Dengue fever transmission between a construction site and its surrounding communities in China

Abstract

Background: Due to an increase in mosquito habitats and the lack facilities to carry out basic mosquito control, construction sites in China are more likely to experience secondary dengue fever infection after importation of an initial infection, which may then increase the number of infections in the neighboring communities and the chance of community transmission. The aim of this study was to investigate how to effectively reduce the transmission of dengue fever at construction sites and the neighboring communities.

Methods: The Susceptible-Exposed-Infectious/Asymptomatic-Recovered (SEIAR) model of human and SEI model of mosquitoes were developed to estimate the transmission of dengue virus between humans and mosquitoes within the construction site and within a neighboring community, as well between each of these. With the calibrated model, we further estimated the effectiveness of different intervention scenarios targeting at reducing the transmissibility at different locations (i.e. construction sites and community) with the total attack rate (TAR) and the duration of the outbreak (DO).

Results: A total of 102 construction site-related and 131 community-related cases of dengue fever were reported in our area of study. Without intervention, the number of cases related to the construction site and the community rose to 156 (TAR: 31.25%) and 10,796 (TAR: 21.59%), respectively. When the transmission route from mosquitoes to humans in the community was cut off, the number of community cases decreased to a minimum of 33 compared with other simulated scenarios (TAR: 0.068%, DO: 60 days). If the transmission route from infectious mosquitoes in the community and that from the construction site to susceptible people on the site were cut off at the same time, the number of cases on the construction site dropped to a minimum of 74 (TAR: 14.88%, DO: 66 days).

Conclusions: To control the outbreak of dengue fever effectively on both the construction site and in the community, interventions needed to be made both within the community and from the community to the construction site. If interventions only took place within the construction site, the number of cases on the construction site would not be reduced. Also, interventions implemented only within the construction site or between the construction site and the community would not lead to a reduction in the number of cases in the community.

Keywords: Community; Construction site; Dengue; Mathematical model; Outbreak.

Fig. 1

Distribution of dengue cases in Chikan District in 2018 and remote sensing images of Community A and the index case. Filled red circle represents construction site A located in the middle of Chikan District

Fig. 2

Flowchart of the development of the dengue transmission model. Parts in red represent two ways to control the number of dengue cases on the construction site to a minimum, the part in blue represents the way to control the number of dengue cases in the community to a minimum. For an explanation of the terminology, refer to “Model structure” section

Fig. 3

The transmission process of dengue virus between the construction site and the neighboring community

Fig. 4

Reported cases of dengue fever on the construction site A and in the surrounding community in Zhanjiang Prefecture, P.R. China, in 2018

Fig. 5

Curve fitting of reported data and Susceptible-Exposed-Infectious/Asymptomatic-Recovered (SEIAR) models without intervention and simulated epidemic curve with no intervention on the construction site (a) and in the neighboring community (b)