Plasmodium is a unicellular parasite that causes malaria in humans. It is transmitted via the bite of infected female Anopheles mosquitoes. Plasmodium has a complex life cycle involving sexual reproduction in mosquitoes and asexual reproduction in humans. When an infected mosquito bites a human, sporozoites enter the liver and later infect red blood cells, causing symptoms such as fever, chills, and anemia. Diagnosis involves examining blood smears under a microscope to identify the Plasmodium species and stages. Treatment involves antimalarial drugs, while control relies on preventing mosquito bites and reducing mosquito populations.

2. Plasmodium
• Plasmodium is an unicellular blood parasite and it
causes malaria disease in humans.
• The word malaria means bad air (Italian words
malo means bad and aria means air).
• Earlier it was believed that people inhaled bad air
during night and became ill with malaria but it is
not so.
• It is the mosquitoes which are likely to be out in
the night air and spread malaria.

3. Plasmodium
• Four species of malaria parasites infect humans,
• Plasmodium vivax
• P. ovale
• P. malariae
• P. falciparum.
• All are transmitted by female Anopheles
mosquitoes
• Geographical distribution - malaria is present
worldwide in tropical and subtropical areas.

4. Habitat
• It is found in parenchymal cells of liver
• Erythrocytes and other organs

5. Transmission
the bite of infected female Anopheles mosquitoes
Malaria is also transmitted via blood transfusion
sharing of contaminated needles among IV drug
abusers
Congenital transmission also has been
documented.

6. Life Cycle Of Malaria
• Plasmodium has two hosts: mosquitoes and
humans.
• Sexual reproduction ( Sporogony) takes place in
the mosquito and the parasite is transmitted to
humans when the mosquito takes a blood meal.
• The asexual reproduction (Schizigony) takes
place in humans.

8. Life Cycle Of Malaria: Humans
• The mosquito injects Plasmodium into a human in the
form of sporozoites.
• The sporozoites first invade liver cells and asexually
reproduce to produce huge numbers of merozoites
which spread to red blood cells where more merozoites
are produced through more asexual reproduction.
• Some parasites transform into sexually reproducing
gametocytes and these if ingested by a mosquito
continue the cycle.

9. Life Cycle Of Malaria: Mosquitoes
• Gametocytes ingested by a mosquito combine in
the mosquito’s stomach to produce zygotes.
• These zygotes develop into motile elongated
ookinites.
• The ookinites invade the mosquito’s midgut wall
where they ultimately produce sporozoites, which
make their way to the salivary glands where they
can be injected into a new human host.

10. Pathogenesis
Plasmodia invades red blood cells grow at host
cells .
Which rupture when schizogony is complete.
Debris of ruptured cells, released merozoites and
their metabolic products stimulates chemoreceptor
of the temperature regulating mechanism of host.
Number of invaded red cells increases and the
sexual cycle of parasite increases.
Pyrogen released produces characteristic chills
and fever of malaria attack

11. Contd……..
• P. vivax prefers to invade young erythrocytes
whereas P. malariae prefers older erythrocytes.
• With each schizogony the parasitized cells are
destroyed and also a considerable destruction of
unparasitized cells due to lysis and phagocytosis
in liver and spleen.
• Blockade of small vessels by sticky parasitized
erythrocytes.

12. Features
• Fever : Three stages
»Cold stage
»Hot stage
»Sweating stage
• Febrile paroxysms
• Anemia
• Splenomegaly
These three stages are not always observed due to
maturation of generations of parasite at different
times

13. Laboratory Diagnosis
• Peripheral blood smear examination
• Thick blood smears are useful for examining larger
quantity of blood quickly when the parasites are few
in the peripheral blood.
• Thin blood smears are useful for examining the
peripheral blood when the parasites are numerous.
• It is only in the thin blood smears that the species of
malarial parasites and the morphological stages of the
organisms such as ring stage, schizont stage, male and
female gametocytes can be diagnosed.
• Serological studies- Indirect haemagglutination
test(IHA), ELISA etc

14. Treatment
• Chloroquine
• Quinine
• Primaquin
• Pyrimethamine + Sulfadoxine

15. Control & Prevention
• Treatment of patient by the use of anti-malarial
drugs.
• Prevention of infection by using protective
measures such as mosquito nets, odomos cream,
mosquito oil, mosquito repellants etc.
• Control of vector by filling ditches; killing larvae
by spraying insecticides, kerosene oil, DDT and
by introducing natural enemies like larvicidal fish
into pond.