Correlation between Scrub Typhus Vectors and Human Cases, Penghu, 2003–2015

DOI: 10.6525/TEB.20161004.32(19).001

Yuan-Fan Chin, Ming-Hui Weng, Hui-Ping Tsai, Pey-Ru Lin,Yao-Wen Hung, Kuo-Ching Cheng, Ming-Der Guo, Chang-Chi Lin

2016 Vol.32 NO.19

Correspondence Author: Yuan-Fan Chin

  • Institute of Preventive Medicine, National Defense Medical Center, Taiwan


We have conducted prevalence surveillance of the etiology of scrub typhus, Orientia tsutsugamushi, from rodents and Leptotrobidium chiggers at 15 locations and same season ten times in Penghu islands during 2003 to 2015. Four species of rodents had been captured, of which Rattus norvegicus and Suncus murinus are both more commensal with human living environment, the other species Mus musculus and Rattus losea are all field live rats. In correlation analysis, parameters included total trapped rats, positive number and percentage of rats parasitizing chiggers, number and percentage of chigger pool from individual rat with positive DNA detection of Orientia tsutsugamushi, and number of rats with positive tsutsugamushi antibody by immunofluorescent assay. All the chiggers collected were diagnosed as Leptotrobidium deliense in the surveillance. The positive numbers and percentages of rats parasitizing chiggers were well correlated with human scrub typhus cases in Penghu (r = 0.74, p = 0.024, 0.025). The estimated number human scrub typhus cases in Penghu in 2015 would be 73 with a 95% confidence interval of 43 to 102.

Keywords:Orientia tsutsugamushi, Rodent, Leptotrobiduim deliense, Penghu islands