The document summarizes the four main Plasmodium species that cause malaria in humans: P. falciparum, P. vivax, P. ovale, and P. malariae. It describes their life cycles, which involve sexual reproduction in mosquitos and asexual reproduction in human liver and red blood cells. P. falciparum causes the most severe disease and is the most likely to result in complications like cerebral malaria and blackwater fever. The life cycle and symptoms of the different species are discussed in detail.

1. PLASMODIUM SPECIES
PRESENTED BY: IDREES AHMED KHAN

2. Disease:
• Malaria is caused primarily by four plasmodia:
Plasmodium vivax.
Plasmodium ovale,
Plasmodium malariae.
Plasmodium falciparum.

3. • Plasmodium vivax and plasmodium falciparum are more common
causes of malaria.
• Plasmodium vivax is most widely distributed.
• Plasmodium falciparum causes the most serious disease.
• A fifth species Plasmodium knowlesi is found in southeast Asia.
• Worldwide, malaria is one of the most common infectious diseases
and one of the leading cause of death.

4. Important Properties:
• The vector and definitive host for plasmodia is the female Anopheles
mosquito.
• There are two phases in the life cycle
Sexual cycle: which occurs primarily in Mosquitoes.
Asexual cycle: which occurs in humans, the intermediate hosts.

5. The sexual cycle is called sporogony because sporozoites are
produced.
Asexual cycle is called Schizogony because schizonts are made.

7. LIFE CYCLE:
• The life cycle in humans begins with the introduction of sporozoites
into the blood from the saliva of the biting mosquito.
• The sporozoites are taken up the hepatocytes within 30 minutes.
• This “exoerythrocytic” phase consist of cell multiplication and
differentiation into merozoites.
• Merozoites are released from the liver cells and infect red blood cells.
• During the erythrocytic phase the organism differentiates into a ring
shaped trophozoite

8. • The ring form grows into an ameboid form and then differentiates
into a schizonts filled with merozoites.
• After release the merozoites infect other erythrocytes.
• This cycle in the red blood cells repeats at regular intervals typical for
each species.
• The periodic release of merozoites causes the typical recurrent
symptoms of chills. Fever and sweats seen in malaria patients.

9. Pathogenesis:
• Red cell are destroyed both by the release of the merozoites and by
the action of the spleen to first sequester the infected red cells and
then to lyse them.
• The enlarge spleen characteristic of malaria is due to the congestion
of sinusoids with erythrocytes, coupled with hyperplasia of
lymphocytes and macrophages

10. • Malaria caused by Falciparum is more severe than that caused by
other plasmodia by occlusion of the capillaries with aggregates of
parasitized red cells.
• This lead to life-threating hemorrhage and necrosis particularly in the
brain(cerebral malaria).
• Extensive hemolysis and kidney damage occur, with resulting
hemoglobinuria.
• The dark color of the patients urine has given rise to the term
“Blackwater fever”.The hemoglobinuria can lead to acute renal failure.

11. • The timing of the fever cycle is 72 hours for P.malariae and 48 hours
for the other plasmodia.
• Disease caused by P.malariae is called quartan malaria because it
recurs every fourth day.
• Wheras malaria caused by other plasmodia is called tertian malaria
because it recurs every third day .
• Tertian malaria is subdivided into malignant malaria,caused by
P.falciparum and benign malaria caused by P.vivax and P.Ovale.

12. • Plasmodium falciparum infects red cell of all ages so causes a high
level of parasitemia.
• P.vivax infect only reticulocytes.
• P.malariae infects only mature red cells, they produce much lower
levels of parasites in the blood.

13. • Individual with sickle cell trait (heterozygotes) are protected against
malaria because their red cells have too little ATPase activity and can
not produce sufficient energy to support the growth of the parasite.
• People glucose-6-phosphatase dehydrogenase(G6PD) deficiency are
also protected against the severe effects of falciparum malaria.

14. Clinical findings:
• Abrupt onset of fever and chills, accompanied by
headache,myalgias,and arthralgias about 2 weeks after the mosquito
bite.
• The fever spike,which can reach 41C.
• Splenomegaly is seen in most patients.

15. Laboratory Diagnosis:
• Microscopic examination of the blood using thick and thin Giemsa
stained smears.
• The thick smear is used to screen for the presence of orgainisms and
the thin smears is used for species identification.
• Schuffner’s dots are found in P.vivax and P.ovale.These are
intracytoplasmic granules that stain red using the Romanovsky stain.
• PCR-based test
• ELISA test

16. Treatment:
• Chloroquine is the drug of choice for treatment of uncomplicated
malaria.
• Primaquine
• Artemether plus lumefantrine.

17. Prevention:
• Chloroquine in areas where organism are sensitive.
• Primaquine to prevent relapses of P.vivax or P.ovale.
• Using insecticides and by draining water from breeding areas.
• Using nets and mosquito repellent.

18. MCQS# 1
• Black water fever is a special manifestation of malaria caused by;
• a. P. falciparum
b. P. malariae
c. P. ovale
d. P. vivax

19. MCQ#2
• Which of the following agent can be used to prevent malaria?
• A.Mabendazole
• B.Chloroquine
• C.Inactivated vaccine
• D.Praziquantel

20. MCQ#3
• MCQ Malaria 3. After sporozoite gain entrance to human body it
undergoes developmental cycle first in liver than in RBC, only after
which fever is seen. This incubation period varies between
plasmodium species, and ………….. species has longest incubation
period.
a. P. falciparum
b. P. malariae
c. P. ovale
d. P. vivax

21. MCQ#4
• Mosquito responsible for malaria transmission
A. Aedes aegypti
B. Aedes albopictus
C. Anopheles
D. Haemagogus

22. Answer key:
• 1.a
• 2.b
• 3.b
• 4.c