Potomac horse fever.

The research presents findings on two disease syndromes produced by E. risticii, known as EEC and EEA, with a particular focus on EEC, commonly referred to as Potomac horse fever. Even though existing diagnostics and treatment methods are discussed, the challenge lies in the unidentified mode of transmission, making prevention difficult.

Understanding the Disease Syndromes

• The bacterium E. risticii originally known to cause Potomac horse fever, is discovered to be the agent behind two disease syndromes known as EEC and EEA. However, there aren’t much clarity on how the pathogen is transmitted even though horses are confirmed to be common hosts based on seroepidemiologic studies.
• EEC, often referred to as Potomac horse fever presents varying clinical signs, making it the most common clinical disease attributable to E. risticii.
• EEA has only been recently recognized as another clinical syndrome caused by E. risticii. This mostly affects pregnant horses, causing them to abort. The aborted fetus appears to be affected by an ehrlichial colitis and placentitis based on histologic examinations.

Current Diagnostic and Treatment Approaches

• Diagnosis of EEC mainly depends on serology, a method which often fails to provide definitive answers and at most provides retrospective diagnosis – a diagnosis made after a disease has progressed or after the patient has died.
• The research suggests the use of a new diagnostic approach, polymerase chain reaction (PCR), which could potentially offer a quick and accurate diagnostic test, however, it’s effectiveness is yet to be established.
• The study mentions antimicrobials such as intravenous oxytetracycline, and the oral combination of erythromycin and rifampin as successful treatments for EEC.
• Because the transmission mode of the disease is still unknown, it’s impossible to prevent EEC. Existing vaccines also do not provide complete protection against the disease.

Impediments to Prevention and Therapeutic Improvements

• While the research indicates that two bacterins are currently available for vaccination, they do not effectively protect against the disease.
• Furthermore, the impact of vaccination and use of antimicrobial treatment on EEA is yet to be studied, making it a research area to prioritize for future studies.