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1

Protozoa are...

- everywhere
- motile
- unicellular eukaryotes
- highly diverse
- symbiotic & commensals: rumen
- parasitic: vertebrate & invertebrate hosts

2

What are extracellular protozoans?

- live inside body, outside cell
- intestinal tract
- blood
- antigen masking

3

What are intracellular protozoans?

- penetrate host cells
- invasive
- parasitophorous vacuole
- invade immune cells

4

What is Sarcodina?

protoplasm amoebae
- contains pseudopodia (extension of cytoplasm shape changes)
- remainder flows forward
- reproduce asexually via binary fission

5

Amoebae causing emoebic gill disease (AGD)?

Neoparamoeba perurans
translates to: 'new-by the side of- amoeba inflamming'

6

N. perurans and economic effects...

- fatal disease
- affects marine fish eg. Atlantic salmon
- costs AUS $230 million /year
- also affects USA, NZ, France, Spain, Ireland & Chile

7

Characteristics of N. perurans...eg. shape, size etc.

14-50mm
sub-spherical
many pseudopodia
different species very similar
identified via PCR

8

N. perurans life cycle...

live & reproduce on gills & reproduce via binary fission -> trophozoites transferred thru water -> into gills of other fish to start cycle again

9

N. perurans symptoms, contributing factors & diagnosis...

symptoms: affect gills (resp & excretory system) turn them whitish thru tissue/capillary damage -> extensive multifocal mucoid lesions. Histopath: hyperplastic lamellar fusion
contributing factors: water >16 degrees, crowding & poor water circulation in sea pens
diagnosis: wet mount obs, histopath., molecular techniques (PCR assay)

10

Entamoeba histolytica...recall everything!

'inside' amoeba 'tissue lysis'
Primary host - human (can also be apes, dogs, cats, pigs)
Live in large intestine
2nd most common cause of parasitic death (1/9 pathogenic)
Life cycle: (draw picture) orally ingested -> LI lives & reproduces -> trophozoites & cysts excreted in faeces (cyst infective) repeat cycle...
clinical signs: mostly asymptomatic, diarrhoea, gas, stomach pain/cramps, bloody diarrhoea, anaemia, fatigue, malnutrition, liver abscesses...
diagnosis: stool sample microscopy (cysts), trophozoites from biopsy, ingested RBCs, WBCs or bacteria
control & prevention: insects (flies/cockroaches), personal hygiene, fruit&veg, pasteurised milk, boiled water
treatment: symptomatic or asymptomatic

11

What is zoomastigophora?

flagellate - draw!
Structures include: elongated general shape, flagellum, photoreceptor, contractile vacuole, pigment shield, chloroplasts, stored polysaccharides (photosynthesis), nucleus & nucleolus, undulating membrane

12

Characteristics of zoomastigophora...

move via flagella
also have undulating membrane
reproduce via asexual & binary division

13

Name the flagellates (include taxonomy)

Diplomonads (Giardia)
Trichomonadida (Trichomonas)
Kinetoplastida (Trypanosoma & Leishmania)

14

Characteristics of Giardia...

Giardia intestinalis (diplomonad) 'double one, unit'
Host: diverse including humans
Lifecycle: cyst & trophozoite excreted in faeces -> only cyst survives -> contaminates food/water/hands etc. -> ingested -> intestines -> grow & reproduce -> repeat cycle
Routes of infection: fmily member, water, raw/undercooked food/unprotected anal sex
Clinical signs: diarrhoea (also fatty dia.), abdo. cramping
Diagnosis: stool Ag test, stool exam
Treatment & prevention: if no/mild symptoms - no treatment; meds if severe/persistent; persons working in day care/nursing. Boiling, iodine, hygiene techniques, safe sex, wash/peel fruit

15

What does Giardia look like?

draw!

16

Characteristics of Trichomonadida...

Tritrichomonas (3-hair-uncut) foetus
- pear shaped, 3 anterior flagella, 1 posterior flagella, undulating membrane, no cyst stage.
- venereal, in human (T. vaginalis)
- Cattle: bulls (penis membranes inside sheath); cows (vagina, uterus, oviduct; swine (nasal); cats (digestive system)
- notifiable disease (infections 5 - 50% in Aus & USA)
- Lifecycle: stays in trophozoite form to decrease energy use, asexual binary fission (no cyst)

17

Name 2 symptoms of Tritrichomonas foetus in cattle (include bulls & cows)...

cows: vaginitis, placentitis, abortion
bulls: pain on micturition, decreased sexual servicing

18

Diagnosis of Tritrichomonas foetus in cattle (include bulls & cows)...

Bulls: 2 weeks sexual rest before testing, observing smegma
Cows: vaginal mucus/foetal tissue -> culture -> microscopy exam; PCR faster diagnosis

19

What are kinetoplastids?

kineto: moveable, plast: form
Leishmania & Trypanosoma

20

What is an amastigote?

a kinetoplastid without flagellum

21

What is a promastigote?

'pro' - anterior: an elongated kinetoplastid with flagellum at posterior end

22

What is an epimastigote?

'epi' - close: elongated kinetoplast posterior but not past nucleus with undulating membrane

23

What is a trypomastigote?

'trypo' - boring: kinetoplast with flagellum and undulating membrane all the way along parasite

24

A bit about Leishmania...

- Endemic to Mediterranean basin, Balkans, Asia, Africa, Sth America
- Can be cutaneous or visceral
- Lifecycle: see slide 52
- Clinical signs: weight loss, enlarged spleen & liver, decrease RBC prod. -> anaemia (no treatment -> death)
- Diagnosis: blood smear, biopsy of infected area, microscopy, culture, PCR
- Treatment: Cutaneous - liquid nitrogen (cryotherapy) or drugs
- Prevention/control: pesticides -> target vector

25

Leishmania lifecycle

sandfly takes blood meal -> injects promastigote into animal (human/dog/roo) -> macrophages phagocytose promastigotes -> promastigotes transform into amastigotes inside macrophages & multiply within macrophages & cells of various tissues -> sandfly takes blood ingesting macrophages infected with amastigotes -> transform into promastigotes in midgut & divide -> migrate to proboscis -> cycle repeats

26

Know histology pics well!

Look and be able to distinguish all of them

27

Re. Leishmania spp, which form is present in which host?

promastigote - insect host
amastigote - vertebrate host or culture

28

How is kinetoplastid Leishmania transmitted?

female sandfly vector

29

Kinetoplastid trypanosoma...

Extracellular in blood of vertebrates
Cattle variety kills 3 million cattle yearly
Causes sleeping sickness (African), or Chagas (American)
Lifecycle - see slide 70
Clinical signs: (cattle) lymphadenopathy, anaemia -> emaciation -> often death
(human) peripheral circulation & CNS, fever, headache, neurologic problems, death
Diagnosis: Cattle - blood samples, human - finding parasite in body fluid or tissue via microscopy
Treatment: Metamidium & diaminazine aceturate usually successful but problematic...
Prevention/control: no vax's or drug for prophylaxis, minimise contact with tsetse flies, chemicals, traps...

30

Which species of trypanosoma affects humans and cattle?

T. brucei

31

What is surra?

Animal trypanosomosis (not present in Aus or Papua New Guinea

32

How many species of trypanosoma in Aus?

5 - platypus, koala, wombat, bandicoot...

33

T. brucei clinical signs (include cattle & humans)

cattle - lymphadenopathy, anaemia -> emaciation, often death
humans - peripheral circulation & CNS (fever, headache, muscle & joint)

34

T. brucei - diagnosis

cattle - no. of blood samples
humans - finding parasite in body fluid or tissue by microscopy

35

T. brucei treatment...

some drugs can be successful - drug resistance in chronic disease
treatment can be problematic