Protozoan Infections 1 Flashcards
What are the 4 major groups of protoza
- ameoba
- Ciliates
- Flagellate
- Sporozoa
what are the 4 sporozoa (+ where are they located)
- Blood (plasmodium + Babesia)
- Tissue (Toxoplasma)
- Intestinal (cryptosporidium)
Sporozoa- intra/extracellular, how they move, what do they have that allows them to attach to host
Intracelular protozoan parasites
- no special organ of locomotion
- has apical complex that secretes enzymes + pros that allow it to attach to host
whaat are the 4 phases of life cycle of sporozoa
- Schizogony/merogony (asexual repro)
- Gametogony (where gametes are formed)
- Syngamy (sexual repro)
- Sporogony (Production of sporozoites)
What is the spp responsible for malaria, what is DH and IH
Plasmodium spp.
DH- female mosquitos
IH- hosting asexual repro (in men)
What are the 2 spp of plasmodium that cause malaria in humans
P vivax P Falciparum (most virulent one)
life cycle of malaria overall
- mosquito injects sporozoite in body
- liver it reproduces asexually
- merozyotes leave liver + enter blood stream and form m+f gametocytes
- new mosquito takes up gamets and form zygote in new mosquito
Process then repeates
2 major virulence factors of malaria that cause damage
- Cytoadherence- of affected RBCs to lining of vessels hiding them from splenic clearence
- Rosette formation- Autoagglutination due to clumping of infected RBCs
What occurs in the 1st phase (exo erythrocytic cycle) of malaria in humans- how long, what happens
1-2 weeks
Sporozoites invade liver cells and form schizonts and merozoites and then rupture out and spill into blood
What are hypnozoites
When some merozoutes settle in liver cells as dormat form
What occurs in the 2nd phase (erythrocutic cycle) of malaria in humans
recurrent cycles of RBC destruction
stage of symptoms of malaria
What is the typical symptoms of malaria
Paroxysms of chills, fever, sweating (duration depends on specific spp.)
How does microscopy of dx of malaria work
blood smear every 12-24hrs
Thick smear- presence of organisms
Thinn smear- Identification + quantification of parasites
How to prevent malaria (2)
- Taking prescription before/during/after trip
2. preventing mosquito bites
How is babesiosis transmitted
Transmitted by ticks
Clinical presentation of babesiosis and how will it look on a blood smear
clinically similar to malaria (flu like symptoms)
-Blood smear will show tetrad form in infected blood cells
What is the life cycle of toxoplasma gondii
- oocysts are shed in felines feces
- IH (birds/rodents) become infected by eating material infected
- Cats become infected after consuming IH
How can humans be infected by toxoplasma(4)
- consuming food/water infected
- Eating undercooked meats
- Blood transfusion
- transplacentally
what occurs in acute infection of toxoplasma gondii
released zoites infect small intestine mucosa and replicate to produce tachyzoites (will eventually enter resting stage)
What occurs in chronic infection of toxoplasma
tachyzoites enter resting stage called Bradyzoites (cyst tissue)
-When immunity declines breakdown of cysts occur releasing zoites which start invading new cells and multiplying rapidly (reactivation)
How does replication happen in tachyzoites vs bradyzoits (toxoplasma)
tachyzoits- Replication in vacules that leads to lysis
Bradyzoits- Replication in cysts that do not lyse cell
what is the clinical picture of toxoplasmosis in immunocompetent + immunocompromised pts.
Immunocompetent- usually asymptomatic/mild (headache, fever, sore throat etc)
immunocompromised- pneumia symptoms (more severe)
What is the clinical triad in congenital toxoplasmosis and when does It happen
During pregnancy only when mother is infected FIRST time
Chorioretinitis
Intracranial calcifications
hydrocephalus
(mainly affects eyes + brain)
What are the two species that cause cryptosporidiosis
- Cryptosporidium hominis
2. Cryptosporidium parvum (not humans)
pathology of cryptosporidiosis
Intracellular parasite of epithelial cells of small intestine (single host where sexual/asexual repro happens in intestines)
Steps of transmission of Cryptosporidiosis
mature oocyst passed in feces
ingestion/fecal oral route of ingestion (low infective dose!)
What is the typical clinical picture of cryptosporidiosis
Watery diarrhea
in immunocompromised can possibly infect other areas such as digestive tract/ respiratory tract
How to diagnose cryptospordiosis
Ooyctes in stools
detection of antigen in stools
