Chemotherapy of head louse (Pediculus humanus capitis) infestation gamma benzene hexachloride (gamma-BHC) among school children in Szu-Hu District, Yunlin County, Central West Taiwan.

In order to evaluate the effectiveness of 1% gamma-BHC emulsion against head louse infestation, 1,527 school children were examined using observation by ocular and combing methods were used and infested children were treated with three regimes of 1% gamma-BHC emulsion. An overall infestation rate of 40% was found. The infestation rate was highest in Tung-Kuang Primary School (59%) and lowest in Chien-Hua Primary Schools (7%). The rate was highest among school children grade 2 (45%) and lowest in grade 3 (35%). The rate of girls (65%) was much higher than that of boys (9%). A total of 443 lice were collected from 78 infested school girls: 56 males, 59 females, and 328 nymph. The average number of head lice in each infested girl was 5.7. Follow-up examination was conducted one week after treatment. The cure rates for dosages of 10.0 ml, 5.0 ml, and 2.5 ml 1% gamma-BHC emulsion were 96%, 88%, 68% for girls and 100%, 92%, and 33% for boys, respectively. Only mild and transient itching and burn sensation of scalp were reported by a few children. The overall infestation rate 5 months (April-September 1981) after treatment was 23% (286/1,245). The rate of girls decreased from 65% to 40% and that of boys from 9% to 3%. Results of the present study indicates that 1% gamma-BHC emulsion is an effective pediculicide at a dosage of 5 ml or 10 ml. However, the overall infestation rate remained high (23%) 5 months after treatment. These findings suggest that treatment of head louse infestation must be conducted continuously.