Protozoa and Disease

Question 1

what is an apicoplast

Answer 1

an organelle similar to a chloroplast

Question 2

what is the purpose of a cyst

Answer 2

long term survival

Question 3

what are the three classes of parasitic causing microorganisms

Answer 3

protozoa, helminths, arthropods

Question 4

what are the WHO list of major parasitic diseases

Answer 4

amoebiasis, hookworm disease, leishmaniasis, schistosomiasis and malaria

Question 5

what is amoebiasis caused by

Answer 5

entamoeba histolytica - grows in water dirty with fecal matter

Question 6

what causes hookworm disease

Answer 6

ancylostoma duodenate and necator americanus

Question 7

what causes leishmaniasis

Answer 7

leishmania via sandfly bite

Question 8

what causes schistosomiasis

Answer 8

contaminated fresh water by parasitic worms

Question 9

what causes malaria

Answer 9

anopheles mosquito bite

Question 10

what microorganism causes malaria

Answer 10

plasmodium genus- bite of female anopheles mosquito

Question 11

which two diseases outdo malaria for cause of death

Answer 11

aids and tuberculosis

Question 12

what are the 5 species of plasmodium

Answer 12

1. p falciparum
2. p vivax
3. p ovale
4. p malariae
5. p knowlesi

Question 13

describe the malaria transmission cycle

Answer 13

1. infection from female anopheles mosquito via sporozoites
2. sporozoites form merozoites in liver cells which causes lysis in hepatocytes
3. merozoites now get into the blood stream
4. RBCs are infected by merozoites
5. merozoites form rings in rbc
6. trophozoites are hence formed from the rings
7. trophozoites multiply to form a schizont and more merozoites - RBCs lyse to release more merozoites into the blood
8. schizont may form gametocytes which a different mosquito ingest and hence will transmit the infection

Question 14

what is the morphology of a P. falciparum trophozoite

Answer 14

headphone shaped or ring shaped

Question 15

what stain is used for observing malaria infected red blood cells

Answer 15

giemsa stain

Question 16

what are the general symptoms of malaria

Answer 16

anaemia, splenomegaly (enlarged spleen), fever, nausea, vomiting, rigor, headache, coma

Question 17

which strain of malaria might cause cerebral malaria

Answer 17

p falciparum

Question 18

what is a hypnozoite

Answer 18

a dormant protozoa that cna form in p ovale and p vivax strains (these strains have remission and relapse cycles)

Question 19

how long is the p ovale and p vivax cycle

Answer 19

48hrs

Question 20

how long is the p malariae cycle

Answer 20

72 hrs

Question 21

what attracts mosquitos

Answer 21

body odour, skin bacteria, pregnancy

Question 22

write a short note on chagas disease

Answer 22

caused by trypanosoma cruzi - parasitic protozoa carried by reduviid bug. prevalent in america. may cause swellings and rashes in the body i,e intestinal swelling

Question 23

write a quick note on babesiosis

Answer 23

caused by babesia microti which is protozoa transmitted by deer tick. it infects RBCs to cause fever and haemolytic anaemia. similar to p falciparum. you’ll see a maltese cross on blood film. immunocompromised and splenectomised people are particularly susceptible to this disease.

Question 24

explain the cryptosporidium spp infection cycle

Answer 24

1. humans ingest thick walled oocyst in contaminated water
2. parasites reproduce in the small intestine
3. oocysts are released into environment via feces
4. water and food contaminated

Question 25

explain the toxoplasmosis infection cycle

Answer 25

caused by toxoplasma gondii
1. cat ingests a cyst from meat of infected animal
2. unsporulated oocyst passed in faeces
3. sporulated cyst forms and is ingested by humans via infected meat or contact with cats

Question 26

which groups of people may be severely affected by toxoplasmosis

Answer 26

immunocompromised (HIV or cancer) and pregnancy (lead to abortion or defects)