• Name means “bad air”-• A life-threatening parasitic disease • 40% of the world’s population is at risk• 90% of the deaths due to Malaria occur in Sub-

Sahara Africa, mostly among young children.• 5 million of people are affected every

year . • At least 1.5 million deaths annually.• It is one of the major public health concerns

How is malaria transmitted?

• Malaria parasites are transmitted from one person to another by the bite of a female anopheles mosquito.

• The female mosquito bites during dusk and dawn and needs a blood meal to feed her eggs.

• Male mosquitoes do not transmit malaria as they feed on plant juices and not blood.

• There are about 380 species of anopheles mosquito but only about 60 are able to transmit malaria.

Female Anopheline

mosquito bite

Mother to child

Blood transfusion

Transmission

What is malaria ?

One of the red blood cell & a vector – borne infectious disease Malaria is a disease caused by the protozoan parasites of the genus Plasmodium. The 4 species that commonly infect man are:

SpeciesMajor features

P. falciparum

The most important species as it is responsible for 50% of all malaria cases worldwide and nearly all morbidity and mortality from severe malaria Found in the tropics & sub-tropics

P. vivax The malaria parasite with the widest geographical distribution Seen in tropical and sub-tropical areas but rare in Africa Estimated to cause 43% of all malaria cases in the world

P. ovale This species is relatively rarely encountered Primarily seen in tropical Africa, especially, the west coast, but has been reported in South America and Asia

P. malariae Responsible for only 7% of malaria cases Occurs mainly in sub-tropical climates

Species Infecting HumansPlasmodium falciparum

– Malignant tertian M. (Cerebral Ma. Or renal failure) (48hr.)

Plasmodium vivax (48hr.)

– Benign tertian M. relapsing M. Plasmodium ovale

- Ovale tertian M. relapsing M. (48hr.) Plasmodium malariae

– Quartan M. (72 hr.) remain for one decade , no dominant(relapsing) stage (7%)

Common & Severe

Rare & Mild

The HostsHuman: _ intermediate host._ victim._ asexual cycle (schizogony cycle).

Female Anopheles mosquitos :_ final hosts._ vector._ sexual cycle (sporogony cycle).

PlasmodiumInfected mosquito bites human; sporozoites migrate through bloodstream to liver of human

Sporozoites undergo schizogony in liver cell; merozoites are produced 2000-40,000 Mer.(6-16)days.

Merozoites released into bloodsteam from liver may infect new red blood cells

Merozoites are released when red blood cell ruptures; some merozoites infect new red blood cells, and some develop into male and female gametocytes

1 2

3

4

6

Asexual reproductionIntermediate host

Merozoite develops into ring stage in red blood cell

Ringstage

Merozoites

Another mosquito bites infected humnan and ingests gametocytes .skin

7

5 Ring stage grows and divides, producing merozoites(6-24)M.

Definitive host

In mosquito’s digestive tract, gametocytes unite to form zygote

8

Male gametocyte.gut

Female gametocyte

Zygote

Sexualreproduction

Resulting sporozoites migrate to salivary glands of mosquito

9

Sporozoites in salivary gland 10,000 sp.

Exo-erythrocytic (hepatic) cycle 6-16 days

Sporozoites

Mosquito Salivary Gland

Malaria Life Cycle

Gametocytes

Oocyst

Erythrocytic

Cycle

Zygote

Schizogony

Sporogony

Hypnozoites(for P. vivax and P. ovale)

Red Blood cell Schizont

Liver cell Schizont

Asexual cycleIntermediate host

Sexualfinal host

Plasmodium vivax &Plasmodium ovale

HYPNOZOITESIllness May Relapse 3 To 5 Years

After Original Infection

Hypnozoites(relapsing)

Hypnozoites:- Are liver-trophozoite stages-Responsible for recurrence of malarial symptoms.

Malarial Paroxysm– Days 1 and 3 for:

– Plasmodium vivax– Plasmodium ovale– and Plasmodium falciparum– Usually persistent fever or daily paroxyms for

Plasmodium falciparum.

Tertian malaria

Days 1, 3, 5, 7, 9,……….

48 hrs.

Days 1, 4, 7, 10,……….

72 hrs.

–Days 1 and 4 for Plasmodium malariaeQuartian malaria

Malarial Paroxysm

•Cold stage•Hot stage•Sweating stage

The clinical course of P.

Asymptomatic parasitaemia (“clinical immunity”)

A. Acute, uncomplicated malaria B. Severe malaria

This is usually seen in older children and adults who have acquired natural immunity to clinical disease as a consequence of living in areas with high malaria endemicity. There are malaria parasites in the peripheral blood but no symptoms. These individuals may be important reservoirs for disease transmission.

Some individuals may even develop anti-parasite immunity so that they do not develop parasitaemia following infection.

A. Asymptomatic parasitaemia

B. Simple, uncomplicated malaria

Children with malaria waiting to be seen at a malaria clinic in the south western part of Nigeria. Identifying children with severe malaria, and giving them prompt treatment, is a major challenge when large numbers attend clinics.

This can occur at any age but it is more likely to be seen in individuals with some degree of immunity to malaria. The affected person, though ill, does not manifest life-threatening disease.

Fever is the most constant symptom of malaria. It may occur in paroxysms fever, chills and rigors (uncontrollable shivering).

Other features of simple, uncomplicated malaria include:

o Vomiting, Diarrhoea,Convulsions, Jaundice o Malaria is a multisystem disease. Other common clinical

features are:

o Anorexia, Cough, Headache, Malaise, Muscle aches, Splenomegaly, hepatomegaly

These clinical features occur in “mild” malaria. However, the infection requires urgent diagnosis and management to prevent progression to severe disease.

C. Severe and complicated malaria

1. Cerebral malaria

2. Severe malaria anaemia

3. Hypoglycaemia

4. Metabolic acidosis

5. Acute renal failure 6. Pulmonary oedema7. Circulatory collapse, shock or

“algid malaria”8. Blackwater fever

Nearly all severe disease and the estimated >1 million deaths from malaria are due to P. falciparum. Although severe malaria is both preventable and treatable, it is frequently a fatal disease.

The following are 8 important severe manifestations of malaria:

Note: It is common for an individual patient to have more than one severe manifestation of malaria!

Malaria Diagnosis• Clinical Diagnosis• Malaria Blood Smear• Serology (ELISA)(IFAT) .• Polymerase Chain Reaction

Blood Smear Prepare smears as soon as possible after collecting venous blood to avoid any Changes in parasite morphology.

the “gold standard”“gold standard” for diagnosis of malaria..

• Hyperendemic areas.

• Fever ,sweat, chills, headache & muscle pain

B.F.F.M.=Blood Film For Malaria

Plasmodium falciparum

Rings: double chromatin dotsmultiple infections in same red cell

Gametocytes: mature (2)andimmature (1) forms (1is rarelyseen in peripheral blood)

Trophozoites: compact*(rarely seen in

peripheral blood)

Schizonts: 8-24 merozoites*(rarely seen in peripheral blood)

Infected erythrocytes: ***normal size (Maurer’s dots)

2 1

1

2 3

4

Plasmodium vivax

Trophozoites: ameboid; deforms the

erythrocyte Gametocytes: roundSchizonts: 12-24 merozoites

Rings one chromatin dots

Infected erythrocytes: enlarged up to 2X **deformed; (Schüffner’s dots)

21

34

Plasmodium ovaleInfected erythrocytes: enlarged (1 1/4 X); **fimbriated; oval; (Schüffner’s dots)

RingsTrophozoites: compact

Schizonts: 6-14 merozoites; dark pigment; (“rosettes”)

Gametocytes: round-oval

1

34

2

Infected erythrocytes: **normal size

Plasmodium malariae

Ring: compact Trophozoite:typical band form

Schizont:6-12 merozoites;coarse, dark pigment

Gametocyte:round; coarse,dark pigment

4

1

2 3

Prevention• Using insecticide to kill a larval stage of

mesquite.• Recovering all ponds and water source

with oil.• Using a mesquite net.• Using prophylaxis when travel to area with

malaria are endemic.• Breeding a special type of fish which

feeding on larval stage of Anopheles.