Comparison of the effect upon onchocerciasis of five drugs and selection of the one best able to prevent ocular complications

Abstract

1. 1) Trials were carried out with five drugs to test their therapeutic action in human onchocerciasis: Cyanine, arsenamide sodium, sodium antimony tartrate, diethylcarbamazine (hetrazan) and suramin sodium (antrypol). 2. 2) None of these drugs was found to kill the adult worms. As dead adults are found in the normal course of events in untreated cases in some of the nodules, it is felt that the true criterion of cure must be the death of every adult worm in every nodule. 3. 3) Hetrazan was successful in destroying the entire microfilarial population of the skin and eye. Six months later the microfilarial population was still greatly reduced. Suramin was only partly successful in destroying the microfilariae. The other drugs had no effect on the microfilariae. 4. 4) Cyanine was used for the first time in onchocerciasis. The toxic complications experienced were headache, shivering, albuminuria and renal casts, thrombosis of the superficial brachial veins, and a fall in the haemoglobin content. 5. 5) Where the I.D.F. is under 6 it is believed that the only risk of ocular complications is when a head nodule exists. Hetrazan is the drug best able to keep the I.D.F. down to this safe level, and it is recommended that a course of 10 grammes is given twice a year where the I.D.F. is over 5. Head nodules should be excised immediately, and three courses a year given to such patients.