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producing otfspr ing known as
mi–
crofilariae.
In areas of heavy fly concentra–
tion where the human population is
scarce, a victim can receive up to
13,000 bites in a single day! The
result is a continuous buildup of
brccding worms within the host
body. In time every square millíme–
ter of skin may be ínfes ted wíth
hundreds of larvae.
The results of constant worm in–
festation are devastating to the vic–
tim. As infection deepens. nodules
appear all over the body. Skin tis–
sue, especially on the legs, turns
white and red. In addition, the skin
tends to thicken, crack and age pre–
maturcly. Pa infuJ itching develops.
and in sorne cases becomes so in–
tense that hapless victims of the
parasite have committed suicide to
end their misery.
The final and perhaps worst result
of the parasi tic invasion is blind–
ness. This is slow to deve lop and
sometimes takes a number of yea rs.
Blindness is caused by the death of
worm embryos in the cornea of the
eye. When this occurs, a tiny
opaque spot appears which , aftcr a
period of time, may completely blot
out the entire cornea.
Th e ravaging effects of river
blindness were described by writer
John Williams: " In one half-a ban–
do ned village, we saw an o ld
woman, squatting on her haunches,
pounding millet with a wooden
pestle. She was blind: milky white–
ness, interlaced with red rivulets,
flooded the entire eye; the colored
parts were gone. In the brilliant
light we could see that she was a
very o ld woman, crouching and
shutfling, the skin horribly thick–
ened and wrinkled. In places the
pigmentation was worn away, leav–
ing splotches of raw baby pink. Our
inte rpreter discovered she was no t
ye t forty"
(Geographical Magazine,
November 1974, p. 78).
River blindness has taken a ter–
rible toll in the atrected nations, es–
pecially in Mali. Upper Yolta ,
Ghana, Togo, Benin , lvory Coas t,
and Niger. Yillage after village has
been abandoned along th e Yolta
Ri ver. Thousands have moved in–
land to more arid arcas to escape
the scourge of the blackfty. This has
drastically atfected the economic de-
20
velopment of already poor coun–
tries. Acco rding to Williams:
"Onchocerciasis is the biggest factor
retarding growth in West Africa"
(ibid. ,
p. 78). Many experts have
concurred with this judgment.
The governments of the atfected
nations are determined to defeat the
blackfty, and it is certain ly in their
best interest to do so. Slow, but en–
couraging progress is being made.
But no one expects to wipe out the
fty completely. "Contro l" is the
watchword.
Kenya's Experience
Sorne 28 years ago, DDT was used
with complete success to rid the Ko–
dera VaUey in Kenya of the black–
fty. River blindness completely
disappeared. But conditions for era–
dication were ideal : The blackfly of
Kenya was a local variety with an
extremely Limited fli ght range, and
the Kodera Yalley was isolated from
other infected arcas, making rein–
fection highly unlikely. In contrast,
the project zone of West Africa is
considerably larger, covering sorne
231.600 square miles (600,000
sq uare ki lometers), making rein–
fection much more difficult to pre–
vent. And the blackfly of the Yo lta,
unlike the Kenyan variety, has a
range of over 100 miles.
At present an Ame rica n product.
Abate, is being used with sorne suc–
cess. Abate has such low toxicity
that it can be safely added to human
water supplies to combat yellow fe–
ver. lt is harmless to fish and fresh–
water organisms, yet is lethal to
blackfly larvae. Systematic spraying
of Abate on blackfly breeding arcas
commenced in late 1974.
The final result may take up to two
decades, however. As uccessful black–
fly control program ca rried out over a
wide area must continue fo r longer
than 20 years- that is, longer than the
worm's life-span within the human
host. The reason for this is that the
blackfly picks up the parasitic worms
from those it bites and transfers them
to its next victims. l f the human
victims of the blackfly contained no
parasites, the bite of the blackfly
would be relatively ha rmless.
Drug Treatments
Humans who are hosts to the para–
si tes have been trea ted with two
drugs with sorne success. The first.
suramine, is injected intravenously.
It kills the worms, but leaves the
embryos a live. The drug can pro–
duce serious side effects and must
be administered only under strictest
medica! supervision.
A second drug. diethylcarbama–
zine, kills the embryos but has no
atfect on the worms.
It
too can have
serious side effects. Diethylcar–
bamazine is taken orally and must
be swallowed regularly, for a life–
time, if the patient remains in an
atfectcd area. lf the individual
moves from an atfected area, treat–
ments must continue up to fifteen
years, since the worms can live that
long in the host body.
Surgery to remove the worm-con–
taining cysts has been performed with
sorne success in Central America , bu t
it is of little value in Africa. Younger
worms are often " free-ftoating"
within the body and are beyond any
surgical procedure. Only the more
obvious concentrations can be re–
moved. These usually contain oldcr.
more localized worms.
Adminis tering comprehensive
drug therapy over large areas where
river blindness is endemic is a diffi–
cult problem at best. Better solutions
will have to be found. The greatest
hope appears to lie in simply elimi–
nating the blackfly from the region.
But this will take sorne two decades to
accomplish. There are no sho rt-term
solutions to the problem.
In the mea ntime, WHO is sup–
porting a research program aimed
at developing more etfective drugs
for thc trcatment of infected popu–
lations. lf current programs succeed,
and new and etfective drugs are de–
veloped, thc fly that blinds could be
defeated. This in turn would faci li–
ta te the agricultura! development of
the atfected nations. Long-aban–
doned vi llages would again be pop–
ulated and rive r-based agricultura!
activities could resume. A massive
burden would be lifted from
presently overtaxed farm areas, and.
sorne believe, the progress of the en–
croaching Sahara Desert could be
measurably slowed.
Only time will tell whether man
will win the battle against the
dreaded blackfly. Present programs
do appear to be producing positivc
results.
O
The
PLAIN TRUTH May 1978