Region-wide synchrony and traveling waves of dengue across eight countries in Southeast Asia

Abstract

Dengue is a mosquito-transmitted virus infection that causes epidemics of febrile illness and hemorrhagic fever across the tropics and subtropics worldwide. Annual epidemics are commonly observed, but there is substantial spatiotemporal heterogeneity in intensity. A better understanding of this heterogeneity in dengue transmission could lead to improved epidemic prediction and disease control. Time series decomposition methods enable the isolation and study of temporal epidemic dynamics with a specific periodicity (e.g., annual cycles related to climatic drivers and multiannual cycles caused by dynamics in population immunity). We collected and analyzed up to 18 y of monthly dengue surveillance reports on a total of 3.5 million reported dengue cases from 273 provinces in eight countries in Southeast Asia, covering ∼10 7 km 2 . We detected strong patterns of synchronous dengue transmission across the entire region, most markedly during a period of high incidence in 1997-1998, which was followed by a period of extremely low incidence in 2001-2002. This synchrony in dengue incidence coincided with elevated temperatures throughout the region in 1997-1998 and the strongest El Niño episode of the century. Multiannual dengue cycles (2-5 y) were highly coherent with the Oceanic Niño Index, and synchrony of these cycles increased with temperature. We also detected localized traveling waves of multiannual dengue epidemic cycles in Thailand, Laos, and the Philippines that were dependent on temperature. This study reveals forcing mechanisms that drive synchronization of dengue epidemics on a continental scale across Southeast Asia.is an arbovirus transmitted by Aedes mosquitos in the tropics and subtropics of the world. The virus causes an estimated 390 million infections per year, resulting in 96 million clinically symptomatic cases (1). DENV has four serotypes (DENV-1, DENV-2, DENV-3, and DENV-4) that each circulate worldwide. The spatial propagation of dengue transmission at short distances by the mosquito vector is well-understood, but the mechanism of long-distance spread has remained unclear. Disease transmission over large geographical distances is difficult to measure directly, but epidemiological coupling of locations revealed by synchrony in population-level disease patterns has been used successfully in the past to infer mechanisms of spread

Epidemiological and ecological determinants of Zika virus transmission in an urban setting

“…In order to resolve whether this was due to a lower transmission potential of ZIKV in 2016/2017 in FSA, we calculated the daily reproductive number ($R_0$) between 2013 and 2017 but found no notable decrease in 2016. Interestingly, the maximum $R_0$ in that period was observed in the season 2015/2016, coinciding with El Niño (Golden Gate Weather Services, 2017) and thus in line with the hypothesis that this phenomenon may temporary boost arboviral potential (Caminade et al, 2017; van Panhuis et al, 2015). By fitting our model to weekly case data we also estimated the observation rate, i.e.…”

“…In particular, our knowledege on parameters of public health importance, such as the basic reproduction number ($R_0$), the duration of infection (Ferguson et al, 2016), attack and reporting rates (Kucharski et al, 2016), the risk of sexual transmission (Maxian et al, 2017; Gao et al, 2016; Moghadas et al, 2017) and birth-associated microcephaly (Bewick et al, 2016; Perkins et al, 2016) has advanced significantly from studies using transmission models. Climate variables are critical for the epidemiological dynamics of Zika and other arboviral diseases, such as dengue (Lourenço and Recker, 2014; Feldstein et al, 2015; Kraemer et al, 2015; van Panhuis et al, 2015) and chikungunya (Poletti et al, 2011; Mourya et al, 2004; Salje et al, 2016). Although these have also been previously addressed in mapping and/or modelling studies (e.g.…”

Synchrony of Dengue Incidence in Ho Chi Minh City and Bangkok

“…precipitation and temperature) and possibly regionally climatic factors may drive these similarities. Trends in climatic factors have previously been shown to be correlated with patterns of dengue disease both within Thailand and in the wider Southeast Asian region [23, 24]. …”

Role of Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse) in local dengue epidemics in Taiwan

“…aegypti eggs due to lower winter temperatures was 48.6 % [29]. DF is a travel-related disease in Taiwan because travelers can carry DENV from endemic areas into the island [30–33]. After the transport of this virus into the island, it is passed on to Aedes mosquitoes, which can cause an outbreak of DF.…”