Difference between revisions of "Streptococcus equi subsp. equi"
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− | + | Causes [[Strangles|Strangles]] | |
− | Causes | ||
− | + | *Epidemiology | |
− | Strangles is highly | + | **[[Respiratory Bacterial Infections - Pathology#Strangles|Strangles]] is a highly infectious disease of horses caused by ''Streptococcus equi'' subsp. ''equi'' |
+ | **[[Respiratory Bacterial Infections - Pathology#In Horses|upper respiratory tract disease of horses]] with fever and abscessation of regional lymph nodes | ||
+ | **Causes [[Nasal Cavity Inflammatory - Pathology#Strangles|rhinitis]], [[Nasopharynx Inflammatory - Pathology|pharyngitis]], lymphadenitis and [[Muscles Inflammatory - Pathology#Abscesses|myositis]] | ||
+ | **Outbreaks in groups of young horses | ||
+ | **Transmitted via purulent exudate discharging from upper respiratory tract or from lymph nodes | ||
+ | **Chronic, carrier state can occur with bacteria im the guttural pouch | ||
+ | **A mild, atypical form can occur | ||
+ | **''S. equi'' shed for 4 weeks beyond clinical resolution | ||
− | + | *Clinical signs | |
+ | **Incubation period 3 to 6 days | ||
+ | **Fever, depression, anorexia | ||
+ | **Purulent nasal discharge | ||
+ | **Swollen, painful regional lymph nodes, especially submandibular | ||
+ | **Abscessation and rupture of lymph nodes | ||
+ | **Guttural pouch empyema | ||
+ | **100% morbidity; 5% mortality | ||
+ | **Death can occur from pneumonia, breathing difficulties from swollen lymph nodes or [[Muscles Degenerative - Pathology#Ischaemia|purpura haemorrhagica]](an immune-mediated disease) | ||
+ | **Bastard strangle may occasionally occur, with abscessaation in many organs of the body | ||
+ | **''S. equi'' may be involved in [[Bacterial skin infections - Pathology#Systemic bacterial infections|cutaneous lesions]] | ||
− | + | *Diagnosis | |
+ | **Clinical signs and history | ||
+ | **Mucoid colonies with beta-haemolysis | ||
+ | **Sugar fermentation allows differentiation of ''S. equi'' from ''S. zooepidemicus'' and ''S. equisimilis'' | ||
+ | **PCR to detect asymptomatic carriers | ||
− | + | *Treatment and control | |
+ | **Penicillin administration to in-contact animals | ||
+ | **Isolation of affected animals | ||
+ | **Quarantne in-coming animals | ||
+ | **Avoid overcrowding and mixing different age groups | ||
+ | **Disinfection of equipment | ||
− | + | *Caused by very pathogenic ''Streptococcus equi subsp. equi'' | |
+ | *Haemolytic streptococci of Lancefield group C are common inhabitants of the equine nasopharynx | ||
+ | *''[[Streptococcus zooepidemicus]]'' and ''S. equisimilis'' are usually non-pathogenic | ||
+ | *Typically [[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|suppurative rhinitis]], [[Nasopharynx Inflammatory - Pathology#Infectious causes of pharyngitis|pharyngitis]] and '''lymphadenitis''' of the lymph nodes of the head and neck that drain the upper respiratory tract, these lymph nodes often rupture and discharge pus 2-3 weeks after the onset of infection | ||
+ | *Infection with ''Streptococcus equi'' occurs after contact with contaminated feed, water bowls or an infected carrier [[Hindgut Fermenters - Horse - Anatomy & Physiology|horse]] | ||
+ | *Organism remains viable in environment for months | ||
+ | *Possibility of other sources of infection - in pharynx of in-contact dogs?, guttural pouches of persistently infected horses | ||
+ | *Attaches to nasopharyngeal epithelial cells, then mucosa, lymphatics and lymph nodes | ||
+ | *Multiplies extra-cellularly | ||
+ | *Gross pathology | ||
+ | **Initial bilateral nasal discharge, serous becoming purulent | ||
+ | **Catarrhal conjunctivitis may be present | ||
+ | *Less frequently, complications can occur as follows : | ||
+ | **Purulent inflammation may extent to [[Guttural Pouches Inflammatory - Pathology|guttural pouches]] or [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|lungs]], [[Paranasal Sinuses Inflammatory - Pathology#Infectious causes of sinusitis|sinusitis]] | ||
+ | **Bacteraemia with metastatic abscesses - most often to the mesenteric and mediastinal lymph nodes, less frequently, other organs such as [[Liver - Anatomy & Physiology|liver]], kidney and brain can be involved - '''Bastard strangles''' | ||
+ | **Retropharyngeal abscesses can rupture onto the skin of neck or into the [[Guttural Pouches Inflammatory - Pathology|guttural pouch]] resulting in '''guttural pouch empyema or chondroid formation''' - carrier state | ||
+ | **[[Muscles Degenerative - Pathology#Ischaemia|'''Purpura haemorrhagica''']]: an acute vasculitis causing urticaria and extensive oedema of ventrum, head and distal limbs | ||
+ | **[[Larynx Degenerative - Pathology#Laryngeal hemiplegia|Laryngeal hemiplegia]] due to enlarged retropharyngeal lymph nodes | ||
+ | **Compression of cranial nerves | ||
− | + | *Interview with Professors Josh Slater and Ken Smith providing an interesting insight into the pathogenesis, prevalence and possible prevention of ''Streptococcus equi'' infections in horses - listen to [http://www.rvc.ac.uk/Review/Podcasts/RVC_Podcast_12.m4a Strangles podcast] | |
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[[Category:Streptococcus species]][[Category:Horse Bacteria]] | [[Category:Streptococcus species]][[Category:Horse Bacteria]] | ||
+ | [[Category:To_Do_-_Bacteria]] | ||
+ | [[Category:Respiratory_Bacterial_Infections]] | ||
+ | [[Category:Respiratory_Disorders_-_Horse]] |
Revision as of 12:24, 29 July 2010
Causes Strangles
- Epidemiology
- Strangles is a highly infectious disease of horses caused by Streptococcus equi subsp. equi
- upper respiratory tract disease of horses with fever and abscessation of regional lymph nodes
- Causes rhinitis, pharyngitis, lymphadenitis and myositis
- Outbreaks in groups of young horses
- Transmitted via purulent exudate discharging from upper respiratory tract or from lymph nodes
- Chronic, carrier state can occur with bacteria im the guttural pouch
- A mild, atypical form can occur
- S. equi shed for 4 weeks beyond clinical resolution
- Clinical signs
- Incubation period 3 to 6 days
- Fever, depression, anorexia
- Purulent nasal discharge
- Swollen, painful regional lymph nodes, especially submandibular
- Abscessation and rupture of lymph nodes
- Guttural pouch empyema
- 100% morbidity; 5% mortality
- Death can occur from pneumonia, breathing difficulties from swollen lymph nodes or purpura haemorrhagica(an immune-mediated disease)
- Bastard strangle may occasionally occur, with abscessaation in many organs of the body
- S. equi may be involved in cutaneous lesions
- Diagnosis
- Clinical signs and history
- Mucoid colonies with beta-haemolysis
- Sugar fermentation allows differentiation of S. equi from S. zooepidemicus and S. equisimilis
- PCR to detect asymptomatic carriers
- Treatment and control
- Penicillin administration to in-contact animals
- Isolation of affected animals
- Quarantne in-coming animals
- Avoid overcrowding and mixing different age groups
- Disinfection of equipment
- Caused by very pathogenic Streptococcus equi subsp. equi
- Haemolytic streptococci of Lancefield group C are common inhabitants of the equine nasopharynx
- Streptococcus zooepidemicus and S. equisimilis are usually non-pathogenic
- Typically suppurative rhinitis, pharyngitis and lymphadenitis of the lymph nodes of the head and neck that drain the upper respiratory tract, these lymph nodes often rupture and discharge pus 2-3 weeks after the onset of infection
- Infection with Streptococcus equi occurs after contact with contaminated feed, water bowls or an infected carrier horse
- Organism remains viable in environment for months
- Possibility of other sources of infection - in pharynx of in-contact dogs?, guttural pouches of persistently infected horses
- Attaches to nasopharyngeal epithelial cells, then mucosa, lymphatics and lymph nodes
- Multiplies extra-cellularly
- Gross pathology
- Initial bilateral nasal discharge, serous becoming purulent
- Catarrhal conjunctivitis may be present
- Less frequently, complications can occur as follows :
- Purulent inflammation may extent to guttural pouches or lungs, sinusitis
- Bacteraemia with metastatic abscesses - most often to the mesenteric and mediastinal lymph nodes, less frequently, other organs such as liver, kidney and brain can be involved - Bastard strangles
- Retropharyngeal abscesses can rupture onto the skin of neck or into the guttural pouch resulting in guttural pouch empyema or chondroid formation - carrier state
- Purpura haemorrhagica: an acute vasculitis causing urticaria and extensive oedema of ventrum, head and distal limbs
- Laryngeal hemiplegia due to enlarged retropharyngeal lymph nodes
- Compression of cranial nerves
- Interview with Professors Josh Slater and Ken Smith providing an interesting insight into the pathogenesis, prevalence and possible prevention of Streptococcus equi infections in horses - listen to Strangles podcast