ADULTICIDAL AND OVICIDAL EFFECT OF EXPERIMENTAL LOTIONS BASED ON IVERMECTIN

VASSENA C, GALLARDO A, GONZALEZ AUDINO P, MOUGABURE CUETO G, TOLOZA AC, PICOLLO MI

Urgup

Conferencia; Reunión: Fourth; 2010

The infestation with the human obligate ectoparasite Pediculus humanus capitis De Geer is a common public health problem affecting mainly schoolchildren worldwide. The high levels of pirethroid resistance in the majority of the lice populations in Buenos Aires, Argentina, challenges us to assess pediculicidal activity of new molecules as control alternatives. Ivermectin is the drug of choice for a variety of parasitic diseases in humans due to its high effect on lice and its wide margin of safety on humans.The aim of the present study is to investigate the adulticidal and ovicidal effect of experimental hidro-alcoholic lotions based on  Ivermectin in comparison to permethrin on head lice in elementary schools from Buenos Aires with resistant levels to permethrin >100. Children aged 3-13 from eight selected elementary schools from Buenos Aires with permethrin resistant levels >100 were examined for head lice. These were removed using a fine-toothed metal head lice comb and transported to our laboratory. After collection, lice were maintained without feeding, 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. The high potential effectiveness of the insecticide was assessed by topical application of the technical product on adults and nits and measured with the parameter Lethal dose 50. The Lethal Dose 50 (LD 50) for ivermectin in comparison to permethrin on Lice resistant with (GR 47,2) showed that ivermectin is 60 times more effective than permethrin on both adults and nits. Laboratory bioassay for evaluating adulticidal activity for experimental lotions: The effectiveness of experimental lotions was evaluated by the immersion method. Batches of at least 10 adults and third nymphs lice were submerged for 2 minutes in 1 ml of the experimental lotions of ivermectin and permethrin. The treated insects were washed with 100 ml of water. They were then placed onto a piece of filter paper (7 cm diameter Whatman Nº 1) moistened with 0.5 ml water. Mortality of exposed lice was recorded after 18 hs.