and thiabendazole, have been conducted. Recently, clinical trials assessing the effectiveness of doxycycline to treat M. perstans infection have also been documented. Generally, DEC is ineffective in the treatment of M. perstans infection. Other drugs such as ivermectin and praziquantel have been tried, but are neither reliable nor rapidly effective. Mebendazole and thiabendazole have a greater effect than previously described drugs, but are not sufficient for treatment alone. Combination treatments with DEC and mebendazole have had the most success. In the most recent clinical trials, doxycycline has had success comparable to, if not better than, that of combination treatments. However, because it is a relatively recent discovery, the use of doxycycline is relatively limited to clinical trials. If the patient is asymptomatic, no treatment is necessary. An analysis of the results of various clinical trials for each drug is illustrated below: Diethylcarbamazine While diethylcarbamazine (DEC) is the most common drug used to treat M. perstans infection, it is often ineffective, especially with the administration of only a single dose. In a 2005 study of 160 patients with symptomatic M. perstans infection in south Chad, DEC was administered in 200 mg. doses, twice daily for 21 days with a gradual dosage increase in the first three days. The single course of DEC lowered microfilarae in 80% of subjects, but did not eliminate the infection or related symptoms. A second course was therefore administered, and was successful in eliminating the microfilarial burden in most cases. No persistent effect of DEC on Microfilaria was noted on long-term follow up. These results accurately represent the general efficacy of DEC in treating M. perstans: two doses are necessary to eliminate the microfilarial burden temporarily, but no persistent effect of DEC on microfilariae was shown long-term. Furthermore, symptoms are usually not entirely alleviated by DEC. It has not been reported to cause adverse side effects in patients with M. perstans infection. Ivermectin While ivermectin is considered a first-line agent for the treatment of many filarial diseases (especially onchocerciasis), it has shown little or no efficacy against M. perstans at a dose of 200 μg/kg body weight or at a dose of 600 μg/kg body weight. A 2009 study in Uganda evaluated the effects of ivermectin, albendazole, and a combined regimen of both drugs on M. perstans infected individuals: Single doses of ivermectin alone had no marked effect on M. perstans microfilaraemias in the 12 months after