This document summarizes information about malaria, including: 1) Malaria is caused by protozoan parasites of the genus Plasmodium, with four species infecting humans. P. falciparum causes the most severe disease. 2) Malaria is transmitted by the bite of infected female Anopheles mosquitoes. The parasite has a complex life cycle alternating between human and mosquito hosts. 3) Symptoms vary depending on the Plasmodium species, but microscopically parasites can be seen in red blood cells on blood smears. Rapid diagnostic tests also detect parasite antigens.

1. Malaria
Arun Kumar Parthasarathy
D.Y Patil Medical College, Kolhapur

2. Malaria parasites
Belongs to the genus Plasmodium
Approx 156 named spp- infect vertebrates
4 – infect humans
1. P.falciparum
2. P.vivax
3. P. malariae
4. P.ovale
Important vector borne disease.
• P. Knowlesi-parasite of monkey but can also affect
humans and many cases affecting man were recently
reported fromAsia.
95% of infection

3. Distribution
P. falciparum- Tropics
P. vivax- widest distribution (Tropics, Subtropics &
Temperate
P. malariae- Sporodically
P.ovale- Rare, common in western Africa
In India- P.vivax & P.falciparum- common
Few cases- P.malariae & P.ovale reported

4. Vector – Female Anopheline mosquito
Out of 45 species of Anopheline mosquitoes in India,
only a few are regarded as vectors of primary
importance.
A. culicifacies rural areas
A. stephensi urban areas
A. fluviatilis hilly areas
A. minimus, A. philippinensis,
A. sundaicus and A. maculatus
Others

5. Life Cycle
Complex life cycle
Intermediate host: man (Asexual Phase)
Definitive host: Mosquito (Female anopheles)- Sexual Phase
Infective form : Sporozoites

6. Stages..
1. Primary exo-erythrocytic stages/ Pre- erythrocytic
schizogony
2. Erythrocytic schizogony
3. Gametogony
4. Secondary exo-erythrocytic or dormant schizogony

8. Pre-patent period
Ring forms are the first asexual form that can be
demonstrated in the peripheral blood.
The time interval betweeen the entry of the parasite into
man and demonstration of the parasites in the peripheral
blood- pre-patent period.
It varies b/w the species
1. P.falciparum- 5 days
2. P.ovale-13 days
3. P.malaraie -9 days
4. P.vivax -8 days

9. P. vivax P. falciparum P. malariae P.ovale
Yellowish
brown, Fine
granules
Dark brown,
one/two solid
blocks
Bark brown,
Coarse granules
Dark yellowish
brown, coarser
than those of P.
vivax
Malarial Pigment…
Plasmodium feeds on haemoglobulin. The undigested product of
haemoglobulin metabolism like hematin, excess protein and iron
porphyrin combine to form malarial pigment

10. P. vivax P. falciparum P. malariae P.ovale
Large, 2.5μm in
diameter,
usually one
chromatin dot
&occasionally 2
chromatin dot
Small, delicate,
1.25-1.5μm in
diameter with 2
chromatin dots, 2
ring in one RBCs
common
Accoles form-
some parasites lie
on RBC membrane
Similar to that
of P.vivax
Similar to
that of
P.vivax
Early Trophozoites/ Ring stage

11. P. vivax P. falciparum P. malariae P.ovale
Large,
amoeboid,
predominant
vacuole
Medium size,
compact &
rounded
Small, compact,
band-shaped,
slightly amoeboid,
vacuole disappears
early
Slightly
amoeboid
Late Trophozoites

12. P. vivax P. falciparum P. malariae P.ovale
Large, 9-10μm
in dm, almost
fills an enlarged
RBCs
Small, 4.5-5μm in
diameter fills two
thirds of normal
size RBCs which
is not enlarged
Small, 6.5-7
μm , almost
fills a of
normal size
RBCs
Small, 6.2 μm
, fills about
three quarters
of slightly
enlarged
RBCs
Schizonts

13. P. vivax P. falciparum P. malariae P.ovale
14-24 14-32 6-12 6-12
Merozoites

14. On 10th day – oocyst is fully mature and releases the Sporozoites (Body cavity of
mosquito )
Through the body fluids – Sporozoites are distributed to various organs of the
body except ovaries
Sporozoites are special predilection for salivary glands and reach in
maximum number ultimately in the salivary ducts .

15. Laboratory Diagnosis
Malaria is one of the few parasitic infections considered to be
immediately life-threatening and a medical emergency
Microscopy:
Blood collection: finger prick or ear lobule
Thick and Thin smears of the blood are prepared on same or
different slides
Thick smear – Dehaemoglobulization is done by keeping the slide
in distilled water in Koplins Jar in vertical position – 5-10 minutes
till the slide becomes white and then air dried
Thick and thin smear are stained with Leishman stain
Then slide examine under 100x with oil

17. Parasite are abundant in peripheral blood, late in the febrile paroxysm
All asexual erythrocytic stages as well as gametocytes can be seen –
peripheral blood (P.vivax, P.malariae, P.ovale)
P.falciparum – ring form and Crescent shape gametocytes
Late Trophozoite and Schizonts – internal organs and appear in
peripheral blood only in severe or perinecious anemia
Malaria pigments may be demonstrated inside the monocytes and
PMNL cells
Presence of malaria pigment and absence of malaria parasites-P.
falciparum infection
RBCs –enlarged in vivax infection

18. Thin film is examined first and if parasites are found – no need to
examine thick smear
If parasite not seen in thin smear in a few minutes the thick smear
should be examined
Parasites are more along the upper and lower margins of the tail
Atleast 200-300 oil immersion field should be examined before the
smears are considered negative

20. Fluorescence microscope: stains with Acridine orange -
allows quicker screening of films, because parasites are
more readily recognized and a low power lens may be used

21. Quantification
Quantification is done by calculating the number of parasites
counted compared to number of WBCs in the thick smear or the
number RBCs counted in the thin smear
Quantification by thick smear =
No. of parasites counted
No. of WBC Counted
X 100
Quantification is helpful for
1. Assessing the severity of infection
2. Monitoring the response to the treatment
3. Detecting drug resistance P.falciparum

22. Rapid Test
Most frequently they employ a dipstick or test strip bearing monoclonal
antibodies directed against the targeted parasite antigens .
Within 15 minutes test can be performed
Targeted antigens:
1. Histidine-Rich Protein II (HRP-II): water soluble protein
produced by trophozoites and young gametocytes of P.falciparum.
2. Parasite Lactate Dehydrogenase (pLDH): produced by asexual
and sexual stages of malaria parasites. They can distinguish
P.falciparum from the non-P.falciparum spp but cannot distinguished
between other 3 spp

23. Dual antigen test
Test detect pLDH (Parasite Lactate Dehydrogenase) produced by
trophozoites and gametocytes of all plasmodium spp and PF-HRP-2
antigen.
2 bands are seen,
one is genus specific (Plasmodium) and other is species specific
(P.flaciparum)
It is a Rapid 2 site sandwich immunoassay
Used for species detection and differentiation of P.vivax and
P.falciparum malaria in areas with high rates of malaria infection.
Disadvantage:- cannot differentiate between P.vivax, P.ovale and
P.malariae

25. Quantitative Buffy Coat Test (QBC)
Developed by Becton and Dickenson Inc.
It involves staining of centrifuged and compressed of red cell layer
with acridine orange
Examination under UV light source
Other Technique
PCR, Serology

28. Culture
Trager and Jensen(1976) successfully
cultivated and maintained P.falciparum in
vitro in human red blood cells
Used RPMI 1640 medium in a continuous
flow system
Human erythrocytes were in a shallow
stationery layered covered by a shallow
layer of medium
Medium was flowed slowly and
continuously under an atmosphere with
7% CO2 , 1-5% O2
Now it is widely used for the production
for the antigen

29. Treatment
Chloroquine – standard treatment for acute malaria for many
years
Quinine is the most reliable and alternative to Chloroquine
Tetracycline and Clindamycin- adjunct to quinine therapy
Mefloquine and Halofantrine – active against Chloroquine
resistant strains
Chlorquine and Quinine – do not eliminate exo-erythrocytic
parasites in liver
For this, Primaquine (8-aminoquinoline drug) should be used but
drug may be precipitate hemolysis in individuals – deficient in
the enzyme Glucose 6 Phosphate Dehydrogenase

30. WHO definition and Classification of Drug
Resistance
Ability of a parasite to multiply or to survive in the presence of
concentrations of a drug that normally destroy parasites of the
same species or prevent their multiplication.
Three levels of resistance[R] are defined by WHO
RI: following treatment, Parasitaemia clears but a recrudescence
occurs
RII: following treatment, there is a reduction but not a clearance
of parasitaemia
RIII: Following treatment, there is no reduction of parasitaemia
Method classifying resistance, based on counting trophozoites
in blood films for upto 7 days after treatment and monitoring
the patient for any subsequent recrudescence

31. Prophylaxis
Spraying Insecticides such as DDT or Malathion
Spraying the breeding sites with petroleum oils and Paris Green
(Copper Acetoarsenite)- larvicides
Using Larvivorous fish (Gambusia affinis),
Bacterium (Bacillus thuringiensis var. israelensis or serotype
H14)- spore forming bacteria produce a crystal of toxic protein(γ-
endotoxin)- spores and crystals are ingested by mosquito larva,
the mouthparts and gut are paralysed and gut epithelium is
destroyed – leading to death
Avoiding exposure to mosquito bite

32. Thank You