Eukaryotic Pathogens: Algae and Protozoans What 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.

Algae:”Plant-like Protists” Based on Nutrition Table 12.1

Cellulose in plasma membrane Unicellular Algal “blooms” cause “red tides” Shellfish ingest dinoflagellates; toxin concentrated through food chain Neurotoxin (saxitoxin) causes paralytic shellfish poisoning Toxic Algae: Photosynthetic Dinoflagellates

Eukaryotic Pathogens: Algae and Protozoans What 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.

The Protozoa: Kingdom Protista Table 12.1

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 Protozoa: “Animal-like Protists” Based on Nutritional Mode Figure 12.16

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

Eukaryotic Pathogens: Algae and Protozoans What 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.

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

Amoebic dysentery (Entamoeba histolytica) Amoebic protozoan

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

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

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

No mitochondria Multiple flagella Giardia lamblia Trichomonas vaginalis (no cyst stage) Archaezoa: Troublesome Flagellates Figure 12.17b-d

Giardiasis -Beaver fever (Giardia lamblia) Trophozoite stage Cysts shed in feces Flagellated protozoan

Trichomoniasis (Trichomonas vaginalis) Flagellated protozoan Unusual undulating membrane

Trypanosomiasis/African Sleeping Sickness (Trypanosoma brucei) Tsetse fly (intermediate host) Flagellated protozoan

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

Malaria (Plasmodium vivax) An Apicomplexan Anopheles mosquito gametocytes in RBC Apicomplexan protozoan ring stage in RBCs nonmotile

Plasmodium: An Apicomplexan Figure Infected mosquito bites human; sporozoites migrate through bloodstream to liver of human Sporozoites undergo schizogony in liver cell; merozoites are produced Merozoites released into bloodsteam from liver may infect new red blood cells Merozoites are released when red blood cell ruptures; some merozoites infect new red blood cells, and some develop into male and female gametocytes Asexual reproduction Intermediate host Merozoite develops into ring stage in red blood cell Ring stage Merozoites Another mosquito bites infected humnan and ingests gametocytes 7 5 Ring stage grows and divides, producing merozoites Definitive host In mosquito’s digestive tract, gametocytes unite to form zygote 8 Male gametocyte Female gametocyte Zygote Sexual reproduction Resulting sporozoites migrate to salivary glands of mosquito 9 Sporozoites in salivary gland

Toxoplasmosis (Toxoplasma gondii) Apicomplexan protozoan

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

Eukaryotic Pathogens: Algae and Protozoans What 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.

SpeciesProtozoan Category HostsDisease Name Disease description How transmitted Sketch Making a Table to Study and Associate Characteristics