The efficacy of herbal shampoo from Cymbopogon citratus and ultrasonic sound to control head lice (Pediculus humanus capitis)

Abstract

Background: Pediculosis capitis is a scalp disease due to the infestation of obligate ectoparasites (mites/lice) species of Pediculus humanus var. Capitis. Pediculosis capitis infects 6 to 12 million people each year in the US. Furthermore, head lice develop resistance to the active ingredients of the chemical drug and become insensitive to treatment. Methods & materials: A filter paper contact method was applied with three concentrations (0.01, 0.1 and 1 mL/cm2) of each Cymbopogon citratus shampoo as well as permethrin pediculicide (positive control) and drinking water (negative control) against eggs, nymphs and adults of Pediculus humanus capitis. Mortality rates of the eggs were recorded after 7 days of incubation while those of nymphs and adults were recorded after 5 minutes of contact. And, ultrasonic sound, those of egg, nymphs and adults were recorded after 5 minutes of contact. Results: Cymbopogon citratus shampoo at the high concentration were highly effective against nymphs and adults, but not effective against the eggs at 5 min showed mortality rates against nymphs at 100% and against adults at 100% with LC50 values of 1 mL/cm2. Ultrasonic sound exhibited the highest efficacy against the egg, nymphs and adults with 100% mortality rate at 5 min. Permethrin pediculicide was not effectively killing the eggs but showed 69.1%–83.2% and 43.4%–61.8% mortality rates against nymphs and adults. Conclusion: These results indicate that Cymbopogon citratus shampoo can be used as an effective nymphicide and adulticide against Pediculus humanus capitis. While ultrasonic sound can be used as effective for all stages of the head lice.