Evaluation of efficacy of four pediculicides against head louse (Pediculus capitis) infestation.

To evaluate the efficacy and to determine the minimum effective dosage of four pediculicides against head louse infestation, as well as to select a safe, effective, practical, and cheap agent, 1,657 infested school children in 25 primary schools in Szu-Hu, Kou-Hu, and Ku-Keng Districts of Yunlin County were treated and 1,611 of them were examined. The overall cure rate was 73% and the rate for boys (84%) was higher than that for girls (71%). The cure rate of Nix (permethrin 1%) cream rinse was 81%. The cure rate for single dosages of 1, 2, 3 and 4 cases/tube (56 gm/tube) was 87%, 83%, 81% and 71%, respectively. The cure rate of Para aerosol (bioallethrine 0.66%) was 78%. The cure rate for single dosages of 30 and 40 cases/tube (90 gm/tube) was 87% and 70%, respectively. The cure rate of Prioderm (malathion 1%) cream shampoo was 64%. The cure rate for single dosages of 10, 15 and 20 cases/tube (40 gm/tube) was 74%, 71% and 52%, respectively. The cure rate of Delice (1% gamma benzene hexachloride) was 71%. The cure rate for single dosages of 5 and 10 ml/case was 64% and 76%, respectively. Of the 226 infested girls, 181 (80%) were found to be infested with 1-10 head lice, 33 (15%) with 11-50 lice, 7(3%) with 51-100 lice and 5 (2%) with over 100 lice. Of the 2,160 head lice collected, 1,788 (83%) were nymphs, 284 (13%) females, and 88 (4%) males. The mean number of head lice in each infested girl was 10 (range 1-137). The low cure rates obtained in the present study may be due to the fact that many school girl & have long hair. In comparison, Nix had the highest cure rate (81%) but the highest price (NT$ 120/case). The cure rate and price of Para aerosol (78%, NT$ 7.2/case) and Delice (71%, NT$ 16.7/case) came next. Prioderm (64%, NT$ 10.0/case) had the lowest rate and a slight offensive smell. Preliminary trials show that based on the cost-effectiveness, Para aerosol is best in head louse infestation control.