The effect of the miteMyocoptes musculinus(C. L. Koch 1840) on the skin of the white laboratory mouse and its control

Abstract

1. The means of attachment of the miteMyocoptes musculinusto the hair of the host, the mouse, and the sites where it is located are given.2. Normal and skin infected withM. musculinusof young (6–8 weeks) and adult (6 months) mice is treated with colchicine and examined histologically.3. Infected skin shows a mitotic count of approximately four times that of normal skin in the adult; there is no appreciable difference in the young.4. Acaricides used to control the mite were benzene hexachloride (0·015%), dieldrin (0·015%), arsenic and sulphur mixture (0·018% arsenic), piperonyl butoxide (5%) and dimethylphthalate (100%); the latter being the most efficacious.5. It is established that the drugs had no effect on the rate of division of the cells of the malpighian layer of the skin.6. The number ofMyobiapresent increases as theMyocoptesare killed unless dimethylphthalate, an oily liquid, is used at intervals.7. Diet in conjunction with signs of mange is discussed.8. Carriers ofM. musculinusare given.I wish to thank Cooper McDougall for supplying the materials used in dipping and swabbing, and the Infestation Control Laboratory of the Ministry of Agriculture for supplying me with a number of specimens of wild mice from different parts of the country. I am also grateful to the Council of the Royal Free Hospital School of Medicine for facilities for carrying out the work; and to Dr A. M. Hughes for her helpful guidance at all stages of the work and especially for reading the paper.