humans = dead end hosts

Question 19

viral encephalomyelitis mortalities

Answer 19

EEE: 75-95%
VEE: 40-90%
WEE: 20-50%
WNV: 30-35%

Question 20

CS of EEE

Answer 20

• starts with low grade fever, then high fever during viral proliferation
• neuro signs 5d after exposure
• death 2-3 days later
• behavior change: irritable, hyperexcitable, dec. food and water consumption, self mutilation
• dementia
• cn deficits
• ataxia –> seizures

Question 21

CN deficits assoc. with EEE

Answer 21

nystagmus
facial paralysis
lingual and pharyngeal paresis

Question 22

seasonality of WNV

Answer 22

higher July through November

Question 23

what part of brain does EEE affect? WNV?

Answer 23

EEE: cerebral cortex
ENV: mid-hind brain/spinal cord

Question 24

vaccination protocol for EEE/WEE in FL

Answer 24

booster every 4-6mo.

• naive horses: 2 vax 2-4wks apart
• best to booster 1 mo. before peak mosquito season

Question 25

vaccination protocol for WNV

Answer 25

(depends on vax used; every 1-2 yrs) - broodmares: 30-60d prior to foaling - foals: begin at 3-4mo. with 3 total vax

Question 26

most common rabies reservoir in FL

Answer 26

raccoons

Question 27

rabies vax protocol for horses

Answer 27

adults: annual vax with killed vax IM foals: 6 mo, 8-9 mo, 10-12 mo. * not a legal requirement in horses

Question 28

risk-based vaccines**

Answer 28

influenza Equine herpesvirus (Rhinopneumonitis) Strangles

Question 29

incubation period of equine influenza

Answer 29

1-3d

Question 30

susceptible equine population for influenza

Answer 30

<3yo, stress/travel

Question 31

CS of influenza

Answer 31

``` high fever (1-5d) "week of rest for every day of fever!" cough for weeks and nasal d/c lethargy reduced appetite muscle soreness ```

Question 32

equine influenza vax protocol

Answer 32

- q6-12mo. to decrease viral shedding - broodmares: IM vax in last 30d of preg. - foals: at least 6 mo. of age

Question 33

3 types of vax for equine influenza

Answer 33

traditional inactivated IM modified live cold-adapted IN canarypox vector vaccine IM

Question 34

EHV-1 vs. EHV-4 char. by

Answer 34

EHV-1: abortion, neonatal death, neurological disease, resp. disease EHV-4: respiratory disease (similar to the flu)

Question 35

Equine herpesvirus (EHV) aka

Answer 35

rhinopneumonitis

Question 36

chars. of EHV-4

Answer 36

- CS like flu - incubation time 2-10 days - shed virus for 2-3wks - most common in weanlings and yearlings

Question 37

trans. of EHV

Answer 37

- respiratory route or contaminated equipment - horses can be asymptomatic carriers - considered directly contagious!** - stress can cause recrudescence

Question 38

prevention of resp. EHV

Answer 38

- vax to dec. shedding of virus and severity of CS - foals and weanlings: start b/w 4-6 mo., 4wks later, then at 10-12 mo. - yearlings: every 6 mo. - broodmares: 5,7,9 mo. of pregnancy, then 30 days prior to foaling with EHV-1 and 4 for colostral immunity

Question 39

EHV abortion occurs at what gestation usually

Answer 39

7-9mo.

Question 40

control of EHV outbreak

Answer 40

- isolate new arrivals - disinfect transport - isolate horses with fever - keep aborted material away from herd; isolate mare