The effect of temperature on the viability of Demodex folliculorum and Demodex brevis.

Demodex folliculorum and Demodex brevis are obligatory parasites of the pilosebaceous unit in humans and are cosmopolitan in terms of their distribution. This study was conducted to explore the effect of temperature on the viability of D. folliculorum and D. brevis. Both types of parasites were collected with the cellophane tape method, then randomly grouped and placed into separate moist cabinets. They were divided into 15 groups and exposed to experimental temperatures ranging from -15 degrees C to 60 degrees C. Curve diagrams and scatter plots on the relationship between temperature and the corresponding survival time were drawn and analyzed. It is demonstrated that temperature has a tremendous influence on the viability of D. folliculorum and D. brevis. Survival time and temperature are inversely correlated in the temperature range of 5-37 degrees C. Both D. folliculorum and D. brevis can survive better at low temperatures than at high temperatures. The most suitable maintenance temperature is 5 degrees C, and the optimal temperature for D. folliculorum and D. brevis to develop in vitro is 16-20 degrees C. Temperatures below 0 degrees C and above 37 degrees C are harmful to the mites. The lethal temperature is 54 degrees C, and the effective temperature that kills Demodex mites is 58 degrees C.