|Onchoceriasis is a common cause of blindness
in parts of West Africa.
This FDC was issued in 1971 by the Rebulique de Haute-Volta (now Burkina Faso)
to highlight this endemic disease. The stamp and the cover show a black fly (members
of the family Simuliidae) which acts as a vector for O. volvulus the parasite responsible
for onchoceriasis; two health workers spraying DDT along river to eradicate the black
fly larvae and adults; and three women blinded by onchoceriasis being led by a sighted