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Streptococcus - URT pathogen - Coggle Diagram
Streptococcus - URT pathogen
Diagnosis
Fine Needle aspiration
Microbial culture
B-haemolytic
Nasal / nasopharyngeal swabs; Nasal / guttural poch washes
Pus from abscess
Chondriods - guttural pouch
Cytology
Gram +ve cocci; chains
Categorisation
Haemolytic patterns
B-haemolytic
Complete haemolysis (clear)
Most pathogenic
A-haemolytic
Partial haemolysis (gray-green)
Human significance
Commensals
Non haemolytic
Lancefield groupings - species specific
Group C - Horses
Polysaccharide variation in cell wall
Bacterial species
Biochemical testing; PCR; MALDI-TOF
Clinical signs
Pyogenic lesions
Suppuration + abscess formation
Regional lymph nodes
Rupture + drain within 2 weeks
Acute duration
Resolved by protective antibodies
Extracellular survival
Type 3 hypersensitivity reactions
Purpura haemorrhagica;
Vasculitis
Diffuse swelling of legs
Sloughing + exudation
Chronic - autoimmune reaction
Glomerulonephritis ; rheumatic fever
Pathogenesis
Virulence factors
Avoid phagocytosis + decrease chemotaxis
M protein*
Prevents complement deposition
Bacterial surface
Ineffective oponisation
Adherence to epithelial cells
Induces antibody production
Develop immunity
Vaccines
Capsule
Antibodies production
Host defence
Polysaccharide / hyaluronic acid
Kill phagocytes
Exotoxin - haemolysin
Vascular damage
Strangles
High morbidity, lower mortality
Young horses: 6mo-5yo
URT inflammation
Abscessation of adjacent lymph nodes
Submandibular + retropharyngeal
Complications
Guttural pouch empyema
"Bastard strangles"
Systemic dissemination
Death - asphyxiation
Pupura haemorrhagica
Type 3 hypersensitivity
Pneumonia
Pre-disposing factors
Stressors
Transportation
Dysfunctional mucociliary escalator
Dehydration; head held up
Endogenous cortisol
Exercise
Exercise Induced Pulmonary Haemorrhage (EIPH)
Blood entry --> LRT
Socialisation ; inhalation
Viral infections
Impaired phagocytic cell function
Bacteriacidal abilities
Loss of cilia , epithelial cells
Disrupt mucosal barrier ; mucociliary function
Stabling
Fomites
Moulds, endotoxin; dust
Ventilation
Ammonia; aerolised pathogens
Overcrowding
LRT infections
Fibrinous pleuropneumonia
Invades sterile areas
Treatment / control
Strangles
Biosecurity
Notifiable in VIC and SA
Disinfectants
Separate items
Boots
Quarantine
6 weeks
-ve culture x3
Antibiotics
Predictable sensitivity pattern
Penicillin
Conditions
Early stages of infection
Inhibit protective immunity
Without abscess
Life threatening
Abscess cannot be drained
Breathing issues
Bastard strangles
Vaccines
Whole cell bacteria
2 in 1 with tetanus
Inactivated
Drainage of abscess
Guttural pouch
Transmission
Commensals
Mucous membranes ; skin
URT, GIT, lower genitourinary tract
Pneumonia
S. equi ss zooepidemicus
Environment
S. uberis - bovine mastitis
Carrier animals - asymptomatic
Maintained in herd
S. equi ss equi
Strangles
Nasal discharge / purulent exudation
Inhalations / contaminated fomites
Obligate parasites
S. agalactiae - cattle mastitis