Based on the current knowledge, head louse (Pediculus capitis) and body louse (Pediculus humanus) are two different species that infest specific parts of the human body and do not interbreed in vivo. In 1991–2002, 6 257 cases of pediculosis were reported in the Czech Republic while 3 138 000 pediculicide packagings, i.e. about 500 times as many as the number of cases, were marketed. Between October 2004 and February 2005, a total of 531 children aged between 6 and 15 years from 16 selected schools in the Zlín and Olomouc regions were screened by dry hair combing. Living lice were detected in 14.1 % of the enrolled children and dead nits alone were observed in other 9.8 % of the subjects. In vitro tests revealed that the collected head lice were highly resistant to malathion, the active ingredient of Diffusil H 92 M. The number of reported cases of pediculosis roughly doubled in 2005.

        Key words: head lice – Pediculus capitis – infestation – control – resistance to insecticides.