Epidemic analysis of hemorrhagic fever with renal syndrome in Nanjing, China and its prevention and control strategy

Abstract

Objective To analyze the epidemiological characteristics of hemorrhagic fever with renal syndrome (HFRS) in Nanjing and explored the prevention and control strategy. Methods We collected the HFRS report data of Nanjing from January 1, 2006 to December 31, 2015, through the National Notifiable Infectious Disease Surveillance System. Epidemiological characteristics and exposure factors of reported HFRS cases in Nanjing from 2006 to 2015 were analyzed by descriptive epidemiological method. We analysed the time, area and population distribution characteristics , clinical features and exposure factors of HFRS cases, and the medical institutions which reported HFRS cases. We compared the epidemiological characteristics of 2011 to 2015 and 2006 to 2010. Results A total of 272 HFRS cases were reported in Nanjing during the period of 2006 to 2015. The average annual incidence was 0.34/100 000 (ranged from 0.22/100 000 to 0.55/100 000), and the reported annual incidence showed a trend of relatively stable (t=1.25, P>0.05). The incidence peaked in spring-to-summer (April to July) and winter (November to February), which accounted for 88.6% of the reported cases. The incidence of male and female was 0.51/100 000 and 0.24/100 000, respectively. The median age was 46 (ranged from 12 to 79), and the age group of 35-60 years old accounted for 70.2% of the patients, while no patient reported was younger than 11 or older than 80 years old. Farmer accounted for 62.1% of the reported cases. The annual average incidence in Gaochun District was 3.35/100 000, which was significantly higher than that in other areas in Nanjing. Compared with 2006 to 2010, the epidemiological characteristics of HFRS cases in 2011 to 2015 were basically similar. 155 cases of HFRS reported during 2011-2015 showed that the proportion of clear history of exposure was 61.3%. Conclusion The incidence of HFRS in Nanjing is stable but higher in Gaochun District and in the population of farmer. Health authorities should further carry out comprehensive measures for prevention and control as rodent control and vaccination. Key words: Hemorrhagic fever with renal syndrome; Hanta virus; Epidemiologic studies; Spatial-temporal clustering analysis