Plasmodium malarial parasite

This slides deeply explain about the malarial parasite plasmodium

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By
A.S.ARUL LAWRENCE
Principal, St.JosephCollege of Education,
Nanguneri-627108, Tamil Nadu.
E-mail : [email protected].

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Causal Agents:
•Blood parasites of the genus
Plasmodium.
•There are approximately 156 named
species of Plasmodium which infect
various species of vertebrates.
•Four are known to infect humans:
P. falciparum, P. vivax , P. ovaleand
P. malariae.

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What is a Malarial Parasite?
The malarial parasite, Plasmodium, is a
very small, single-cell blood organism, or
'protozoan'.
It lives as a parasite in other
organisms, namely man and mosquito. The
parasite is the cause of the tropical disease
Malaria.
The Plasmodium parasite is dependent on
a single species of
mosquito, Anopheles, which is the only
species capable of serving as host for it.

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Male & Female Plasmodium.

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Classification
Phylum : Protozoa
Sub-Phylum :Sporozoa
Class :Telosporea
Sub-Class :Coccidia
Order :Eucoccida
Sub-Order : Hamosporidiidea
Family :Plasmodiidae
Genus :Plasmodium

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Worldwide, malaria usually
restricted to tropical and subtropical
areas and altitudes below 1,500 m.
P. vivaxis more common in Central
America and the Indian subcontinent
Geographic Distribution.

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Infection rate.
WHO estimates that yearly 300-500
million cases of malaria occur and
more than 1 million people die of
malaria.
P. vivaxand P. falciparumare the most
common.

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Mode of
Infection.

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Vector & Parasite.

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Life cycle.
A malaria-infected female Anopheles
mosquito inoculates sporozoites into the
human host during a blood meal.
Sporozoites infect liver cells and mature into
schizonts, which rupture and release
merozoites (exo-erythrocytic schizogony).
In P. vivax and P. ovale a dormant stage
(hypnozoites) can persist in the liver for
weeks, or even years. The merozoites infect
red blood cells.

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Life cycle…
•The ring stage trophozoites mature into
schizonts, which rupture releasing merozoites
(erythrocytic schizogony).
•Some parasites differentiate into sexual
erythrocytic stages (gametocytes).
•The gametocytes are ingested by an Anopheles
mosquito during a blood meal.
•The microgametes penetrate the macrogametes
generating zygotes in the mosquito's stomach.

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Life cycle…..
•The zygotes become ookinetes and invade the
midgut wall where they develop into oocysts.
•The oocysts grow, rupture, and release
sporozoites, which make their way to the
mosquito's salivary glands (sporogonic cycle).

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Sporozoite Invasion.

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Erythrocytic Schizoite.

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Amoeboid Stage.

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Ring Stage.

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Male Gamete.

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Female Gamete.

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Fertilization.

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Mature Oocyst.

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Rupturing of Oocyst.

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MALARIAL PARASITE’S
DIFFERENT CYCLES
CYCLES OF PARASITE
HUMAN -ASEXUAL
(SCHIZOGONY)
MOSQUITO -SEXUAL
(SPOROGONY)
EXOERYTHROCYTIC
CYCLE
(LIVER)
ENDOERYTHROCYTIC
CYCLE
(BLOOD)

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Sickle cell anaemia and malaria
A genetic disorder, called sickle cell anaemia, happens
when a person inherits two faulty genes to make the
haemoglobin in their red blood cells which then break
open and cause serious damage due to blood clots.
Carriers who possess one faulty haemoglobin gene and one
normal gene do not suffer from anaemia but are found to
have some protection against infection by the malaria
parasite.
In areas where malaria is common, the amount of sickle
cell carriers is higher than in other parts of the world.
In an unusual example of Darwin's principle of survival of
the fittest, carriers of the genetic disorder are actually
more likely to survive than people with two unaffected
genes for haemoglobin.

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Species
Plasmodium
vivax
Plasmodiu
m
ovale
Plasmodiu
m
malaria
e
Plasmodium
falciparum
Pre-erythrocytic cycle (days)
1
8 9 13 5.5-6
Pre-patent period (days)
2
11-13 10-14 15-16 9-10
Incubation period (days)
3
13 (12-17) or up
to 6-12
months
17 (16-18)
or
longer
28 (18-40)
or
longer
12 (9-14)
Exo-erythrocytic cycle (secondary)
4
Present Present
Present in
some
strains
?
Absent
Approximate number of merozoites
per tissue schizont
Over 10,000 15,000 2000 40,000
Erythrocytic cycle (hours)
5
48 49-50 72 48
Parasitemia (per l (mm
3
) Average 20,000 9000 6000 20,000-500,000
Maximum 50,000 30,000 20,000 2,000,000
Primary attack severity Mild to severe Mild Mild
Severe in non-
immunes
Febrile paroxysm (hours)
6
8-12 8-12 8-10 16-36 or longer
Relapses ++ ++ +++ -
Period of recurrence
7
Long Long Very long Short
Duration of infection (years) 1.5-3 1.5-3 3-50 1-2

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1.Vivax malaria
2.Tertian malaria

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Symptoms:
The most frequent symptoms include
fever and chills, which can be
accompanied by headache, myalgias,
arthralgias, weakness, vomiting, and
diarrhea.
Other clinical features include
splenomegaly, anemia, thrombocytopenia,
hypoglycemia, pulmonary or renal
dysfunction, and neurological changes.

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Laboratory Diagnosis:
MicroscopyMicroscopic identification is the
method most frequently used to demonstrate an
active infection.
Comparison of Plasmodium species
Molecular diagnosistechniques can complement
microscopy, especially in species identification.
Antibody Detectioncan detect past (not
necessarily active) infections.
Immunologic/Biochemical detectionof malaria
parasite products are available and under
evaluation

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Treatment:
•Treatment varies according to the
infecting species, the geographic
area where the infection was
acquired, and the severity of the
disease.
•A complete guide for treatment of
malaria can be found in The Medical
Letter(Drugs for Parasitic
Infections), as well as on the Division
of Parasitic Diseases Web site.

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Prevention.
•Personal protection against
mosquito bites is the first line of
defence against malaria.
•In addition, travellers should
take chemoprophylaxis where
appropriate

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