Malaria rapid diagnostic tests by Dr. Basil Tumaini, presented at Kilema hospital in Moshi District Council.

1. MALARIA
AND
MALARIA RAPID DIAGNOSTIC
TESTS (mRDT)
Dr. Basil B. Tumaini, MD
2nd August 2012
Kilema Hospital

2. Outline
Introduction to malaria
Lifecycle of Plasmodium
Clinical features observed in malaria
Malaria Case definitions
Necessity of lab.-based malaria Dx
mRDT
Health education on compliance to
malaria confirmed diagnosis strategy

3. INTRODUCTION
Malaria is a curable infectious disease due
to the presence of parasitic protozoa of the
genus Plasmodium⃰ within the RBCs.
Transmission: via the bite of an infected
female Anopheles mosquito.
The disease is confined mainly to tropical
and subtropical areas.

4. LIFE CYCLE
Parasites in the blood of an infected person
Stomach of mosquito Multiplication
Salivary glands Blood stream
Liver &other organs Multiplication
[IP:12/7(Pf)-10/12(Pv⃰)]
RBCs: rapid multiplication & destruction
Clinical features

5. Clinical features 1
Fever and other unspecific features e.g.,
joint pains, muscle pains, nausea and
vomiting and headache.
Under fives with Severe malaria present
with general danger signs:
 Inability to drink or breastfeed
 Vomiting everything
 Convulsion in this illness or the child is convulsing now
 Lethargy or unconsciousness

6. Clinical features 2
In Tanzania the commonest clinical
features of severe malaria are severe
anaemia and cerebral malaria.
Malaria has no pathognomonic feature.
Hence a diagnostic test either by
microscopy or an mRDT is required.

7. Malaria Case definitions⃰ 1
Suspected malaria case: this is a patient
suspected of having malaria, with fever or
h/o fever*.
Clinical malaria case: this is a suspected
malaria case that was not tested for
malaria parasites (mRDT/BS) but was
nevertheless treated as malaria⃰.
Malaria cases: symptoms of malaria +
positive test (mRDT/BS).⃰

8. Malaria Case definitions 2
Other diagnosis: suspected malaria cases
for whom a malaria diagnostic test was
negative.
Think for other possible causes of fever:
viral illness, RTI, ear infection, UTI, skin
infection, bacterial/viral diarrhoea,
septicaemia, Borrelia and other blood
borne parasitaemia, HIV related
conditions, etc.

9. Necessity of laboratory-based
malaria diagnosis
Good clinical practice
Improved care of suspected Pts
Identification of parasite negative Pts in
whom another Dx must be thought and
early Rx given
Avoids unnecessary use of antimalarial
drugs in parasite negative Pts: side effects,
drug resistance, cost, trust.

10. Consequences of not having
malaria parasitological
confirmation
Pts are mistreated with antimalarial
drugs: cost, SEs, resistance, drug wastage.
Pts are misdiagnosed: high mortality, less
Pt’s satisfaction.

11. Malaria Rapid Diagnostic Test
(mRDT)
Malaria Rapid Diagnostic Test (mRDT) is
a device that assists in the Dx of malaria
by providing evidence of the presence of
malaria parasites in the human blood
within a short time (15-20 min).
Malaria RDTs detect malaria-specific
antigens in a person’s lysed blood using
immuno-chromatographic methods.

12. Malaria antigens detected
Histidine-rich protein (HRP2)
Plasmodium lactate dehydrogenase
(pLDH)
Others: pGluDH, pAldo.

13. Malaria antigens detected
HRP2  Specific for P.f
 Produced by trophozoites
& young gametocytes
 Remains positive for 2 or
more weeks after Rx
 False positive in RA
pLDH  Produced by asexual and
sexual stages of all malaria
parasites (Pan)
 Does not persist in blood
after successful Rx

14. Importance of mRDTs
Simplicity and rapidity
Reliable (sensitivity:88-99%, specificity
95-100%)
Cost-effective
Rational use of antimalarial drugs
Avoiding malaria over diagnosis.

15. Limitations of mRDT
The result is qualitative not quantitative
Not ideal for monitoring Rx outcomes
Limited ability to differentiate species
Damaged by heat and humidity
Result can be influenced by performance
of HCW
Cannot be reused.

16. mRDT algorithm and SOPs
mRDT algorithm
How to perform mRDT & its SOPs
Reading mRDT results
mRDT safety precautions
Monitoring of malaria Dx through
recording and reporting
mRDT QA and QC at health facility level

17. Compliance to malaria
confirmed diagnosis strategy
Ensure malaria microscopy and/or mRDT
are always functioning at health facility
Perform mRDT to all OPD malaria
suspected Pts
Record both malaria microscopy and
mRDT results in Pt register (BS or mRDT
“NEGATIVE” or “POSITIVE”
Do not give antimalarial to “mRDT
negative Pts”

18. If the result is positive, give antimalarial
and record “malaria” in Pt register
Record “clinical malaria” if an antimalarial
was prescribed without testing the Pt
Record “mRDT negative” result and any
other diagnosis if antimalarial Rx was not
given

19. If malaria treatment failure is suspected
after “mRDT positive” result and full
course of ACT, repeat blood test through
malaria microscopy.
If fever persists a few days after a negative
mRDT result regardless of other
appropriate management given, it is
advised to re-test the Pt with mRDT

20. Admitted Pts with suspected severe
malaria should be tested for both malaria
microscopy and mRDT. Complete a full
course of antimalarial treatment if one or
both test results is positive.

21. THANKS