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Discovery of New Intracellular Pathogens by Amoebal Coculture and Amoebal Enrichment Approaches
Published on: October 27, 2013
Free-living, amphizoic and opportunistic amebas
1University of Pittsburgh School of Medicine, Neuropathologist, Pathology Department (Neuropathology), Presbyterian University Hospital, Pittsburgh, PA 15213, USA.
Brain Pathology (Zurich, Switzerland)
|January 1, 1997
Summary
Free-living amebas like Naegleria, Acanthamoeba, and Balamuthia cause severe infections. Naegleria fowleri leads to fatal Primary Amebic Meningoencephalitis (PAM), while Acanthamoeba and Balamuthia cause Granulomatous Amebic Encephalitis (GAE) and Acanthamoeba keratitis (AK).
Area of Science:
- Medical Parasitology
- Infectious Diseases
- Neuroscience
Background:
- Free-living amebas (Naegleria, Acanthamoeba, Balamuthia) are ubiquitous protozoa found globally in soil, water, and air.
- Human infections from these amebas, affecting the brain, skin, lungs, and eyes, have notably increased in the past decade.
- The epidemiology, immunology, protozoology, pathology, and clinical presentations of infections caused by these amebas vary significantly.
Purpose of the Study:
- To review the distinct epidemiological, pathological, and clinical characteristics of infections caused by Naegleria, Acanthamoeba, and Balamuthia.
- To highlight the increasing incidence and diverse manifestations of amebic infections in humans.
Main Methods:
- Review of reported cases and scientific literature on infections caused by Naegleria fowleri, Acanthamoeba spp., and Balamuthia mandrillaris.
- Analysis of disease transmission routes, host susceptibility, and pathological findings.
- Comparison of clinical features and outcomes for Primary Amebic Meningoencephalitis (PAM) and Granulomatous Amebic Encephalitis (GAE).
Main Results:
- Naegleria fowleri causes acute, rapidly fatal Primary Amebic Meningoencephalitis (PAM) following olfactory neuroepithelium entry, often linked to warm recreational water exposure.
- Balamuthia mandrillaris and Acanthamoeba spp. cause Granulomatous Amebic Encephalitis (GAE), typically in immunocompromised individuals, with probable respiratory or skin entry and hematogenous CNS spread.
- Acanthamoeba spp. are also a major cause of chronic, sight-threatening Acanthamoeba keratitis (AK), particularly in contact lens wearers.
Conclusions:
- Naegleria, Acanthamoeba, and Balamuthia infections represent a growing public health concern with distinct and severe clinical outcomes.
- Understanding the specific pathogenesis and clinical presentations is crucial for diagnosis and management of these rare but devastating amebic infections.
- Increased awareness and further research are needed to combat the rising incidence of amebic encephalitis and keratitis.
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