Investigation on Epidemiology and Affecting Factors of Autumn-winter Type Scrub Typhus in Fei County, Shandong Province

Investigation on epidemiology and affecting factors of autumn-winter type scrub typhus in four towns of Fei county were carried out from 1994 to 1997. The results revealed that the average morbidity rates in the investigated area were varied from 0.0014/10 6 to 0.0109/10 6, the villages that cases appeared were occuppied 56.68% of the total villages. In this case-appeared villages, the case number of Minzhai village, 13, was the largest in all of the villages, average morbidity rate of this village was 0.0345/106.The peak of scrub typhus in this area was in mid- and later October ,and the morbidity rate in the age group of 26～35 was higher than that in the others.The ratio of men to women cases was 1.3:1.Most of the cases were peasants.The results of case- control study indicated that staying on the grass field residing in humid circumstance and residing in the edge of village were the risk factors of scrub typhus,in addition,the density of rodents and leptotrombidium scutell were important factors affecting the morbidity rate of scrub typhus.