In vitro survival of scabies mites.

BACKGROUND

The correct treatment and management of scabies is expensive and time-consuming, and may have a negative impact on patients and their families.

AIM

To investigate the effects of permethrin 5% cream on scabies mites, and explore mite survival times outside the human body.

METHODS

We performed a nonrandomized controlled study. In total, 20 petri dishes were coated with permethrin 5% cream (treatment group) and 20 plain petri dishes (control group) each had one scabies mite placed in them, and were then observed at baseline and 3, 4, 5, 6, 7, 8 and 12 h from baseline. In the second part of our study, 30 scabies mites from infested patients were investigated in an observational experiment in 30 plain petri dishes at days 0, 3 and 4.

RESULTS

Our data showed that 65% of scabies mites survived after 8 h in the treatment group compared with 75% of mites in the control group. After 12 h, 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 was alive on day 3, but all mites were dead by day 4.

CONCLUSIONS

This study showed no significant effects of mite survival times with 5% topical permethrin after 8 h, while its efficacy was stronger and significant after 12 h. We recommend the isolation of all mite-infested items for at least 4 days.