Malaria is the third leading cause of death due to infectious disease. It affects 300- 500 million people annually worldwide and accounts for over 100 million deaths, mainly in African children under the age of 5 years. A child in Africa dies every 30 seconds of malaria. Years of research and Millions of Dollars have been spend in the quest to eradicate this deadly infectious disease. The War is still on but is the mission impossible. This presentation was made during a graduate class to review the victories and the challenges so far in the treatment and vaccination against this disease. More still need to be done but their seems to be light at the end of the tunnel. Malaria is not inevitable, it can be eradicated, the mission is possible if only we devote ourselves to quality research and we never give-up. (Oseni Saheed Oluwasina (2013))

2. 2

3.  DEFINITION
 AETIOLOGY & TAXONOMY
 EPIDEMIOLOGY
 LIFE CYCLE
 MORPHOLOGY
 CLINICAL SIGNS
 PATHOGENESIS AND IMMUNOLOGY
 DIAGNOSIS
 CONTROL ( VACCINE DEVELOPMENT)
 TREATMENT
3

4. DEFINITION
 A protozoan disease caused by Plasmodium species of the
phylum Apicomplexa.
 Transmitted by the bite of infected female anopheline
mosquitoes.
 It is characterized by periodic paroxysm with shaking
chills, high fever, heavy sweating.
 Anemia and splenomegaly may also occur in cases.
4

5. AETIOLOGY
Four species of Plasmodium cause malaria in human.
 P. vi vax (benign t ert ian malaria)
 P. oval e (benign t ert ian malaria)
 P. mal ari ae (quart an malaria)
 P. f al ci parum(malignant t ert ian malaria)
Each species has its own morphologic, biologic,
pathogenic, and clinical characteristics.
5

6. TAXONOMY
 Kingdom: Prot ist a
 Sub-Kingdom: Prot ozoa
 Phylum: Apicomplexa
 Class: Sporozoasida
 Order: Eucoccidiorida
 Family: Plasmodiidae
 Genus: Plasmodium
 Specie: P. falciparum 6

7. EPIDEMIOLOGY
7

8. EPIDEMIOLOGY
 Malaria is t he t hird leading cause of deat h due
t o inf ect ious disease.
 I t af f ect s 300- 500 million people annually
worldwide and account s f or over 100million
deat hs, mainly in Af rican children under t he age
of 5yrs. A child in Af rica dies every 30 seconds
of malaria.
 Endemic around t he t ropics and sub-t ropics
alt hough it is world wide in dist ribut ion.
8

9. FEMALE ANOPELES MOSQUI TO 9
TRANSMI SSI ON

10. DISTRIBUTION OF PLASMODIUM
FALCIPARUM
10

11. DISTRIBUTION OF PLASMODIUM
VIVAX
11

12. WATERSHEDS OF THE AFRI CAN CONTI NENT
12
Mosquitoes are aquatic insects
Population
density

13. LI FE CYCLE
13

14. 14

15. LIFE CYCLE CONT’D
15

16. 16

17. PLASMODI UM
MORPHOLOGY
17

18. PLASMODIUM ANATOMY
18

19. 19

20. 20

21. EX-FLAGELLATI ON OF THE
MI CROGAMETOCYTE
OF A MALARI A PARASI TE I N MOSQUI TO
STOMACH
21

22. PORTI ON OF AN I NFECTED MOSQUI TO
STOMACH.
NOTE NUMEROUS OOCYSTS ON OUTER WALL.
22

23. SPOROZOI TES OF MALARI A I N I NFECTED
MOSQUI TO STOMACH PREPARATI ON
23
Light Micrograph
SEM

24. ERYTHROCYTIC STAGES OF MALARIA:
ALL INFECTIONS BEGIN WITH THE RING STAGE
REGARDLESS OF THE SPECIES
24
Ring stage

25. 25

26. CLINICAL SIGNS & SYMPTOMSCLINICAL SIGNS & SYMPTOMS
26
Cold stage

27. MALARIAL PAROXYSM
 Cold stage
f eeling of int ense cold
vigorous shivering
last s 15-60 minut es
 Hot stage
int ense heat
dry burning skin
t hrobbing headache
last s 2-6 hours
 Sweating stage
prof use sweat ing
declining t emperat ure
exhaust ed and weak →sleep
last s 2-4 hours
27

28. UNCOMPLICATED MALARIA
 Uncomplicat ed malaria is def ined as:
Sympt omat ic inf ect ion wit h malaria parasit aemia
wit hout signs of severit y and/ or evidence of
vit al organ dysf unct ion.
28

29. SEVERE MALARIA
 Severe malaria is defined as symptomatic malaria in a patient with P.
f al ci parumasexual parasitaemia with one or more of the following
complications:
 Cerebral malaria (unrousablecomanotattributabletoothercauses).
 Generalised convulsions (> 2episodeswithin24hours)
 Severe normocyt ic anaemia (Ht< 15%orHb< 5g/dl)
 Hypoglycaemia (gloodglucose< 2.2mmol/lor40mg/dl)
 Met abolic acidosis wit h respirat ory dist ress (arterialpH< 7.35orbicarbonate< 15mmol/l)*
 Fluid and elect rolyt e dist urbances
 Acut e renal f ailure (urine< 400ml/24hinadults; 12ml/kg/24hinchildren)
 Acut e pulmonary oedema and adult respirat ory dist ress syndrome*
 Abnormal bleeding
 J aundice
 Haemoglobinuria
 Circulat ory collapse, shock, sept icaema (algid malaria)
 Hyperparasit aemia (> 10%innon-immune; > 20%insemi-immune)
29

30. RELAPSE
A specif ic at t ack t hat it is up t o mont hs or even years
af t er t he primary at t acks.
Tachysporozoit e grow in t he hepat ic cell and mult iply
t o f orm exoeryt hrocyt ic schizont s and t hen invade
RBCs t o clinic malaria.
Bradysporozoit es in t he liver spend a rest and sleeping
t imes of mont hs or even years , t hen t hey st art
develop in exoeryt hrocyt ic st age and eryt hrocyt ic
st age. at t his t ime, t he pat ient occurs paroxysm ,
showing as periodic f ever like t he primary at t acks, it is
called Relapse.
NB: Relapse only occurs in P.vi vax.
30

31. Paroxysms (acute febrile episodes)
associated with synchrony coincide
with the Merozoite release.
Temperature is normal and patient
feels well.
P. falciparum may not exhibit
classic paroxysms (continuous
fever)
31
Plasmodium falciparumPlasmodium falciparum
Plasmodium vivax
Plasmodium ovale
Plasmodium vivax
Plasmodium ovale
Plasmodium malariaePlasmodium malariae

32. 32
Chronic
Asymptomatic
Infection
Placental
Malaria
Anemia
Infection
During
Pregnancy
Developmental
Disorders;
Transfusions;
Death
Low
Birth weight
Increased
Infant
Mortality
Non-severe
Acute Febrile
disease
Cerebral
Malaria
Death
CLINICAL PICTURECLINICAL PICTURE

33. COMPLICATIONS OF MALARIA :
CEREBRAL MALARIA
33

34. COMPLICATIONS OF MALARIA :
34
Child with severe malaria anaemia in conjunction
with acidosis and respiratory distress
Pulmonary Edema

35. 35
Hepato-splenomegalyHepato-splenomegaly
survivors part ially immuned
of t en wit h splenomegaly

36. MALARIAL HAEMOGLOBINURIA
36
Clinical Picture :
Patients with glucose-6-phosphate
dehydrogenase (G6PD) deficiency may
develop intravascular haemolysis and
haemoglobinuria precipitated by Primaquine
and other oxidant drugs, even in the absence
of malaria.
Haemoglobinuria associated with malaria
(“blackwater fever”) is uncommon and
malarial haemoglobinuria usually presents in
adults as severe disease with anaemia and
renal failure.

37. PATHOGENESIS
&
IMMUNOLOGY
37

38. SUSCEPTI BI LI TY TO MALARI A, ANTI BODY
PRODUCTI ON, AND LETHALI TY
38

39. PATHOGENESIS
39

40.  The f unct ions of most of t he met abolic product s of P.
falciparumare not known. I t is known t hat t hey are
resist ant t o t reat ment wit h prot eases.
 P. falciparumuses hemoglobin as a source of energy and
produces hemozin t o digest hemoglobin, t his t oxin is
st ored in t he pigment of P. falciparum.
 This pigment has been linked t o over product ion of
t umor necrosis f act or alpha, t he gamma int erf eron
and int erleukin-1.
 These are import ant and nat ural part s of human
immune syst ems, but over product ion can lead t o f ever
and t he dest ruct ion of healt hy host cells.
Information for the following slides adapted from: Chen, Q., M. Schlichtherle, and M. Wahlgren.
2000. Molecular aspects of severe malaria. Clin. Microbiol. Rev. 13:439-450
40

41. TOXI CI TY AND PATHOGENI CI TY
 I nf ect ion by P. falciparumalso radically changes t he cell membrane of
red blood cells.
 The membrane of inf ect ed cells becomes rigid and t he parasit e
creat es channels t hrough t he membrane in order t o t ransport
nut r ient s int o t he cell.
 Prot ein component s of t he cell membrane are digest ed by t he
parasit e and are replaced by t he “knobs” (elect ron rich
prot rusions of ~100 micromet ers).
 The knobs are used t o bind t o uninf ect ed RBCs and t o t he walls
of veins and art eries. This is known as roset t ing and can lead t o
some of t he most severe complicat ions of malaria, including
cerebral malaria, wher e such roset t es occur in t he brain.
41

42. 42

43.  There are f ive recept ors on RBC which are t hought t o
be involved wit h t he f ormat ion of roset t es. They include
blood group ant igens A and B, CD-36, compliment
recept or 1 and HS-like GAGs (heparin sulf at e
glycosaminoglycans).
 Roset t es f ormed in blood t ypes A and B are larger,
t ight er and st ronger t han t hose f ormed in persons wit h
O t ype blood. Blood t ype A is most of t en af f ect ed by
severe malaria.
 P. Falciparum also binds using knobs t o bot h I gG and I gM.
The reason f or having accumulat ions of I gM is not
precisely known, but it is t heorized t hat such
accumulat ions hinder t he access of ant ibodies specif ic
t o inf ect ed cells and t hus help malaria t o evade t he
43

44. ANTIGENIC VARIATION
 Malaria has many t ools t o evade t he immune syst em. P. falciparumhas a
very high degree of ant igenic variat ion, making it dif f icult f or t he
immune syst em t o recognize malaria. P. falciparumhas t wo dif f erent ways
in which t o vary which ant igens it expresses.
 The f irst way in which t his might occur is during t he sexually
reproducing st age in t he lif ecycle when P. Falciparumrecombines genet ic
mat erial. This has unlimit ed pot ent ial t o change t he genome of P.
Falciparum.
 The second way in which ant igenic variat ion can occur is t hr ough
variable genes and point mut at ions during asexually repr oducing
st ages of t he lif ecycle. P. Falciparum o has several f amilies of variable
ant igenic genes.
 These are varf amily, t he roset t in/ rif f amily, and t he p60 f amily.
 Wit h such a large amount of variabilit y available t o malaria it is no
wonder t hat it can successf ully evade t he immune syst em and cause
many recurring inf ect ions if not properly t reat ed.
44

45. VAR FAMILY
 There are ~40-50 genes in t he var f amily wit h a f ew except ion t hey
are ext remely variable. The var genes are scat t ered t hroughout t he
chromosomes, but concent rat ed on t he 4, 7, and 12 chromosomes.
 Using t he high variabilit y in t hese regions at least 2% of individuals
vary t heir ant igenic expression each generat ion. These genes are
t hought t o be involved wit h resist ance t o chloroquine and t o help P.
falciparumevade t he host ’s immune syst em.
 Mut at ions at t his sight are f ound in 100% of all resist ant st r ains of P.
falciparum. The ef f icacy of t he resist ance is gr eat er when a mut at ion also
occurs at a sight known as pf mdr1 (P. falciparummult idrug resist ance gene).
 I nf or mat ion f or t he f ollowing slides adapt ed f r om: Chen, Q., M. Schlicht her le, and M. Wahlgren. 2000. Molecular
aspect s of sever e malar ia. Clin. Microbiol. Rev. 13:439-450
 Dorsey, G., M. R. Kamya, A. Singh, and P. J . Rosent hal. 2001. PolymorphismsinthePlasmodiumfalciparumpfcrtandpfmdr-1 genesandclinicalresponsetochloroquinein
Kampala, Uganda. J . I nf ect . Dis. 183:1417-1420.
45

46. CROSS OVER AND VAR FAMILY
46

47. DRUG-RESISTANTMALARIA
47
Red - chloroquine resistant
Green - chloroquine sensitive
Black - chloroquine and mefloquine resistant

48. ENTRYOFSPOROZOITESINTOPARENCHYMALCELLSOF
THELIVER
48

49. TRANSMI SSI ON EM OF MEROZOI TE ENTERI NG A RED
CELL.
NOTE POI NTS OF ATTACHMENT
49

50. MECHANISMS OF RED CELL
INVASION
BY PLASMODIUM
50

51. TRANSMISSION EM: RBC INFECTED
WITH P. FALCIPARUM
51
N = Nucleus; F = food vacuole
“Knobs” of histidine-rich protein.
Points of attachment to endothelial cell

52. DI AGNOSI S
52

53. DI AGNOSI S
LI GHT MI CROSCOPY
RAPI D DI AGNOSTI C TEST
SEROLOGY: ELI SA KI TS-
MOLECULAR TECHNI QUES: PCR (18S rRNA
Assay, Nest ed PCR Assay, real-t ime PCR),
LAMP.
53

54. 54
Trophozoites
Gametocyte
Schizont
Cytoplasm
Stippling
Vacuole
Nucleus/chromatin dot
Dr.
Osenium®

55. LABORATORY DIAGNOSIS OF
MALARIA
Plasmodium falciparum
55
Diagnostic Points:
 Small, regular, f ine t o
f leshy cyt oplasm
 I nf ect ed RBCs not
enlarged
 Numerous, mult iple
inf ect ion is common
 Ring, comma, marginal or
accole f orms are seen;
of t en have double
chromat in dot s
 Maurer’s dot s not clearly
visible
CCMOVBD
Multiple infection
Marginal form
Double chromatin

56. LABORATORY DIAGNOSIS OF
MALARIA
56Rapid diagnostic tests detect
malaria antigens

57. 57
Plastic cassette format of
RDT
RAPID DIAGNOSTIC TESTS DETECT MALARIA
ANTIGENS

58. 58

59. CONTROL
AND
VACCINE
DEVELOPMENT 59

60. RTS,S VACCI NE - PRE- ERYTHROCYTI C
VACCI NE
 Hybrid cont aining t he cent ral repeat s and most of t he C-
t erminal of t he CSP f used wit h hepat it is B surf ace
ant igen
 Complex adj uvant mixt ure AS02
 Complet ely prot ect ed six out of seven volunt eers
 Field st udy in The Gambia showed good short -t erm
prot ect ion
 A clinical t rial in Mozambique and Tanzania showed delay
of inf ect ion and reduct ion in incidence of severe malaria
in young children
 The vaccine advanced t o Phase I I I t rial.
60

61. 61
Liver Stage
Sporozoites
Pre-erythrocytic
Stage

62. PRE- ERYTHROCYTI C STAGE VACCI NES
 How t hey work:
Gener at es Ab response against spor ozoit es
and prevent s t hem f r om invading t he liver
Pr event s int r a-hepat ic mult iplicat ion by killing
parasit e-inf ect ed hepat ocyt es
 I nt ended Use:
I deal f or t raveler s - prot ect s against malar ia
inf ect ion
62

63. 63
Merozoites
Asexual
Eryt hrocyt
ic
St age

64. ASEXUAL ERYTHROCYTI C STAGE VACCI NES
 How t hey wor k:
Elicit ant ibodies t hat will inact ivat e
mer ozoit es and/ or t ar get malarial Ag
expr essed on RBC surf ace
I nhibit development of parasit e in RBCs
 I nt ended Use:
Morbidit y r educt ion in endemic count r ies
64

65. 65
Malar ia: Plasmodium Lif e Cycle
Sexual
Stage

66. SEXUAL STAGE VACCI NES
 How t hey wor k:
I nduces Ab against sexual st age Ag
Prevent s development of inf ect ious
sporozoit es in salivary glands of
mosquit oes
Prevent or decrease t r ansmission of
par asit e t o new host s
 I nt ended Use:
Decreased malar ia t r ansmission
66

67. VACCINE PORTFOLIO
67
Ad5 CSP/
LSA/TRAP
Pre-Clinical
Evaluation
Phase 1
+/- Challenge
Phase 1b
endemic
Phase 2b
endemic
Phase 3
MSP-2
in ISCOM
PvR II
in AlOH
PvR II
in ASO2
MSP-2
in ISA 720
RTS,S
in ASO1
RTS,S
in ASO2
Pfs-16
MSP-4
LSA-1
in ASO1
LSA-1
in ASO 2
MSP-1C
in Alum-CPG
CP2.9
in ISA 720
RTS,S
in ASO2
Development
Manufacture
Ad5 CSP/
LSA/TRAP
AMA-1C
in ISA 720
Pfs-16
MSP-5
Ad5 MSP-
AMA 1
MSP-4
AMA-1
in ASO1
AMA-1
in ASO2

68. RECENT LANDMARKS I N MALARI A GENOMES -
SEQUENCI NG
 2002:
 Complet e genome sequence of P. falciparum
 A par t ial sequence of r odent par asit e, P. berghei
 2005:
sequences of several ot her rodent parasit es
 P. vivax (a human malar ia par asit e)
 P. knowlesi (pr imar ily a monkey parasit e)
 + sequence of :
Human genome
Anopheles mosquit o
 New Candidat es f or drug and vaccine pipeline 68

69. OTHER VACCINE AVENUES
 Several ant igens expressed during t he blood st ream
and liver st age of P. falciparumhave been shown t o elicit an
immune response in humans.
 The st udy showed t hat liver st age ant igen 3 was highly
immunogenic and a good candidat e f or use in a vaccine
t o prevent t he invasion of RBC by P. falciparum. I mmune
memory of t he ant igens (especially LSA3) last ed up t o
9 mont hs when t est ed in chimpanzees.
 I nf or mat ion f or t his slide f rom: Pouniot is DS, Proudf oot O, Minigo G, Hanley J C, Plebanski M. Long-TermMultiepitopic
Cytotoxic-T-LymphocyteResponsesInducedinChimpanzeesbyCombinationsofPlasmodiumfalciparumLiver-StagePeptidesandLipopeptidesI nf ect ion and I mmunit y, August
2004, p. 4376-4384, Vol. 72, No. 8
69

70. VACCI NATI NG MOSQUI TOES
 I n mosquit oes, t here are prot eins on t he surf ace
of gamet es and ookinet s t hat may prove usef ul in
f ormulat ing a vaccine t hat prot ect s mosquit oes
f rom inf ect ion.
 Ant ibodies t o t hese prot eins prevent t he
parasit e f rom t aking up residence in t he midgut
of mosquit oes and f orming oocyst s. However, in
order f or such vaccines t o reach mosquit oes
t hey must be combined wit h ef f ort s t o vaccinat e
people living in endemic areas.
70

71. PARATRANSGENESI S
 Parat ransgenesis is t he manipulat ion of symbiot ic
bact eria such as E. coli t o make t he host immune t o
a pat hogen.
 Bact eria are engineered t o produce prot eins or
pept ides t hat eit her block binding of or kill
parasit es.
 Several bact eria known t o live in t he anopheles
midgut including Escherichia, Pseudomonas , and
bacillus .
 When f ed wit h E. coli t hat produced ant ibodies t o
P. berghei, Anopheles mosquit oes showed a reduct ion in
oocyst f ormat ion of 95%.
71

72.  Transgenic mosquit oes expressing bee venom
known as Phospholipidase A2 have also been
shown t o resist oocyst f ormat ion by up t o 87%.
Synt het ic molecules have also been st udied as
ways of reducing suscept ibilit y.
 Anopheles mosquit oes wit h a synt het ic gene
expressing SM1 pept ide were f ound t o have 82%
reduct ion in f ormat ion of oocyst s.
 Information on this slides from Michael A. Riehle, Prakash Srinivasan, Cristina K. Moreira and
Marcelo Jacobs-Lorena. Towards genetic manipulation of wild mosquito populations to combat
malaria: advances and challenges. The Journal of Experimental Biology 206, 3809-3816 (2003)
72

73. CHALLENGES FOR MALARI A
VACCI NE
 Four ant igenet ically dist inct malaria species
Each has ~6,000 genes
First gene was only ident if ied in 1983
 I mmunit y in malaria is complex and immunological
responses and corr elat es of pr ot ect ion ar e
incomplet ely underst ood.
 I dent if ying and assessing vaccine candidat es
t akes t ime and is expensive
 Ther e is no clear ‘best approach’ f or designing a
malaria vaccine
73

74. OTHER CONTROL METHODS
Biological Cont rol
Mosquit o f ishes (Gambusia affinis) have been
f ound t o be predat ory on t he anopheles larvae.
Chemical Cont rol
Spray insect icides: DDVPand so on.
Use mosquit o net s, screen, or mosquit o repellent s
t o prot ect t he person f rom mosquit o bit es.
Physical Cont rol:
Eradicat e t he breeding places of mosquit oes. 74

75. TREATMENT
75

76. ACTION OF ANTIMALARIAL DRUG IN THE DIFFERENTACTION OF ANTIMALARIAL DRUG IN THE DIFFERENT
LIFE STAGES OF THE MALARIA PARASITELIFE STAGES OF THE MALARIA PARASITE
76
Tissue SchizontocidesTissue Schizontocides
•Pr imaquinePr imaquine
•Pyr imet haminePyr imet hamine
•Tet r acyclineTet r acycline
•Pr oguanilPr oguanil
Anti-relapse (P.vivax)
•Primaquine
Blood Schizontocides
•Chlor oquine
•Sulf adoxine/ Pyr imet hamine
•Quinine
•Quinidine
•Ar t emisinins
GametocycideGametocycide
PrimaquinePrimaquine
SporontocideSporontocide
ss
•Pr imaquinePr imaquine
•Pyr imet haminePyr imet hamine
•Pr oguanilPr oguanil

77. Symptomatic and supportive
treatment
Aetiologic treatment
77

78. SYMPTOMATIC AND SUPPORTIVE
TREATMENT
High fever, convulsion, cerebral edema, black water
fever, etc.
 Keep warm for shaking chill;
 Physical and chemical deffervescence methods for
high fever, such as ice bag, air condition.
 Corticosteroid may be given , if necessary.
 Diazepam and wintermin for convulsion.
78

79. AETIOLOGIC TREATMENT
 Falciparum easily t reat ed bef ore complicat ions as no
relapses and no para-eryt hrocyt ic st age
 Chloroquine is t reat ment of choice f or sensit ive st rains of
Plasmodia (merozoit es)
 Primaquine (Hypnozoit es)
 Mef loquineorquinine and doxycycline (Chloroquine resist ant
st rains of f alciparum)
 At ovaquone and proguanil (Malarone) f or Chloroquine
resist ance of P. f alciparum.
 Art emet her and lumef ant rine (newer)
79

80. CONCLUSION
Malaria is not inevit able, it can
be er adicat ed, t he mission is
possible if only we devot e
our selves t o qualit y resear ch
and we never give-up.
Oseni Saheed Oluwasina (2013)
80

81. 81

82. 82