The efficacy, tolerability and safety of diethylcarbamazine-fortified salt in the treatment of the microfilaraemias of brugian filariasis: an open, hospital-based study.

Cooking salt fortified with diethylcarbamazine (DEC) has been successfully used to control lymphatic filariasis in several parts of the world. The kinetics and efficacy of DEC-fortified salt in clearing microfilaraemias of Brugia malayi and the salt's tolerability and safety are examined in this study. Twenty individuals with B. malayi microfilaraemias (pre-treatment levels of 108-6358 microfilariae/ml; median = 309/ml) consumed DEC-fortified salt (0.2%, w/w) with their food for 1 year, initially in hospital (for 1 week) and later at home. The mean daily intake of DEC was 21.4 mg (range = 9.0-39.4 mg). Even on the first day of consuming the salt, there was a decrease in the microfilarial levels of 14 patients and a sharp increase in six patients. Microfilarial levels tended to fluctuate thereafter but there was a progressive, general decline. At the end of the study year, eight patients were amicrofilaraemic and microfilarial clearance was > 95% in 58% of the patients. Eight patients did not develop any adverse reactions. Lymph-node tenderness and enlargement were seen in eight patients (40%), and dilated, inflamed lymphatic channels standing out as cords ('string sign') were seen in another five patients. These reactions were transient and did not require any specific treatment. The DEC-fortified salt was well accepted by the study population. The DEC content of fortified salt and the duration of its use for the control of brugian filariasis need to be re-examined. Health education should include messages that mild, self-limiting, adverse reactions are likely to occur even with the use of such salt.