In Huzhu area of Qinghai province 746 peasants of the Tu nationality were surveyed for demodex. The results showed: the infection rate was 34.18% (255/746), the infection rate in male and female was 37.63%and 30.75% respectively. There was significantly difference in sex (P<0.05). The infection rate were increased along with age. in order to prevent the infection. the most important thing was pay attention to public and personal hygiene, avoid contact with the patients as well as avoid inderectly transmissi...