3.4 SFTSV and Rickettsia nucleic acid detection and virus isolation results
From the 5 confirmed cases of SFTSV, 2 SFTSV strains were successfully isolated and named LNHDD2019-9 (from Dandong City, Liaoning Province) and LNHDG2019-6 (from Donggang City, Liaoning Province). NoRickettsia nucleic acid was detected in the serum or blood cells of the 17 patients suspected of SFTSV.
A total of 492 tick samples were collected from the patient’s residence and surrounding areas (including Dandong City and, under its jurisdiction, Fengcheng City, Donggang City; Kuandian Manchu Autonomous County; and Zhuanghe City under the jurisdiciton of Dalian,which are all Changbai Mountain forest areas in the border area between China and North Korea). Environmental free tick samples (samples not collected in Beipiao City) were all identified by molecular biology. Among them, 12 samples were positive for SFTSV nucleic acids, with a positivity rate of 2.4%. Two SFTSV strains were successfully isolated from tick samples and were named LNTEDG2019-6 (collected from Erdaogou, Dandong City, Liaoning Province) and LNTYJ2019-6 (collected from Yanji City, Jilin Province) (Figure 1).