MALARIA

MALARIA

¥ (Otherwise known as AGUE (acute fever
¥ Derived from Italian: Mal’ aria= bad’ air (Horace Walpole in 1740)
¥ Malaria continues to be most important cause of fever and morbidity in the Tropical world.

HISTORY
2700 BC: China- Huang Di Nei Jing
Described one form of intermittent fever recurring every one, two or three days
Hippocratic corpus (400 B.C.) was the first to describe the manifestations of the disease and to relate them to the time of the year and where the patient lived.
• The periodic fever episodes characteristic for malaria have been described by physician early on in human history.
• People recognized a connection between malaria and swamps.
• It was thought that swamps exude a miasma or poison which causes the disease
• Giovanni Maria Lancisi (1654-1720)
• He first described a characteristic black pigmentation of the brain and spleen in the victims of malaria.
• Lancisi linked malaria with poisonous vapors of swamps or stagnant water on the ground.
• Discovery of the Malaria Parasite (1880)
• 6th of November 1880.
• Charles Louis Alphonse Laveran, a French army surgeon concluded that “Swamp fevers are due to a germ”
• Parasites in the blood of a patient suffering from malaria.
• Unable to identify the species.
• 1883 - Methylene blue stain - Marchafava
• 1891 - Polychrome stain- Romanowsky

Discovery that mosquitoes transmit malaria
On august 20th, 1897, RONALD ROSS, a British officer in the Indian medical service, demonstrated that malaria parasites could be transmitted from infected patients to mosquitoes.

In further work with bird malaria, Ross showed that mosquitoes could transmit malaria parasites from bird to bird.

The mystery of malaria transmission was solved.

Discovery of the transmission of the human malaria parasites
• In 1898, led by Giovanni Batista Grassi, a team of Italian investigators, collected Anopheles claviger mosquitoes and fed them on malaria patients.
• The complete sporogonic cycle of Plasmodium falciparum, P. vivax, and P. malariae was demonstrated.
• In 1899, mosquitoes infected by feeding on a patient in Rome were sent to London where they fed on two volunteers, both of whom developed malaria.
• Camillo Golgi
• An Italian neurophysiologist, established that there were at least two forms of the disease
• -one with tertian periodicity (fever every other day) and one with quartan periodicity (fever every third day).
• He prepared high quality micrographs and described the asexual replication of the parasite within the RBC.
• He observed that fever coincided with the rupture and release of merozoites into the blood stream.
• 1948 - Site of Exoerythrocytic development in Liver by Shortt and Garnham

• Major Developments in 20th Century
• 1955
• WHO
• Malaria eradication programme using DDT
• 1970
• Resistance to DDT
• Programme fails
• 1976
• Trager & Jensen
• Invitro-cultivation of the parasite

NOBLE LAURETES
• ROSS
• Oocyst of Plasmodium in gut-wall of mosquito
• 1897-Aug-20
• 1902
• LAVERAN
• Noticed parasite in the blood of a patient
• 1880-Nov-6
• 1907
• PAUL MULLER
• High efficient of DDT as a contact poison against several arthropods
• GOLGI
• Asexual reproduction of Plasmodium in RBC
•
Why is it important…..?????
Malaria remains the world's most devastating human parasitic infection.
Malaria affects over 40% of the world's population.

WHO, estimates that there are 350 - 500 million cases of malaria worldwide, of which 270 - 400 million are falciparum malaria, the most severe form of the disease.

MALARIA Kills more people than AIDS
Malaria kills in one year what AIDS kills in 15 years.
For every death due to HIV/AIDS there are about 50 deaths due to malaria.
To add to the problem is the increasing drug resistance to the established drug.

TRANSMISSION
• Mosquito Bite (Female Anopheles)
• Blood
– Maximum with fresh blood up to 5 days.
– No infection - stored blood > 5 days.
– No infection - Plasma Transfusion
– Syringes
– Drug Addict / Iatrogenic.
– Congenital Malaria
– Mother to Child ( Rare ) ( AIDS )
–
• Mosquito serves as a vector of human malaria because……
• Susceptible to infection by malarial parasite.
Repeatedly bite humans rather than animals for their blood-meal.
Present in adequate number near human habitats.

Live long enough for the development into sporozoits in the midgut

FACT FILES
• Affects >2400 million people, over 40% of the world's population, in more than 100 countries
• About 1.5 million to 3 million people die of malaria every year (85% of these occur in Africa)
• One child dies of malaria somewhere in Africa every 20 sec., and one malarial death every 12 sec somewhere in the world
• Estimated annual expenditure on malaria research, prevention and treatment: $ 84 million.
• Eradicated in Europe, USA, Korea, japan, Most of N&S America
• In India, Orissa constitutes 25% of cases

CLASSIFICATION

TAXONOMIC CLASSIFICATION
Kingdom = protista
Subkingdom = protozoa
Phylum = apicomplexa
Class = hematozoea
Order = hemosporida
Family = plasmodiidae
(Genus = plasmodium (subgenera-lavarania & plasmodium
Species = falciparum , malariae , ovale , vivax

There are 165 known species of Plasmodium- may infect reptiles, birds and mammals
Of these, 4 were known to infect humans.
A new species- Plasmodium knowlesi- causes malaria in macaques but can also infect humans.

• 72species of anopheles mosquito (♀) cause malaria
90%of cases are
Plasmodium
Falciparum
• 95%
malarial
Death
======
• Plasmodium
vivax
====
• Plasmodium
Ovale
====
• Plasmodium
Malariae
========
Plasmodium falciparum:-Welch
falx=cresent/sickle + parere=to bring forth.
Malignant tertian or Estivo-autumnal or falciparum malaria
Plasmodium vivax:-Grassi&Feletti,1890
vivax or tertian malaria.
Occurrence of true relapses in characteristic.
Described by Laveran- but not as a distinct species in 1880
Golgi described it as a distinct species.
Plasmodium malariae:-Laveran,1881
malariae malaria or quartan malaria.
Natural parasite of chimpanzee
synonym= Pl.rodhaini
Plasmodium ovale:-Stephans,1922
relatively restricted distribution.
Ovale malaria


The morphological characteristics and features of the life cycle acts a major criteria in GARNHAM’S CLASSIFICATION.
These include:
 Shape of the tropozoite
 Gametocyte
 Oocyst
 Number of nuclei in erythrocytic & exo-erythrocytic schizonts
 Aspect and distribution of pigment
 Nature of damage induced in host cell
General characteristics:
 Alternation of generation accompanied by alternation of hosts.
 Schizogony(asexual) takes place in humans
 Sporogony(sexual) takes place in mosquito
 Typically, pigment is produced during the developing stages parasite in RBC

M O R P H O L O G Y
PARASITE FORMS
Blood forms: merozoites, rings, trophozoite, schizonts
Mosquito forms: gametocytes, Oocyst, ookinete, sporozoite

There is a Plant inside Malaria !
(secondary endosymbiosis)
Plasmodium- contains a broken down old chloroplast (an Apicoplast) that doesn't do any photosynthesizing.
The Apicoplast is however, needed for the parasite to invade new cells.
Even more fascinating- common herbicides that are generally pretty non-toxic to humans seem to stop the Apicoplast from working.

Plasmodium blood forms:
the ring stage
1st 14-16 hours spent as ring stage, or young trophozoite
little to no Hb degradation
only form seen in blood films of P. falciparum
THE TROPHOZOITE
• It is the form found inside the erythrocyte after 10-18 hours post-infection
• It interact with the host cell in a very sophisticated way:
• 1) it takes up the red blood cell hemoglobin and digests it inside a food vacuole. Many of the drugs in use target this compartment;
• 2) it transports proteins from the parasite to the surface of the erythrocyte for its own benefit.

THE SCHIZONT
• Schizogony: form of asexual reproduction in which multiple mitoses take place, followed by cytokinesis resulting in multiple daughter cells
• multiple mitoses produce 20-24 nuclei
• once nuclei & organelles replicated cytokinesis occurs
• rupture of RBC membrane releases merozoites

P.Falciparum
Why is it important……????
• Sticky knobs - obstruction to blood flow
• Rosettes - clogs microcirculation
• Secondary organ dysfunction
• Pregnancy - adhere to placenta, so maternal anemia & low birth weight
Character
Relative age of infected RBC
Appearance of infected RBC
Stippling infected RBC

P.falciparum
May infect cells of all ages
Normal size, no distortion
Maurer’s dots

P.vivax
Only those are young &immature
Enlarged, distorted
Schuffner
dots

P.ovale
Only those are young &immature
Oval enlarged, distorted with ragged cell walls
James’s dots

P.malariae
Only mature cells
Normal size, no distortion
Ziemann’s dots
====
Circle configuration/ head-phone configuration
Scanty cytoplasm&small vacuole
Multiple rings common
Accole forms are seen Delicate cytoplasmic ring measuring 1/3 RBC
Single chromatin dot
Ring surrounds a vacuole Similar to P.vivax
Ring larger than P.vivax
Often thick&amoeboid Smaller than P.vivax
Occupies 1/6th RBC
Heavy chromatin dot
Pigment forms early
RING FORM OF P.Falciparum --
RING FORM OF P.VIVAx
ring form of P.ovale

The ring form of P. Malariae is :
Smaller than P.vivax
Occupies 1/6th RBC
Heavy chromatin dot
Pigment forms early

Heavy rings common with fine pigment granules
Mature forms seen only in severe infections Irregular, amoeboid
Ring remnants common
Brown pigment Ring appearance usually maintained until late In development
Amoeboid tendencies not as evident as P.vivax Non-amoeboid solid cytoplasm
Coarse dark brown pigment that masks chromatin
No vacuoles in mature forms
Trophozoite form of P.F trophozoite of P.V
trophozoite of P.O

Trophozoite form of P.Malariae is :
Non-amoeboid solid cytoplasm
Coarse dark brown pigment that masks chromatin
No vacuoles in mature forms

Maurer's clefts can be seen in P. falciparum infections containing older ring-form trophozoites and asexual stages.
Maurer's clefts resemble the Schüffner's dots seen in P. vivax and P. ovale, but are usually larger and more coarse.
Visualization of these structures is dependent on the quality of the smear preparation and the pH of the Giemsa stain.
Like Schüffner's dots, Maurer's clefts appear to play a role in the metabolic pathways of the infected RBCs.

===================================================================
P.falciparum Immature scizont :
Multiple chromatin bodies surrounded by cytoplasm
Only detected in severe infection
P. F mature scizont :
8-36 merozoites.
in clusters
Only in severe infections

P.VIVAX immature scizont :
Mature chromatin bodies
Brown pigment
P.V mature scizont :
12-24 merozoits
Surrounded by cytoplasmic material

=============================

P.OVALE immature scizont :
Progressive dividing chromatin surrounded by cytoplasmic material
P.OVALE mature scizont :
Parasites occupy ¾ RBC
8-12 merozoites
Rosettes of an average of 8merozoites
==================

P.Malariae immature scizont :
Similar to P.vivax, only smaller and may contain large dark peripheral granules
P.maariae mature scizont :
6-12 merozoites in rosettes
Central arrangement of brown green pigment

==============================================

Micro Gametocyte of P.F :
Sausage/cresent shaped
Dispersed central chromatin with nearly black pigment visible
The macro gametocyte of P.F
Sausage/cresent shaped
Compact chromatin
Black pigment visible
========================================

Micro Gametocyte P.vivax :
Large pink to purple chromatin mass surrounded by colorless to pale halo.
Brown pigment present

Macro Gametocyte P.vivax :
Round to oval cytoplasm
Eccentric chromatin mass
Light brown pigment
====================================
Microgametocyte P.ovale :
Similar to P.vivax, smaller in size

Macrogametocyte P.ovale :
Similar to P.vivax, smaller in size
=================================
The micro & macro gametocytes in P. malariae are both similar to VIVAX but smaller in size