OBJECTIVE: The Guanzhong Plain of Shaanxi Province is a severely afflicted hemorrhagic fever with renal syndrome (HFRS) epidemic area, while HFRS prevalence has decreased in most epidemic areas in China. Little information is available regarding the leading fine-scale influencing factors in this highly HFRS-concentrated area and the roles of natural environmental and socioeconomic factors. To investigate this, two regions in the Guanzhong Plain, that is, the Chang'an District and Hu County, with similar geographical environments, different levels of economic development, and high epidemic prevalence, were chosen as representative areas of the HFRS epidemic. METHODS: Maximum entropy models were constructed based on HFRS cases and fine-scale influencing factors, including meteorological, natural environmental, and socioeconomic factors, from 2014 to 2016. RESULTS: More than 95% of the HFRS cases in the study area were located in the northern plains, which has an altitude of less than 800 m, with topography contributed 84.1% of the impact on the spatial differentiation of the HFRS epidemic. In the northern plains, precipitation and population density jointly affected the spatial differentiation of the HFRS epidemic, with contribution rates of 60.7% and 28.0%, respectively. By comparing the influencing factors of the northern plains of Chang'an District and Hu County, we found that precipitation and the normalized difference vegetation index (NDVI) dominated the HFRS epidemic in the relatively developed Chang'an District, while land-use type, temperature, precipitation and population density dominated the HFRS epidemic in the relatively undeveloped Hu County. CONCLUSION Topography was the primary key factor for HFRS prevalence in the Chang'an District and Hu County, and the spatial differentiation of HFRS was dominated by precipitation and population density in the northern plains. Compared with the influencing factors of the relatively developed Chang'an District, the developing Hu County was more affected by socioeconomic factors. When formulating targeted HFRS epidemic prevention and control strategies in the targeted areas, it is crucial to consider the local economic development state and combine natural environmental factors, including the meteorological environment and vegetation coverage.
Humans ; Hemorrhagic Fever with Renal Syndrome/epidemiology* ; China/epidemiology* ; Epidemics ; Socioeconomic Factors ; Altitude

BACKGROUND: Yeoncheon is an endemic region for hemorrhagic fever with renal syndrome (HFRS) and has been reporting HFRS cases intermittently in other seasons, including autumn. This study was conducted to determine whether a seasonal variation pattern of HFRS exists in Yeoncheon. MATERIALS AND METHODS: From 2002 to 2016, raw data of the number of patients with HFRS in Yeoncheon and nationwide was collected from the Korea Center for Disease Control and Prevention. On the basis of the raw data, the incidence per 100,000 population was calculated for each month of the year. The twelve months were divided into four quarters, and the proportion of the disease by each quarter was calculated. The effects of sex, age, quarter, and time on HFRS occurrence were analyzed by Poisson regression analysis. RESULTS: A total of 6,132 HFRS cases occurred nationwide, and 62 cases occurred in Yeoncheon. The incidence of the disease in Yeoncheon (9.07/100,000) was statistically higher than that nationwide (0.81/100,000). The quarterly incidence showed that occurrence proportion of HFRS was high in the third and fourth quarters (12.9%, 67.5%) nationwide, whereas it was relatively similar in all quarters in Yeoncheon (17.7%, 21.0%, 25.8%, 35.5%). The Poisson regression model showed that the relative risk of HFRS nationwide was 1.322 in the third quarter and 6.903 in the fourth quarter, but Yeoncheon had no risk increase by quarter. CONCLUSION: In this study, HFRS in Yeoncheon demonstrated no seasonal variation pattern compared to that in nationwide Korea, which may be considered a regional characteristic. Furthermore, in other regions where HFRS is endemic, like Yeoncheon, HFRS may arise regardless of seasonal variations.
Centers for Disease Control and Prevention (U.S.) ; Endemic Diseases ; Epidemiology ; Hemorrhagic Fever with Renal Syndrome* ; Humans ; Incidence ; Korea* ; Seasons*

BACKGROUND: Yeoncheon is an endemic region for hemorrhagic fever with renal syndrome (HFRS) and has been reporting HFRS cases intermittently in other seasons, including autumn. This study was conducted to determine whether a seasonal variation pattern of HFRS exists in Yeoncheon. MATERIALS AND METHODS: From 2002 to 2016, raw data of the number of patients with HFRS in Yeoncheon and nationwide was collected from the Korea Center for Disease Control and Prevention. On the basis of the raw data, the incidence per 100,000 population was calculated for each month of the year. The twelve months were divided into four quarters, and the proportion of the disease by each quarter was calculated. The effects of sex, age, quarter, and time on HFRS occurrence were analyzed by Poisson regression analysis. RESULTS: A total of 6,132 HFRS cases occurred nationwide, and 62 cases occurred in Yeoncheon. The incidence of the disease in Yeoncheon (9.07/100,000) was statistically higher than that nationwide (0.81/100,000). The quarterly incidence showed that occurrence proportion of HFRS was high in the third and fourth quarters (12.9%, 67.5%) nationwide, whereas it was relatively similar in all quarters in Yeoncheon (17.7%, 21.0%, 25.8%, 35.5%). The Poisson regression model showed that the relative risk of HFRS nationwide was 1.322 in the third quarter and 6.903 in the fourth quarter, but Yeoncheon had no risk increase by quarter. CONCLUSION: In this study, HFRS in Yeoncheon demonstrated no seasonal variation pattern compared to that in nationwide Korea, which may be considered a regional characteristic. Furthermore, in other regions where HFRS is endemic, like Yeoncheon, HFRS may arise regardless of seasonal variations.
Centers for Disease Control and Prevention (U.S.) ; Endemic Diseases ; Epidemiology ; Hemorrhagic Fever with Renal Syndrome* ; Humans ; Incidence ; Korea* ; Seasons*

Objective: To analyze the epidemiological and temporal-spatial distribution characteristics of hemorrhagic fever with renal syndrome (HFRS) in Shandong province during 2010-2016 and provide references for developing prevention and control measures. Methods: Based on the data of Infectious Disease Reporting Information System in China, the incidence and temporal-spatial distribution of HFRS in Shandong from 2010 to 2016 were analyzed by spatial autocorrelation and space-time scan statistics. Results: A total of 9 114 HFRS cases were reported in Shandong during this period. The cases were mainly distributed in age group 30-70 years, and the male to female ratio of the cases was 2.63 ∶ 1. Most cases were farmers. The higher incidence rate was reported in southeastern Shandong, while the lower incidence rate was reported in northwestern Shandong. Among the epidemic periods, the highest incidence rate was 1.87/100 000 in 2013. The results of spatial autocorrelation and space-time scanning indicated that the high-high clusters of HFRS were concentrated in southeastern Shandong and then spread to central Shandong. The cluster mainly occurred from the end of 2011 to the first half of 2015. Both the incidence rate and the cluster decreased in 2016. Conclusions: The epidemic and cluster of HFRS still existed in Shandong from 2010 to 2016. The key areas for the prevention and control of HFRS were in southeastern and central Shandong.
Adolescent ; Adult ; Aged ; China/epidemiology* ; Epidemics ; Female ; Hantaan virus ; Hemorrhagic Fever with Renal Syndrome/virology* ; Humans ; Incidence ; Male ; Seasons ; Spatio-Temporal Analysis ; Young Adult

Objective: To understand the epidemiological characteristics of hemorrhagic fever with renal syndrome (HFRS) in Wei River Basin from 2005 to 2015, and analyze the environmental factors that cause the differences of spatial distribution. Methods: HFRS reported cases in Wei River Basin from 2005 to 2015 were collected form "National Disease Reporting Information System" , and the epidemiological features of HFRS were analyzed. Boosted regression trees (BRT) model was applied to evaluate the environment factors on the geographical distribution of HFRS in Wei River basin at 5 km×5 km gird scale. Results: The number of HFRS cases was 18 629, and the average annual incidence from 2005-2015 in Wei River basin was 7.24/100 000. The highest morbidity was 15.18/100 000 in 2012. The middle and lower reaches of Wei River basin had high incidence of HFRS, such as Xi'an, Weinan city. Patients' age was mainly between 16 to 60, and the largest morbidity occured in people over 60 years old. Boosted regression trees modle identified building land, farmland coverage percentage and altitude had higher contribution to the distribution of HFRS. Conclusions: The epidemiological characteristics of HFRS changed significantly. Patients older than 60 years old were having the highest incidence rates. Environmental factors such as buildup land, farmland and altitude played important roles in the geographical distribution of HFRS in the Wei River basin.
Adolescent ; Adult ; Age Distribution ; China/epidemiology* ; Endemic Diseases ; Hemorrhagic Fever with Renal Syndrome/epidemiology* ; Humans ; Incidence ; Middle Aged ; Rain ; Risk Factors ; Rivers

OBJECTIVETo take effective strategies and measures for the prevention and control of hemorrhagic fever with renal syndrome (HFRS) endemic areas by investigating its dynamic geographical boundaries in Shandong Province, China.

METHODSThe incidence of HFRS from 1982 to 2008 in Shandong Prvince, China, was detected with inverse distance weighting (IDW) interpolation based on geographical information system (GIS). Dynamic geographical boundaries of HFRS endemic areas in Shandong Province, China, were analyzed by geographical boundary analysis.

RESULTSThe HTN-type endemic areas of HFRS were located in Linyi City in phase 1 (1982-1986), the SEO-type endemic areas of HFRS were located in Jining City in phase 2 (1987-2003), and the endemic areas of HFRS in Jining City gradually disappeared and the endemic areas of HFRS with mixed-types of reservoir rodents were located in Linyi City in phase 3 (2004-2008). Meanwhile, new endemic areas emerged in the northwestern Shandong province, China.

CONCLUSIONThe SEO-type endemic areas of HFRS are located in western Shandong Province, China, and the HTN-type endemic areas of HFRS are located eastern Shandong Province, Chin, indicating that the endemic areas of HFRS should be vaccinated and rodents should be controlled.

China ; epidemiology ; Endemic Diseases ; Geography ; Hemorrhagic Fever with Renal Syndrome ; epidemiology ; Humans ; Population Surveillance

OBJECTIVETo compare the differences between the direct immuno-fluorescent assay (DFA) and real-time quantitative PCR in detecting the Hantavirus (HV) in rat lungs.

METHODSFrom April to October in 2012, a total of 479 rats were caught by mouse-trap in residential or wild areas in Huxian, Jingyang, and Meixian of Shaanxi province, where haemorrhagic fever with renal syndrome (HFRS) was highly prevalent. The rats were dissected to take the two lungs, one was frozen and applied immuno-fluorescent assay to detect HV antigen while the other one was extracted its RNA and detected HV nucleic acid by real-time quantitative PCR. Then we compared the positive rate of the two methods.

RESULTSOut of the 479 rats, 105 were caught from residential areas and the other 374 were caught from wild areas. Among the 105 rats caught from residential areas, no HV were detected out neither by DFA nor by real-time quantitative PCR. Among the 374 wild rats, 13.1% (49/374) were detected HV positive by DFA and 14.7% (55/374) were detected HV positive by real-time quantitative PCR. The difference showed no statistical significance (χ(2) = 0.402, P = 0.526). When detecting each lung sample, the HV positive rate was 10.2% (49/479) under the detection by DFA while the HV positive rate was 11.5% (55/479) under the detection by real-time quantitative PCR. The difference had no statistical significance (χ(2) = 1.286, P = 0.257) and the consistency coefficient was 68.2% under the paired chi-square test analysis, which showed high consistency (u = 11.759, P < 0.05). The sensitivity of real-time quantitative PCR to detect HV was 77.6% (38/49) comparing with DFA as standard, and the specificity was 96.1% (413/430). Out of the 9 suspected HV positive sample detected by DFA, 6 were confirmed positive by real-time quantitative PCR and 3 were denied.

CONCLUSIONCompared with the DFA, real-time quantitative PCR could also be used to detect the infection of HV in rats, and the result might be more stable.

Animals ; Fluorescent Antibody Technique, Direct ; Hantavirus ; isolation & purification ; Hemorrhagic Fever with Renal Syndrome ; epidemiology ; prevention & control ; Lung ; virology ; Rats ; Real-Time Polymerase Chain Reaction

This study describes the epidemiology of hemorrhagic fever with renal syndrome (HFRS) in the past 10 yr (2001-2010) in Korea. During this period, a total of 3,953 HFRS patients and an average prevalence rate of 0.81 per 100,000 population were recorded, with a total of 40 fatal cases, corresponding to a case fatality rate of 1.01%. More HFRS cases were found in men than in women (57% vs 43%), and a higher prevalence rate of HFRS was observed in patients older than 40 yr (82.1%). The highest numbers of HFRS cases were found amongst farmers (35.6%). The majority of HFRS cases (71.3%) occurred in the last quarter of the calendar year (October to December). More HFRS cases occurred in the western part than in the eastern part of Korea (68.9% vs 31.1%). The incidence of HFRS was significantly higher (P < 0.001) in rural areas than in urban areas (80.3% vs 19.7%). HFRS still occurs commonly among men, in autumn, and in western rural area of Korea.
Adult ; Female ; Hemorrhagic Fever with Renal Syndrome/*epidemiology/mortality ; Humans ; Male ; Middle Aged ; Prevalence ; Republic of Korea/epidemiology ; Seasons

OBJECTIVETo explore the influence of landscape elements on the transmission of hemorrhagic fever with renal syndrome (HFRS) in Changsha.

METHODSA total of 327 cases of HFRS diagnosed between year 2005 - 2009 were recruited in the study. Based on the demographic data, meteorological data and the data of second national land survey during the same period, a GIS landscape elements database of HFRS at the township scale of Changsha was established. Spatial-temporal cluster analysis methods were adopted to explore the influence of landscape elements on the spatial-temporal distribution of HFRS in Changsha during the year of 2005 - 2009.

RESULTSThe annual incidences of HFRS in Changsha between year 2005 - 2009 were 1.16/100 000 (70 cases), 0.95/100 000 (58 cases), 1.40/100 000(87 cases), 0.75/100 000(47 cases) and 1.02/100 000(65 cases) respectively. The results of poisson regression model analysis of principal component showed that the incidence of HFRS was positively correlated with farmland area (M = 29.00 km2) and urban and rural area (M = 6.12 km2; incidence rate ratios (IRR) = 1.34, 95% CI: 1.27 - 1.41); but negatively correlated with forestland area (M = 39.00 km2; IRR = 0.67, 95% CI: 0.55 - 0.81) and garden plot area (M = 0.99 km2; IRR = 0.74, 95% CI: 0.63 - 0.86). A significant cluster of the spatial-temporal distribution of HFRS cases was found in the study. The primary cluster (28.9 N, 113.37 E, radius at 22.22 km, RR = 5.23, log likelihood ratio (LLR) = 51.61, P <0.01, 67 cases of HFRS and incidence at 4.4/100 000) was found between year 2006 and 2007; and the secondary cluster (28.2 N, 113.6 E, RR = 10.77, LLR = 16.01, P < 0.01, 11 cases of HFRS and the incidence at 10.6/100 000) was found between year 2008 and 2009.

CONCLUSIONThe landscape elements were found to be closely related to the prevalence and transmission of HFRS.

China ; epidemiology ; Climate ; Geographic Information Systems ; Hemorrhagic Fever with Renal Syndrome ; epidemiology ; transmission ; Humans ; Regression Analysis ; Space-Time Clustering

OBJECTIVETo study the comprehensive monitoring mechanism of mouse and the effect of hemorrhagic fever with renal syndrome (HFRS) vaccine in the high prevalence areas of natural focus infectious disease of Zhejiang province in 1994 - 2010.

METHODSThe night trapping method was used to monitor the population proportion, density and the rate of hantavirus (HV) carriers in mice in Xikou township Longyou county in August and September from 1994 to 2010. The healthy residents in Xikou township aged 16 to 60 years were recruited. The subjects were randomly selected as vaccination group and control group according to age, sex, occupational distribution (10 178 in intervention group and 16 159 in control group). Intervention group was given purified and inactivated vaccine from suckling mouse brain, while the control group received no intervention. The prevention effect was evaluated by protective rate of vaccine.

RESULTSThe mouse population was stable in the sixteen years and the apodemus agrarius was the main type (76.5% (564/737)). The average density of mouse was 4.73% (1170/24 727). The average rate of virus carrier of mouse was 3.87% (41/1033). In 1994 - 1995, the density of mouse was 22.82% (186/815) and the rate of virus carrier was 7.0% (10/143). In 2009 - 2010, the density of mouse decreased to 2.75% (119/4330) and the rate of virus carrier was 5.5% (13/237). The average antibody positive rate of mouse from 2005 to 2010 was 4.8% (35/728) and the rate was 4.4% (6/138), 0.0% (0/113), 11.8% (16/136), 1.0% (1/104), 3.7% (4/109) and 6.3% (8/128) in each year (P < 0.01). The protective rate of HFRS vaccine was 96.2% (1 case in intervention group and 41 cases in control group).

CONCLUSIONThe density of mouse decreased significantly in Zhejiang province. The rate of virus carrier of mouse is stable. The vaccine is effective.

Adolescent ; Adult ; Animals ; China ; epidemiology ; Disease Reservoirs ; Environmental Monitoring ; Female ; Hantavirus ; Hemorrhagic Fever with Renal Syndrome ; epidemiology ; prevention & control ; Humans ; Male ; Middle Aged ; Muridae ; Vaccination ; Viral Vaccines ; therapeutic use ; Young Adult