Spatial-Temporal Distribution Pattern of Dengue Fever and Spatial Relationship of the Aedes Mosquito Larvae Index in Phuket Province

Abstract

Dengue fever is influenced by physical environmental factors that control the population dynamics of Aedes mosquito vectors. Studying the spatial distribution patterns of dengue patients using geographic information system tools, combined with surveys of Aedes mosquito larvae index through public health methods, can help understand the phenomenon and the spatial relationships with land use patterns. This study aims to investigate the spatial and temporal distribution of dengue fever in Phuket Province and examine the spatial relationship of the Aedes mosquito larvae index. A broad overview of the entire province using dengue patient data from 2007 to 2017 revealed a significant outbreak in 2013, with the majority occurring during the rainy season, and only a few cases in other seasons. Furthermore, village-level patient data were linked with Geographic Information Systems (GIS) data to map the epidemic locations, showing that the highest number of cases were consistently found in Mueang Phuket District every year. However, when considering the incidence rate per 100,000 people, a different pattern emerged, indicating the highest outbreak concentration in two specific villages within Thalang District. Field data collection of the Aedes mosquito larvae index in six communities showed a significant spatial relationship with land use characteristics in the surrounding area when considering the Aedes species. In the end of the rainy season, Aedes aegypti was predominantly found in urban areas, while both Aedes aegypti and Aedes albopictus were found in semi-rural and forested areas. Additionally, in both the summer and rainy seasons, both species could be found in the same containers. This indicates that besides the natural habitat in natural water containers, Aedes albopictus also lay eggs in the containers around human dwellings. Aedes albopictus is not only a vector for dengue fever, but also for Chikungunya and Zika viruses, which increases threat to humans. Therefore, communities near agricultural and forested areas should exercise extra caution. Public health authorities are supposed to plan the prevention of dengue fever and other mosquito-borne diseases to ensure a balance among health, society, economy and the environment.