Parasitology

Question 1

Mention 2 protozoa that are susceptible to metronidazol!

Answer 1

Entamoeba histolytica Giardia lamblia Trichomonas vaginalis

Question 2

What are the 3 modes of transmission for human Toxoplasma gondii infection?

Answer 2

Eating undercooked meat containing tissue cysts,

Contact with cat feces or consuming food or water containing oocysts Transplacental transmission

Question 3

Which protozoon may infect the human foetus transplacentally and cause developmental malformations?

Answer 3

Toxoplasma gondii

Question 4

Which species are the causative agents of malaria?

Answer 4

Plasmodium vivax, P. ovale, P. malariae, P. falciparum, (P. knowlesi)

Question 5

What is the definitive (ultimate) host of Plasmodium species?

Answer 5

female Anopheles mosquito

Question 6

What is the laboratory diagnosis of malaria?

Answer 6

Giemsa-stained blood smears. Thick smear is used to screen for the agent, thin smear is used to identify the species.

Question 7

How long is the erytrocytic cycle of Plasmodium vivax and P. ovale?

Answer 7

48 hours

Question 8

How long is the erytrocytic cycle of Plasmodium malariae?

Answer 8

72 hours

Question 9

What is the causative agent of malignant malaria?

Answer 9

Plasmodium falciparum

Question 10

Which Plasmodium species may cause relapse of malaria due to presence of hypnozoites?

Answer 10

Plasmodium vivax, P. ovale

Question 11

Mention a potentially fatal complication of Plasmodium falciparum infections!

Answer 11

cerebral malaria

Question 12

Mention an agent that may be effective in the treatment of acute malaria attack!

Answer 12

chloroquine, quinine, artemether+lumefantrine, etc.

Question 13

Mention an antimalarial drug active against hypnozoites!

Answer 13

Primaquin

Question 14

How can one diagnose the African sleeping sickness disease?

Answer 14

Giemsa-stained blood smears are used for direct demonstration. Serology may be helpful

Question 15

What are the causative agents of African sleeping sickness?

Answer 15

Trypanosoma brucei gambiense and rhodesiense

Question 16

Specify the 3 forms of leishmaniasis!

Answer 16

cutaneous, mucocutaneous and visceral

Question 17

How can one diagnose amebic dysenetery?

Answer 17

Microscopic demonstration of E. histolytica cysts and trophozoites from feces

Question 18

How can one diagnose Trichomonas vaginalis infection?

Answer 18

Direct demonstration of protozoa in wet mount or stained smear of clinical specimens (vaginal, urethral or prostatic secretions). Isolation by culture.

Question 19

What is the definitive (ultimate) host of Echinococcus granulosus?

Answer 19

dog

Question 20

How can one diagnose intestinal taeniasis?

Answer 20

Demonstration of characteristic proglottis and eggs (ova) in faeces.

Question 21

How can one diagnose Hymenolepis infection?

Answer 21

Demonstration of eggs (ova) in faeces

Question 22

Mention a worm species for which ab ano ad os auto-reinfection is characteristic in childhood!

Answer 22

Enterobius vermicularis

Question 23

Mention 2 worm species that migrate through the human lungs in the larval stage!

Answer 23

Ascaris lumbricoides Ancylostoma duodenale Necator americanus Strongyloides stercoralis

Question 24

How can one diagnose Ascaris infection?

Answer 24

Demonstration of eggs (ova) in faeces

Question 25

How can one diagnose trichuriasis?

Answer 25

Demonstration of eggs (ova) in faeces

Question 26

How can one diagnose Enterobius infection?

Answer 26

Demonstration of eggs (ova) recovered from perianal skin (Scotch tape technique). Not from feces!

Question 27

Mention 3 tissue infecting filarial nematodes!

Answer 27

Wuchereria bancrofti Loa loa | Oncocerca volvulus

Question 28

How is human Fasciola hepatica infection acquired?

Answer 28

By eating aquatic vegetation containing encysted larvae (Rarely: by eating raw sheep liver containing adult worms)

Question 29

What disease is caused if humans are infected per os with Taenia solium eggs?

Answer 29

human cysticercosis (encysted larvae in brain, eyes, etc.)

Question 30

How is human Trichinella spiralis infection acquired?

Answer 30

By eating raw or undercooked meat containing encysted larvae

Question 31

Mention 2 helminths whose larvae enter the human body by penetrating the intact skin!

Answer 31

Schistosoma Ancylostoma duodenale Necator americanus Strongyloides stercoralis

Question 32

Which developmental form of Echinococcus granulosus can occur in humans?

Answer 32

Hydatid cyst

Question 33

What are the definitive, and the intermediate hosts of Taenia saginata, respectively?

Answer 33

definitive host: human intermediate host: cattle

Question 34

What are the definitive, and the intermediate hosts of Taenia solium, respectively?

Answer 34

definitive host: human intermediate host: swine (pig)

Question 35

What is the infectious form of Strongyloides stercoralis?

Answer 35

filariform larva

Question 36

What is the infectious form of Trichuris trichiura?

Answer 36

embryonated egg

Question 37

Which form of Taenia saginata is infectious for humans?

Answer 37

cysticercus (in beef)

Question 38

Is autoreinfection possible in Ascaris lumbricoides infection? If yes, when?

Answer 38

No, the eggs must mature in the soil for several days to become infectious (embryonated)

Question 39

Is autoreinfection possible in Strongyloide stercoralis infection? If yes, when?

Answer 39

yes, especially in immunosuppression (for example: AIDS)

Question 40

Is autoreinfection possible in Enterobius vermicularis infection? If yes, when?

Answer 40

yes, the eggs become infectious in a few hours, and ab ano ad os autoinfection may occur (especially in children)