From the Director's Office . . . .
The Edna McConnell Clark Foundation
250 Park Avenue, New York, NY 10177-0026
Tel: (212) 986-7050 Fax: (212) 986-4558
Efforts in Onchocerciasis Outside the EMCF Program
by Jeff Mecaskey and Brian Duke
The Foundation's support of research to develop a vaccine against onchocerciasis
is complementary to a range of other activities related to controlling disease
and blindness resulting from infection by Onchocerca volvulus. The
following summaries outline four major initiatives that are complementary
to the Foundation's development.
The Onchocerciasis Control Program (OCP) was launched in 1973 by 19 international
donors (with an annual budget of $25 million) to control the blinding disease
in West Africa and thereby allow farmers and their families to reclaim valuable
land. Initially based on control of the black fly vector by spraying insecticides
into the rivers and streams with aircraft, this program is now using ivermectin
in its control activities. Of 35 million people at risk of infection with
O. volvulus in Africa, approximately one third living in 11 countries
of West Africa are now, or will be, protected by the OCP. This leaves two-thirds
of those at risk unprotected, except by national programs that have begun
using ivermectin as treatment. The OCP is now expected to end in 1997.
Successful devolution of the program includes the need for the 11 countries
to continue the ivermectin treatments in order to maintain control until
all adult worms infecting humans have died and, therefore, transmission
cannot occur.
The Mectizan (ivermectin) distribution program began in 1987 when Merck
& Company agreed to donate the drug free-of-charge to countries instituting
oncho control programs. Managed by the Carter Center in Atlanta, the Mectizan
Expert Committee reviews proposals and approves dispensing of the drug for
national control efforts. It should be noted that although drug resistance
occurs more slowly in helminths because their replication periods are much
longer than those of bacteria, it can occur. The emergence of drug resistance
to malaria points to the value of continued basic research on parasitic
biology. Additionally, ivermectin may have to be administered annually
for 7 to 15 years (the life span of the adult worm); so far, while seven
million people will have received one treatment by the end of 1992, only
four million are likely to be under continuous treatment programs.
The MACROFIL project is an effort to discover and develop a drug that will
kill the adult onchocerca worms; it is jointly sponsored by the OCP and
the UNDP/WB/WHO Special Programme for Training in Tropical Disease Research
in Geneva. The OCP has recognized that, while ivermectin can relieve symptoms
and halt blinding sequelae, control would be more efficient if a macrofilaricidal
drug will be used. One drug, amocarzine (CibaGeigy Company), has received
human trials. Given over three days, it kills adult worms, but side effects
suggest that it will be difficult to use. Several other compounds are being
tested in animals.
The River Blindness Foundation (RBF) was established in March, 1990 as
a Private Voluntary Organization based in Texas, U.S.A. Founded and funded
by John and Becky Moores, its object is to distribute Mectizan to persons
in the Third World who are suffering from onchocerciasis and/or at risk
of River Blindness.
The RBF has its own distribution projects in North Cameroon, in five states
in Nigeria, and in Uganda. It is also funding distribution projects which
are being executed by other non-governmental organizations such as Africare,
Christoffel Blinden Mission and the International Eye Foundation, or by
others in South Cameroon, Central African Republic, Chad, Congo, Ecuador,
Guatemala, Malawi, Nigeria, Sudan and Tanzania.
The Chairman of the RBF is John J. Moores; William R. Baldwin is the President;
and its headquarters are at: One Sugar Creek Place, 14141 South-West Freeway,
Sugarland, Texas, 77478, U.S.A.