Protozoan Infections 1

Question 1

What are the 4 major groups of protoza

Answer 1

1. ameoba
2. Ciliates
3. Flagellate
4. Sporozoa

Question 2

what are the 4 sporozoa (+ where are they located)

Answer 2

1. Blood (plasmodium + Babesia)
2. Tissue (Toxoplasma)
3. Intestinal (cryptosporidium)

Question 3

Sporozoa- intra/extracellular, how they move, what do they have that allows them to attach to host

Answer 3

Intracelular protozoan parasites

• no special organ of locomotion
• has apical complex that secretes enzymes + pros that allow it to attach to host

Question 4

whaat are the 4 phases of life cycle of sporozoa

Answer 4

1. Schizogony/merogony (asexual repro)
2. Gametogony (where gametes are formed)
3. Syngamy (sexual repro)
4. Sporogony (Production of sporozoites)

Question 5

What is the spp responsible for malaria, what is DH and IH

Answer 5

Plasmodium spp.

DH- female mosquitos
IH- hosting asexual repro (in men)

Question 6

What are the 2 spp of plasmodium that cause malaria in humans

Answer 6

P vivax
P Falciparum (most virulent one)

Question 7

life cycle of malaria overall

Answer 7

1. mosquito injects sporozoite in body
2. liver it reproduces asexually
3. merozyotes leave liver + enter blood stream and form m+f gametocytes
4. new mosquito takes up gamets and form zygote in new mosquito

Process then repeates

Question 8

2 major virulence factors of malaria that cause damage

Answer 8

1. Cytoadherence- of affected RBCs to lining of vessels hiding them from splenic clearence
2. Rosette formation- Autoagglutination due to clumping of infected RBCs

Question 9

What occurs in the 1st phase (exo erythrocytic cycle) of malaria in humans- how long, what happens

Answer 9

1-2 weeks

Sporozoites invade liver cells and form schizonts and merozoites and then rupture out and spill into blood

Question 10

What are hypnozoites

Answer 10

When some merozoutes settle in liver cells as dormat form

Question 11

What occurs in the 2nd phase (erythrocutic cycle) of malaria in humans

Answer 11

recurrent cycles of RBC destruction

stage of symptoms of malaria

Question 12

What is the typical symptoms of malaria

Answer 12

Paroxysms of chills, fever, sweating (duration depends on specific spp.)

Question 13

How does microscopy of dx of malaria work

Answer 13

blood smear every 12-24hrs

Thick smear- presence of organisms

Thinn smear- Identification + quantification of parasites

Question 14

How to prevent malaria (2)

Answer 14

1. Taking prescription before/during/after trip

2. preventing mosquito bites

Question 15

How is babesiosis transmitted

Answer 15

Transmitted by ticks

Question 16

Clinical presentation of babesiosis and how will it look on a blood smear

Answer 16

clinically similar to malaria (flu like symptoms)

-Blood smear will show tetrad form in infected blood cells

Question 17

What is the life cycle of toxoplasma gondii

Answer 17

1. oocysts are shed in felines feces
2. IH (birds/rodents) become infected by eating material infected
3. Cats become infected after consuming IH

Question 18

How can humans be infected by toxoplasma(4)

Answer 18

1. consuming food/water infected
2. Eating undercooked meats
3. Blood transfusion
4. transplacentally

Question 19

what occurs in acute infection of toxoplasma gondii

Answer 19

released zoites infect small intestine mucosa and replicate to produce tachyzoites (will eventually enter resting stage)

Question 20

What occurs in chronic infection of toxoplasma

Answer 20

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)

Question 21

How does replication happen in tachyzoites vs bradyzoits (toxoplasma)

Answer 21

tachyzoits- Replication in vacules that leads to lysis

Bradyzoits- Replication in cysts that do not lyse cell

Question 22

what is the clinical picture of toxoplasmosis in immunocompetent + immunocompromised pts.

Answer 22

Immunocompetent- usually asymptomatic/mild (headache, fever, sore throat etc)

immunocompromised- pneumia symptoms (more severe)

Question 23

What is the clinical triad in congenital toxoplasmosis and when does It happen

Answer 23

During pregnancy only when mother is infected FIRST time

Chorioretinitis
Intracranial calcifications
hydrocephalus

(mainly affects eyes + brain)

Question 24

What are the two species that cause cryptosporidiosis

Answer 24

1. Cryptosporidium hominis

2. Cryptosporidium parvum (not humans)

Question 25

pathology of cryptosporidiosis

Answer 25

Intracellular parasite of epithelial cells of small intestine (single host where sexual/asexual repro happens in intestines)

Question 26

Steps of transmission of Cryptosporidiosis

Answer 26

mature oocyst passed in feces

ingestion/fecal oral route of ingestion (low infective dose!)

Question 27

What is the typical clinical picture of cryptosporidiosis

Answer 27

Watery diarrhea

in immunocompromised can possibly infect other areas such as digestive tract/ respiratory tract

Question 28

How to diagnose cryptospordiosis

Answer 28

Ooyctes in stools

detection of antigen in stools