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Flashcards in Protozoa Deck (23)
1

Protozoa

single celled eukaryotes with nuclei

2

4 groups of protozoa based on locomotion

1. flagellate
2. amoeboid
3. sporozoid
4. ciliate

3

two forms a protozoa takes during life cycle

1. cyst form
2. trophozoite form

4

cyst form

protects from desiccation, temperature and toxins
the normal infective stage
fecal/oral contamination moves cysts from host to host

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trophozoite form

feeding stage
causing symptoms
motile

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protozoa reproduction

asexually through budding, fission or shizogeny

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schizogeny

parasite divides repeatedly in host cell to form many parasites that are eventually released

8

Mastigophora

(Archaezoa)
Flagellate
most primitive
many lack mitochondria and Golgi
Trypanosoma brucei
Trypanosoma cruzi
Giardia
Trichonomas vaginalis

9

Trypanosoma brucei

African sleeping sickness
neurotoxins eventually reach CNS- treatment effective if before infection reaches brain
can alter surface antigens to escape detection by immune system

reservoir- lion, hyena, antelope
vector- tse tse fly

10

Trypanosoma cruzi

Chagas disease
chronic- death from heart failure

reservoir- opossum and armadillo
vector- reduviid bug

bug bites on lips, defecates near bite, scratching deposits feces into bite

11

Giardia

hikers diarrhea
interferes with peristalsis
Van Leeuwenhoek observed Giardia cysts in his own feces
heart shaped with 2 nuclei
cysts can survive up to 2 months

person to person by cysts/ personal contact
water, food contaminated by human or animal feces

boiling, filtering, chemicals (chlorine) required to kill cysts

12

Trichomonas vaginalis

infects female reproductive tract and male urinary tract
no cyst in life cycle
reservoir- human
transferred by intercourse
macrophages with CD4 receptors enter damaged area

13

Sarcodina

amoeboid
Entamoeba
Naegleria
Pseudopodia

14

Entamoeba histolytica

amoebic dysentery
can be extra intestinal (leaves digestive tract and enters body)
cysts transmitted in fecal contaminated water/food
10% world population infected with Entamoeba

15

Naegleria fowleri

causes amoebic meningitis
exists as part of normal flora in children
ameoba enters body through cuts, scrapes, conjunctiva during swimming in warm water
reaches brain through nasal passages

16

Apicomplexa

sporozoid
intracellular parasites
Plasmodium
Toxoplasma
Cryptosporidium
usually requires more than one host
all characterized by schizogeny

17

Plasmodium

malaria
infects 40% world population
vector- female Anopheles mosquito
host- human
treatment- removal of standing water, bed netting and insecticide, remaining inside at night

18

malaria life cycle

-gametes form zygote in mosquito
-zygotes divide by meiosis into sporozoites, move to salivary glands
-sporozoites injected into humans, move through blood to the liver
-sporozoites divide by schizogeny to produce and release merozoites that infect red blood cells
- merozoites form trophozoites in RBCs
-trophozoites divide by schizogeny to form more merozoites
-merozoites released to reinfect RBCs, some form gametes
- gametes taken up by mosquito to complete life cycle

19

Toxoplasma

encephalitis
host- non specific- 200 host species- mostly cats
intermediate hosts- rodents and birds
parasites make rodents less afraid of cats
humans usually infected through fecal contamination
can cross placenta and infect fetus- damage depends on stage of pregnancy

20

Toxoplasma life cycle

-trophozoites invasive stage in host- forms oocysts
-oocysts released with feces
-infect other hosts when ingested

21

Cryptosporidium

diarrhea disease
3-30% of population in developing countries carry cysts
fecal contaminated water/food/ oysters
reservoir- mammal and bird
hosts- cattle, pigs, chickens and reptiles
cysts can be chlorine resistant and too small to filter- initiated water purification through UV RADIATION
cysts detected using acid fast staining procedure

22

Ciliophora

ciliate
largest group
macronuclei and micronuclei
Balantidium coli

23

Balantidium coli

balantidiosis- common diarrhea disease outside of the US
only known ciliate human pathogen
reservoir- pig