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Flashcards in Malaria diagnosis Deck (17)
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1

Name the 6 types of diagnosis method.

1) Clinical diagnosis
2) Microscopy
3) Quantitive buffy coat (QBC)
4) Antigen detection
5) RT-PCR
6) Antibody detection

2

1) Clinical diagnosis

fever followed by:
a) cold stage
b) hot stage
c) sweating stage

3

2) Microscopy

~ perform blood smear (detect sp. + count no.)
~ two types: thick + thin

4

3) Quantitive buffy coat (QBC)

a) add acridine orange (fluorescent dye)
b) parasite seen between RBC layer + granulocytes in buffy coat

5

4) Antigen detection

~ rapid detection tests
e.g. Paracheck pf + BinaxNOW

6

5) RT-PCR

plasmid controls for all 4 species + run against sample to determine sp. of Plamodium

7

6) Antibody detection

e.g. ELISA + IFAT

8

Sweating stage

increased sweating causes decrease in temp

9

Thick film

sensitivity = proportion of true +ves

10

Thin film

specificity = proportion of true -ves

11

Paracheck pf

~ detects HRP2 = protein synthesised by P. falciparum
~ as sensitive as microscopy at detecting true malaria cases

12

BinaxNOW

detects HRP2 (P.f) + aldose (panmalarial antigen)

13

ELISA

a.k.a. enzyme-linked immunosorbent assay
~ antigens used to qualify parasite-related antibodies
~ doesn't indicate state of infection - could be from previous infection

14

IFAT

a.k.a. indirect fluorescence antibody test
~ fluorescent antibodies used to test for specific antibody
~ expensive + used before ELISA available (now outdated)

15

Laboratory diagnosis

~ RT-PCR
~ ELISA/IFAT
~ Microscopy/QBC
~ requires laboratory, infrastructure + trained staff

16

Field diagnosis

~ Paracheck pf
~ BinaxNOW (results in 15mins) - uses fingerstick blood collection
~ easy to interpret + no trained staff needed

17

What is the limitation of Paracheck pf?

frequent false positive results --> could could resistance to treatment