The never-ending itch

-- (Credit: Vishwajyoti)ONCHOCERCIASIS afflicts a person infected with filaroid worms of the genus
Onchocerca, transmitted by biting flies.
Onchoceriasis is now endemic in 17
of Uganda's 39 districts, affecting
between 1.2 and 1.5 million people
mainly in the north and west. One of the
reasons for the neglect of the strain of
onchocerciasis that does not cause
blindness is that itching is its main
symptom and itching is not treated as a
serious problem.

In a desperate attempt to assuage the
itching, people scratch themselves with
stones, twigs or knives ending up with
bleeding wounds, sores and pain.
"Sometimes patients die from secondary infections like tetanus, because
of scratching their wounds with stones
or metal," says Richard Ndyomugenyi,
national coordinator for onchocerciasis
control in Uganda. Mugisa, a peasant
farmer who lives in south-western
Uganda, says the condition has forced
him to stop working on his farm.

People suffering from the skin
disease are also socially stigmatised
because of the physical defects that go
with it. They are thought of as being
dangerous and dirty and are avoided for
fear that they might transmit their
disease to others.

The itching is caused by parasitic
worms that develop into mature
microfilariae. These minute organisms
multiply by the million and spread
throughout the body. "These foreign
bodies in one's skin cause extensive
damage due to itching," explains
Albert Guma of the Uganda River
Blindness Foundation. The parasites are
transmitted by female blackflies which
breed in fast-flowing rivers and infect
people living within a 15 kin radius;
wind-assisted female blackflies can fly
upto 25 kms.

In the '60s and '70s, blackfly control
took on great importance and serial
spraying of rivers to kill the larvae were
common. This programme method has
proved successful in certain places like
west Africa and a section of the river
Nile in east-central Uganda. But it has
failed in areas where river courses are
heavily forested and breeding sites inaccessible. Farmer Mugisa's home district, where the river Munyanga runs through
the impenetrable Bwindi forest, is one
such area.

In other parts of the
country, brakes were
applied on the carrier
control programme due
to years of political strife
and the fly managed to
reclaim areas where it had
earlier been eliminated.
Moreover, drugs such as
suramin produced such
severe side-effects that
they were discontinued.
The procurement of the
drug ivermectin in 1987,
represented a significant
advance for mass treatment in endemic areas.
Michel Pawue, heading
the Sight Savers Ivermectin programme, says
the tablets are "Safer than
aspirin". Each tablet costs
US $3 and treatment
requires tip to two tablets
a year for up to 15 years as
the drug kills only young
worms, and adult worms
have a 15-year lifespan.
The World Health Organization hopes that by
1997 it will have identified
a new drug - a 'macrofilaricide'- which could
cure the disease in a single
dose.