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Flashcards in Introduction to Parasites Deck (59)
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1

What is a parasite

An organism that lives in another organism (host) and gets its food at the expense of this host
They are simple organisms but more complex than bacteria and consist of a wide range of pathogens

2

Where can parasites cause infections

Tropics
Subtropics
Temperate climated

3

What parasitic disease causes the most deaths globally

Malaria

4

What are the three main groups of parasites

Protozoa
Helminths (worms)
Arthropods

5

What type of organisms are classified as protozoa

Malaria
Amoebae
Flagellates

6

What type of organisms are classified as helminths (worms)

Roundworms
Tapeworms
Flukes

7

What type of organisms are classified as arthropods

Lice
Ticks
Mites

8

What are protozoa

Microscopic one celled organisms
Can be free-living or parasitic in nature
Can multiply in humans

9

How can protozoa be transmitted

Fecal-oral route
Arthropod vector

10

Why type of protozoa use the fecal-oral route transmission

Protozoa that live in a human's intestine

11

Why type of protozoa use the arthropod vector transmission

Protozoa that live in the blood or tissue of a human

12

What are roundworms also known as

Nematodes

13

What are tapeworms also known as

Cestodes

14

What are flatworms also known as

Trematodes

15

How can a definitive diagnosis be made

From the identification of parasites in the host tissue or excreta should be obtained
Using microscopy to identify the different stages (i.e. parasites, cysts and ova) in the faeces

16

Why should serology be used instead of a culture

Culture is rarely possible
Serology can be useful to detect antibodies (e.g. when parasite is located in deep tissue sites

17

Give examples of protozoan infections

Malaria
Amoebic Dysentery
Leishmaniasis

18

What is malaria

A mosquito-borne disease (uses Anopheles mosquito as its vector) caused by a parasite

19

What do patients with malaria normally experience

Fever
Chills
Flu-like illnesses
If left untreated they may develop severe complications and die

20

How many types of the plasmodium species are there which can cause malaria

4

21

Which plasmodium species has the highest mortality rate for malaria

P. falciparum

22

What types of blood films will be used for malaria

Thick and thin giemsa stained blood films will show the infected red cells

23

What are parasite infected red blood cells called

Parasitaemia

24

Describe the life cycle for malaria

Sporozoites are injected under the skin by the mosquito
This travels through the blood and will enter the liver where it matures and re-enters the circulation as merozoites
They invade red cells, multiply and lyse to reinvade more red cells

25

What happens to the crescent shaped gametocytes produced in the malaria life cycle

They are taken up by the mosquito

26

How can malaria be prevented

Use of insecticide treated mosquito nets (ITNs)
Prophylaxis

27

How many cases of amoebic dysentery are there a year

200-400 million cases/yr
100,000 deaths/yr

28

What is amoebic dysentery

An infection which causes diarrhoea with blood/pus
The trophozoite ingests red cells by removing pseudopodia (‘hot stool’)

29

When are the symptoms of amoebic dysentery most common

During an infection by Entamoeba histolytica

30

What can be seen under a microscope in amoebic dysentery

Cysts formed in the stool