## Overview Bastard strangles, also called metastatic strangles, is a serious complication of infection with Streptococcus equi equi (the bacterium that causes classic strangles). In ordinary strangles the bacteria stay in the lymph nodes of the head and neck and form abscesses there. In bastard strangles the bacteria spread through the blood or lymphatics and form abscesses in distant sites such as the abdomen, thorax, or other lymph nodes. This form raises the risk of death substantially compared with uncomplicated strangles. ## Causes The primary cause is infection with Streptococcus equi equi. Metastatic spread occurs when the bacteria escape the regional lymph nodes. Factors that may increase the chance of metastasis include severe or prolonged infection, incomplete immunity, and possibly certain bacterial strains, although the evidence is limited on host or bacterial predictors. ## Diagnosis Horses with bastard strangles often show non-specific signs such as intermittent fever, weight loss, colic, or respiratory difficulty rather than the classic swollen head lymph nodes. Ultrasound or radiography can locate internal abscesses. Culture or polymerase chain reaction testing of abscess material or nasal washes confirms the organism. Bloodwork commonly shows chronic inflammation. ## Treatment Unlike many uncomplicated strangles cases, bastard strangles usually requires prolonged antimicrobial therapy (commonly procaine penicillin) plus intensive supportive care. Drainage of accessible abscesses and treatment of secondary problems such as colic or pneumonia are important. Isolation and biosecurity measures remain essential because the horse can still shed bacteria. ## Recovery and Prognosis Prognosis is guarded to poor. Mortality rises markedly once metastatic abscesses develop. Survivors may need weeks to months of treatment and can have lasting organ damage. Some horses become long-term carriers in the guttural pouches even after clinical recovery. ## Prevention Prompt isolation of new or febrile horses, good hygiene, and appropriate use of vaccination where indicated reduce the incidence of strangles outbreaks and therefore the chance of metastatic disease. Early veterinary attention to classic strangles cases may limit spread within the body.
intermittent fever; chronic weight loss; colic or abdominal pain; respiratory difficulty; depression; internal abscesses on imaging
## Overview Bastard strangles, also called metastatic strangles, is a serious complication of infection with Streptococcus equi equi (the bacterium that causes classic strangles). In ordinary strangles the bacteria stay in the lymph nodes of the head and neck and form abscesses there. In bastard strangles the bacteria spread through the blood or lymphatics and form abscesses in distant sites such as the abdomen, thorax, or other lymph nodes. This form raises the risk of death substantially compared with uncomplicated strangles. ## Causes The primary cause is infection with Streptococcus equi equi. Metastatic spread occurs when the bacteria escape the regional lymph nodes. Factors that may increase the chance of metastasis include severe or prolonged infection, incomplete immunity, and possibly certain bacterial strains, although the evidence is limited on host or bacterial predictors. ## Diagnosis Horses with bastard strangles often show non-specific signs such as intermittent fever, weight loss, colic, or respiratory difficulty rather than the classic swollen head lymph nodes. Ultrasound or radiography can locate internal abscesses. Culture or polymerase chain reaction testing of abscess material or nasal washes confirms the organism. Bloodwork commonly shows chronic inflammation. ## Treatment Unlike many uncomplicated strangles cases, bastard strangles usually requires prolonged antimicrobial therapy (commonly procaine penicillin) plus intensive supportive care. Drainage of accessible abscesses and treatment of secondary problems such as colic or pneumonia are important. Isolation and biosecurity measures remain essential because the horse can still shed bacteria. ## Recovery and Prognosis Prognosis is guarded to poor. Mortality rises markedly once metastatic abscesses develop. Survivors may need weeks to months of treatment and can have lasting organ damage. Some horses become long-term carriers in the guttural pouches even after clinical recovery. ## Prevention Prompt isolation of new or febrile horses, good hygiene, and appropriate use of vaccination where indicated reduce the incidence of strangles outbreaks and therefore the chance of metastatic disease. Early veterinary attention to classic strangles cases may limit spread within the body.
intermittent fever; chronic weight loss; colic or abdominal pain; respiratory difficulty; depression; internal abscesses on imaging