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Questions and Answers
Where is Naegleria fowleri found most often in nature? Please select the single best answer
People may become infected with Naegleria fowleri by drinking contaminated water.
False
What did Byers base his 1991 classification of the genus Acanthamoeba species on? Please select the single best answer
All of the following are free-living amoebae EXCEPT: Please select the single best answer
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What is the most common way for humans to acquire a free-living amoeba infection? Please select the single best answer
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What is the most frequently used method for the diagnosis of primary amoebic meningoencephalitis (PAM)? Please select the single best answer
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The Centers for Disease Control and Prevention (CDC) has published on their website clearly defined methods for the prevention of infections from Balamuthia mandrillaris.
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Which of the following is the pathogenic free-living amoeba with a flagellate state? Please select the single best answer
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Which pathogenic free-living amoeba is most commonly isolated from soil, but has also been isolated in both fresh and salt waters? Please select the single best answer
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What is the etiologic agent for primary amoebic meningoencephalitis (PAM)? Please select the single best answer
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Study Notes
Naegleria fowleri and Its Habitat
- Naegleria fowleri thrives in warm fresh waters like ponds, lakes, and rivers, preferring temperatures between 30° C and 46° C.
- Notable locations include minimally chlorinated swimming pools and geothermally heated water.
- This amoeba is sensitive to freezing and is not found in saltwater.
Infection Transmission
- Drinking contaminated water does not lead to infection due to stomach acids killing the amoebae.
- Infection occurs primarily through nasal exposure to contaminated water.
Acanthamoeba Classification
- Byers classified Acanthamoeba based on RNA sequences, categorizing it into 17 different genotypes (T1-T17).
Identifying Free-Living Amoebae
- Entamoeba polecki is not considered a free-living amoeba; it is primarily a parasite of swine and monkeys but can infect humans.
Routes of Infection
- The main route for free-living amoeba infection is through infectious cysts or trophozoites found in soil or water, especially during recreational activities.
- These amoebae do not require an intermediate host, and their flagellate form (e.g., Naegleria) is non-infective.
Diagnosis of PAM
- Examination of cerebrospinal fluid (CSF) is the most effective method for diagnosing primary amoebic meningoencephalitis (PAM) and can provide the earliest results.
- Other methods like indirect immunofluorescence assays (IFA) and PCR are available but not widely accessible.
Prevention of Balamuthia mandrillaris Infections
- Currently, there are no clearly defined methods for preventing infections from Balamuthia mandrillaris.
Flagellate-Free-Living Amoeba
- Naegleria fowleri is the only pathogenic free-living amoeba that possesses a flagellate stage in its life cycle.
Balamuthia mandrillaris Characteristics
- Commonly isolated from soil, Balamuthia mandrillaris has also been found in both fresh and saltwater, posing risks to both immunocompetent and immunocompromised individuals.
- Unlike Naegleria fowleri and Acanthamoeba, Balamuthia can survive in saltwater.
Etiologic Agent for PAM
- Naegleria fowleri is the sole etiologic agent for primary amoebic meningoencephalitis among over 35 identified Naegleria species.
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Description
This quiz covers the habitats and infection routes of Naegleria fowleri and Acanthamoeba species. Explore how these free-living amoebae thrive in specific environments and the risks they pose to humans. Understand the classification and identification of these microscopic organisms.
