Comparative susceptibility of mosquito populations in North Queensland, Australia to oral infection with dengue virus.

Dengue is the most prevalent arthropod-borne virus, with at least 40% of the world's population at risk of infection each year. In Australia, dengue is not endemic, but viremic travelers trigger outbreaks involving hundreds of cases. We compared the susceptibility of Aedes aegypti mosquitoes from two geographically isolated populations to two strains of dengue virus serotype 2. We found, interestingly, that mosquitoes from a city with no history of dengue were more susceptible to virus than mosquitoes from an outbreak-prone region, particularly with respect to one dengue strain. These findings suggest recent evolution of population-based differences in vector competence or different historical origins. Future genomic comparisons of these populations could reveal the genetic basis of vector competence and the relative role of selection and stochastic processes in shaping their differences. Lastly, we show the novel finding of a correlation between midgut dengue titer and titer in tissues colonized after dissemination

Epidemiology trend with particular spatio-temporal distribution of DIR in Malaysia

Previous epidemiology record shows obvious trend of dengue fever that contribute to significant upsurge in the increasing number of dengue cases and deaths until the late nineteenth century with the sharp straight trend. This virus is transmitted to human by the bite of a female Aedes Aegypti mosquito, that could simply recognise by a white marking on its legs and lyre on the upper surface of its thorax. In Malaysia, dengue fever has been occurred since the first case in Penang around 1901 and continuously showed an intensity increment over the past few decades. The epidemics of dengue in Malaysia were observed predominantly confined to the densely populated and urbanised areas of Peninsular Malaysia (East of Malaysia) focusing in the Selangor state. Dengue cases that recorded in the nine district of Selangor state over seven years' period were used to ample evidence of dengue and peak transmission occurred in 2014, 2015 and 2019. The objective of this study was to access the dengue incidence rate according to the district in Selangor. The results were clustered by district based on the mean annual dengue incidence rate (DIR) values to classify the dengue risk categories. Among highest incidence rates were located at four districts; Petaling, Hulu Langat, Klang and Gombak where surrounding federal territory of Kuala Lumpur in the center of the region is on of main interest from high population densities and conclusion has been made that high DIR is strongly increase the risk of dengue incidence in that state

Population density, water supply, and the risk of dengue fever in Vietnam: cohort study and spatial analysis.

BACKGROUND: Aedes aegypti, the major vector of dengue viruses, often breeds in water storage containers used by households without tap water supply, and occurs in high numbers even in dense urban areas. We analysed the interaction between human population density and lack of tap water as a cause of dengue fever outbreaks with the aim of identifying geographic areas at highest risk. METHODS AND FINDINGS: We conducted an individual-level cohort study in a population of 75,000 geo-referenced households in Vietnam over the course of two epidemics, on the basis of dengue hospital admissions (n = 3,013). We applied space-time scan statistics and mathematical models to confirm the findings. We identified a surprisingly narrow range of critical human population densities between around 3,000 to 7,000 people/km² prone to dengue outbreaks. In the study area, this population density was typical of villages and some peri-urban areas. Scan statistics showed that areas with a high population density or adequate water supply did not experience severe outbreaks. The risk of dengue was higher in rural than in urban areas, largely explained by lack of piped water supply, and in human population densities more often falling within the critical range. Mathematical modeling suggests that simple assumptions regarding area-level vector/host ratios may explain the occurrence of outbreaks. CONCLUSIONS: Rural areas may contribute at least as much to the dissemination of dengue fever as cities. Improving water supply and vector control in areas with a human population density critical for dengue transmission could increase the efficiency of control efforts. Please see later in the article for the Editors' Summary