Malaria is a protozoan disease transmitted by mosquitoes that causes fever and symptoms like chills, sweats and fatigue. It is endemic in 91 countries and causes approximately 1200 deaths per day. The document outlines the epidemiology, etiology, pathogenesis, clinical manifestations and management of malaria. It discusses the life cycle and species of Plasmodium that cause malaria in humans. Malaria predominantly affects sub-Saharan Africa and young children/pregnant women are most vulnerable. Treatment involves monitoring parameters like parasitemia, hematocrit, blood glucose and renal function.

1. Malaria
By Mulugeta A.(MD,INTERNIST)

2. “Humanity has but three great enemies: Fever, famine, and
war; of these by far the greatest, by far the most terrible, is
fever.”
—William Osler, 1896

3. • learning objectives
• understand the burden of the disease
• know the pathogenesis and clinical featuers
• able to identify the severity featuers
• able to approach a febrile patient

4. • Outlines
• Introduction
• Epidimplogy
• Etiology
• Pathogenesis and life cycle
• Clinical manifsations and lab findings
• DDx
• Overview on management
• Prevention

5. Introduction
• Malaria
• is a protozoan disease transmitted by the bite of infected female Anopheles
mosquitoes.
• characterized by paroxysms of fever, chills, sweats, fatigue, anemia, and
splenomegaly
• The most important of the parasitic diseases of humans
• preventable and treatable
• malaria is transmitted in 91 countries containing 3 billion people and causes
~1200 deaths each day.
• Mortality rates have decreased dramatically over the past 15 yrs

6. cont..
• Malaria was eliminated from the United States, Canada, Europe, and
Russia >50 years ago
• but ts prevalence rose in many parts of the tropics
• An increasing number of countries are now targeting malaria
elimination
• threatened by increasing resistance to antimalarial drugs and insecticides
• remains a heavy burden on tropical communities, a threat to
nonendemic countries, and a danger to travelers

8. Epidemology
• approximately 90% of the world’s malaria cases occur in Africa.
• P. falciparum predominates in Africa, New Guinea, and Hispaniola
(i.e., the Dominican Republic and Haiti)
• P. vivax is more common in Central and South America.
• P. malariae is found in most endemic areas,especially throughout sub-
Saharan Africa
• P. ovale is relatively unusual outside of Africa
• Young children and pregnant women are particularly vulnerable to
malaria infection and death.

9. epid...
• Endemicity traditionally has been defined in terms of rates of
microscopy-detected parasitemia or palpable spleens in children 2–9
years of age and has been classified as
• hypoendemic (<10%),
• mesoendemic (11–50%),
• hyperendemic(51–75%), and
• holoendemic (>75%).

11. Etiology and Pathogenesis
• Six species of the genus Plasmodium cause nearly all malarial
infections in humans.
• P. falciparum,
• P. vivax
• P. ovale (curtisi and wallikeri)
• P. malariae
• P. knowlesi (the monkey malaria parasite)
• almost all deaths are caused by falciparum malaria.

12. • Human infection begins when a female anopheline mosquito
inoculates plasmodial sporozoites from its salivary glands during a
blood meal
• carried rapidly via the bloodstream to the liver
• invade hepatic parenchymal cells and begin a period of asexual
reproduction.
• amplification process (known as intrahepatic or preerythrocytic
schizogony)

13. • a single sporozoite may produce from 10,000 to >30,000 daughter
merozoites
• The swollen infected liver cells eventually burst,discharging motile
merozoites into the bloodstream
• merozoites then invade red blood cells (RBCs) to become trophozoites
and multiply six- to twentyfold every 48 h
• In P. vivax and P. ovale infections, a proportion of the intrahepatic
forms do not divide immediately but remain inert for a period ranging
from 2 weeks to ≥1 year.

14. • Attachment of merozoites to erythrocytes is mediated
• several specific erythrocyte surface receptors.
• erythrocyte binding antigen 175 and glycophorin A.
• merozoite reticulocyte-binding protein homologue 5 (PfRh5) plays a critical
role binding to red cell basigin (CD147, EMMPRIN).
• The Duffy blood-group antigen Fya or Fyb plays an important role in invasion.
• Most West Africans and peoplewith origins in that region carry the Duffy-negative FyFy
phenotype
• P. knowlesi also invades Duffy-positive human RBCs preferentially.

15. • Multiple nuclear divisions have taken place (schizogony or merogony)
• The infected RBC then ruptures to release 6–30 daughter merozoites
• disease in human beings is caused by the direct effects of the asexual
parasite—RBC invasion and destruction—and by the host’s reaction.
• Some of the blood-stage parasites develop into morphologically
distinct, longer-lived sexual forms (gametocytes) that can transmit
malaria.

16. • After being ingested in the blood meal of a biting female anopheline
mosquito, the male and female gametocytes fuse to form a zygote in
the insect’s midgut.
This zygote matures into an ookinete, which penetrates and encysts in
the mosquito’s gut wall

19. Contd.
• Monitoring:
• Parasitemia +Hct every 6-12 hrs
• Exchange transfusion
• parasite density>10%
• patient has altered mental status
• non–volume overload pulmonary edema
• If Hct <20% transfussion
• Blood glucose every 4-6 hours
• RFT daily
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