Background Definition of malaria Malaria is an infectious disease caused by protozoan organisms of the genus Plasmodium falciparum ovale vivax malariae ID: 360705
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Slide1
MalariaSlide2
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..Slide3
life cycle:
asexual phase (schizogony)
sexual phase (sporogony)
Slide4
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
……Slide5
Sporogonous Cycle
:
Mosquito Stages
Gametocytes
P. falciparum
P. vivax
P. ovale
P. malariae
Human Liver Stages
Exo-erythrocytic
(hepatic) Cycle:
Human Blood Stages
Erythrocytic Cycle
:
Malaria LifecycleSlide6
Epidemiology
Malaria is
the most
important cause of fever and morbidity in
the tropical world.Slide7
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
V:48h
o:48h m:72h
headache.Slide8
:
Relapse
Short-term relapse
Longterm relaps Slide9
Malaria: Clinical manifestations
•
Febrile paroxysms have 3 classic stages
–
Cold stage
Pt feels cold and has shaking chills
-
mins. prior to fever
–
Hot stage
41°
Lassitude, loss of appetite, bone and joint aches
Tachycardia, hypotension, cough, HA, back pain,
N/V, diarrhea, abdo pain, altered consciousness– Sweating stageMarked diaphoresis followed by resolution of fever,
profound fatigue, and sleepinesshours after onset of hot stageSlide10
Malaria: Clinical manifestations
•
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 hypoxiaKidneys: renal failure
Brain: hypoxia, CNS dysfunction, coma, seizures
Lungs: pulmonary edema– Jaundice and hemoglobinuria (blackwater fever)Slide11
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 quicklyThin smears allow for positive identification
of the malaria species.Slide12
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, hypoglycemiaSlide13
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
. Slide14
All Plusmudim Species Except Chloroquine-Resistant P. Falciparum
Oral Drug
of Choice
chloroquine phosphate
Parenteral
Drug of
Choice
q
uinidine gluconateSlide15
chloroquine-Resistant P.
Falciparum
Oral
drug
of
Choice
Quinine sulfate pl
us tetracycline‘
Alterative
Oral
regimens:
Quinine sulfate plus pyrimethamine-sulfadoxineMefloquineAtovaquone
Plus proguanilSlide16
chloroquine-Resistant P. Falciparum
Parenteral Dnrg of
Choice:
Quinidine
gluconateSlide17
Primaquine phosphate
(after completion
of
chloroquine)
Prevention of Relapses: P. viva and P. ovaleSlide18
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, andalgid malaria (sepsis syndrome with vascular collapse).Slide19
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