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Richard Porter
Richard Porter, Executive director,
Sight Savers International and Task Force member of Vision 2020
writes about the efforts directed at the prevention and cure of
onchocerciasis.
Onchocerciasis is a blinding disease which
occurs in some 30 countries in Africa. More than 17 million people
are at risk from the disease and as many as one million are already
blind or severely visually impaired.
The fly which spreads onchocerciasis breeds
in fast flowing rivers, so that the disease mainly affects fishing
and farming communities, often those in remote rural areas.
When highly prevalent, onchocerciasis forces communities away
from the fertile river valleys as village blindness rates reach
devastating proportions. With too few able-bodied people left
to tend fields, food shortages and economic collapse force residents
to abandon homelands. Moving to hard scrabble highlands offers
some respite from further infection, but is not without its own
problems, poor soils and little water cripple farming efforts.
Ninety-nine percent of the world's river blindness cases occur
in Africa, with the remaining cases located in isolated areas
of Yemen and six Latin American countries.
The tackling of onchocerciasis is one of
the most successfully co-ordinated
programmes between international institutions, national governments,
international non-governmental organisations and a pharmaceutical
company. Two concerted programmes, the Onchocerciasis Control
Programme and the African Programme for Onchocerciasis Control
along with the commitment from Merck and Co to supply the drug,
Mectizan(r), for as long as necessary, have led to significant
progress in tackling onchocerciasis in Africa.
Commonly
called river blindness after its geographic locus and most visible
symptom, those infected with the Onchocerca vovulus parasite are
cursed with interminable itching, thickening and depigmentation
of the skin, and in an average 10 per cent of cases, permanent
blindness.
Before
international action, in some heavily infected villages in West
Africa, this figure was several times higher Blindness among adults
often ran above 30 per cent. For those infected, the adult worms
(macrofilaria), live coiled in the host for 10-14 years, spewing
forth millions of tiny worms (microfilaria). These microfilaria
move around the body, eventually invading the eye and causing
irreversible blindness. The microfilaria can mature to adult worms
only after undergoing an intermediate maturation in the blackfly
that transmits the disease.
The
first concerted effort to tackle the disease was the Onchocerciasis
Control Programme (OCP) for West Africa. OCP was founded in 1974
as an unprecedented collaboration between the international donor
community and UN agencies, including the World Bank and World
Health Organisation. The programme was created with the dual mandate
of eliminating the disease and building local capacity for surveillance
to ensure that the disease does not return. This strategy opens
oncho-freed areas to resettlement and cultivation in the near
term and promotes increased, sustainable agricultural production
in the long term. Initially operating in seven West African countries,
OCP expanded in 1986 and now involves 11 countries.
OCP
has virtually stopped transmission of onchocerciasis by spraying
environmentally safe insecticides at the breeding sites of the
black flies. Since the early 1990s, OCP has also used the drug
Mectizan" (ivermectin). These methods have reclaimed 25 million
hectares of land which had been abandoned. It is estimated that
this area is capable of producing food to feed an additional 17
million people per year, utilising existing local technologies
and cultural practices
The
remarkable success of OCP and the prevalence of onchocerciasis
in the remainder of sub-Saharan Africa led to the development
of a second programme, the African Programme for Onchocerciasis
Control (APOC), launched in 1996. APOC's objective is to rid the
remainder of Africa of onchocerciasis. The programme extends Mectizan(r)
coverage to the remaining 19 endemic African countries, using
its principal strategy of Community-Directed Treatment (CDTI).
In the 1980s a drug called Mectizan(r) was developed by Merck
and Co as a safe and effective treatment for onchocerciasis.The
drug kills the immature, worms in people but because it does not
kill the adult worms, the drug must be taken annually. The adult
worm usually lives for around 15 years so the drug has to be taken
for that period to interrupt transmission. Merck and Co have committed
themselves to supplying the drug free for 'as long as needed to
as many as need it'. The challenge, therefore, is to deliver Mectizan(r)
to everyone who needs it every year over a long period.
The
principle of CDTI is to empower the community affected by onchocerciasis
to take responsibility for the management of the annual treatment
cycle. This has enabled communities to successfully fight river
blindness in their own villages, relieving suffering, boosting
productivity, and slowing transmission across the entire region-from
Western, Central, and Eastern Africa in the North to the Democratic
Republic of Congo, Malawi, and Tanzania in the South.
The
treatment methodology has to suit their needs and fit in with
their seasonal activities, if it is to be sustained over 15 years.
Thus communities select their own Community Directed Distributors
(CDDs) who are trained in the basic facts of the disease and on
how to organise a village treatment programme. The CDDs, register
everyone living in each household, arrange to pick up the tablets
from the local health centre, and supervise the treatment. They
keep the records, retain enough tablets for absentees, and return
the unused tablets to the health centre.
After
just six years of operations, APOC has established 74 projects,
which shortly will treat 40 million people per year living spread
over 14 countries. As the program expands over the next few years,
60 million people will be treated annually in 19 countries. These
results have been achieved by all of APOC's stakeholders, working
in partnership, each focused on its specific strengths. By the
end of its operations, this partnership will have achieved significant
results, including:
* Preventing approximately 40,000 cases of blindness annually
in the 19-country area
* Alleviating unbearable itching and eliminating skin disease
* Protecting the US$556 million investment in the Onchocerciasis
Control Programme by eliminating the threat of re-invasion from
neighboring countries, notably Nigeria
* Eliminating onchocerciasis as a public health problem throughout
the entire continent of Africa, where 99 per cent of the world's
cases occur.
Sight
Savers International (SSI), the leading development organisation
in the UK dealing with the prevention of blindness, has been involved
in tackling Onchocerciasis for over 10 years, mainly through supporting
the work of distributing the drug Mectizan(r). SSI works closely
with national governments to provide training for the community
directed distributors and logistical support, such as bicycles
which can mean the difference between reaching 2 or 5 villages.
SSI is currently supporting the treatment of 7.5 million people
in 10 countries in Africa.
There
are still a further 30 million people at risk from onchocerciasis
in Africa in need of treatment, most of them living in communities
in areas of conflict, with little or no access to health services.
In order to reach these people, the NGDO Group and its partners
need to attract additional funds, and encourage other international
and local NGDOs to undertake new projects, especially those with
expertise in conflict areas. This is the challenge for the next
ten years.
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