2. Definition
•P. falciparum
•P. vivax
•P. malariae
•P. ovale
• Malaria is a mosquito-borne infectious disease of humans
and other animals caused by parasitic protozoans belonging
to the genus Plasmodium .
• It is transmitted by the biting of an infected female
Anopheles mosquito, and the symptoms usually begin ten to
fifteen days after being bitten.
Etiology
The four species of human
malarial parasites are:
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5. Malaria Transmission Cycle
Parasite undergoes
sexual reproduction in
the mosquito
Some merozoites
differentiate into male or
female gametocyctes
Erythrocytic Cycle:
Merozoites infect red
blood cells to form
schizonts
Dormant liver stages
(hypnozoites) of P.
vivax and P. ovale
Exo-erythrocytic (hepatic) Cycle:
Sporozoites infect liver cells and
develop into schizonts, which release
merozoites into the blood
MOSQUITO HUMAN
Sporozoires injected
into human host during
blood meal
Parasites
mature in
mosquito
midgut and
migrate to
salivary
glands
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6. Incubation Period
Following the infective bite by the Anopheles
mosquito a period of time (the "incubation
period") goes by before the first symptoms
appear.
The incubation period in most cases varies
from 7 to 30 days.
The shorter periods are observed most
frequently with P. falciparum and the longer
ones with P. malariae.
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7. Period of communicability
• In vivax infections, gametocyte appears in blood 4-5
days after appearance of asexual parasites whereas in
falciparum they do not appear until 10-12 days.
Epidemiology
• Malaria continues to be one of the most important and
devastating infectious diseases in developing areas of
the world.
• Worldwide, over 40% of the population lives in areas
where malaria transmission occurs (i.e., parts of
Africa, Asia, the Middle East, Central and South
America, Hispaniola, and Oceania)
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9. Uncomplicated Malaria
The classical (but rarely observed)
malaria attack lasts 6-10 hours. It
consists of
• a cold stage (sensation of cold,
shivering)
• hot stage (fever, headaches,
vomiting; seizures in young
children)
• sweating stage (sweats, return
to normal temperature,
tiredness)
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10. Malignant malaria
Malaria caused by P.falciparum. is more severe than
that caused by other plasmodia.
Complication of P.falciparum
• cerebral malaria (involving the brain)
• massive haemoglobinuria (blackwater fever) in which
the urine becomes dark in color, because of acute
hemolysis of RBC
• Pulmonary oedema
• Anemia
• severe gastrointestinal symptoms
• shock and renal failure which may cause death.
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12. Laboratory diagnosis
laboratory diagnosis of malaria is confirmed by the
demonstration of malarial parasites inthe blood film
under microscopic examination.
• Thin film
• Thick film
Appearance of Thick and Thin Smears
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13. Serology in Malaria
• Serology detects antibodies
against malaria parasites,
using either indirect
immunofluorescence (IFA)
or enzyme-linked
immunosorbent assay
(ELISA). Serology does not
detect current infection but
rather measures past
exposure.
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14. Molecular Diagnosis
• Parasite nucleic acids are detected
using polymerase chain reaction
(PCR). Although this technique
may be slightly more sensitive
than smear microscopy, it is of
limited utility for the diagnosis of
acutely ill patients in the standard
healthcare setting. PCR results are
often not available quickly
enough to be of value in
establishing the diagnosis of
malaria infection.
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15. Rapid diagnostic test
• Antigen Detection
• Various test kits are available to detect
antigens derived from malaria
parasites. Such immunologic tests
most often use a dipstick or cassette
format, and provide results in 2-15
minutes. These "Rapid Diagnostic
Tests" (RDTs) offer a useful
alternative to microscopy in situations
where reliable microscopic diagnosis
is not available. Malaria RDTs are
currently used in some clinical
settings
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16. 16
ALGORITHM FOR DIAGNOSIS AND TREATMENT OF
MALARIA
Whether microscopy results are available within 24 hrs.
Clinically suspected malarial case
Prepare slides for microscopy
P. Vivax
CQ 3 days+
PQ 14 days
P. Falciparum
ACT 3days+
PQ single dose
on 2 day
Negative
Needs further
evaluation
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Where microscopy results are not available within 24 hrs
Clinical suspected malaria case
Perform RDT
Perform RDT and also
prepare blood smear
Bivalent RDT
RDT positive
ACT 3 days + PQ
single dose on 2 day
RDT negative
Send blood slides to laboratory
CQ 3 days & wait for microscopy results
(+) P.V-PQ for 14 days
(+) P.F-ACT 3days+PQ single dose
Positive
Treat according to
species
Negative
Needs further
evaluation
18. Chemoprophylaxis
• Indicated for travellers travel to endemic areas
in Malaysia.
• Mefloquine 250mg weekly (up to 1 year) or
doxycycline 100mg daily (up to 3 month), to
start 1 week before and continue till 4 weeks
after leaving the area.
20. Malaria Vaccine
• Scientists are working on a new malaria
vaccine.
• The vaccine would help protect children from
deadly malaria.
• The vaccine boosts the immune response
against malaria.
• However, the vaccine is still being tested.
• Many valid candidate vaccines have been slow
to enter clinical trial & an efective vaccine is
thought to be 10 years away.
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