The basic generally accepted practical classification of the
medically important parasitic protozoa Amoebae Entamoeba
histolytica Acanthamoeba species Naegleria species Flagellates
Giardia lamblia Trichomonas vaginalis Trypanosoma species
Leishmania species Ciliates Balantidium coli Coccidia Blood and
tissue coccidia: o Plasmodium species o Toxoplasma gondii
Intestinal coccidia: o Isospora belli o Cryptosporidium parvum o
Cyclospora cayetanensis Microsporidia Encephalitozoon species
Enterocytozoon species
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Malaria Malaria is Potentially life-threatening disease caused
by Plasmodium protozoa, transmitted to humans from infected female
Anopheles mosquitoes Malaria parasites are intracellular protozoa.
The Plasmodium parasite infect the red blood cells (RBCs) Malaria
is mainly a disease of tropical and subtropical areas. Malaria is
preventable and curable If left untreated, the development of
severe complications can cause death
Slide 4
Malaria Have Indirect life cycle. Anopheles mosquito is the
definitive host (development of the parasite refer as sporogony).
Human is the intermediate host (development of the parasite refer
as schizogony).
Slide 5
taxonomy Kingdom Animalia Subkingdom Protozoa Phylum
Apicomplexa Class Sporozoasida Order Eucoccidiorida Family
Plasmodiidae Genus Plasmodium Species falciparum, malariae, ovale,
vivax
Slide 6
Plasmodium species: Plasmodium falciparum. Plasmodium vivax.
Plasmodium ovale. Plasmodium malariae. Plasmodium knowlesi, has
recently been identified as a clinically significant pathogen in
humans in Southeast Asia Among patients with malaria, 5-7% are
infected with more than a single Plasmodium species. P falciparum
and P vivax are responsible for most new infections. Each species
has a defined area of endemicity, although geographic overlap is
common.
Slide 7
Distribution Of Plasmodium falciparum
Slide 8
Distribution Of Plasmodium vivax
Slide 9
The vector
Slide 10
Mode of Transmission Mosquitoes bites Blood transfusions
Transplacental
Slide 11
Life cycle The malaria parasite life cycle involves two hosts
During a blood meal, a malaria-infected female Anopheles mosquito
inoculates sporozoites into the human host Sporozoites infect liver
cells and mature into schizonts which rupture and release
merozoites Merozoites leave the liver and infect red blood cells
(erythrocytic schizogony) The trophozoites (ring stage the feeding
stage of a protozoan parasite )mature into schizonts or gametocyte
The schizonts rupture releasing more merozoites The gametocytes is
sexual erythrocytic stages, wait for mosquito
Slide 12
Life cycle Gametocytes ingested by mosquito. Male and female
gametes produce Zygote which is become an ookinete The ookinete
attach to the mosquito gut and give oocyst. Mature oocyst ruptures
and release the Sporozoites reach salivary glands of mosquito.
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Clinical features and pathology of malaria The characteristic
feature of malaria is fever caused by the release of toxins (when
erythrocytic schizonts rupture) which stimulate the secretion of
cytokines from leucocytes and other cells. Incubation period 6-19
days The classical attack lasts 6-10 hours. a cold stage (sensation
of cold, shivering) a hot stage (fever, headaches, joint &
muscle pain vomiting; seizures in young children) and finally a
sweating stage (sweats, return to normal temperature,
tiredness)
Severe malaria manifests as follows: Cerebral malaria: This
feature is always caused by P falciparum infection, Coma may occur.
Severe anemia Renal failure: a rare complication of malarial
infection. Respiratory symptoms: Patients with malaria may develop
metabolic acidosis and associated respiratory distress. Black water
fever; rare complication, occur due to rapid massive intravascular
hemolysis of both parasitized & nonparasitized RBCs,
haemoglobinaemia, haemoglobinuria& renal failure.
Slide 18
Laboratory diagnosis The diagnosis of malaria is by: Detecting
and identifying malaria parasites microscopically in blood films.
Concentrating parasites in venous blood by centrifugation when they
cannot be found in blood films. Using a malaria rapid diagnostic
test (RDT) to detect malaria antigen.
Slide 19
Malaria parasites in thick and thin blood films stains by
Fields stain Giemsa stain Results Chromatin of
parasite................ Dark red Cytoplasm of
parasite.................... Blue Schuffners
dots......................... Red Red cells.................. Grey
to pale mauve
Slide 20
Trphozoite of plasmodium
Slide 21
Gametocyte of plasmodium
Slide 22
????
Slide 23
p. falciparum In peripheral blood Not in peripheral blood:
16-26
Slide 24
???
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Rapid Diagnostic test ParaSight F and ICT Malaria PF: o
Helpful, not need microscope o It depends on detection of
P.falciparum histidinerich protein 2 (HRP-2) o Disadvantage is used
for p. falciparum only OptiMal test: o Detects plasmodium lactate
dehydrogenase (pLDH), o Advantage that is used for all species
