High potential risk of dengue transmission during the hot-dry season in Nha Trang City, Vietnam

Abstract

We visited houses and inspected water-holding containers to determine the potential risks of dengue transmission during different seasons. This survey was conducted in 2 neighbourhoods of Nha Trang City in July and December 2006, which correspond to the middle of the hot-dry season and the beginning of the cool-wet season, respectively. We inspected a total of 1,438 wet containers in 196 premises during both survey periods; 20% of the containers were positive for Aedes aegypti larvae and 8% for Ae. aegypti pupae. Indoor water-holding containers, which were sparsely distributed, exhibited high pupal productivity and efficiency (pupal productivity of a type of container/prevalence of that type of container) in either the first survey conducted in July, or the second, conducted in December. Although rainfall may not influence the number and distribution of water-holding containers in the city, the high average temperature in the first survey period resulted in a higher potential risk of dengue transmission.Our analysis suggests that if intensive source reduction is conducted in summer and containers with high pupal productivity and efficiency are targeted, the risk of dengue transmission in the city could be effectively reduced.

Temperature and Dengue Virus Infection in Mosquitoes: Independent Effects on the Immature and Adult Stages

“…aegypti 37,[57][58][59] as well as the relationship between temperature and the occurrence of dengue in nature. [34][35][36][37] The current experiment did not test mosquitoes at multiple time points post-exposure to dengue virus to identify the extrinsic incubation period (the time between initial acquisition of the pathogen and when transmission is possible). Adult life history traits for mosquitoes exposed to dengue-1 virus (experiment 2).…”

“…aegypti mosquitoes and its role on the incidence of dengue in nature. [34][35][36][37] Despite the long history of relating temperature to vector biology, relatively few studies have evaluated the net effect of temperature on multiple traits (adult lifespan and vector competences for viruses) as it relates to risk of disease transmission.…”

Climate Variability and Dengue Fever in Warm and Humid Mexico

“…It could also indicate that rainfall does not influence the survival of adult vectors directly 38 because of their indoor activity or that water-holding containers used as breeding sites in the region may be mainly man-filled containers. 39 Increases in human population in urban areas, uncontrolled urbanization, and lack of adequate public services are common in Mexico. 7 High levels of urbanization increase the risk of DF.…”

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“…5 The breeding sites of dengue vector mosquitoes (i.e., Aedes aegypti ) are located in and around households and may include indoor water jars, basins, and vases. [6][7][8][9] Because such containers are often indispensable, it is difficult to limit their use. 9 As a result, household residents are highly susceptible to Ae.…”