Eukaryotic Pathogens: Algae and Protozoans What types of eukaryotic organisms are pathogenic, and how do they differ from bacteria?

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Eukaryotic Pathogens Algae and ProtozoansWhat
types of eukaryotic organisms are pathogenic, and
how do they differ from bacteria?

• Algae dinoflagellates and saxitoxin
• Protozoans
• Classification and special structures
• Pseudopodia, flagella, cilia
• Pellicles, cysts
• Important protozoan pathogens
• Amoebic dysentery
• Balantidiasis (Balantidium dysentary)
• Giardia, Trichomoniasis, Trypanosomiasis
• Malaria, Cryptosporidium
• Eukaryotic pathogens are mostly parasitic and are
  difficult to target selectively with drugs since
  their cells are so similar to human cells.

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AlgaePlant-like Protists Based on Nutrition
Table 12.1
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Toxic Algae Photosynthetic Dinoflagellates

• Cellulose in plasma membrane
• Unicellular
• Algal blooms cause red tides
• Shellfish ingest dinoflagellates toxin
  concentrated through food chain
• Neurotoxin (saxitoxin) causes paralytic shellfish
  poisoning

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Eukaryotic Pathogens Algae and ProtozoansWhat
types of eukaryotic organisms are pathogenic, and
how do they differ from bacteria?

• Algae dinoflagellates and saxitoxin
• Protozoans
• Classification and special structures
• Pseudopodia, flagella, cilia
• Pellicles, cysts
• Important protozoan pathogens
• Amoebic dysentery
• Balantidiasis (Balantidium dysentary)
• Giardia, Trichomoniasis, Trypanosomiasis
• Malaria, Cryptosporidium
• Eukaryotic pathogens are mostly parasitic and are
  difficult to target selectively with drugs since
  their cells are so similar to human cells.

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The Protozoa Kingdom Protista
Table 12.1
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Protozoa Animal-like Protists Based on
Nutritional Mode

• Eukaryotic
• Unicellular
• Chemoheterotrophs
• Vegetative form is a trophozoite
• Some produce cysts, or dormant forms (often the
  infective agent)
• Some have an outer support layer pellicle
• Asexual reproduction by fission, budding, or
  schizogony
• Sexual reproduction by conjugation

Figure 12.16
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Pathogenic Protozoans

• Protozoans can be studied according to their type
  of locomotion
• Amoebas (sarcodines)
• move using pseudopodia
• Ciliates (ciliates) move
• using beds of cilia
• Flagellates (mastigophorans)
• move using one or more flagella
• Apicomplexans are non-motile,
• intracellular parasites

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Eukaryotic Pathogens Algae and ProtozoansWhat
types of eukaryotic organisms are pathogenic, and
how do they differ from bacteria?

• Algae dinoflagellates and saxitoxin
• Protozoans
• Classification and special structures
• Pseudopodia, flagella, cilia
• Pellicles, cysts
• Important protozoan pathogens
• Amoebic dysentery
• Balantidiasis (Balantidium dysentary)
• Giardia, Trichomoniasis, Trypanosomiasis
• Malaria, Cryptosporidium
• Eukaryotic pathogens are mostly parasitic and are
  difficult to target selectively with drugs since
  their cells are so similar to human cells.

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Important Pathogenic Protozoans

• Amoebas
• Entamoeba histolytica - amoebic dysentery
• Ciliates
• Balantidium coli - Severe colitis/dysentery
• Flagellates
• Giardia lamblia - giardiasis/beaver fever
• Trypanosoma brucei -trypanosomiasis/African
  sleeping sickness
• Trichomonas vaginalis - trichomoniasis
• Apicomplexans
• Plasmodium vivax - malaria
• Toxoplasma gondii - toxoplasmosis

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Amoebic dysentery(Entamoeba histolytica)
Amoebic protozoan
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Pathogenic Protozoans

• Amoebas
• Entamoeba histolytica - amoebic dysentery
• Ciliates
• Balantidium coli - Severe colitis/dysentery
• Flagellates
• Giardia lamblia - giardiasis/beaver fever
• Trypanosoma brucei -trypanosomiasis/African
  sleeping sickness
• Trichomonas vaginalis - trichomoniasis
• Apicomplexans
• Plasmodium vivax - malaria
• Toxoplasma gondii - toxoplasmosis

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Severe colitis/dysentery( Balantidium coli)A
Ciliate
Parasite primarily of cows, pigs and horses Seen
mostly in farm workers and other rural dwellers
by ingestion of cysts in fecal material of farm
animals Symptoms similar to amoebic dysentery but
milder.
Only known pathogenic ciliated protozoan
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Pathogenic Protozoans

• Amoebas
• Entamoeba histolytica - amoebic dysentery
• Ciliates
• Balantidium coli - Severe colitis/dysentery
• Flagellates
• Giardia lamblia - giardiasis/beaver fever
• Trypanosoma brucei -trypanosomiasis/African
  sleeping sickness
• Trichomonas vaginalis - trichomoniasis
• Apicomplexans
• Plasmodium vivax - malaria
• Toxoplasma gondii toxoplasmosis
• Cryptosporidium

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Archaezoa Troublesome Flagellates

• No mitochondria
• Multiple flagella
• Giardia lamblia
• Trichomonas vaginalis (no cyst stage)

Figure 12.17b-d
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Giardiasis -Beaver fever (Giardia lamblia)
Cysts shed in feces
Flagellated protozoan
Trophozoite stage
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Trichomoniasis (Trichomonas vaginalis)
Unusual undulating membrane
Flagellated protozoan
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Trypanosomiasis/African Sleeping
Sickness(Trypanosoma brucei)
Tsetse fly (intermediate host)
Flagellated protozoan
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Pathogenic Protozoans

• Amoebas
• Entamoeba histolytica - amoebic dysentery
• Ciliates
• Balantidium coli - Severe colitis/dysentery
• Flagellates
• Giardia lamblia - giardiasis/beaver fever
• Trypanosoma brucei -trypanosomiasis/African
  sleeping sickness
• Trichomonas vaginalis - trichomoniasis
• Apicomplexans
• Plasmodium vivax - malaria
• Toxoplasma gondii toxoplasmosis
• Cryptosporidium

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Malaria (Plasmodium vivax)An Apicomplexan
gametocytes in RBC
ring stage in RBCs
Apicomplexan protozoan
nonmotile
Anopheles mosquito
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Plasmodium An Apicomplexan
1
2
Sporozoites undergo schizogony in liver cell
merozoites are produced
Infected mosquito bites human sporozoites
migrate through bloodstream to liver of human
Sporozoites in salivary gland
Resulting sporozoites migrate to salivary glands
of mosquito
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3
Merozoites released into bloodsteam from liver
may infect new red blood cells
Sexualreproduction
Asexual reproduction
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In mosquitos digestive tract, gametocytes unite
to form zygote
Zygote
Intermediate host
Female gametocyte
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Merozoite develops into ring stage in red blood
cell
Male gametocyte
Ring stage
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Ring stage grows and divides, producing
merozoites
Definitive host
Another mosquito bites infected humnan and
ingests gametocytes
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6
Merozoites are released when red blood cell
ruptures some merozoites infect new red blood
cells, and some develop into male and female
gametocytes
Merozoites
Figure 12.19
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Toxoplasmosis(Toxoplasma gondii)
Apicomplexan protozoan
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Cryptosporidium (An Apicomplexan)
Causes watery diarrhea, dehydration, cramps and
nausea Shed in feces spread easily by
contaminated food and water, especially uncooked
foods Caused by Crytposporidium parvum
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Eukaryotic Pathogens Algae and ProtozoansWhat
types of eukaryotic organisms are pathogenic, and
how do they differ from bacteria?

• Algae dinoflagellates and saxitoxin
• Protozoans
• Classification and special structures
• Pseudopodia, flagella, cilia
• Pellicles, cysts
• Important protozoan pathogens
• Amoebic dysentery
• Balantidiasis (Balantidium dysentary)
• Giardia, Trichomoniasis, Trypanosomiasis
• Malaria, Cryptosporidium
• Eukaryotic pathogens are mostly parasitic and are
  difficult to target selectively with drugs since
  their cells are so similar to human cells.

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Making a Table to Study and Associate
Characteristics