The document summarizes information about Plasmodium species that cause malaria in humans. It discusses the four main species that infect humans - P. falciparum, P. vivax, P. malariae, and P. ovale. It describes their life cycles, which involve development in both human and mosquito hosts. Symptoms in humans include febrile paroxysms and potential complications like cerebral malaria, blackwater fever, and anemia. Diagnosis involves examining blood smears microscopically to identify the parasite stages. Rapid diagnostic tests and quantitative buffy coat analysis can also be used. Treatment depends on the species but may include chloroquine, quinine, and primaquine.

1. PLASMODIUM SPECIES
PRESENTED BY : PRABIN SHAH , B.Sc. MLT 5th
semester

2.  Malaria parasite belong to the genus Plasmodium which
include over 125 species infecting reptile, birds and mammals.
Human parasite belong to subgenera P.(Plasmodium) and P.
(Laverania).
Malaria parasite infecting to human belongs to 4 species
P.(Laverania)falciparum
P.(Plasmodium)vivax
P.(Plasmodium)malariae
P.(Plasmodium) ovale

3. Plasmodium falciparum
 It is found mainly in the hotter and more humid regions of
the world. It is found in the tropical and sub tropical Africa and
the parts of Central America and South America , Bangladesh,
Nepal, Srilanka etc.
Plasmodium vivax
It is widely distributed in the temprate and sub tropical areas
(South America , Northern Africa, India, Nepal, Pakistan etc)

4. Plasmodium malarie
It has much lower prevalence than P.falciparum and P. vivax.
It account for 25% of Plasmodium infection.
 It is found in the tropical and sub tropical regions (Guyana, India,
Srilanka etc ).
Plasmodium ovale
 It is mainly found in West Africa , China, Indonesisa, Philippines,
South East Asia.
 It accounts for 10% of infection.

5. LIFE CYCLE OF PLASMODIUMLIFE CYCLE OF PLASMODIUM
SPECIESSPECIES

6. Malaria parasite exhibits a complex life cycle
involving alternating cycles of asexual division
occurring in man and sexual development in the
mosquito.
Definite host : Mosquito(Female anopheles)
Intermediate host : Man

7.  Sporozoite are the infective form of the parasite, they
are present in the salivary glands of mosquito.
• Man get infection by biting of infected female
mosquito.
•Proboscis of the mosquito pierces the skin and saliva
containing sporozoites are injected directly to the
blood stream.

8. The cycle in man comprises of following stages
(a) Primary exoerythrocytic schizogony
(b) Erythrocytic schizogony
(c) Gametogony
(d) Secondary exoerythrocytic schizogony
Primary exoerythrocytic schizogony
• Within 1hour all the sporozoites leave the blood stream and enter
into liver parenchyma cells.
The elongated, spindle shaped bodies become rounded inside liver
cells.
• They undergo multiple nuclear division, followed by
cytoplasmic division and develop into primary exoerythrocytic
schizont.
• When this schizogony is complete, liver cell ruptures and release
merezoites into blood stream.

9. •Merozoites liberated from the primary exoerythrocytic
schizogony enter the blood stream and invade the red cells
where they multiply at the expense of the host cells.
•Here they pass through the stages of trophozoite, schizonts
and merozoites.
•Depending on the species, 6-12 nuclei are produced followed
by cytoplasmic division and red cells ruptures and releases
merozoites.
•Plasmodium falciparum differs from other species, where
developing erythrocytic schizonts aggregate in the capillaries of
the brain and other internal organs.

10. • After erythrocytic schizogony, some merozoites develop
within red cells into male (microgametocyte) and female
gametocytes (macrogametocyte).
• Only mature gametocytes are found in the peripheral
blood.
• Host carrying gametocytes is known as carrier.
• Microgametocyte of all 4 species are small, cytoplasm stain
light blue and the nucleus is diffuse and enlarge.
• Macrogametocyte are larger, cytoplasm stains deep blue
and nucleus is compact and small.

11. •In case of P. vivax and P. ovale, some sporozites on entering
into hepatocytes enter into a resting (dormant) stage
before undergoing asexual multiplication.
•The resting stage of the parasite is rounded, 4-6 µm in
diameter, uninucleate and is known as hypnozoite.
•After a period of weeks, months or years hypnozoites are
reactivated to become secondary exoerythyic schizonts and
release merozoites which infect RBC producing relapse of
malaria.

12. Sexual cycle actually starts in the human host itself by
the formation of gametocytes which are present in the
peripheral blood.
In the mosquito, only the mature sexual forms are
capable of further development and rest die.
 From one microgametocyte eight thread-like
filamentous structures called microgametes are formed
by the process of exflagellation.
The macrogametocyte develops into macrogamete,
which fertilizes with microgamete within 20 mins – 2 hrs.

13. In next 24 hrs the zygote lengthens and matures into
ookinete, which penetrate the epithelial lining of the
stomach of mosquito and develops into oocyst.
Sporozoites develop inside the oocyst which no. varies
from a few hundred to few thousands in each oocyst.
On about 10th
day the oocyst is fully mature, ruptures and
releases sporozoites in the body cavity of mosquito.
The sporozoites are distributed through the body fluid to
the various organs of the body except the ovaries.
Sporozoites have special predilection for salivary glands
and ultimately reach in maximum no. at which the
mosquito is capable of infecting human.

14. Besides infection by the bite of infected female
mosquito the infection may also be transmitted by
Transfusion of blood from a patient of malaria (
TRANSFUSION MALARIA)
Transmission of infection to foetus in utero through
some placental defect ( CONGENITAL MALARIA)
By the use of contaminated syringes particularly in
drug addicts.

15. The above conditions are also known as ‘trophozoite
induced malaria’ where
No primary & secondary exoerythrocytic schizogony
Incubation period is short
No relapse.
After incubation period patient develops malaria which
consists of
1.Febrile paroxysm
2.Anaemia
3.Splenomegaly

16. It generally begins in the early afternoon and
comprises of 3 successive stages
Cold stage ( 15- 60 mins)
Hot stage ( 2-6 hrs)
Sweating stage
The periodicity of attack varies within species as
P. vivax – 48 hrs
P. ovale – 48 hrs
P. malariae – 72 hrs

17. After a few paroxysms, anaemia of a microcyctic or a
normocyctic hypochromic type develops because of
Mechanical destruction of parasitized red cells
Reduced erythropoiesis in the bone marrow
Lysis and phagocytosis of uninfected red cells.
In addition, in a small no. of patients with malignant
tertian malaria there is autoimmune destruction of red
cells.

18. It is due to the massive proliferation of macrophages
which phagocytize both parasitized and non-parasitized
RBCs
The condition is characterized by massive and chronic
splenomegaly with high levels of IgM, malaria antibody
and circulating immune complexes and a moderately
enlarged liver with hepatic sinusoidal lymphocytosis
The patient is usually anaemic (normocyctic) and has
low white cell and platelet counts.

19. This is the most commonest cause of coma and death in
falciparum malaria, particularly in children and non-
immune adults
Many parasitized cells can be found in the capillaries of
the brain and in the late stages, haemorrhaging from
small blood vessels can occur.

20. It is a rare but acute condition in which there is a rapid
and massive intravascular haemolysis of both parasitized
and non parasitized red cells
It results in haemoglobinaemia, haemoglobinuria and fall
in haemoglobin
The urine appears dark red to brown- black due to the
presence of free haemoglobin hence the name
BLACKWATER FEVER
It can occur in non-immune adults with severe
falciparum malaria and also as a complication of quinine
treatment.

21. Disease Severity and Duration
vivax ovale malariae falciparum
Incubation
Period
8-27 8-27 16->40 6-25
Severity of
Initial
Paroxysms
moderate to
severe
mild mild to
moderate
severe
Average
Parasitemia
20,000 9,000 6,000 50,000-
500,000
Maximum
Parasitemia
50,000 30,000 20,000 2,500,000
Typical
Symptom
Duration
3-8 weeks 2-3 weeks 3-24 weeks 2-3 weeks
Maximum
Infection
Duration
5-8 years 12-20 months 20-50 years 6-17 months
Anemia ++ + ++ ++++
Other
Complications
- - Renal Cerebral

22. MICROSCOPY
Diagnosis of malaria can be established by demonstration of
malaria parasites in the blood
Thick and thin smears of the blood are prepared on the same or
different slides
Blood is taken by pricking a finger or ear lobule before starting
treatment with antimalarials
For preparation of thick smear a large drop of blood is taken
on the slide and then spread in an area of 12 mm sq;
dehaemoglobinization of thick smear is done by keeping the
slide in distilled water in Koplin’s jar in vertical position for 5-10
mins till the slide become white and then dried in air.

23. All asexual erythrocytic stages as well as gametocytes
can be seen in peripheral blood in infection with P. vivax
, P. malariae and P. ovale but in P. falciparum infection ,
only the ring forms and crescent shaped gametocytes
can be seen
The occurrence of multiple rings in an individual red
blood cell with accole forms is diagnostic of P.
falciparum infection

24. Both thick and thin smears can be stained by following
stains:
Leishman stain
Giemsa stain
Field stain
J.S.B.(Jaswant singh ,Bhattacharjee ) stain

25. Schizont of P.malaria Gametocyte of P.falciparum

26. Ring form of P.ovale Ring form of P.vivax

27. RDTs are based on the detection of antigens derived
from malaria patients in lysed blood, using immuno-
chromatographic methods
Most frequently they employ a dipstick or test strip
bearing monoclonal antibodies directed against the
target parasite antigens
The tests can be performed in about 15 mins.

28. Histidine-rich protein 2 (HRP-2) is water soluble
protein produced by trophozoites and young
gametocytes of P. falciparum; commercial kits currently
available detect HRP-2 from P. falciparum only
Parasite lactate dehydrogenase ( pLDH) is produced by
asexual and sexual stages of malaria parasites

29. In QBC test, malaria parasites are concentrated by
centrifuging blood in a special capillary tube
The tube is coated with acridine orange and an anticoagulant
which contains a small plastic cylinder
Following centrifugation, the white cells, platelets and upper
layer of the red cells which contain the malaria parasites can be
found in the space between the float and inside wall of the
capillary
When examined by fluorescence microscopy at × 600
magnification, the acridine orange stained malaria parasites
fluresce green yellow against a dark red-black background with
the nucleus of trophozoites and merozoites of schizonts
fluorescing bright green.

30. Chloroquine was the standard treatment for acute malaria for
many years. However, resistance to this drug in P. falciparum is
widespread
Quinine is the most reliable alternative to chloroquine for the
treatment of malaria caused by chloroquine-resistant strains.
Tetracycline and clindamycin exhibit some anti-malarial activity
and are used as an adjunct to quinine therapy; Mefloquine and
halofantrine are also active against chloroquine resistant strains
but resistant to these drugs has also been reported
Chloroquine and quinine donot eliminate exoerythrocyctic
parasites in the liver. For this primaquine (8-amino quinoline
drug ) should be used. However, this drug may precipitate
haemolysis in individuals deficient in the enzyme glucose-6-
phosphate dehydrogenase.

31. Malaria can be controlled by the integration of following
measures:
Spraying the breeding sites with petroleum oils and Paris
green as larvicides
Using larcivorous fish, Gambusia affinis and a bacterium,
Bacillus thuringiensis var. israelensis or serotype H14 of B.
thuringiensis in breeding places
Flooding and flushing of breeding places
Eliminating breeding places such lagoons and swamps
Avoiding exposure to mosquito bites by various
physiochemical means
Use of antimalarial prohylaxis chloroquine , pyrimethamine
and proguanil
Early diagnosis and prompt treatment of patients.

32. D.R.ARORA, B.ARORA Medical Parasitology
Monica Cheesbrough District Laboratory Practice in
Tropical Countries Part 2
www.google.com
Godkar, Textbook of Medical Laboratory Technology