Parasitic Protozoa, Fungi, and Helminths: Key Infections and Pathogens

Entamoeba histolytica (cysts & trophs)

Amebiasis (aka amoebic dysentery)

Protozoa - Amoebozoa

fecal-oral route - cysts in feces contaminate water

actin microfilaments, pseudopodia

Giardia lamblia (cysts & trophs) (also G. intestinalis or G. duodenalis)

Giardiasis

Protozoa - Excavata
fecal-oral route - cysts in feces contaminate water

have an excavate (depression on surface of cell)

Trichomonas vaginalis

Trichomoniasis

Protozoa - Excavata

sexually transmitted disease (STD)

flagellae, mononucleate, granular

Trypanosoma brucei gambiense

African Trypanosomiasis (aka African Sleeping Sickness)​

Protozoa - Excavata

diagnosed from blood smear, parasitic

undulating, squiggly membrane

Balantidium coli (cysts & trophs)

Balantidiasis

Protozoa - Chromalveolata

parasitic intestinal illness, rarely serious unless immunocompromised

ciliated, apical complex

Plasmodium falciparum

Malaria (anopheles sp. mosquito)

Protozoa - Chromalveolata

diagnosed via blood smear

“diamond ring” shape in RBC

Cryptosporidium parvum

Cryptosporidiosis

Protozoa

fecal-oral route - cysts in water; intestinal symptoms + diarrhea

diagnosed via fecal smear

Amoeba proteus

Pseudopodia, amorphous

Protozoa - Amoebozoa

Paramecium caudatum

Ciliated

Protozoa

Candida albicans

Candidiasis (skin and nails, vaginal yeast infection, oral thrush)

Fungi - ascomycota, pseudohyphae + daughter buds

fungal yeast infection, lives on skin normally

diagnosed via evaluation of secretions

Aspergillus sp.

Aspergillosis (cutaneous & respiratory)

Fungi - ascomycota (septate hyphae), both ascospores (sexual) and conidia (asexual)

bread mold, respiratory transmission, diagnosed via patient history/culturing

Rhizopus sp.

Mucormycosis

Fungi - zygomycete (nonseptate hyphae), saphrophytic, asexual sporangiospores (zygospores), haploid nuclei

sporangium, “puffy ball”

Penicillium notatum

Source of penicillin, “spirit fingers”

Fungi - ascomycota (septate hyphae), conidia (asexual)

Trichinella spiralis

Trichinosis (aka trichenellosis)

Helminth (nematoda, roundworm)

diagnosed via biopsy/serological testing

Schistosoma mansoni

Schistosomiasis

Helminth (platyhelminth, flatworm) - fluke (trematode)

fecal-oral (and urinal/gastrointestinal) route

freshwater snails

Fasciola hepatica

Fascioliasis

Helminth (platyhelminth, flatworm) - fluke (trematode)

Taenia sp.

Taeniasis

Helminth (platyhelminth, flatworm) - cestode (segmented)

pork/beef consumption

diagnosed via fecal smear

Clonorchis sinensis

Clonorchiasis

Helminth (platyhelminth, flatworm) - fluke (trematode)

fish consumption

Enterobius vermicularis

Enterobiasis

Helminth (nematoda, roundworm)

aka Pinworm, most common nematode infection in U.S.

eggs laid in anal area at night

Ascaris lumbricoides

Ascariasis

Helminth (nematoda, roundworm)

fecal-oral route

fecal smear

Necator americanus

Hookworm

Helminth (nematoda, roundworms)

fecal-oral route

fecal smear

Trichuris trichiura

Trichuriasis

Helminth (nematoda, roundworm)

aka whipworm

fecal-oral route

fecal smear