Forty African countries showed reductions in malaria
transmission between 2000-2010, but despite this progress, more
than half (57 per cent) of the population in countries endemic for
malaria continue to live in areas of moderate to intense
transmission, with infection rates over 10 per cent. The findings
are based on a series of prevalence maps for malaria.
A team led by Dr Abdisalan Noor and Professor Robert Snow of the
KEMRI-Wellcome Trust Research Programme produced the maps by
geocoding data from surveys in 44 African countries and territories
endemic for malaria in order to identify which populations were at
risk of the disease in 2000 and 2010.
The time period coincides with the launch of the Roll Back
Malaria Partnership, which brought with it a large increase in
investment targeting malaria control, and the team aimed to
investigate the progress in reducing transmission during this
period. Their maps revealed that the number of people living in
high-risk areas, where more than 50 per cent of the population are
likely to carry infections, fell from 219 million in 2000 to 184
million in 2010, a fall of 16 per cent.
However, the maps also identified that just 10 countries harbour
87 per cent of the population remaining at high-risk of disease
transmission and intensity remained high or unchanged in eight
countries including the Democratic Republic of Congo, Uganda,
Malawi and South Sudan.
To ensure accuracy, the study used measurements for the
prevalence of malaria in populations where diagnosis had been
confirmed through laboratory techniques.
"Health information systems in many African countries are weak
and it has been difficult to reliably estimate how many people get
sick, or die, of malaria" said Dr Noor. "The population surveys we
used in this study are a more reliable indicator for tracking and
we hope our study will help countries assess their progress and
adapt their strategies for more effective malaria control."
Professor Snow said: "The results of our analysis are pause for
thought. On the one hand it's a glass half full, with several
countries showing significant reductions in malaria transmission,
and on the other it's a glass half empty, where, despite a decade
of massive investment in malaria control the populations living in
several African countries are as likely to be infected with malaria
in 2000 as they were 10 years later."
Dr Noor added: "Advanced skills in spatial statistics and
computing are enabling us to measure changes in malaria
transmission in new ways and where they are most needed. By
continuing to bring together dedicated scientists in Africa we can
have better monitoring and tailor control of malaria transmission
in the future."
Despite the reductions seen, the paper highlights the need for
global support to sustain and further accelerate a decrease in
malaria transmission.
The paper, The changing risk of plasmodium falciparum malaria infection in
Africa: 2000-10: A spatial and temporal analysis of transmission
intensity, is published in The
Lancet.