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Control of the human head louse with disulfiram and benzyl benzoate emulsions. A laboratory study
Abstract:
The effects of disulfiram, benzyl benzoate and DDT, all components of a common preparation (Tenutex) for the control of the head louse, were tested on louse eggs. A significant higher mortality of eggs was evident after treatment with (i) disulfiram, (ii) benzyl benzoate, (iii) these two substances mixed, and (iv) Tenutex. DDT in this concentration had no effect on the survival of the eggs. Long-time exposure to Tenutex and Tenutex without DDT significantly lowered the hatching frequency of eggs. Almost no hatching occurred after exposure for 24 hours. The survival of larvae hatched from eggs treated with Tenutex was lower than for those treated with Tenutex without DDT. DDT seemed to have an effect primarily on the survival of larvae. Newly hatched larvae were more sensitive to the two Tenutex preparations than older larvae.
Insights
Disulfiram and benzyl benzoate in Tenutex effectively kill head louse eggs, while DDT primarily impacts larval survival. Long exposure to Tenutex significantly reduces egg hatching rates.
Area of Science:
- Parasitology
- Entomology
- Public Health
Background:
- Head lice infestations are a common public health concern.
- Effective pediculicides are crucial for controlling head louse (Pediculus humanus capitis) populations.
- Tenutex is a widely used preparation for treating head lice.
Purpose of the Study:
- To evaluate the efficacy of individual components of Tenutex (disulfiram, benzyl benzoate, DDT) and the combined preparation against head louse eggs and larvae.
- To determine the impact of different exposure durations on egg mortality and hatching frequency.
- To assess the role of DDT in the overall efficacy of Tenutex.
Main Methods:
- Head louse eggs were exposed to disulfiram, benzyl benzoate, DDT, and Tenutex (with and without DDT) at specific concentrations.
- Egg mortality, hatching frequency, and larval survival rates were recorded.
- Different exposure times were utilized to assess time-dependent effects.
Main Results:
- Disulfiram, benzyl benzoate, and Tenutex demonstrated significant ovicidal effects, increasing egg mortality.
- DDT at the tested concentration showed no significant effect on egg survival.
- Long-term exposure to Tenutex (with and without DDT) drastically reduced egg hatching; almost no hatching occurred after 24 hours.
- Larval survival was lower when hatched from eggs treated with Tenutex compared to Tenutex without DDT.
- DDT appeared to primarily affect larval survival, with newly hatched larvae being more susceptible.
Conclusions:
- Disulfiram and benzyl benzoate are the primary active agents responsible for the ovicidal effects of Tenutex.
- DDT's main contribution to Tenutex's efficacy lies in its impact on larval survival.
- Tenutex is highly effective in preventing head louse hatching, especially with prolonged exposure, and also impacts larval viability.