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Y2 MCD - Microbiology - Laz DC > Parasitic Infections > Flashcards

Flashcards in Parasitic Infections Deck (75)
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1

Define parasite.

An organism living in or on a host and dependent on the host for nutrition – causing damage

2

What is the difference between an endoparasite and an ectoparasite?

Endoparasite – exist INSIDE the host
Ectoparasite – exist on the host

3

What are the two groups of endoparasites and what are the features of organisms within these two groups?

Protozoa
 Unicellular
 Eukaryotes (membrane bound nucleus)
 Some have insect vectors
 NO eosinophilia
Metazoa
 MULTIcellular
 They are helminths/worms
 Free living, intermediate hosts and vectors
 Cause eosinophilia if they invade the blood

4

State the classes of organisms within the two groups of endoparasites.

Protozoa
 Amoeba
 Coccidia
 Ciliates
 Flagellates
Metazoa
 Roundworms
 Flatworms
 Flukes

5

Give some examples of amoeba.

Entamoeba histolytica
Entamoeba dispa

6

Give some examples of coccidia.

Plasmodium species
Toxoplasma
Cryptosporidium

7

Give an example of a ciliate.

Balantidium coli

8

Give some examples of flagellates.

Trypanosoma
Trichomonas
Giardia
Leishmania

9

What is the main difference between the two types of amoeba?

Entamoeba histolytica can cause invasive amoebiasis
Entamoeba dispar is a normal commensal of the GI tract

10

What is amoeba infection caused by?

Ingestion of mature cysts in food or water contaminated by faeces

11

Describe how E. histolytica infection causes disease.

The cysts enter the small intestine and release active amoebic particles (trophozoites), which invade the epithelial cells of the large intestines, causing flask-shaped ulcers
Infection can spread from the intestines to other organs e.g. liver, lungs and brain
Invasive amoebiasis may often cause amoebic liver abscesses

12

How many nuclei are there in mature cysts?

4

13

What are the treatment options for amoebiasis?

Nitroimidazole derivatives (kills trophozoites but not the cysts)
Parmomycine or Diloxanide Furoate

14

What are the five types of plasmodium that cause malaria?

Falciparum
Malariae
Vivax
Ovale
Knowlesi

15

What are the two types of host for plasmodium?

Human
Female anopheles mosquito

16

What are the two stages of malaria in humans?

Liver
Blood

17

Describe the symptoms of malaria.

PAROXYSMAL (occurs every 4-8 hours)
Fever
Chills
Headaches
Vomiting
Muscle pain

18

State some complications of malaria.

Severe anaemia (due to intravascular haemolysis)
Cerebral malaria
Liver failure
Shock
Pulmonary oedema
Abnormally low blood sugar
Kidney failure
Swelling and rupturing of the spleen

19

What are the treatments for uncomplicated malaria?

Chloroquine (look at notes for the rest of the treatment options)

20

What is the treatment for severe malaria?

Artemisinin-based combination therapy

21

How is malaria diagnosed?

Blood film (+ Giemsa stain)

22

What are the routes of infection of toxoplasma gondii?

Eating undercooked meat of animals harbouring tissue cysts
Consuming food or water contaminated with cat faeces
Blood transfusion
Organ transplantation
Transplacentally from mother to foetus

23

Which group of patients are particularly vulnerable to toxoplasma infection?

Immunocompromised

24

What can toxoplasma infections cause in these individuals?

CNS disease
Brain lesions
Pneumonitis
Retinochoroiditis

25

What does cryptosporidium cause?

DIARRHOEA (mainly in the immunocompromised)

26

How is it treated?

Fluid rehydration

27

How are most diarrhoeal protozoal diseases diagnosed?

Stool examination

28

What are the reservoirs of balantidium coli?

Primates
Rodents
Pigs

29

What are the effects of balantidium coli infection in immunocompromised patients?

Persistent DIARRHOEA
Dysentery
Abdominal pain
Vomiting
Nausea

30

How can drinking water be cleared of ovoid giardia lamblia cysts?

Filtration
Ovoid cysts can survive standard chlorination procedures