Protozoa

Front 1

Entamoeba histolytica

Back 1

amebiasis, bloody D, dysentery, liver abcess, RUQ pain
Cysts in water
dx with serology &/or trophozoites or cysts in stool
tx with metronidazole and iodoquinol

Front 2

giardia lamblia

Back 2

giardiasis, bloating, flatulence, foul-smelling D-campers/hikers
Cysts in water
Dx with cysts or trophozoites in stool
tx with metronidazole

Front 3

Cryptosporidium

Back 3

severe D in AIDS pts, milder dz in non-HIV pts
cysts in water
dx with cysts on acid fast stain
no tx

Front 4

Toxo

Back 4

brain abcess in HIV, birth defects (ring enhancing brain lesions
cysts in meat or cat poo
dx with serology or bx
tx with sulfadiazine + pryrimethamine

Front 5

Trichomonas vaginalis

Back 5

vaginitis, foul smelling greenish d/c, itching and burning
sexual transmission
dx with motile trophozoites on wet mount
tx with metronidazole

Front 6

trypanosoma cruzi

Back 6

chaga's dz- dilated CM, megacolon, megaesophagus
Reduviid bug transmission
dx with blood smear
tx with nifurtimox

Front 7

Trypanosoma
T. gambiense
T. rhodesiense

Back 7

Africa sleeping sickness
tsetse fly
dx with blood smear
tx wtih suramin-bloodborne, melarsoprol-CNS penetration

Front 8

Leishmania donovani

Back 8

visceral leishmaniasis
sandfly
dx with macs containing amastigotes
tx with sodium stibogluconate

Front 9

Babesia

Back 9

fever and anemia
Ixodes tick
dx with blood smear: no RBC pigment-maltese cross
tx with quinine, clindamycin

Front 10

Naegleria

Back 10

rapidly fatal meningoencephalitis
swimming in fresh water lates (enters via cribiform plate))
dx with amebas in spinal fluid
no tx

Front 11

P. vivax and ovale

Back 11

Vivax and ovale also have a hypnozoite liver stage where the parasite is dormant for months-years.
Severe fever but death is rare because parasitemia is limited by the requirement that vivax can only invade reticulocytes. The Duffy blood group antigen is also required for invasion.
Vivax and ovale have a dormant stage in the liver – this stage is the hypnozoite

Front 12

P. falciparum

Back 12

In addition to fever, P. falciparum causes cerebral coma, dangerous anemia, lactic acidosis, hypoglycemia, acute renal failure, splenomegaly, and pregnancy complications.
Falciparum infections are a medical emergency.

Front 13

Malaria life cycle

Back 13

Mosquito bite transmits sporozoites, a few of which will invade hepatocytes. These replicate into thousands of merozoites, which go to bloodstream to infect RBC.
RBCs burst, releasing around 20 merozoites that infect other RBC. Fevers, headache, and pain coincide with schizont rupture from RBCs.

A very tiny fraction of these sometimes become gametocytes that are infective for the next mosquito bite. These mature, leaving creating sporozoites in the mosquito salivary glands for future infection.
Disease is from the RBC infection, not the liver infection!

Front 14

Malaria tx

Back 14

Chloroquine
Primaquine to prevent relapse of vivax and ovale
Sulfadoxine + pyrimethamine, mefloquine, quinine
selectively inhibit the detoxification of heme inside the parasites by inhibiting formation of the “malaria pigment polymer” used by Plasmodium to sequester heme.

They only attack this late stage, and can’t prevent transmission to new hosts.
--Chloroquine (drug of choice for all species of Plasmodium)
--Mefloquine (drug of choice for prophylaxis of chloroquine-resistant falciparum)
--Quinine (drug of choice for treatment of chloroquine-resistant falciparum). Quinine is a stereoisomer of quinidine. Major toxicity of Quinine is cinchonism (tinnitus, headache, visual disturbance).