Ivermectin treatment of mansonellosis in Blanchisseuse, Trinidad, West Indies - abstract

ABSTRACT

The first double-blind-placebo field trial, using the drug ivermectin to control M. ozzardi microfilariae, was conducted in Blanchisseuse, North Trinidad. A preliminary trial indicated that there were no major constraints in administering the drug ivermectin within the community. In 16 patients before treatment, the microfilariae density ranged from 1 to 5,679 mf/ml, and the geometric mean was 697 mf/ml compared to 4 to 2,042 mf/ml and 362 mf/ml in the 14 patients given the placebo. Following treatment 87.5 percent (14/16) experienced side effects including fever and arthralgia (12 cases), myalgia (3 cases), headaches (11 cases) and chills (8 cases). All symptoms disappeared after 24 hours. Twenty-four hours after the ivermectin treatment the M. ozzardi microfilariae densities significantly (p < 0.001) declined to zero in 11 out of 16 cases (68.8 percent) while in 5 cases densities declined by > 95 percent. One week post-treatment there were no microfilariae observed in 93.8 percent (15/16) of cases, with one patient not attending the clinic. Blood samples collected 1 and 5 months after ivermectin treatment revealed M. ozzardi microfilariae in 3 patients. These 3 patients were re-treated with 6 mg of ivermectin, but two patients demonstrated persistent parasitaemias in subsequent blood samples. Within the placebo group, fluctuating levels of microfilariae were observed (AU)