L7: Infectious Dz Prevention Programs pt.2

Question 1

is strangles a reportable dz in FL?

Answer 1

yes

Question 2

pathogenesis of strangles

Answer 2

-streptococcus equi equi

Question 3

CS of strangles

Answer 3

• fever
• LN enlargement and abscessation
• purulent nasal d/c
• resp. distress due to retropharyngeal LN enlargement

Question 4

transmission of strangles

Answer 4

ingestion or inhalation of infected discharges

• horse/horse, fomite
• highly contagious
• high morbidity, low mortality

Question 5

incubation period of strangles

Answer 5

• 3-14d (shedding begins 1-2d after onset of fever)

- isolate horses with fever ASAP!

Question 6

detection/confirmation of Strangles

Answer 6

• culture of pharynx/Guttural pouch (Gold Standard)
• PCR: nasal swab or nasal flush/guttural pouches (recent outbreaks: 3 neg. PCR to be released from quarantine)
• serology for SeM protein (surface protein of Strep equi equi) –> particularly good for confirming pupura or bastard strangles

Question 7

strangles horses are infectious until?

Answer 7

> or = 4 wks. after CS resolve

• GP is clear
• GP samples negative

Question 8

levels of positive for SeM protein serology

Answer 8

weak positive: repeat in 7-14d
moderate positive: exposure in last 2-3wks or an infection in last 6mo.-2yrs
high positive: complications of S. equi infections or recent vaccination

Question 9

Strangles outbreak hygiene

Answer 9

PPE
foot baths
disinfect stables/transport vehicles
rest pastures - 4wks

Question 10

when to vaccinate for strangles

Answer 10

previously affected farms
farms w/ young stock
sale/show stables
vaccine not completely preventative and may be deleterious

Question 11

IM Strangles vaccine and protocol

Answer 11

M-protein based (IM)

• start at 4-6mo. of age
• boost 1-2x/yr
• can cause abscesses at injection site

Question 12

IN Strangles vax and protocol***

Answer 12

• start at 6-9mo.
• may be more effective
• cannot be used for colostral immunity!!**
• can cause abscess

Question 13

risks of strangles vax

Answer 13

• immune-mediated pupura hemorrhagica (more common in horses with high titer)
• mild form of dz
• abscess formation
• best to check titer and not vax if titer is high

Question 14

regionally used vaccines

Answer 14

Botulism
Potomac Horse Fever
Equine Viral Arteritis (EVA)
Rotavirus

Question 15

botulism causes what syndromes in horse

Answer 15

"Shaker foal syndrome"
Forage poisoning (adult horses)

Question 16

pathogenesis of botulism

Answer 16

toxin blocks transmission of impulses in nerves –> weakness, dysphagia, death, flaccid paralysis

Question 17

Botulism endemic area

Answer 17

Kentucky

mid-Atlantic seaboard

Question 18

2 types of botulism

Answer 18

B and C

Question 19

botulism vax

Answer 19

type B toxoid

• no cross-protection for type C
• recommended in pregnant mares in endemic areas to prevent disease in foals
• give last trimester

Question 20

Potomac Horse Fever cause and endemic region

Answer 20

Neorickettsia risticii

• eastern US, CA
• seasonal (summer)

Question 21

trans. of PHF

Answer 21

trematode parasites of fresh water snails - horses eat caddis flies

Question 22

CS of PHF

Answer 22

severe d/fever

2ary laminitis

Question 23

tx of PHF

Answer 23

oxytetracycline, supportive care

Question 24

vax of PHF

Answer 24

• questionable due to lack of seroconversion and multiple strains of bacteria
• may lessen severity of dz
• start w/ 2 doses 3–4wks apart
• booster q6-12mo.

Question 25

CS/trans/dx of Equine Viral Arteritis

Answer 25

• abortion
• resp/semen trans.
• Dx: titers, virus isolation

Question 26

EVA vax uses***

Answer 26

• used to control outbreaks and prevent trans. from carrier stallions to unaffected broodmares
• must document negative status of stallions before vaccination: vax causes seroconversion and may interfere w/ requirements for export of semen***

Question 27

EVA vax protocol

Answer 27

• modified live
• can use in stallions and open mares
• vax colts at 6-12mo. and seronegative mares if bred to infected stallion

Question 28

rotavirus chars. (all)

Answer 28

• most common cause of infectious d in foals!
• CS: profuse watery d, fever, lethargy
• highly contagious
• tx: supportive care
• prevent: vax pregnant mares before foaling in endemic herds

Question 29

lyme vax

Answer 29

may use canine lyme vax on horses in endemic areas

-dx/tx difficult

Question 30

acute vs. chronic Equine Infectious Anemia

Answer 30

• retrovirus trans. by biting flies or blood contam. needles (mechanical transmission)
• acute: fever, depression, petechia
• chronic: icterus, anemia, dependent edema

Question 31

dx of EIA

Answer 31

“Coggins” test or ELISA

• need neg. test q6-12mo. for travel, show
• reportable dz!

Question 32

is piroplasmosis a FAD?

Answer 32

yes

-US considered non-endemic for now

Question 33

infectious agent of Piroplasmosis

Answer 33

Theileria equi

Babesia caballi

Question 34

trans. of piroplasmosis

Answer 34

tick-borne

mechanical vector

Question 35

CS of piroplasmosis

Answer 35

acute: fever, anemia, jaundice, hemoglobinuria
chronic: weak, decreased appetite

Question 36

Dx of piroplasmosis

Answer 36

cELISA

-used on imports into US