Testing the impact of virus importation rates and future climate change on dengue activity in Malaysia using a mechanistic entomology and disease model

Abstract

We aimed to reparameterize and validate an existing dengue model, comprising an entomological component (CIMSiM) and a disease component (DENSiM) for application in Malaysia. With the model we aimed to measure the effect of importation rate on dengue incidence, and to determine the potential impact of moderate climate change (a 1 °C temperature increase) on dengue activity. Dengue models (comprising CIMSiM and DENSiM) were reparameterized for a simulated Malaysian village of 10 000 people, and validated against monthly dengue case data from the district of Petaling Jaya in the state of Selangor. Simulations were also performed for 2008-2012 for variable virus importation rates (ranging from 1 to 25 per week) and dengue incidence determined. Dengue incidence in the period 2010-2012 was modelled, twice, with observed daily weather and with a 1 °C increase, the latter to simulate moderate climate change. Strong concordance between simulated and observed monthly dengue cases was observed (up to r = 0·72). There was a linear relationship between importation and incidence. However, a doubling of dengue importation did not equate to a doubling of dengue activity. The largest individual dengue outbreak was observed with the lowest dengue importation rate. Moderate climate change resulted in an overall decrease in dengue activity over a 3-year period, linked to high human seroprevalence early on in the simulation. Our results suggest that moderate reductions in importation with control programmes may not reduce the frequency of large outbreaks. Moderate increases in temperature do not necessarily lead to greater dengue incidence.

Bibliometric analysis of peer-reviewed literature on climate change and human health with an emphasis on infectious diseases

“…The model aims to apply the statistical equations to future climate scenarios in order to predict the actual distribution of the disease. These models have been applied to malaria and dengue fever [27,76,[103][104][105][106][107][108]. The case incidence of dengue fever has multiplied 30fold since the 1960s [109].…”

Climate change and the epidemiology of selected tick‐borne and mosquito‐borne diseases: update from the International Society of Dermatology Climate Change Task Force

“…For dengue fever, changes in rainfall and humidity have been associated with increased risk in Vietnam . In Malaysia, a moderate increase in temperature (1 °C) was not necessarily attributed to increased dengue incidence . Climate models also predicted that future changes in climate could influence the geographic range of the disease vectors of dengue fever in the Americas and Europe, as well as eastern China .…”

Abbreviations and acronyms

“…Studies in Australia suggest that future changes in Ae. aegypti distribution in the country may not be directly caused by climate change but rather, by human response to changing rainfall patterns by increased or decreased use of water storage containers (Beebe et al, 2009;Russell et al, 2009;Williams et al, 2010Williams et al, , 2014Williams et al, , 2015Bannister-Tyrrell et al, 2013).…”