In-vitro survival of scabies mites.
The correct treatment and management of scabies is expensive, time consuming and may have negative impacts on patients and their families.We sought to investigate the effects of 5 % permethrin cream on scabies mites, and explore mite survival times outside the human body.We performed a non-randomised controlled study. Twenty petri dishes were coated with 5 % permethrin cream, each with one scabies mite (treatment group), and twenty plain petri dishes with one scabies mite each (control group) were observed at baseline and 3, 4, 5, 6, 7, 8 and 12 hours from baseline. In the second part of our study, thirty scabies mites from infested patients were investigated in an observational study in 30 plain petri dishes at days 0, 3 and 4.Our data showed that 65% of scabies mites survived after eight hours in the treatment group, when compared with 75% of mites in the control group. After 12 hours, 25% of mites in the treatment group, and 60% in the control group were still alive. Data from the observational survival study showed that one mite survived for three days, but all mites were dead by day four.This study showed no significant effects of mite survival times with 5 % topical permethrin after eight hours, while its efficacy was stronger and significant after 12 hours. We recommend the isolation of all mite-infested items for at least four days.