IELTS
JOURNAL
176
Table 1: Annual distribution
of malaria infection, approximate, selected regions
Sub-
Saharan
Africa
Southeast
Asia
Indian
subcontinent
South
America
Northeast
Asia
New cases
(average per
year)
of which
children
(average per
year)
Deaths
(average per
year)
135
million
48 million
2.1 million
66 million
23 million
360 000
46 million
19 million
320 000
17 million
5.1 million
110 000
6 million
1.7 million
57 000
Incidences
of cerebral malaria, which is caused by Plasmodium falciparum, the more
dangerous of the two main malaria parasites, have been responsible
for the growing
number of fatalities in East Africa since the late 1980s. When treatment using
chloroquine, which in many cases is not even effective, is not available, victims of
cerebral malaria may survive as little as 24 hours.
In the 1950s, sub-tropical
regions in the United States, southern Europe and elsewhere
were sprayed with DDT, which eliminated the malaria parasite where used
appropriately but resulted in resistant mosquitoes where sprayed too often. In other
parts of
the world at this time, chloroquine was introduced as a means of preventing
infection, and it was thought to be effective in bringing down the number of malaria
cases until the 1970s, when chloroquine-resistant strains of the parasite began to
appear. The resistance kept getting
stronger as time went on, and in some areas, such
as Malawi and Kenya, malaria is now no longer preventable with commonly used
drugs.
Increasing urbanisation is also responsible for the renewed spread of malaria in Africa.
Because the parasite is more commonly found in rural
areas where mosquitoes can
breed in large numbers, people who are raised there have a significantly higher
immunity to it than those reared in the towns and cities. Indeed, 5% of children in the
countryside
die of malaria, and the many who survive it go on to become adults with a
high degree of natural resistance. This is not the case with people living in urban areas;
when such people go to visit relatives in the countryside, they
are at a much higher risk
of contracting malaria.
