MALARIA

MALARIA

Agent: Plasmodium sp.

P. falciparum

P. vivax

P. ovale

P. malariae

Vector: Anopheline

Reservoir: Man

MALARIA

Mode of Transmission:

Mosquito

Man Man

Mosquito

1-3 yrs : P. vivax

1 yr : P. falciparum

Incubation period:-

P. vivax: 14 days

P. falciparum: 12 days

MALARIA

Factors Influencing Transmission:

Host factors

Parasite factors

The vector

The environment

MALARIA

Host factors:

-Age and sex

- Immunity

- Pregnancy

- Genetic factor

MALARIA

Parasite factors:

-Species

- Strain

- Stage

- Antigenic diversity

- Resistance to Chemotherapeutics

MALARIA

The vector:

-Distribution & Density

- Resting area

- Blood meal preference

- Frequency of meals

- Duration of sporogony

- Longivity (survival)

- Flight range

- Resistance to insecticide

MALARIA

The environment:

- Temperature

- Humidity

- Rainfall

MALARIA

Importance:

• 3.2 Billions

(> 100 countries)

> ½ W. pop.

•500 millions infection /year.

•200 millions disease /year.

MALARIA

Importance:

•Major killer in the tropics

Mainly P. falicparum

Children with other problems

Untreated P. falicparum < 25%

MALARIA

Endemicity: (Spleen rate)

Hypoendemic 0-10%

Mesoendemic 11-50%

Hyperendemic 51-75%

Holoendemic >75%

MALARIA

Hypoendemic 0-10% Unstable

Mesoendemic 11-50% Malaria

Hyperendemic 51-75% Stable

Holoendemic >75% Malaria

MALARIA

Immunity:

Unstable malaria:

All population groups.

Stable malaria:

Newborn (immune mothers):

3-6/12 (IgG).

Clinical malaria throughout childhood:

Intermittent absence of parasitaemia.

Lower parasite density.

Premunition.

Splenomegally.

MALARIAImmunity:

Stable malaria:

Adolescents and adults:

Parasitaemia: sometimes

Clinical symptoms: occasional

Pregnant: especially primigravidae

Use of prophylaxis:

Delays the process of immunity

Serious disease on re-exposure

MALARIA

Control (and Prevention):

Vector Reduction

Vector-host contact reduction

Parasite reduction

Research

MALARIA

Control (and Prevention):

Vector Reduction:

Breeding sites

Destruction of larvae

Adult anophelines

MALARIA

Control (and Prevention):

Vector-host contact reduction:

Well screened areas.

Mosquito nets (ITN).

Cover most of the body.

Use repellent on exposed skin.

Insecticide spray.

Antisporozoite vaccine?

MALARIAControl (and Prevention):

Parasite reduction:

Chemotherapy

Chemoprophylaxis

Antimerozoite vaccine?

Antigamitocyte vaccine?

Research

MALARIA

The problem is increasing

(resurgence):

Vector:

Breeding site

Cost and resistance

Changing habits

Parasite:

Resistance and Cost

MALARIA

(resurgence)

Population:

Movement.

In-cooperation.

Neighboring countries

Inadequate Control:

Political and economic.

Technical.

MALARIA

RBM

- ITN

- Treatment

- Anemia

- IPT