Protozoa - Part 1Chapter 5

Learning Objectives

1. State the general characteristics of each class of Protozoa.

2. Define terminology specific for protozoa.

3. State the recommended methods of diagnosis of protozoal infections.

4. State any vector or intermediate host involved in the transmission of protozoal diseases.

5. Describe in graphic form the general life cycles for the protozoa in each class.

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Learning Objectives

6. State the type of pathology caused by infection with protozoa.

7. State and correctly spell the scientific and common names of protozoa that parasitize humans.

8. Identify accidental protozoal infections of humans that are of medical importance.

9. Identify the type of specimen that would most likely contain the diagnostic stages of each pathogenic protozoon.

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Learning Objectives

10.Discriminate between the cyst and trophozoite stages of protozoa on the basis of the morphologic criteria and the infectivity of various genera.

11.Discriminate between pathogenic and nonpathogenic amebae on the basis of morphologic criteria.

12.Differentiate species of Plasmodium and Trypanosoma by morphology, symptomatic criteria, or both.

13.Discuss the medical importance of accurate identification of protozoa in humans.

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Learning Objectives

14. Discuss the importance of protozoal zoonoses.

15. Discuss how the development of genetic resistance to chemicals affects protozoal diseases, such as malaria.

16. Given an illustration or photograph, identify diagnostic stages of protozoa.

17. Differentiate the diagnosis of protozoa and helminth infections.

18. Compare and contrast life cycles of protozoa and helminths.

19. Predict the effects of immunosuppression on patients harboring various protozoal or helminth parasites.

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Introduction

General characteristics Means of locomotion

Amoeba – pseudopods Flagellates – flagella Ciliates – cilia Apicocomplexa – sporozoa – non-motile

Modes of transportation from host to host

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Class Lobosea: Considered Organisms

Entamoeba coli

Entamoeba histolytica/dispar

Entamoeba hartmanni

Entamoeba gingivalis

Endolimax nana

Iodamoeba bütschlii

Blastocystis hominis

Naegleria fowleri

Acanthamoeba spp.

Balamuthia mandrillaris

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Class Lobosea Amoebida

General characteristics Pseudopods Trophozoites cyst

Diagnostic features size Nucleus number

Karyosome Chromatin

Chromatoid bars

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Nagleria life cycle

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Acanthamoeba life cycle5-10

Entamoeba histolytica (ameba)

Method of diagnosis Specimen requirements Diagnostic stage Disease names Major pathology and symptoms Treatment Distribution

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E. Histolytica Life Cycle5-12

E. Histolytica5-13

E.histolytica/dispar cyst 10-20 um

Nuclei Cyst 1-4

Troph 1

Karyosome – small, central

Chromosome – fine even distribution

Chromatoid body – cigar shaped

Troph – ingested RBC

E. histolytica/dispar is non pathogenic. No ingested RBCs in troph

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E.histolytica trophozoite5-15

E.histolytica trophozoite5-16

E.histolytica trophozoite5-17

E.histolytica cysts

1-4 nuclei

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E. hartmanni – troph & cystnon-pathogenic ; can only be distinguished from E.histolytica by its small size ( < 10 um)

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Entameoba coli

Size - >10 um

Nuclei

Cyst 1-8

Troph 1

Karyosome – eccentric

Chromatin – dark, irregular

Chromatin body – rough; sharp pointed edges “splinters”

Troph – cytoplasm coarse; ingested bacteria

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E. Coli cysts & trophs5-21

Entamoeba coli trophs5-22

E.coli cyst & troph5-23

E.nana

Size 6-12

Nuclei

Cyst 1-4

Troph 1

Karyosome – large & irregular ( clumpy)

No peripheral chromatin

Cyst has oval shape

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Endolimax nana5-25

E.nana5-26

Iodamoeba butschlii

Size 8-10 um

Nuclei – cyst (1) ; troph (1)

Large irregular karyosome

No peripheral chromatin

Cyst – large glycogen vacuole; stains w/ iodine

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Iodamoeba butschlii5-28

Iodamoeba butschlii5-29

Blastocystis hominis

Cyst 6-40

Trophs – rare

Large central vacuole

Nuclei in cytoplasm around vacuole

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