Emergence And Circulation of Dengue Virus Serotype 2 In Guangzhou Over A Period of 20 Years

Objectives The dengue epidemic in Guangzhou has imposed a rising burden on society and health infrastructure. Here we present the genotype data for dengue virus serotype 2 (DENV-2) to improve the understanding of dengue epidemic. Methods We sequenced the envelope gene of DENV-2 obtained from patient serum sample, and subsequently performed the maximum-likelihood phylogenetic analysis using PhyMLv3.1, the maximum clade credibility analysis using BEAST v.1.10.4 and selection pressure analysis using Datamonkey 2.0 . Results The DENV-2 prevalent in Guangzhou region related to the strains of Southeast Asian countries.Our results suggest that the Malaysia/Indian subcontinent genotype is prevalent in Guangzhou and no genotype shift has occurred during the last 20 years. Episodic positive selection was detected at one site. Conclusions Prevention and monitoring imported cases are important for local control. The shift between the lineages of the Malaysia/Indian subcontinent genotype, which originated at different time points, may be the underlying cause of rising DENV-2 cases in Guangzhou.The low rate of dengue haemorrhagic fever in Guangzhou may be explained by the dominance of the less virulent Malaysia/Indian subcontinent genotype.

The Epidemic Risk of Dengue Fever in Japan: Climate Change and Seasonality

Dengue fever is a leading cause of illness and death in the tropics and subtropics, and the disease has become a threat to many nonendemic countries where the competent vectors such as Aedes albopictus and Aedes aegypti are abundant. The dengue epidemic in Tokyo, 2014, poses the critical importance to accurately model and predict the outbreak risk of dengue fever in nonendemic regions. Using climatological datasets and traveler volumes in Japan, where dengue was not seen for 70 years by 2014, we investigated the outbreak risk of dengue in 47 prefectures, employing the temperature-dependent basic reproduction number and a branching process model. Our results show that the effective reproduction number varies largely by season and by prefecture, and, moreover, the probability of outbreak if an untraced case is imported varies greatly with the calendar time of importation and location of destination. Combining the seasonally varying outbreak risk with time-dependent traveler volume data, the unconditional outbreak risk was calculated, illustrating different outbreak risks between southern coastal areas and northern tourist cities. As the main finding, the large travel volume with nonnegligible risk of outbreak explains the reason why a summer outbreak in Tokyo, 2014, was observed. Prefectures at high risk of future outbreak would be Tokyo again, Kanagawa or Osaka, and highly populated prefectures with large number of travelers.

A Model of Vaccination for Dengue in the Philippines 2016–2018

A mathematical model of the dengue epidemic in the Philippines is developed to analyse the vaccination of children in 2016–2017. Reported case data and reported mortality data from the Philippines Department of Health is used to analyze quantitatively this vaccination program. The model compares the epidemic outcomes of no vaccination of children, vaccination only of previously infected children, and vaccination of all children.

Levantamento de dados sobre a epidemia de dengue na cidade de Alto Paraíso, Paraná, Brasil: Uma questão de saúde pública / Data survey of dengue epidemic in the city of Alto Paraíso, Paraná, Brazil: A public health issue

O presente estudo tem como objetivo levantar e analisar dados da dengue, doença transmitida pelo Aedes aegypti e Aedes albopictus, na última década epidemiológica (2011/2020), mediante dados oficiais registrados. Como metodologia, foram utilizados boletins epidemiológicos disponibilizados online, informações advindas da Secretaria de Saúde de Alto Paraíso – PR, com base no SINAN. Os dados revelam que houve uma estabilidade no número de casos de 2011 até 2014, sendo que em 2015 tivemos um leve aumento, de 2016 a 2018 os números permaneceram estáveis, aumentando em 2019 e alcançando níveis epidêmicos em 2020. Os dados levantados refletem concordância com o Estado do Paraná e outras cidades comparadas da macrorregião noroeste e localidades próximas. Não foram registrados óbitos no município em decorrência da doença e a faixa etária mais acometida compreende de 20 a 39 anos. Mesmo com investimentos públicos, espera-se a retomada da atenção à doença, assim como a sensibilização da comunidade, além do combate às fake news sobre o tema.

Dengue transmission risk in a changing climate: Bangladesh could experience a longer dengue fever season in the future

Our changing climate is already affecting the transmission of vector borne diseases such as dengue fever. This issue presents a significant public health concern for some nations, such as Bangladesh, which already experience regular seasonal outbreaks of dengue fever under present day conditions. To provide guidance for proactive public health planning to potentially mitigate future infections, we explore the impact of climate change on dengue infections by calculating the change in vectorial capacity of Aedes aegypti mosquito at a seasonal level for all regions in Bangladesh under two atmospheric greenhouse gas concentrations for the period 2050-2099. For each of the four climate models used, and for both scenarios, our analysis reveals that the annual vectorial capacity remains at a level that would enable potential dengue epidemic transmission in all regions during the time period examined. We found a slight decline in vectorial capacity in half of the regions examined during the last two decades of 21st Century for the lower-concentration scenario, with a pronounced decline in vectorial capacity in all geographic regions beginning in 2060 for the higher-concentration scenario. The likely reason is that in many regions greenhouse warming is leading to temperatures beyond the optimum for mosquito breeding. However, seasonal differences in vectorial capacity dissipate as the climate warms, to the point that there is almost no observable seasonality for the higher-concentration scenario during the last two decades of the century. This suggests the potential for the dengue season to extend all year, with outbreaks occurring at any time. These findings suggest that disease surveillance and control activities would need to be geographically and temporally adapted to mitigate dengue epidemic risk.