Strep equi Flashcards
What is the most common agent identified in horses in the United States, 6 to 10 years old?
Strep. equi
What are the first signs of Strep equi infection occurring 3 to 14 days after exposure and before most horses are contagious?
Pyrexia with lethargy
What clinical signs of strangles are present that may accompany horses reluctant to eat or drink?
significant pharyngitis
Squeezing the larynx in horse with strangles causes what clinical signs?
marked pain
stridor
gagging followed by coughing
Which lymph nodes are typically involved in Strangles?
submandibular
retropharyngeal
LNs
When do abscesses typically develop and rupture in Strangles?
-lymphaenopathy is a typical C/S
-abscess develop a thick fibrous capsule
-rupture in 7 days and 4 weeks after infection
What percentage of horses with guttural pouch empyema exhibit an intermittent unilateral nasal discharge and cough?
approximately 50%
What neurologic signs can be seen with strangles?
-neuropraxia (external trauma) resultign in temporary laryngeal hemiplegia, dysphagia or both
-recurrent laryngeal nerve damage– difficulty breathing
-dysphagia
Not all infections are with S. equi are confined to the upper respirtory tract with abscesses reported in multiple sites referred to as:
bastard strangles
Upon entering the mouth or nose, S. equi attaches to the cells located where?
w/in crypts of lingual and palatine tonsils & to follicular assoc epithelium of the pharyngeal and tubal tonsils
Why, are nasal and nasopharyngeal samples culture negative in the early stages of infection?
b/c a few hours after infection, a few hours after infection, the organism is difficult to detect on mucosal surface, but visible within epithelial cells and subepithelial tonsillar follicles
Visible abscessation after S. equi infection occurs in what time frame after S. equi enters the lymph nodes?
3 to 5 days
How does Strep equi resist phagocytosis?
hyaluronic acid capsule
anti-phagocytic SeM protein
H factor binding Se 18.9
Mac protein
When does nasal shedding occur after infection with S. equi?
2 to 3 days after onset of fever and persists for 2 to 3 weeks in most animals
Systemic and mucosal immune responses are evident within what time frame after infection and coincide with mucosal clearance of strangles?
2 to 3 weeks after infection
If not treated with antibiotics, what percentage of horses with strangles develop long-term convalescent immunity as a result of individual immune response as well as natural exposure to disease over time contributing to reboosting and herd immunity?
approximately 75%
Approximately what percentage of horses become susceptible to a second attack of strangles within several months? and due to what?
approximately 20 to 25%
– failiure to produce or maintain adequate mucosal & systemic antibodies
–ongoing exposure to S. equi
Which horses can develop catarrhal or atypical strangles (mild form)?
-older horses with residual immunity
-foals with waning maternal antibody protection
-vaccinated animals have limited susceptibilty
What animals shed virulent S. equi that will produce severe disease in more susceptible, often young, horses?
horses with catarrhal or atypical strangles
milk from mares that have recovered froms trangles contains which immunoglobulins?
-IgGb and Iga specificities
When does shedding of strangles occur?
not until 1 or 2 days after onset of pyrexia
**makes it possible to isolate new cases before they can transmit infection
nasal shedding of strangles typically persists for how long?
2 to 3 weeks in most animals
Horses can be infectious for at least how many weeks after their purulent discharges have dried up?
at least 6 weeks
Persistent guttural pouch infection with strangles may result in intermittent shedding for how long?
**persist intermittent shedding for years
