The document summarizes information about Plasmodium falciparum molecular diagnosis, drug resistance, and vaccine development. It discusses conventional laboratory diagnosis methods like microscopy and rapid diagnostic tests (RDTs), and highlights the increased sensitivity of molecular diagnostic methods like PCR. Molecular tests can also detect markers of drug resistance for antimalarials. While vaccines aimed at different stages of the parasite's life cycle are being developed, none are currently licensed. Overall molecular methods improve on the limitations of conventional diagnosis, and progress is being made in vaccine development, but more work is still needed.

1. Plasmodium
falciparum:
molecular diagnosis,
drug resistance,
and vaccine
By Abay Atnafu
November 11/2019

2. Contents
2
Introduction
Objective
Method
Result and discussion
Conclusion
Recommendation
Reference

3. Introduction
Malaria is caused by
intraerythrocytic protozoan
parasites in the genus
Plasmodium.
- Five species known to cause
malaria.
- Here the focus is P.falciparum
malaria
-P. falciparum is
responsible for the bulk of
malaria-related deaths.
3

4.  Commonly transmitted
through an infected Anopheles
mosquito.
- Also through blood
transfusion and across the
placenta during pregnancy or
delivery.

5. Laboratory Diagnosis
RDTsMicroscopy
Molecular
method
5

6. “  Conventional Methods
o Microscopy
 Stained blood film are
examined for presence
of parasite.
6

7. Cntd..
⪢ RDTs
⪢ Either antibody or antigen
coated.
7

8. Cntd..
⪢ Molecular testing
⪢ The majority of molecular
assays are PCR-based
including conventional and
real time format.
8

9. Cntd..
⪢ Nearly all NAATs target the
18S small subunit ribosomal
RNA gene (ssu rDNA), which is
present in approximately five
copies per Plasmodium spp.
genome.
9

10. Cntd..
10
Nucleic
acid
target
genes
18S rDNA

11. 11
Molecular methods:
-Conventional PCR
- Real-time PCR
- Multiplex real-time PCR
- Real-time PCR with 4 primers
- SYBR Green-based real-time PCR
- LAMP(Loop-Mediated Isothermal Amplification)

12. Cntd..
In addition to detection and species
differentiation, molecular tests can be used to
detect gene mutations or amplifications
associated with resistance to commonly used
antimalarials.
12

13. Cntd..
⪢ markers of resistance:
⪢ for chloroquine (P. falciparum chloroquine-
resistance transporter gene, Pfcrt)
⪢ sulfa- doxine (dihydropteroate synthase
gene, dhps)
⪢ pyrimethamine (dihydrofolate reductase
gene, dhft)
⪢ mefloquine (P. falciparum multi-drug-
resistancegene 1, Pfmdr-1),

14. Antimalaria drug resistance
Definition
- is an ability of a parasite
strain to survive and/or
multiply despite the
administration and absorption
of a drug given in doses equal to
or higher than those usually
recommended but within
tolerance of the subject.

15. Cntd..
Initially, resistance has been
described for:
 P. falciparum and P. vivax.
P. falciparum has developed
resistance to nearly all
antimalarials in current use.
15

16. Vaccine against
malaria
 Effective vaccine prevents new Plasmodium infections
 Most vaccine available today belongs to one of the three
categories: Attuenated microbe, Killed Microbe, and/or
protein sub unit.
16

17. Objective
 General objectives
- To review the molecular diagnosis, resistance of anti
malarial drugs, and issues pertaining the development
of vaccine of plasmodium falciparum malaria.
 Specific objective
- To identify the shortcomings of microscopy and RDTs
used for the diagnosis of plasmodium falciparum
malaria.
- To compare the microscopical and RDTs method with
the molecular method

18. Method
Systematic
review was
used.
Data sources:
PubMed, Lancet,
PlosOne Medscape
and the WHO
publication
Library.
Inclusion
criteria:Full
text articles
articles in
the area of
our topic
Exclusion
criteria:
Articles with
out full text 18

19. Cntd..
 PRISMA model was used for
screening process.
19

20. Result and discussion
 Searched articles: 62
 After screening: 26 left for final
review.
Findings:
Lab. diagnosis
 Microscopy
 RDTs
 Molecular methods
20

21. And tables to compare data
A B C
Yellow 10 20 7
Blue 30 15 10
Orange 5 24 16
21
Microscopy RDTs Molecular methods
Less sensitive
than the two
methods
Less sensitive
than molecular
method
Higher sensitivity
than the two methods
Less expensive A bit more
expensive than
microscopy
Expensive
Require trained
microscopist
No specialization
required
Expert needed
Enables species
differentiation
No species
differentiation
Allow species
differentiation
Sometimes it is
subjective
Maybe there is an
error bias in the
reader
Maybe an error
interpretation with
lack of experience

22. Anti malarial Drug resistance
 Anti malarial drugs:
⪢ Chloroqiune phosphate - used for drug
sensitive P.falciparum.
⪢ Quinine - used for drug resistant P.f
⪢ Doxycycline – used as part of combination
therapy for P.f management.
⪢ Atovaquone – used for uncomplicated P.f in
children.
⪢ Arthemether and lumafantrine –
used for acute uncomplicated P.f malaria
⪢ Artimesenin
22

23. Cntd..
⪢ Resistance has been reported against
almost all anti malarial drugs except
Artemisinin.
⪢ reported for both P.falciparum and
P.vivax
⪢ Chloroquine resistant P. falciparum
malaria has been reported from
sevaral parts of the world.
⪢ The first case of quinine resistance
was reported from South America
nearly a century ago.
23

24. Cntd...
⪢ The sulphadoxine-pyrimethamine
combination was used as a drug of
choice to treat chloroquine resistant
malaria.
⪢ Resistance to SP was first described
from the Thai-Cambodian border in
1960s.
⪢ No report yet that shows a resistance
against Artemisinin
24

25. Cntd..
Vaccine
⪢ began with studies in mice using
irradiated sporozoite.
⪢ No licensed product over the past 50
years.
⪢ Categories of vaccines:
⪢ Pre erythocytic vaccine - designed to
target sporozoites or schizont infected
liver cells.
25

26. Cntd..
⪢ Blood stage vacccine –
targets the merozoite and
infected erythrocyte.
⪢ Transmission blocking
vaccines - induce a highly
effective transmission
blocking activity.
⪢ Whole organism vaccine –
target is sporozoite.
26

27. Cntd..
27
⪢ DNA vaccines and live recombinant
vaccines and other vaccines such as
plasmid DNA vaccines and live
recombinant vaccines

28. Vaccine candidates
 RTS,S
 MSP-1
 AMA-1
 MSP-3
 Pfs 48/45
 Pfs 230
 Pfs 25
 Pfs 28
28

29. Conclusion
29
⪢ Molecular method alleviates many of
the drawbacks of conventional
methods.
⪢ An advancement in vaccine
development was seen in past few
years and seems to be promising to
see a breakthrough sometimes in
near the future.

30. “  Recommendation
- Despite the cost, things
would be changed if
molecular methods
applied to a routine
diagnosis of parasitic
infection such as that of
P.falciparum malaria.
30

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32. THANK YOU