Republic of Guinea 

These five stamps feature the campaign against river blindness. The first stamp shows slit-lamp examination in a sufferer, the second stamp a laboratory worker conducting experiment on the filaria, the third stamp eradication of river blindness vectors ie. the blackfly  through the use of insecticide, the fourth stamp looking for the filaria in the biopsy tissue and finally surgeon removing subcutaneous nodules from sufferers to reduce the parasitic load.