Human Loiasis in a Cameroonian Village: A Double-Blind, Placebo-Controlled, Crossover Clinical Trial of a Three-Day Albendazole Regimen

Abstract

Because of the life-threatening, post-treatment reactions that have occurred in patients with loiasis treated with ivermectin, evaluation of a short-course albendazole regimen was undertaken in a Loa-endemic region of Cameroon. In a placebo-controlled, double-blinded, crossover study, 99 subjects with microfilaremia (100-3,3837/mL) were assigned to receive albendazole (400 mg; n = 48) or placebo (n = 51) for three days and were followed for 180 days; at day 180, the groups were crossed over and followed for an additional six months. In those initially receiving albendazole (ALB/PLAC), microfilarial levels decreased significantly by day 90 (P < 0.043), but returned to baseline by day 180. In those receiving albendazole at day 180 (PLAC/ALB), microfilarial levels also decreased following albendazole (P = 0.005). Blood eosinophil and antifilarial IgG levels did not change significantly for either group, although antifilarial IgG4 levels did in the ALB/PLAC group at day 180. Most subjects continued to have elevations in microfilaremia, suggesting that more intensive regimens of albendazole will be necessary to reduce Loa microfilaremia to levels safe enough to allow for ivermectin use.

The African Eye Worm: A Case Report and Review

“…However, it is contraindicated in patients with elevated microfi lariae levels because of its association with severe neurological side effects. 5,6 Though DEC is thought to be curative in most cases, multiple courses of therapy may be needed and relapses may still occur. DEC has activity against both microfi lariae and adult worms, and therefore, a sustained decrease in microfi larial intensity occurs following treatment.…”

“…The relative risk of developing marked or serious reactions was signifi cantly higher when the L loa load exceeded 8,000 microfi lariae/mL and are particularly notable in patients with L loa microfi laria greater than 20,000 to 50,000 microfi lariae/mL. 5,11 Since our patient was from an area endemic for both L loa and onchocerca, skin snip testing was done initially to rule out onchocerca. Apheresis was then performed to decrease the level of microfi laremia before administering escalating doses of DEC to minimize the possibility of side effects.…”

“…Albendazole has been shown to temporarily reduce microfi laremia when used for 3 weeks at doses of 200 mg twice a day; however, relapses are likely to occur. 5,9,10 Concomitant L loa infection in patients with underlying Onchocerca volvulus infection is particularly problematic. Agents like ivermectin which were widely distributed throughout West Africa for the safe and effective control of onchocerciasis have been associated with severe post-treatment effects including death when administered to patients with concomitant L loa and O volvulus infection.…”

“…Agents like ivermectin which were widely distributed throughout West Africa for the safe and effective control of onchocerciasis have been associated with severe post-treatment effects including death when administered to patients with concomitant L loa and O volvulus infection. 5,11 Due to these adverse effects, the public health use of this drug in the forest habitat of the L loa vector has been constrained. Occurrence of serious reactions was related to the intensity of pretreatment L loa microfi laremia.…”

Encephalopathy Related to Ivermectin Treatment of Onchocerciasis in Loa loa Endemic Areas: Operational Considerations

“…There is an urgent need of interventions to prevent its health consequences. In that regard, albendazole may be a useful tool (Tabi et al, 2004). The mass distribution of ivermectin and albendazole within CDTI projects within the Global Programme to Eliminate Lymphatic Filariasis (GPELF) will have an incidental impact on Loa loa infection (Chippaux et al, 1998;Tsague-Dongmo, 2002).…”