A study group of 175 mf carriers of varying ages and mf densities, were treated for 5 or 6 days at 6 mg/kg and again after 6 mo. with a total dose of DEC between 60 and 72 mg per kg of body weight and examined regularly for microfilariae by two 20 cmm samples of blood at 1 week, 6 months, and 2 and 3 years after the beginning of therapy.
The frequency of adverse reactions to the first administration of DEC varied directly with the pretreatment mf density of the carriers and with the age group receiving treatment: carriers with initially low counts and in the younger age groups, 0 to 19 years, experienced significantly fewer reactions to DEC than those with higher counts or in the older age groups, suggesting that, whatever the nature of these reactions, they appear to be related to the intensity of the infection and to the length of exposure to mf products.
No correlation could be found between age groups or sex distributions and the percentage of carriers who remained positive 1 week after therapy or several months or years later. A significant positive correlation, however, was consistently found between pretreatment mf density and percentage of carriers found positive at various intervals after treatment, in that the highest positive rates after treatment were found among the carriers with highest initial counts, indicating that the dosage of DEC may have to be gauged to the pretreatment mf density of the individual person or to the population at risk, in order to insure optimal therapeutic results.