Adulticidal and ovicidal effect of experimental lotions based on Ivermectin

CLAUDIA VASSENA, ANABELLA GALLARDO, PAOLA GONZÁLEZ AUDINO, GASTÓN MOUGABURE CUETO, ARIEL TOLOZA & MARIA I. PICOLLO

Urgup, Cappadocia

Congreso; 9. Fourth International Conference on Phthiraptera (ICP4); 2010

International Society of Phthirapterists

The high levels of pyrethroid resistance in the majority of the lice populations in Buenos Aires, Argentina, challenges us to assess pediculicidal activity of Ivermectin, a drug used for a variety of parasitic diseases due to its high activity and its safety on humans. We investigated the adulticidal and ovicidal activity of Ivermectin technical and experimental hidro-alcoholic lotions based on this insecticide against permethrin-resistant head lice. Children aged 3-13 were examined for head lice, which were removed by a fine-toothed metal comb. After collection, lice were maintained in an environmental chamber at 18 ± 0.5 °C and 70- 80% RH in the dark for a maximum of one hour before their use in toxicological bioassays. Insecticidal activity was assessed by topical application on adults and nits. The Lethal Dose 50% for Ivermectin and permethrin showed that Ivermectin was 60 times more effective than permethrin on both adults and nits. The effectiveness of experimental lotions was evaluated by the immersion method. Batches of 10 adults were submerged for 2 minutes in 1 ml of insecticide lotions, and washed with 100 ml of water. Mortality was recorded after 18 h. The ovicidal activity of lotions was evaluated by 10 min immersion of batches of 10 eggs fixed to glass slide, washed in 50 ml water and dried over filter paper. Treated eggs were maintained at 28°C- 75 % RH until hatching of untreated eggs. The Lethal Concentration 50% showed that the lotions with ivermectin are more effective than those with permethrin on both adults and nits, indicating that are a good alternative for commercial head lice products.