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| Study shows elimination of river blindness feasible
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Geneva, Switzerland (PANA) -
The first evidence that onchocerciasis (river blind
ness) elimination is feasible with ivermectin treatment
was published Tuesday in the open-access journal PLoS Neglected Tropical Disease
s, according to a statement from the World Health
Organisation (WHO).
"This evidence is an historic milestone -- it has far-reaching implications for
the fight against this disease. Prior to this study we did not know if we
would ever be able to stop treatment," said Uche Amazigo, the Director of the Af
rican Programme for Onchocerciasis Control (APOC). APOC is the
organization charged with implementing control of the disease across Africa.
The multi-country study showed that treatment with ivermectin stopped further in
fections and transmission in 3 specific areas in Africa, where the disease
has existed continuously (an endemic area).
Onchocerciasis, called river blindness because the blackfly which transmits the
disease breeds in rivers; often blinds people, as well as causing debilitating
skin disease. Over 37 million people are infected, often living in poor, rural A
frican communities.
Ivermectin kills the larvae but not the adult worms of Onchocerca volvulus, the
parasite that causes the disease, so annual or biannual treatments are required
t
o
prevent resurgence.
Merck & Co., Inc., the company that discovered and manufactures the drug, agreed
in 1987 to donate the drug free of charge to countries where onchocerciasis is
e
ndemic.
This has resulted in annual treatments to all eligible community members – over
60 million people were treated in 26 African countries in 2008.
But although this large scale treatment has enabled the control of onchocerciasi
s in Africa, it has not been clear whether it could also be used to eliminate in
f
ection and
transmission to the extent that treatment with ivermectin could be safely stoppe
d. Many scientists have doubted whether onchocerciasis elimination with ivermec
t
in is feasible
in Africa, where more than 99% of cases are found.
This new study in three areas in Mali and Senegal, where onchocerciasis was ende
mic, has now provided the first evidence of the feasibility of onchocerciasis el
i
mination
with ivermectin in some endemic areas in Africa.
Previously it was thought that elimination of onchocerciasis was only possible i
n the limited, isolated areas in the Americas where the disease is endemic. Howe
v
er,
the studies showed that after 15 to 17 years of six monthly or annual treatments
, only a few infections remained in the human population.
Transmission levels were below predicted thresholds for elimination, so treatmen
t was subsequently stopped in test areas and follow-up evaluations after 1.5 to
2
years
showed that no further infections or transmission occurred.
Although further studies are needed to determine to what extent these findings c
an be extrapolated to other areas in Africa, the principle of onchocerciasis eli
m
ination with
ivermectin treatment has been established.
Dr Robert Ridley, Director of TDR, the Special Programme for Research and Traini
ng in Tropical Diseases (that coordinated the study), said, "This is an excellen
t
example of
how research like this can not only provide important answers to major health qu
estions, but with this type of partnership, can also help develop research capac
i
ty in low income countries."
As a result of the study, the board of APOC has already adopted a new objective
for the programme to determine where and when treatment can be safely stopped in
the 16 African countries where APOC is supporting mass ivermectin treatment prog
rams.
The studies were undertaken by research teams from the ministries of health of M
ali and Senegal, in collaboration with the WHO Multi-Disease Surveillance Centre
in Burkina Faso.
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| Geneva - 21/07/2009 |
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