Central nervous system infections caused by pathogenic free-living amoebae: An Indian perspective

Area of Science:

• Neurology
• Infectious Diseases
• Microbiology

Background:

• Pathogenic free-living amoebae (FLA) like Acanthamoeba sp., Naegleria fowleri, and Balamuthia mandrillaris cause fatal human CNS infections globally.
• This review focuses on FLA-induced CNS infections documented in India, analyzing patient demographics, clinical presentations, diagnostic methods, and treatment outcomes.

Purpose of the Study:

• To review and analyze case reports of central nervous system (CNS) infections caused by Acanthamoeba, Naegleria fowleri, and Balamuthia mandrillaris in India.
• To understand the demographic characteristics, clinical manifestations, diagnostic challenges, and treatment strategies for these rare but severe infections.

Main Methods:

• Systematic review of case reports of CNS infections caused by FLA in India.
• Analysis of demographic data, symptoms, diagnostic findings (microscopy, CT/MRI, CSF analysis), and treatment regimens from documented cases.

Main Results:

• 42 Acanthamoeba GAE, 25 N. fowleri PAM, and 4 B. mandrillaris BAE cases were reported in India.
• Common symptoms include fever, headache, vomiting, seizures, and altered sensorium. Males were predominantly affected. Immunosuppression and freshwater exposure were noted risk factors.
• Diagnosis relied on CSF microscopy (69% for GAE, 96% for PAM) and histopathology (25% for GAE, 100% for BAE). Treatment involved combinations of antibiotics and antifungals, with varying success.

Conclusions:

• Central nervous system infections by FLA pose a significant threat in India, predominantly affecting males and presenting with severe neurological symptoms.
• Accurate and timely diagnosis through direct microscopy and histopathology is crucial for effective management.
• Optimizing treatment strategies requires a thorough search for these amoebae in CNS samples and further research into effective therapeutic interventions.