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

Abstract

1. The means of attachment of the mite Myocoptes musculinus to the hair of the host, the mouse, and the sites where it is located are given.2. Normal and skin infected with M. musculinus of 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 of Myobia present increases as the Myocoptes are killed unless dimethylphthalate, an oily liquid, is used at intervals.7. Diet in conjunction with signs of mange is discussed.8. Carriers of M. musculinus are 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.