BACKGROUND AND OBJECTIVE: With an aim of developing an effective disease monitoring and surveillance of dengue fever, this study intends to analyze the spatial distribution of dengue incidences in the National Capital Region (NCR), across four years of reported dengue cases.
MATERIALS AND METHODS: Data used was provided by the Department of Health (DOH) consisting of all reported dengue cases in NCR from 2010-2013. For mapping and visualization, a shapefile of NCR was made readily available by www.philgis.org. Both Moran's I and Kulldorff's spatial scan statistics (SaTScan) were used to identify clusters across the same time period.
RESULTS AND CONCLUSION: The analyses identified significant clustering of dengue incidence and revealed that the northern cities of NCR, such as Caloocan, Malabon, Navotas and Valenzuela, exhibited high spatial autocorrelation using local Moran's I and Kulldorff's SaTScan. A temporal analysis of the results also suggested movement in increased dengue incidence through time, from the northwest cities to the northeast cities. Presence of spatial autocorrelation in dengue incidence suggests possible enhancements of early detection schemes for dengue surveillance. Moreover, the results of these analyses will be of interest to both policymakers and health experts in providing a basis for which they can properly allocate resources for the prevention and treatment of dengue fever.

Dengue ; Disease Hotspot

Objective: To analyze HIV transmission hotspots and characteristics of cross-regional transmission in Guangxi Zhuang autonomous region (Guangxi) based on the molecular network analysis, and provide evidence for optimization of precise AIDS prevention and control strategies. Methods: A total of 5 996 HIV pol sequences sampled from Guangxi between 1997 and 2020 were analyzed together with 165 534 published HIV pol sequences sampled from other regions. HIV-TRACE was used to construct molecular network in a pairwise genetic distance threshold of 0.5%. Results: The proportion of HIV sequences entering the molecular network of HIV transmission hotspots in Guangxi was 31.5% (1 886/5 996). In the molecular network of HIV cross-regional transmission, the links within Guangxi accounted for 51.6% (2 613/5 062), the links between Guangxi and other provinces in China accounted for 48.0% (2 430/5 062), and the links between Guangxi and other countries accounted for 0.4% (19/5 062). The main regions which had cross-regional linked with Guangxi were Guangdong (49.5%, 1 212/2 449), Beijing (17.5%, 430/2 449), Shanghai (6.9%, 168/2 449), Sichuan (5.7%, 140/2 449), Yunnan (4.2%, 102/2 449), Shaanxi (3.8%, 93/2 449), Zhejiang (2.8%, 69/2 449), Hainan (2.0%, 49/2 449), Anhui (1.5%, 37/2 449), Jiangsu (1.3%, 33/2 449), and other regions (each one <1.0%), respectively. The risk factors of entering the molecular network of HIV transmission hotspots in Guangxi included being aged ≥50 years (compared with being aged 25-49 years, aOR=1.68,95%CI:1.46-1.95), males (compared with females, aOR=1.21,95%CI:1.05-1.40), being single (compared with being married, aOR=1.18,95%CI:1.00-1.39), having education level of high school or above (compared with having education level of junior high school or below, aOR=1.21,95%CI:1.04-1.42), acquired HIV through homosexual intercourse (compared with acquired with HIV through heterosexual intercourse, aOR=1.77, 95%CI:1.48-2.12). The risk factors of cross-regional transmission included males (compared with females, aOR=1.74,95%CI:1.13-2.75), having education level of high school or above (compared with having education level of junior high school or below, aOR=1.96,95%CI:1.43-2.69), being freelancer/unemployed/retired (compared with being farmers, aOR=1.50,95%CI:1.07-2.11), acquired HIV through homosexual intercourse (compared with acquired with HIV through heterosexual intercourse, aOR=3.28,95%CI:2.30-4.72). Conclusion: There are HIV transmission hotspots in Guangxi. Guangxi and other provinces in China form a complex cross-regional transmission network. Future studies should carry out social network surveys in high-risk populations inferred from the molecular network analysis for the timely identification of hidden transmission chains and reduction of the second-generation transmission of HIV.
Acquired Immunodeficiency Syndrome ; China/epidemiology* ; Disease Hotspot ; Female ; HIV Infections/epidemiology* ; Heterosexuality ; Humans ; Male