Head lice 喜歡乾淨頭髮架,and actually very common among international schools.
My friend's daughter got it, she took her to see a doctor in Sanatorium Hospital, the doctor prescribed her the Malathion Lotion. It worked very well, just need to use it twice, all the head lice and nits are gone!
Have a check in the internet, It's indeed chemical but I don't think it will make any long term harm to human because you just need to use it twice!
My friend couldn't find those special comb either but she used the "hair-iron" (supposed to straighten your hair) on her daughter's hair to make sure all the leftover "eggs" are killed.