Strangles Flashcards
Strangles is caused by
Streptococcusequi
virulent isolates are/are not encapsulated
are encapsulated
The capsule
impedes neutrophils to bind/ingest/kill
Transmission
purulent discharge
direct and indirect contact
Are there carriers?
Yes. Some horses continue to shed the bacteria weeks after clinical signs have disappeared
Bacteria enter through the __________________ and affect the___________
mouth/nose
tonsils
The __________________ is infected in 10% of horses
guttural pouch
This develops in the guttural pouch of some horses
empyema
The empyema allows the horse to transmit disease for
years
Bacteria reach the _________________ and ________________ lymph nodes within _________
mandibular and suprapharyngeal
hours
Clinical signs: Fever ______ days after exposure
3 - 14
Clinical signs: ____________ nasal discharge
mucopurulent
Clinical signs: swelling and __________ formation
abscess
Clinical signs: behavioral
anorexia, depression
Clinical signs: discharge from the
eyes (ocular)
Older horses develop a milder/stronger disease
milder
Nasal shedding of bacteria (timeframe, start/stop)
after latent period of 4-14 days and stops 3-7 weeks post acute infection unless guttural pouches infected.
Irritations (3)
pharyngitis, laryngitis, rhinitis
In infection of the guttural pouch, pus collects
on the ventral floor
the thickened, congealed pus that results from empyema
chondroids
Diagnosis of strangles
Culture of nasal swabs/ washes/ aspirated pus
Blood tests - serology
Compare titers between sequential samples
PCR (most sensitive)
Serum titers peak at ___ (days/weeks/months) after exposure and remain high for at least ___
5 weeks
6 months
The greatest challenge with strangles is the
asymptomatic carriers
_____ % of horses on farms with recurring strangles are carriers
4-50%
All horses that had signs of infection should be tested __ times and be negative on all before being reintroduced to healthy horses
3
Treatment (feed)
soft, moist, palatable
Antibiotics are only useful before
abscess formation
most horses do/do not require antibiotics
do not
Challenge of horses treated with antibiotics
do not develop immunity and are highly likely to be reinfected if they are exposed again
Abscess treatment
hot packs/ichthamol to enhance maturation/drainage
lance once matured
daily flushing of open abscess with 3-5% povidone
NSAIDS
maybe antibiotics (penicillin, cephalosporins, macrolides) after abscess is suppurated
If antibiotics are used, treatment usually takes
weeks
antibiotic of choice
penicillin
Bastard Strangles
Metastasis (spread) may occur to other locations - carried by bloodstream or lymphatic vessels, causing abscesses in other parts of the body: lung, liver, spleen, kidqneys, brain
Bastard strangles can happen in up to ___% of infected horses
30%
Other complications
septic arthritis
pneumonia
purpura hemorrhagica
Purpura Hemorrhagica caused by
immune complexes attacking good vessel walls
Treatment of Purpura Hemorrhagica
Dexamethasone + antibiotics
Immunity to strangles persists
5+ years
Vaccine types
IM, intra-nasal
Horses that have had strangles in the previous year should/should not be vaccinated
should not
What makes quarantine of strangles horses difficult?
sub-clinical carriers
movement of horses
Always handle _____ horses first
“clean”
Pastures used to house infected horses should be rested for ___ days/weeks/months
4 weeks
The __________ vaccine provides the best local immunity
intranasal
Improper vaccination can result in
poor protection or complications at injection site
Do not vaccine during
an outbreak or after clinical infection
_______________ testing can help determine better timing for vaccination
blood antibody
Penicillin challenges
IM is very painful
Oral is less effective
IV must be given at hospital
