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Name means “bad air”A life-threatening parasitic disease
40% of the world’s population is at risk
90% of the deaths due to Malaria occur in SubSahara Africa, mostly among young children.
• 5 million of people are affected every year .
• At least 1.5 million deaths annually.
• It is one of the major public health concerns
How is malaria transmitted?
• Malaria parasites are transmitted from one
person to another by the bite of a female
anopheles mosquito.
• The female mosquito bites during dusk and
dawn and needs a blood meal to feed her
eggs.
• Male mosquitoes do not transmit malaria
as they feed on plant juices and not blood.
• There are about 380 species of anopheles
mosquito but only about 60 are able to
transmit malaria.
Transmission
Female Anopheline
mosquito bite
Mother to child
Blood transfusion
What is malaria ?
One of the red blood cell & a vector – borne infectious disease
Malaria is a disease caused by the protozoan parasites of the genus
Plasmodium. The 4 species that commonly infect man are:
Species Major features
P. falciparum
 The most important species as it is responsible for 50% of all malaria
cases worldwide and nearly all morbidity and mortality from severe
malaria
 Found in the tropics & sub-tropics
P. vivax
 The malaria parasite with the widest geographical distribution
 Seen in tropical and sub-tropical areas but rare in Africa
 Estimated to cause 43% of all malaria cases in the world
P. ovale
 This species is relatively rarely encountered
 Primarily seen in tropical Africa, especially, the west coast, but has
been reported in South America and Asia
P. malariae
 Responsible for only 7% of malaria cases
 Occurs mainly in sub-tropical climates
Species Infecting Humans
Plasmodium falciparum
– Malignant tertian M. (Cerebral Ma. Or
renal failure) (48hr.)
 Plasmodium vivax (48hr.)
– Benign tertian M. relapsing M.
 Plasmodium ovale
Common & Severe
- Ovale tertian M. relapsing M. (48hr.)
 Plasmodium malariae
– Quartan M. (72 hr.) remain for one decade ,
no dominant(relapsing) stage (7%)
Rare & Mild
The Hosts
Human:
_ intermediate host.
_ victim.
_ asexual cycle (schizogony cycle).
Female Anopheles mosquitos :
_ final hosts.
_ vector.
_ sexual cycle (sporogony cycle).
Plasmodium
2 Sporozoites
1 Infected mosquito bites
Sporozoites in
salivary gland
10,000 sp.
undergo
schizogony in liver
cell; merozoites
are produced
2000-40,000
Mer.(6-16)days.
human; sporozoites
migrate through
bloodstream to
liver of human
9 Resulting sporozoites migrate
to salivary glands of mosquito
3
Sexual
reproduction
8 In mosquito’s
Zygote
Female
gametocyte
Male
gametocyte.gut
digestive tract,
gametocytes unite
to form zygote
Asexual
reproduction
Merozoites
released into
bloodsteam from
liver may infect
new red blood
cells
Intermediate host
4 Merozoite develops
into ring stage in red
blood cell
Ring
stage
Definitive host
7 Another mosquito bites
6 Merozoites are released when
infected humnan and ingests
red blood cell ruptures; some
gametocytes .skin
merozoites infect new red
blood cells, and some
develop into male and female
gametocytes
Merozoites
5 Ring stage
grows and
divides,
producing
merozoites
(6-24)M.
Malaria Life Cycle
Sporogony
Oocyst
Sporozoites
Mosquito Salivary
Gland
Zygote
Sexual
final host
Gametocytes
Red Blood
cell Schizont
Schizogony
Asexual cycle
Intermediate host
Exoerythrocytic
(hepatic) cycle
6-16 days
Hypnozoites
(for P. vivax
and P. ovale)
Erythrocytic
Cycle
Liver cell Schizont
Hypnozoites(relapsing)
Hypnozoites:
- Are liver-trophozoite stages
-Responsible for recurrence of malarial symptoms.
Plasmodium vivax &Plasmodium ovale
HYPNOZOITES
Illness May Relapse 3 To 5 Years After
Original Infection
Malarial Paroxysm
– Days 1 and 3 for: Days 1, 3, 5, 7, 9,……….
– Plasmodium vivax
– Plasmodium ovale
– and Plasmodium falciparum
48 hrs.
Tertian malaria
– Usually persistent fever or daily paroxyms for
Plasmodium falciparum.
Days 1, 4, 7, 10,……….
–Days 1 and 4 for Plasmodium malariae
Quartian malaria
72 hrs.
Malarial Paroxysm
•Cold stage
•Hot stage
•Sweating stage
The clinical course of P.
Asymptomatic parasitaemia (“clinical
immunity”)
A. Acute, uncomplicated malaria
B. Severe malaria
A. Asymptomatic parasitaemia
This is usually seen in older children and adults who have
acquired natural immunity to clinical disease as a consequence
of living in areas with high malaria endemicity. There are malaria
parasites in the peripheral blood but no symptoms. These
individuals may be important reservoirs for disease
transmission.
Some individuals may even develop anti-parasite immunity so
that they do not develop parasitaemia following infection.
B. Simple, uncomplicated malaria
This can occur at any age but it is
more likely to be seen in individuals
with some degree of immunity to
malaria. The affected person,
though ill, does not manifest lifethreatening disease.
Fever is the most constant
symptom of malaria. It may occur in
paroxysms fever, chills and rigors
(uncontrollable shivering).
Children with malaria waiting to be seen
at a malaria clinic in the south western
part of Nigeria. Identifying children with
severe malaria, and giving them prompt
treatment, is a major challenge when
large numbers attend clinics.
Other features of simple,
uncomplicated malaria include:
o Vomiting, Diarrhoea,Convulsions, Jaundice
o Malaria is a multisystem disease. Other common
clinical features are:
o Anorexia, Cough, Headache, Malaise, Muscle
aches, Splenomegaly, hepatomegaly
These clinical features occur in “mild” malaria.
However, the infection requires urgent
diagnosis and management to prevent
progression to severe disease.
C. Severe and complicated
malaria
Nearly all severe disease and the estimated >1 million deaths from
malaria are due to P. falciparum. Although severe malaria is both
preventable and treatable, it is frequently a fatal disease.
The following are 8 important severe manifestations of malaria:
1.
2.
3.
4.
Cerebral malaria
Severe malaria anaemia
Hypoglycaemia
Metabolic acidosis
5. Acute renal failure
6. Pulmonary oedema
7. Circulatory collapse, shock or
“algid malaria”
8. Blackwater fever
Note: It is common for an individual patient to have
more than one severe manifestation of malaria!
Malaria Diagnosis
• Clinical Diagnosis
• Hyperendemic areas.
• Fever ,sweat, chills, headache
& muscle pain
• Malaria Blood Smear
• Serology (ELISA)(IFAT) .
• Polymerase Chain Reaction
B.F.F.M.=Blood Film For Malaria
Blood Smear Prepare smears as soon as possible
after collecting venous blood to avoid any
Changes in parasite morphology.
the “gold standard” for diagnosis of malaria..
Plasmodium falciparum
Infected erythrocytes: ***normal size (Maurer’s dots)
4
2
1
Gametocytes: mature (2)and
1
immature (1) forms (1is rarely
seen in peripheral blood)
Rings: double chromatin dots
multiple infections in same red cell
3
2
Trophozoites: compact
*(rarely seen in
peripheral blood)
Schizonts: 8-24 merozoites
*(rarely seen in peripheral blood)
Plasmodium vivax
Infected erythrocytes: enlarged up to 2X **deformed; (Schüffner’s dots)
1
2
Rings one chromatin dots
Schizonts: 12-24 merozoites
3
Trophozoites: ameboid; deforms the erythrocyte
4
Gametocytes: round
Plasmodium ovale
Infected erythrocytes: enlarged (1 1/4 X); **fimbriated; oval; (Schüffner’s dots)
1
2
Trophozoites: compact
Rings
3
Gametocytes: round-oval
Schizonts: 6-14 merozoites;
dark pigment; (“rosettes”)
4
Plasmodium malariae
Infected erythrocytes: **normal size
1
2
Ring: compact
Trophozoite:
typical
band form
3
Schizont:
6-12 merozoites;
coarse, dark pigment
4
Gametocyte:
round; coarse,
dark pigment
Prevention
• Using insecticide to kill a larval stage of
mesquite.
• Recovering all ponds and water source
with oil.
• Using a mesquite net.
• Using prophylaxis when travel to area with
malaria are endemic.
• Breeding a special type of fish which
feeding on larval stage of Anopheles.