Strangles and its complications

Abstract

Summary Strangles, caused by the Gram‐positive bacteria Streptococcus equi subspecies equi (S. equi), is a highly contagious upper respiratory infection in horses. The infection is transmitted by inhalation or direct contact with mucopurulent discharge from an infected animal, resulting in fever, depression, and submandibular and retropharyngeal lymph node enlargement that can lead to respiratory distress. Complications include secondary cellulitis at external abscessation sites, guttural pouch empyema and its persistence into the carrier state, purpura haemorrhagica, metastatic abscessation, emergency tracheostomies and rarely secondary S. equi pneumonia or myositis. Control of outbreaks requires strict isolation protocols and hygiene measures. Detection methods of the index case and carrier state are constantly being refined to assist in the identification and prevention of disease perpetuation.

Staphyloccocus aureus‐associated infarctive purpura haemorrhagica, immune‐mediated haemolytic anaemia and myocarditis in a Quarter Horse mare

“…; Duffee et al . ; Valberg ; Boyle ). Further complications may include myocarditis, endocarditis, panophthalmitis, periorbital abscesses, ulcerative keratitis, paravertebral abscesses, septic arthritis, tenosynovitis and immune‐mediated complications such as IMHA, IMTP and myopathies (Pusterla et al .…”

“…; Kaese et al . ; Boyle ). Clinical pathological changes often include anaemia, leukocytosis, neutrophilia, hyperfibrinogenaemia, moderate elevations in creatine kinase (CK), aspartate aminotransferase (AST) and globulins.…”

“…; Duffee et al . ; Valberg ; Boyle ). Notably, in both human and equine patients, purpura has also been associated with other pathogens, medications and vaccines (Michel et al .…”

“…Purpura haemorrhagica is a relatively rare condition of aseptic necrotising vasculitis observed in horses. Clinical signs most commonly reported include: asymmetric, welldemarcated subcutaneous oedema of all four limbs, mucous membrane petechiation, fever, lethargy, anorexia, weight loss, reluctance to move and colic (Pusterla et al 2003;Kaese et al 2005;Boyle 2016). Clinical pathological changes often include anaemia, leukocytosis, neutrophilia, hyperfibrinogenaemia, moderate elevations in creatine kinase (CK), aspartate aminotransferase (AST) and globulins.…”

“…Histopathology of skin biopsy samples from affected individuals is characterised by leukocytoclastic vasculitis with neutrophil infiltration (Pusterla et al 2003). Some horses exposed to Streptococcus equi (S. equi) may suffer from immune-mediated complications such as myositis with progressive muscle atrophy (Lewis et al 2007;Waller 2014;Valberg 2015;Boyle 2016), infarctive purpura haemorrhagica affecting muscles and organs including the gastrointestinal tract and lungs, immunemediated haemolytic anaemia (IMHA), immune-mediated thrombocytopenia (IMTP) and myocarditis (Pusterla et al 2003;Kaese et al 2005).…”