scholarly journals Climatological, virological and sociological drivers of current and projected dengue fever outbreak dynamics in Sri Lanka

2020 ◽  
Vol 17 (167) ◽  
pp. 20200075 ◽  
Author(s):  
Caroline E. Wagner ◽  
Milad Hooshyar ◽  
Rachel E. Baker ◽  
Wenchang Yang ◽  
Nimalan Arinaminpathy ◽  
...  

The largest ever Sri Lankan dengue outbreak of 2017 provides an opportunity for investigating the relative contributions of climatological, epidemiological and sociological drivers on the epidemic patterns of this clinically important vector-borne disease. To do so, we develop a climatologically driven disease transmission framework for dengue virus using spatially resolved temperature and precipitation data as well as the time-series susceptible-infected-recovered (SIR) model. From this framework, we first demonstrate that the distinct climatological patterns encountered across the island play an important role in establishing the typical yearly temporal dynamics of dengue, but alone are unable to account for the epidemic case numbers observed in Sri Lanka during 2017. Using a simplified two-strain SIR model, we demonstrate that the re-introduction of a dengue virus serotype that had been largely absent from the island in previous years may have played an important role in driving the epidemic, and provide a discussion of the possible roles for extreme weather events and human mobility patterns on the outbreak dynamics. Lastly, we provide estimates for the future burden of dengue across Sri Lanka using the Coupled Model Intercomparison Phase 5 climate projections. Critically, we demonstrate that climatological and serological factors can act synergistically to yield greater projected case numbers than would be expected from the presence of a single driver alone. Altogether, this work provides a holistic framework for teasing apart and analysing the various complex drivers of vector-borne disease outbreak dynamics.

2013 ◽  
Vol 18 (21) ◽  
Author(s):  
E Schwartz ◽  
E Meltzer ◽  
M Mendelson ◽  
A Tooke ◽  
F Steiner ◽  
...  

In April 2013, ten cases of dengue fever in travellers returning from Luanda, Angola, to five countries on four continents, were reported to the globally distributed GeoSentinel Surveillance network. Dengue virus serotype 1 was identified in two cases. The findings indicate that a major dengue outbreak is currently ongoing in Luanda. This report illustrates how cases from an emerging arboviral epidemic focus can spread internationally and highlights the risk of dissemination of a vector-borne disease into receptive areas


2018 ◽  
Vol 104 (2) ◽  
pp. 80-83
Author(s):  
D Biggs

AbstractIntroductionWhen on operational deployment, or where a vector-borne disease threat has been identified, military personnel wear uniform that has been pre-impregnated with permethrin insecticide to prevent insect bites, as part of an integrated approach to bite avoidance in order to reduce disease non-battle injury. This article reports a study that was carried out to investigate whether the clothing treatments currently in use are effective at preventing insect bites.MethodsA human volunteer study was conducted using two different species of mosquito and clothing subjected to different washing schedules. The number of landing events and probing events, and insect mortality, were recorded.ResultsThere was a marked increase in mosquito activity as the amount of viable permethrin was reduced through washing. There was a statistically significant difference between 50 washes and the negative control, and between 50 and 5 washes. As clothing is increasingly washed, its effectiveness is reduced.ConclusionThe use of pre-impregnated uniform does not provide complete protection against biting insects throughout the life of the garment. No single means of protection will prevent personnel from being bitten, and a suite of personal and communal measures should be employed to reduce the risk of vector-borne disease, including the use of insect repellent, mosquito nets, anti-malarial chemoprophylaxis and re-treatment of clothing against biting insects in order to reduce the risk of disease transmission. Since this study, alternative means of clothing treatment have been sought to reinforce the pre-treated uniforms issued. Advice and direction is available, specific to the environment personnel are deploying to, based upon risk.


Author(s):  
Mya Myat Ngwe Tun ◽  
Rohitha Muthugala ◽  
Lakmali Rajamanthri ◽  
Takeshi Nabeshima ◽  
Corazon C. Buerano ◽  
...  

2020 ◽  
pp. 1-4
Author(s):  
Fahim Aslam ◽  

Dengue virus is one of major public heath burden in several countries, it is described to be “a fast-emerging pandemic prone viral disease” by the WHO and is one of the most common form of vector borne diseases worldwide. The disease is transmitted through the female Aedes mosquito and most commonly found in tropical countries. A reported 400 million reported dengue cases occur yearly and an estimated 3 billion people could be affected by the disease in the upcoming decade making it a global crisis. The disease is caused by four serotypes of the dengue virus (DENV1-4) making it difficult for the treatment to work on the patients due to its different virulent mechanism. Using the data available from the Ministry of Health, Epidemiology Unit in Sri Lanka the dengue reported cases from 2014 to 2018 are analyzed over the five years to identify the trends and occurrence patterns [1,2].


2021 ◽  
Vol 288 (1949) ◽  
Author(s):  
Paul J. Huxley ◽  
Kris A. Murray ◽  
Samraat Pawar ◽  
Lauren J. Cator

Laboratory-derived temperature dependencies of life-history traits are increasingly being used to make mechanistic predictions for how climatic warming will affect vector-borne disease dynamics, partially by affecting abundance dynamics of the vector population. These temperature–trait relationships are typically estimated from juvenile populations reared on optimal resource supply, even though natural populations of vectors are expected to experience variation in resource supply, including intermittent resource limitation. Using laboratory experiments on the mosquito Aedes aegypti , a principal arbovirus vector, combined with stage-structured population modelling, we show that low-resource supply in the juvenile life stages significantly depresses the vector's maximal population growth rate across the entire temperature range (22–32°C) and causes it to peak at a lower temperature than at high-resource supply. This effect is primarily driven by an increase in juvenile mortality and development time, combined with a decrease in adult size with temperature at low-resource supply. Our study suggests that most projections of temperature-dependent vector abundance and disease transmission are likely to be biased because they are based on traits measured under optimal resource supply. Our results provide compelling evidence for future studies to consider resource supply when predicting the effects of climate and habitat change on vector-borne disease transmission, disease vectors and other arthropods.


Acta Tropica ◽  
2018 ◽  
Vol 188 ◽  
pp. 142-151 ◽  
Author(s):  
Robert T. Jones ◽  
Lucy S. Tusting ◽  
Hugh M.P. Smith ◽  
Sylvester Segbaya ◽  
Michael B. Macdonald ◽  
...  

2019 ◽  
Vol 374 (1775) ◽  
pp. 20180272 ◽  
Author(s):  
G. Chowell ◽  
K. Mizumoto ◽  
J. M. Banda ◽  
S. Poccia ◽  
C. Perrings

Predicting the impact of natural disasters such as hurricanes on the transmission dynamics of infectious diseases poses significant challenges. In this paper, we put forward a simple modelling framework to investigate the impact of heavy rainfall events (HREs) on mosquito-borne disease transmission in temperate areas of the world such as the southern coastal areas of the USA. In particular, we explore the impact of the timing of HREs relative to the transmission season via analyses that test the sensitivity of HRE-induced epidemics to variation in the effects of rainfall on the dynamics of mosquito breeding capacity, and the intensity and temporal profile of human population displacement patterns. The recent Hurricane Harvey in Texas motivates the simulations reported. Overall, we find that the impact of vector-borne disease transmission is likely to be greater the earlier the HREs occur in the transmission season. Simulations based on data for Hurricane Harvey suggest that the limited impact it had on vector-borne disease transmission was in part because of when it occurred (late August) relative to the local transmission season, and in part because of the mitigating effect of the displacement of people. We also highlight key data gaps related to models of vector-borne disease transmission in the context of natural disasters. This article is part of the theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes’. This issue is linked with the subsequent theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control’.


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