16-18. Malaria

Question 1

How does malaria rank in terms of causes of mortality throughout the world?

Answer 1

Number 8 globally.

8-10 million deaths/year

Death rate can be as high as 30% live births
*kids < 5yo. are primary burden of infectious diseases

Most deaths are in Africa, 90% of the burden of disease & death is in subsaharan Africa
(but it is still the #1 problem in Myanmar & Papua New Guinea)

Question 2

How does malaria get transmitted?

Answer 2

Via mosquito vectors.

Mosquito bites, injecting saliva to stop blood clotting and also injects parasite at the same time.

Parasite enters bloodstream and heads to liver to undergo hundreds of nuclear divisions. A single infected liver cell can create thousands of new parasites.

The next generation of parasites are modified to infect RBCs. Inside RBC, parasite hides from host immune system, and causes cell to become sticky, gripping to vessel walls (avoiding detection & removal in spleen). Once mature, infected cells burst and spreads more parasites.

Question 3

What are symptoms of malaria?

Answer 3

Blood loss
Convulsions
Fever
Brain damage
Coma
can lead to death

Question 4

Who is most affected by malarial infections?

Answer 4

10% of people on Earth will be struck down
Most people who die from the disease are pregnant women & children under 5 yo.

Est. 300-500 mill. cases/yr (110 mill. reported)

Question 5

When was malaria & its transmission discovered?

Answer 5

1880 discovery in blood

1897 discovery of transmission by mosquitoes

Question 6

Taxonomic classification of malaria

Answer 6

Phylum: Apicomplexa (single cell, has apical end)
Genus: Plasmodium

4 species infect humans:

• P. falciparum (responsible for most death)
• P. vivax (responsible for most morbidity w/o death)
• P. ovale
• P. malariae
• P. knowlesi (primate to human, not yet human to human)

Many other species infect animals

Question 7

How many forms does the parasite exist in?

Answer 7

3 forms:

• mosquito
• liver
• blood

*changes morphologically

Question 8

What other effects does malaria have socially & economically?

Answer 8

• est $12 billion direct costs (less now, approx $650 mill)
• 10% yearly household spending in Africa
• work & school absenteeism

Question 9

Where does the malarial life cycle begin?

Answer 9

anopheles mosquito