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Flashcards in An Introduction to Parasites Deck (38)
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1
Q

What is a parasite?

A

An organism that lives in another organism (host) and gets its food at the expense of the host

2
Q

How does the complexity of parasites compare to bacteria?

A

They are simple organisms but more complex than bacteria

3
Q

What do parasites cause?

A

Many diseases with malaria causing the most deaths globally

4
Q

What are the 3 classes of parasites?

A

Protozoa

Helminths (worms)

Arthropods

5
Q

What are examples of protozoa?

A

Malaria

Amoebae

Flagellate

Leishmaniasis

6
Q

How is malaria spread?

A

By mosquito

7
Q

What are symptoms of amoebae?

A

Diarrhoea with blood/pus and cysts formed in stool

8
Q

What does leishmaniasis cause?

A

Skin or mucosal ulceration

Leads to fever and weight loss

9
Q

How does leishmaniasis spread?

A

Bite by sandflies

10
Q

How is leishmaniasis diagnoses?

A

Histology of biopsy material

11
Q

What are examples of helminths?

A

Roundworms (nematodes)

Tapeworms (cestodes)

Flukes (trematodes)

12
Q

What is the scientific name of roundworms?

A

Nematodes

13
Q

How are nematodes diagnosed?

A

Pressing adhesive tape againt perianal region in the morning

14
Q

Where are nematodes ova seen?

A

In microscopy

15
Q

How are nematodes transmitted?

A

Faecal-oral route

16
Q

What is a common nematode and what does it do?

A

Ascaris lumbricoides which is a mass of worms that may obstruct the intestine or bile duct

17
Q

What are common cestodes?

A

Taenia saginata (beef)

Taenia solium (pork)

18
Q

How do cestodes spread?

A

Larvae cysts ingested in meat

19
Q

Where are cestodes ova seen?

A

In stool

20
Q

What is a species of cestodes carried by dogs and transmitted by humans ingesting eggs?

A

Echinococcus spp

21
Q

What is the scientific name of flukes?

A

Tramatodes

22
Q

What is the scientific name of tapeworms?

A

Cestodes

23
Q

What are common kinds of trematodes?

A

Schistosomes species:

S.haematobium (bladder)

S.mansoni (intestinal)

S.japonicum (intestinal)

24
Q

Where are high rates of trematodes found?

A

Near fresh water

25
Q

What is an important thing in the life cycle of trematodes?

A

Snails

26
Q

What are examples of arthropods?

A

Lice

Ticks

Mites

27
Q

What are protozoa?

A

Microscopic once celled organisms that can be free living or parasitic in nature

28
Q

How are protozoa transmitted?

A

Faecal-oral route (live in human intestine)

Arthropod vector (live in blood or tissue)

29
Q

Where do protozoa that are transmitted by the faecal-oral route live?

A

Human intestine

30
Q

Where do protozoa that are trasmitted by a arthropod vector live?

A

Blood or tissue

31
Q

What is the life cycle of malaria?

A

1) Sprozoites injected under skin by mosquito
2) Travels through blood and enters liver
3) Matures in liver and re-enters circulation at merozoites
4) Invade red cells, multiply and lyse cells

32
Q

What is the life cycle of schistosomiasis?

A

1) Miracidia released in fresh water
2) Penetrate body of snail
3) Cercaria emerge from snail after 4-6 weeks
4) Penetrate human skin
5) Travel from lungs to liver
6) Mature in liver into worms (schistosomes) that migrate to the bladder venules
7) Lay eggs that cause inflammation

33
Q

When does a definitive diagnosis of a parasite happen?

A

Once the parasite is identified in host tissue or excreta

34
Q

What are the different stages present in microscopy?

A

Parasites

Cysts

Ova

35
Q

What is rarely possible for parasites?

A

Culture

36
Q

What is used to diagnose malaria?

A

Blood films

37
Q

What is serology?

A

Detection of antibodies

38
Q

Is serology used to detect parasites?

A

Yes it can be useful, especially for parasites in deep tissue