protozoa Flashcards
Parasites are divided to
- Protozoa
2. Helminthes
Helminthes are divided to
- Nematodes (roundworms)
- Cestodes (tapeworms)
- Trematodes (flukes)
Protozoa infections are divided to
- GI infections
- CNS infections
- Hematologic infections
- other infections (visceral infections and STD)
Protozoa GI infections - bugs and diseases
- Giardia lamblia - giardiasis
- Entamoeba histolytica - amebiasis
- Cryptosporidium - diarrhea
Giardia lamblia - disease and symptoms
Giardiasis: 1. bloating 2. flatulence
3. foul smelling, fatty diarrhea
Giardiasis is often seen in
campers/hikers
Giardia lamblia - transmission
cysts in water
Giardia lamblia - diagnosis
multinucleated trophozoites or cysts in stool
trophozoite?
a growing stage in the life cycle of some sporozoan parasites, when they are absorbing nutrients from the host. (pathogenic state)
Giardiasis - treatment
metronidazole
Entamoeba histolytica - disease and symptoms
Amebasis: 1. bloody diarrhea (dysentery)
- liver abscess (anchovy paste exudate)
- RUG pain
amebiasis - gross appearance
flask-shaped ulcer in colon
Entamoeba histolytica - rout from colon to liver abscess
invades through the intestinal wall to enter to the bloodstream
anchovy paste exudate
Amoebic abscesses of the liver produce brownish pus, which is described as looking like “anchovy paste”
Entamoeba histolytica - transmission
cysts in water
Entamoeba histolytica infection - diagnosis
- serology and/or
- trophozoites with RBCs in the cytoplasm
or cysts with up to 4 nuclei in stool
Entamoeba histolytica infection - treatment
- metronidazole
2. iodoquinol for asymptomatic cyst passers
Cryptosporidium - disease and symptoms
severe nonbloody diarrhea in AIDS Mild disease (watery diarrhea) in immunocompoment
Cryptosporidium - transmission
oocysts in water
Cryptosporidium - diagnosis
oocysts on acid-fast stain
Cryptosporidium - treatment/prevention
prevention by filtering city water supplies
notazoxamide in immunocompetent hosts
no clear treatment for AIDS patient
Protozoa - CNS infection - bugs and diseases
Toxoplasma gondi - toxoplasmosis
Naegleria fowleri - rapidly fatal meningoencephalitis
Trypanosoma brucei - African sleeping disease
Toxoplasma gondi infection and symptoms
- Congenital toxoplasmosis –> classic triad of chorioretinitis, hydrocephalus, intracranial calcification
- reactivation in aids –> brain abscess
Toxoplasma gondi transmission
cysts in undercooked meat (MC)
oocysts in cat feces
crosses placenta
Toxoplasma gondi - pregnant women should
avoid cats
Toxoplasma gondi - diagnosis
serology
biopsy (tachyzoite)
CT/MIR ring-enhancing lesion
Toxoplasma gondi in AIDS - CT/MIR
ring-enhancing lesion
Toxoplasma gondi infection - treatment
sulfadiazine + Pyrimethamine
Trypanosoma brucei - subspecies
- Trypanosoma brucei rhodesiense
2. Trypanosoma brucei gambiense
Trypanosoma brucei - disease and symptoms
African sleeping disease: 1. enlarged lymph nodes
2. recurring fever 3. somnolence 4. Coma
Mechanism of recurring fever in African sleeping disease
antigenic variation
African sleeping disease - transmission
Tsetse fly, a painful bit
African sleeping disease - diagnosis
Trypomastigote in blood smear
African sleeping disease - treatment
suramin for blood-borne disease
melarsoprol for CNS penetration
Naegleria fowleri - disease and symptoms
rapidly fatal meningoencephalitis
Naegleria fowleri - transmission
swiming in freshwater lakes –> enters via cribriform plate
Naegleria fowleri - diagnosis
amoebas in spinal fluid
Naegleria fowleri - treatment
amphotericin B has been effective for a few survivors
Protozoan hematologic infections - bugs and diseases
- Plasmodium –> Malaria
2. Babesia –> Babesiosis
Protozoan hematologic infections - Babesia - disease and symptoms
Babesiosis –> fever and hemolytic anemias
high risk of severe disease with asplenia
Babesios - area (map)
northeastern US
Babesios - high risk in
asplenia
Babesios - tranmission
ixodes tick
Babesiosis - treatment
Atovaquone + azithromycin
Babesios - diagnosis
- Blood smear: ring form and Maltese cross
2. PCR
Plasmodium - bugs
P. vivax
P. oval
P. falciparum
P. malariae
Malaria - general symptoms
- fever
- headache
- anemia
- splenomegaly
Malaria - fever according to bug
P. vivax/ovale –> 48hr cycle (tertian: fever on first day and third day, thus fever are actually 48hr apart)
P. falciparum –> severe. irregular fever pattern
P. malariae –> 72 hr cycle (quartan)
malaria is AKA
blackwater fever
other complications of malaria, beside general symptoms
occlude capillaries in brain (cerebral malaria), kidney, lung (esp with P. Falciparum)
Malaria - transmission
anopheles mosquito (sporozoites)
Briefly describe the life cycle of plasmodia parasite
sporozoites in mosquito salive enter into human blood –> sporozoites enter liver cells and multiply and differentiate –> Merozoites are release from liver cells and enter RBCs –> Multiplication and differentiation into trophozoites and gamezytes within RBCs –> RBCs rupture releasing moro trophozoites, merozoites and gametocytes –> mosquito picks up male and female gametocytes when ingesting human blood
Malaria - relapse vs recrudescence
Relapse occurs in P. vivax and P. ovale infection ressults from hypnozoites –> reactivation of hypnozoites in liver
Recrudescence occurs in P. malariae and P. falciparum infections and results from incomplete eradication of the parasites
Malaria - diagnosis
- Blood smear: trophozoites ring within RBCs, schizont containing merozoites
- Red granules (Schuffner stippling) through RBC cytoplasm seen with P. vivax/ovale
Schuffner stippling
Red granules through RBC cytoplasm seen with P. vivax/ovale
Malaria - treatment for every situation
- Chloroquine (for sensitive species)
- Mefloquine or atovaquone/proquanil (for resistant)
- IV quinidine or artesunate (If life threatening) –> test for G6PD
- P. vivax/ovale add primaquine for hypnozoite –> test for G6PD
antimalaria drugs –> test for G6PD with which drugs
- quinidine
- artesunate
- primaquine
Protozoa visceral infections - bugs and disease
- Trypanosoma cruzi –> Chagas disease
2. Leishmania donovani –> Visceral leishmaniasis (kala-azar), cutaneous leismaniasis
Leishmania donovani - disease and symptoms / aka
A. Visceral leishmaniasis (kala-azar): 1. spiking fevers 2. hepatosplenomegaly 3. pancytopenia B. cutaneous leismaniasis: 1. Skin ulcers
Leishmania donovani - transmission
sandfly
Visceral leishmaniasis (kala-azar) - diagnosis
macrphages contating amastigotes
Visceral leishmaniasis (kala-azar) - treatment
amphotericin B
sodium stibogluconate
Trypanosoma cruzi - disease and symptoms
Chagas disease:
- dialted cardiomyopathy with apical atrophy
- megalcolon
- megaesophagus
Trypanosoma cruzi - disease / map
Chagas disease
SOUTH AMERICA
Chagas disease sign
ROMANA SIGN: unilateral periorbital swelling –> characteristic of acute stage
Trypanosoma cruzi - Transmission
Reduviid bug (kissing bug) feces, deposited in a painless bite
Trypanosoma cruzi - diagnosis
Trypomastigote in blood smear
Trypanosoma cruzi -treatment
Benzidazole or nifurtimox
Protozoa sexual transmitted infections - bugs and disease
Trichomonas vaginalis –> vaginitis
Trichomonas vaginalis - disease and symptoms
vaginitis:
foul-smelling, greenish discharge, itching and burning
bacterial vaginosis vs protozoal vaginitis according to symptoms
vaginitis: foul-smelling, greenish discharge, itching and burning
Bcterial vaginosis: gray vaginal discharge with fishy smell, nonpainful
Trichomonas vaginalis - transmission
sexual
Trichomonas vaginalis - outside human form
cannot exits outside human because it cannot form cysts
Trichomonas vaginalis - diagnosis
trophozoites (motile) on wet mount
strawberry cervix
Trichomonas vaginalis - treatment
Metronidazole for patient and partner (prophylaxis)
treatment for all protozoal infections (except malaria)
Giardiasis –> Metronidazole
amebiasis –> metronidazole, iodoquinol for asymptomatic cyst passers
cryptosporidium –> prevention by filtering city water supplies, nitazoxanide in immunocompetent, no clear treatment for aids
Toxoplasma gondi –> Sulfadiazine+pyrimethamine
Naegleria fowleri –> Amphotericin B
Trypanosoma brucei –> Suramin for blood-borne disease or melarsoprol for CNS penetration
Babesia –> atovaquone + azithromycin
Tripanosoma cruzi –> Benzidazole or nifurtimox
Leishmania donovavi –> amphotericin sodium stibogluconate
trichomonas vaginalis –> Metronidazole for patient and partner (prophylaxis)
Malaria - treatment for every situation
- Chloroquine (for sensitive species)
- Mefloquine or atovaquone/proquanil (for resistant)
- IV quinidine or artesunate (If life threatening) –> test for G6PD
- P. vivax/ovale add primaquine for hypnozoite –> test for G6PD
protozoa infection in asplenia
Babesia
Chloroquine - mechanism of action
Blocks detoxification of heme into hemozoin –> Heme accumulates and is toxic to plasmodia (block polymerase)
Chloroquine - clinical use
plasmodium species other than P. falciparum (resistance)
Chloroquine - P. falciparum (why)
resistance –>membrane pump that decreases intracellular concentration in drugs
P. falciparum - treatment
artemether/lumefantrine or atovaquone/proquanil
Chloroquine - toxicity
- Retinopathy
2. Pruritus (esp in dark-skinned individuals)