Free-Living Amoeba as Agents of Infection

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Garland E. Pendergraph, PhD, JD, MLS(ASCP)SM, HCLD/CC(ABB); Tamika E. Gosha, BS, MLT(ASCP)
Reviewers: Judi Bennett MT, BSM and Alexandru Casapu, MBA, MLS(ASCP)CM

Most protozoa are free-living and have little or no impact on human health. They are found throughout the environment, particularly in soil and water. However, there are four free-living amoeba that have been associated with serious human infections. This course seeks to identify these amoeba and discuss their life cycles, methods of infection, and the symptoms that occur, as well as determine preventive measures that may be available.

Continuing Education Credits


  • Identify the primary free-living amoeba that infect humans and contrast their life cycles.
  • Recognize the method of infection and symptoms that occur for each of the free-living amoeba reviewed.
  • Determine preventive measures for each of the free-living amoeba.

Course Outline

  • Introduction
      • Terms to Remember
      • Introduction
  • Naegleria fowleri
      • Introduction: Naegleria fowleri
      • Life Cycle: Naegleria fowleri
      • Possible Mechanisms of Infection: Naegleria fowleri
      • Illness and Symptoms: Naegleria fowleri
      • Laboratory Diagnostic Methods: Naegleria fowleri
      • Laboratory Diagnostic Methods, continued: Naegleria fowleri
      • Case of a Survivor: Naegleria fowleri
      • Where is Naegleria fowleri found most often in nature?
      • People may become infected with Naegleria fowleri by drinking contaminated water.
      • Treatment: Naegleria fowleri
      • Prevention: Naegleria fowleri
  • Acanthamoeba Species
      • Introduction: Acanthamoeba Species
      • Possible Mechanisms of Infection: Acanthamoeba Species
      • Life Cycle: Acanthamoeba Species
      • Illness and Symptoms: Acanthamoeba Species
      • Illness and Symptoms, continued: Acanthamoeba Species
      • Illness and Symptoms, continued: Acanthamoeba Species
      • Laboratory Diagnostic Methods: Acanthamoeba Species
      • Treatment: Acanthamoeba Species
      • Prevention: Acanthamoeba Species
      • What did Byers base his 1991 classification of the genus Acanthamoeba species on?
  • Balamuthia mandrillaris
      • Introduction: Balamuthia mandrillaris
      • Life Cycle: Balamuthia mandrillaris
      • Life Cycle: Balamuthia mandrillaris, continued
      • Possible Mechanisms of Infection: Balamuthia mandrillaris
      • Illness and Symptoms: Balamuthia mandrillaris
      • Laboratory Diagnostic Methods: Balamuthia mandrillaris
      • Treatment and Prevention: Balamuthia mandrillaris
  • Additional Suggested Reading
      • Additional Suggested Reading
  • References
      • References

Additional Information

Level of instruction: Basic
Intended Audience: Medical laboratory scientists, medical technologists, and technicians. This course is also appropriate for medical laboratory science students and pathology residents. 
Author information: Garland E. Pendergraph, PhD, JD, MLS(ASCP)SM, HCLD/CC(ABB) is Laboratory Director & Director of Laboratory Operations, Quest Diagnostics-Valdosta RRL. Dr. Pendergraph is the laboratory director for Quest Diagnostics in Valdosta, GA and Miller County Hospital in Colquitt, GA. Dr. Pendergraph received his MSPH from the University of Kentucky in Lexington, his PhD in medical parasitology and mycology from the University of  North Carolina in Chapel Hill and his law degree with a concentration in health care law from Concord Law School, Kaplan University. He also did a Fellowship in Tropical Medicine at Louisiana State University School of Medicine. He is the author of a textbook in phlebotomy, a number of scientific articles, plus internet training programs.
Co-auther information: Ms. Tamika Gosha is a medical laboratory technician at Quest Diagnostics, Inc./Solstas Lab Partners Valdosta laboratory. She is presently working on her master’s degree at Kaplan University.
Reviewer information:  Judi Bennett MT, BSM is currently a Program Director for MediaLab, Inc. in Lawrenceville, GA. She has over 30 years of medical laboratory experience in an acute care hospital setting as a laboratory manager, senior clinical applications specialist, point-of-care coordinator, microbiology supervisor, and generalist technologist. 
Reviewer Information: Alexandru Casapu, MBA, MLS(ASCP)CM, PBTCM has over 20 years of experience as an MLS, section supervisor, and laboratory manager. A former Director of Clinical Laboratory Technology Program at Georgia Piedmont Technical College, he is currently a Program Director at MediaLab, Inc. 

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