Zhao et al.
Epidemiological characteristics and spatial analysis of tick-borne encephalitis in Jilin Province, China.
Am. J. Trop. Hyg. 2019; in press, doi: 10.4269/ajtmh.18-0958
Historically, the first TBE case in China has been reported in 1943 and the first strains have been isolated from Chinese individuals and ticks in 1952.
TBE virus predominantly circulates in northeastern, northwestern and southwestern regions of China. More than 98% of TBE cases have been reported in northeastern China and about a third of all cases occur in the northeastern province Jilin (~ 27,533,000 inhabitants living in 1,002 administrative townships). Ixodes persulcatus is the main vector.
Until 2010, TBE cases were only observed in 45 townships and then, 50 new township foci emerged. 846 reported TBE cases from 2006 to 2016 have been analyzed, of which six were fatal. Until 2010, the number of cases remained stable (less than 20 cases per year). Since then, a sharp increase has been observed (more than 100 cases per year). Most cases happened between May and July (93.1%). The mean age of the patients was 46 years. Most patients were farmers (60.99%), followed by domestic and forest workers. Auto-regression analyses showed that TBE cases were associated with the density of population, the percentage coverage of forest, rainfed cropland, temperature, relative humidity and precipitation. The results of the study are based on a passive surveillance system and there may be an underreporting in the number of TBE cases. The authors concluded that TBE has expanded during recent years and that TBE remains an important public health problem in Jilin Province.