Parasitic protozoa II - Tissue + blood Flashcards
Triad of chorioretinitis, hydrocephalus, intracranial calcifications
Toxoplasma gondii
Widespread infxn that causes flu-like symptoms and then typically bcomes dormant
- can be reactivated if immunocompromised
toxoplasmosis
Toxoplasma gondii
- intra or extracellular?
- infects what?
Intracellular parasite that can infect any cell
How are toxplasma gondii transmitted?
fecal oocysts
–> cysts multiply in muscles (raw meat)
If maternal of toxoplasmosis infection occurs during 1st trimester, incidence of fetal infxn?
15%, but disease in neonate is most severe
If maternal infection of toxoplasmosis occurs during 3rd trimester, incidence of fetal infxn?
65%
Neonate is usually asymptomatic at birth but may have more learning disabilities and neurological sequelae
If maternal infxn of toxoplasmosis occurs how many mo b4 conception, risk of fetal infxn increases as mother may not have developed enough immunity.
less than 6 mo
Toxoplasmosis
- dividing form
- dormant form
- dividing form: tachyzoites
- dormant form: bradyzoites
How does the triatomine bug (reduviid bug) infect you with trypanosoma cruzi?
It bites and takes blood meal form you –>
it poos on you –>
you scratch it –>
it gets into blood
Chagas disease
- dilated cardiomyopathy
- Atypical atrophy
- Megacolon
- megaesophagus
- Unilateral periorbital edema (romana sign)
Leishmaniasis
- Intra or extracelluar
- INfects what cells?
- transmission?
Intracellular parasite of macrophages
Bite of infected sand flies
Visceral leishmaniasis
Spiking fevers
Hepatosplenomegaly
Pancytopenia
Trypanosoma brucei
- causes what disease?
- transmission?
African sleeping sickness
Tsetse fly
How to dx:
Toxoplasma gondii
Naegleria fowleri
Trypanosoma brucei
Toxoplasma gondii- serology, biopsy (tachyzoites)
Naegleria fowleri
- Amoebas in spinal fluid
Trypanosoma brucei
- blood smear
Malaria (P. vivax) sx
fever, HA, anemia (really bad in preggos), splenomegaly
Paroxysms:
fever on 1st day and 3rd day (48 hrs apart)
- cold, then hot, then sweating phase
Which plasmodium species have paroxysmal attacks occuring every 2nd day? 3rd day?
2nd: falciparum, vivax, ovale
3rd:
malariae
People negative for Duffy blood group (protein)
resistant to infxn by P vivax
*so are heterozygotes for sickle cell
Dx babesia
Blood smear
Maltese cross
Serology, PCR
Life cycle and pathogenesis of Toxoplasma gondii
Ingest bradyzoites in cysts (undercooked, inadequately frozen meat) Or Ingest oocysts (in food contaminated with cat feces) --> Oocyst transform into tachyzoites --> localize in neural and muscle tissue --> develop into tissue cyst bradyzoites
Most common protozoan infxn in US
T. gondii
Life cycle and Pathogenesis of Trypanosoma cruzi (Chagas disease)
Triatomine (reduviid) bug takes blood meal from hu –>
releases trypomastigotes in feces near site of bite wound –>
Trypomastigotes enter host thru wound or thru intact mucosal membrane (conjunctiva) –>
Invade host IN cells near the site of inoculation –>
Trypomastigotes differentiate into intracellular Amastigotes –>
Amastigotes multiply by binary fission –>
differentiate into extracellular Trypomastigotes –>
Release into blood stream –>
Cycle betwn Trypomastigotes and Amastigotes (clinical manifestations) –>
Kissing bug feeds on infected human or animal blood containing circulating parasite –>
Ingested Trypomastigotes transform into Epimastigotes in vector’s midgut –>
Multiply and
differentiate into infective Trypomastigotes in hindgut
Life cycle and pathogenesis of Leishmania donovani
Female sandfly bite hu –>
Inject the promastigotes (infective stage) –>
Phagocytized by macrophages –>
Promastigotes transform into amastigotes (tissue stage) –>
Multiply by simple division –>
Infect other mononuclear phagocytic cells –>
Sandflies ingest infected cells during blood meals –>
In sandflies, Amastigotes transform into Promastigotes
Life cycle and pathogenesis of Trypanosoma brucei
Tsetse fly painfully bites hu –>
Injects metacyclic trypomastigotes into skin –>
Enters lymphatic system and pass into bloodstream –>
Transform into bloodstream trypomastigotes –>
carried throughout body and reach other body fluids (lymph, spinal fluid) –>
replicate by binary fission
Life cycle and pathogenesis of PLasmodium spp.
Anopheles mosquito inoculates hu host w/ sporozoites –>
Infect liver cells –>
Mature into schizonts –> Schizonts rupture and release merozoites –>
Merozoites infect RBC –>
Becomes immature trophozoite (ring stage) –>
mature into RBC shizonts –>
Rupture and release merozoites –>
Some differentiate into sexual erythrocytic stages (gametocytes of Plasmodium) –>
Blood stage parasites = clinical manifestations –>
Ingested by anopheles mosquito –>
multiply inside via sporogonic cycle
