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Malaria
Background
Definition of
malaria
Malaria is an infectious disease caused by
protozoan organisms of the genus Plasmodium
(falciparum, ovale, vivax, malariae). It is
characterized by high fever and erythrocytic
infection resulting in anemia..
• life cycle:
asexual phase (schizogony)
sexual phase
(sporogony)
human host
There are four species of malaria that infect humans. All of them are transmitted in
the same way,
Mosquito bites human
Sporozoites injected into human host during blood meal
Sporozoites infect liver cells, develop into schizonts, which release merozoites into
the blood stream by rupturing the liver cells.
Merozoites penetrate red blood cells and form schizonts; red blood cells release
merozoites
Some merozoites differentiate into male gametocytes or female gametocytes.
Gametocytes are taken in by mosquito from a blood meal.
Mosquito stage
Parasites undergo sexual reproduction, develop into oocysts which release
sporozoites that invade the mosquito's salivary glands.
And the cycle continues on……
Malaria Lifecycle
Human Liver Stages
Mosquito Stages
Exo-erythrocytic
(hepatic) Cycle:
Sporogonous Cycle:
Human Blood Stages
P. falciparum
Gametocytes
P. vivax
P. ovale
P. malariae
Erythrocytic Cycle:
Epidemiology
Malaria is the most important cause of fever and
morbidity in the tropical world.
Clinical Manifestations
The clinical manifestations of malaria range from
asymptomatic infection to fulminant illness and
Death .
Febrile paroxysms.
classic symptoms of the febrile paroxysms of
malaria include high fever, rigors, sweats, and
headache.
V:48h o:48h m:72h
Relapse:
Short-term relapse
Longterm relaps
Malaria: Clinical manifestations
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•Febrile paroxysms have 3 classic stages
–Cold stage
Pt feels cold and has shaking chills
-mins. prior to fever
–Hot stage
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Lassitude, loss of appetite, bone and joint aches
Tachycardia, hypotension, cough, HA, back pain,
N/V, diarrhea, abdo pain, altered consciousness
–Sweating stage
Marked diaphoresis followed by resolution of fever,
profound fatigue, and sleepiness
hours after onset of hot stage
Malaria: Clinical manifestations
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•Other symptoms depend upon the strain of malaria
•P. vivax, ovale and malariae: few other sxs
•P. falciparum:
–Dependent upon host immune status
No prior immunity/splenectomy high levels of
parasitemia
: profound hemolysis
–Vascular obstruction and hypoxia
Kidneys: renal failure
Brain: hypoxia, CNS dysfunction, coma,
seizures
Lungs: pulmonary edema
–Jaundice and hemoglobinuria (blackwater fever)
Laboratory and Imaging Studies
The diagnosis of malaria is established by
identification of organisms on stained smears of
peripherd blood.
timing of the smears is less important than their
being obtained several times each day over 3
successive days.
Thick smears are used to scan large numbers of .
Erythrocytes quickly.
Thin smears allow for positive identification of the
malaria species.
Diagnosis
Key of diagnosis is to identify P. falciparum
New assays:
ELISA for antigen, immunoassay for LDH, –
PCR PCR
Anemia, elevated LDH, increased reticulocytes,
thrombocytopenia
Elevated unconjugated bilirubin without increases
in hepatic enzymes
Elevated serum creatinine, proteinuria,
hemoglobinuria, hypoglycemia
Differential Diagnosis
the possibility of malaria in any child who has fever,
chills, splenomegaly, anemia, or decreased level of
consciousness with a history of recent travel or
residence in an endemic area, regardless of the
use of chemoprophylaxis.
DDX:
tuberculosis, typhoid fever, brucellosis, relapsing
fever,
infective endocarditis, influenza, polio, yellow fever,
trypanosomiasis, kalaazar, and amebic liver abscess.
All Plusmudim Species Except
Chloroquine-Resistant P. Falciparum
• Oral Drug of Choice
chloroquine phosphate
• Parenteral Drug of Choice
quinidine gluconate
chloroquine-Resistant P. Falciparum
• Oral drug of Choice
Quinine sulfate plus tetracycline‘
• Alterative Oral regimens:
• Quinine sulfate plus pyrimethamine-sulfadoxine
• Mefloquine
• Atovaquone Plus proguanil
chloroquine-Resistant P. Falciparum
• Parenteral Dnrg of Choice:
Quinidine gluconate
Prevention of Relapses: P. viva and P.
ovale
• Primaquine phosphate
(after completion of chloroquine)
Complications
• Cerebral malaria :
is a complication of P.falciparum infection and a
frequent cause of death (20% to 40%),
Especially among children and nonimmune adults
occur among patients with intense parasitemia
(~5%).
• Other complications include splenic rupture,renal
failure, severe hemolysis (blackwater fever), pulmonary
edema, hypoglycemia, thrombocytopenia, and
• algid malaria (sepsis syndrome with vascular
collapse).
Prognosis
• Death may occur with any of the malarial species,
• is most frequent with complicated P. falciparum
malaria.
• The likelihood of death is increased in children
with preexisting health problems, such as measles,
intestinal parasites, schistosomiasis, anemia, and
malnutrition.
Death is much more common in poor developing
countries