Protozoa

Question 1

What are protozoa?

Answer 1

single celled
eukaryotic - so have a definitive nucleus
consume bacteria, algae and fungi
eaten by invertebrates

Question 2

What are the 5 major groups of protozoa?

Answer 2

Flagellates 
Amoebae
Cilliates 
Sporozoa 
Microsporidia

Question 3

Name one important intestinal flagellate

Answer 3

Giardia lamblia

Question 4

What are the medically important flagellates?

Answer 4

Giardia lamblia (GIT)
Trypanosoma (blood) - causes sleeping sickness and Chagas disease
Trichomonas vaginalis (other sites) - vaginal discharge, inflammation, erosion of epithelium, males usually asymptomatic

Question 5

Do Giardia have flagella?

Answer 5

Yes - they are of the Flagellates group

Question 6

Name an amoeba that causes amoebic dysentery

Answer 6

Entamoeba histolytica

Question 7

What are the symptoms/signs of infection with Entamoeba histolytica?

Answer 7

bloody diarrhoea
abdominal cramps
liver abscess- causing upper right quadrant pain

Question 8

Which group of protozoa does Plasmodium belong to?

Answer 8

Sporozoa (specifically of the order Haemosporidia)

Question 9

What medically important protozoa belong to the group Sporozoa?

Answer 9

Cryptosporidium hominis
Toxoplasma gondii
Plasmodium

Question 10

What symptoms does cryptosporidiosis cause?

Answer 10

watery diarrhoea with no blood
abdominal pain
vomiting

Question 11

What is done to diagnose cryptosporidiosis?

Answer 11

stool microscopy for ova, cysts and parasites

Question 12

What is toxoplasmosis and what are the symptoms?

Answer 12

host is the cat - faeces containing cysts ingested either directly by humans or an intermediate host eg a cow ingests the cysts and the protozoa form cysts in the muscle and the brain of the cow, which are then eaten by humans if the beef is uncooked
in the immunocompromised causes glandular fever like symptoms, but in the immunocompromised causes retinochoroiditis, and meningoencephalitis as well as ring enhancing lesions in the brain, headaches, visual disturbance and weakness

Question 13

What are the 4 main species of Plasmodium?

Answer 13

P. falciparum
P. ovale
P. vivax
P. malariae

Question 14

What is the name of the mosquito that transmits malaria?

Answer 14

Anopheles

Question 15

What are the clinical features of malaria?

Answer 15

fever
nausea/vomiting 
diarrhoea
anaemia 
rigors 
myalgia 
high bilirubin
low platelets 
jaundice 
splenomegaly 
maybe confusion/drowsy

Question 16

What are the problems experienced in treatment and control of malaria?

Answer 16

Increasing resistance of parasite to anti-malarials
Increased resistance of mosquito to insectides
Ecological & climate changes
Increased travel to endemic areas

Question 17

What is the lifespan of a female anopheles mosquito?

Answer 17

3-4 weeks

Question 18

When do the mosquitoes prefer to bite?

Answer 18

at night

bites indoors

Question 19

Why does the mosquito need blood?

Answer 19

to develop its eggs

Question 20

How long does it take the mosquito to develop its eggs?

Answer 20

20 days

Question 21

At what stage do the mosquitoes have a blood meal?

Answer 21

after their eggs have been fertilised

Question 22

Which plasmodium species have a hypnozoite stage?

Answer 22

P. vivax

P. ovale

Question 23

What should you immediately consider if a person has a fever and has come from an endemic area?

Answer 23

MALARIA

Question 24

What happens in P. falciparum that infects the brain?

Answer 24

infected RBCs accumulate in the capillaries in the brain causing hypoxia, confusion and then coma

Question 25

What are the clinical features of P. falciparum in adults?

Answer 25

coma ARDS hypoglycaemia renal failure - due to hypovolaemia and microvascular blockade Shock - secondary to bacterial sepsis or due to cytokine release, or due to bleeding as low platelets

Question 26

What are the clinical features of malaria in children?

Answer 26

stop crying, playing, eating tachypnoea anemia hypoglycaemia

Question 27

What are the clinical features of cerebral malaria in children?

Answer 27

``` encephalopathy coma raised intracranial pressure opisthotonus convulsions ```

Question 28

How is malaria diagnosed?

Answer 28

``` thick and thin films rapid diagnostic test (is a lateral flow assay that detects plasmodium antigens in the blood) clinical presentation anaemia low platelets hyperbilirubinaemia ```

Question 29

What are the features of complicated malaria?

Answer 29

``` impaired consciousness or seizures hypoglycaemia high parasite count Hb <8g/dL spontaneous bleeding/DIC haemoglobinuria without G6PD renal impairment or electrolyte/acid-base disturbance pulmonary oedema or ARDS shock ```

Question 30

How is complicated falciparum malaria treated?

Answer 30

IV ARTESUNATE (IV quinine is second line to this due to side effects)

Question 31

How is uncomplicated falciparum malaria treated?

Answer 31

PO Riamet or | PO Quinine and Docycyline

Question 32

What drug is used to treat non-falciparum malaria?

Answer 32

PO chloroquinine

Question 33

Which drug is used to treat P. vivax and P. ovale in the hypnozoite stage and what would you need to check before giving this drug?

Answer 33

primaquine (check pt doesn't have G6PD or pregnant, as can cause horrible reaction)

Question 34

Why is malaria more severe in pregnant women?

Answer 34

being pregnant is a form of immunocompromisation