Parasitic ProtozoaParasitic Protozoa

parasiteparasite

- an organism that obtains food and shelter from another organism and derives all benefits from this association.

obligate facultative

ecto-parasiteendoparasite

pathogenic commensal

hosthost

- the organism that harbors the parasite and suffers a loss caused by the parasite

definitive

reservoir

intermediate

- an organism (usually an insect) that is responsible for transmitting the parasitic infection

vectorvector

Summary

OrganismTransmission

Symptoms Diagnosis Treatment

Entameba histolytica

Oro-fecalDysentery with blood and necrotic tissue. Chronic: abscesses

Stool: cysts with 1-4 nuclei and/or trophs.

Trophs in aspirate.

GI: Iodoquinol orMetronidazoleAbscess: Metronidazole

Giardia lamblia Oro-fecalFowl-smelling, bulky diarrhea; blood or

necrotic tissue rare.

Stool: typical old man giardia troph and/or

cyst.

Iodoquinol or Metronidazole.

Balantidium coli Oro-fecal; zoonotic

Dysentery with blood and necrotic tissue but

no abscesses.

Stool: ciliated trophs and/or cysts.

Iodoquinol or Metronidazole.

Cryptosporidium parvum

Oro-fecal Diarrhea Ooocysts in stoolParomycin

(investigational)

Isospora belli Oro-fecal Giardiasis-like Ooocysts in stool Sulpha drugs

Trichomonasvaginalis

SexualVaginitis; occasional urethritis/prostatitis.

Flagellate in vaginal (or urethral) smear.

Mebendazole; vingar douche; steroids

Giardia lamblia - a human parasite of the gastrointestinal tract.

Balantidium coli trophozoites. These are characterized by: their large size (40 µm to more than 70 µm)  the presence of cilia on the cell surface

Summary

Organism Transmission Disease/symptoms Diagnosis Treatment

Trypanosoma brucei

Tsetse fly. Sleeping sickness; cardiac failure.

Hemoflagellate in blood or lymph node.

Blood stage: Suramin or petamidine isethionate;

T. cruzi Reduvid (kissing) bug.

Chagas disease: megacolon, cardiac failure.

Hemoflagellate in blood or tissue.

CNS: melarsoperolNifurtimox and Benzonidazole.

Leishmania donovani

Sand fly Visceral leish-maniasis, granulo-matous skin lesions.

Intracellular (macrophages) leishmanial bodies.

Pentosam; Pentamidine isethionate.

L. tropica Sand fly. Cutaneous lesions. As for L. donovani. As for L. donovani.

L. braziliensis Sand fly Mucocutaneous lesions. As for L. donovani. As for L. donovani.

Plasmodium falciparum P. ovale, P. malariae and P. vivax

Female anopheline mosquito.

Malarial paroxysm: chills, fever, headache, nausea cycles.

Plasmodia in rbc, typical of the species involved.

Quinine derivatives ProguanilLariam

Babesia microti Tick Hemolytic anemia, Jaundice and fever

Typical organism (Maltese cross) in rbc.

None; self resolving.

Toxoplasma gondii

Oral from cat fecal material;or meat

Adult: flu like;congenital: abortion, neonatal blindness and neuropathies.

Intracellular (in macrophages) tachyzoites.

Sulphonamides, pyemethamine, possibly spiramycin (non-FDA).

Pneumocystis jiroveci

Cough droplets PneumoniaPneumocystis in sputum.

Trimethoprim and sulphamethoxazole.

Structure of Trypanosome brucei

Young boy with advanced African trypanosomiasis (or sleeping sickness) exhibiting marked wasting and skin damage caused as a result of the intense itching which can accompany late-stage disease

Tsetse fly. The vector of African trypanosomiasis 

Trypanosoma cruzi, crithidia

Riduvid bug, the vector of American trypanosomiasis

Ramana's sign: unilateral conjunctivitis and orbital edema 

Skin ulcer due to leishmaniasis, hand of Central American adult

Profile view of a teenage boy suffering from visceral leishmaniasis. The boy exhibits splenomegaly, distended abdomen and severe muscle wasting. 

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