Dengue in Java, Indonesia: Relevance of Mosquito Indices as Risk Predictors

Abstract

BackgroundNo vaccine is currently available for dengue virus (DENV), therefore control programmes usually focus on managing mosquito vector populations. Entomological surveys provide the most common means of characterising vector populations and predicting the risk of local dengue virus transmission. Despite Indonesia being a country strongly affected by DENV, only limited information is available on the local factors affecting DENV transmission and the suitability of available survey methods for assessing risk.Methodology/principal findingsWe conducted entomological surveys in the Banyumas Regency (Central Java) where dengue cases occur on an annual basis. Four villages were sampled during the dry and rainy seasons: two villages where dengue was endemic, one where dengue cases occurred sporadically and one which was dengue-free. In addition to data for conventional larvae indices, we collected data on pupae indices, and collected adult mosquitoes for species identification in order to determine mosquito species composition and population density. Traditionally used larval indices (House indices, Container indices and Breteau indices) were found to be inadequate as indicators for DENV transmission risk. In contrast, species composition of adult mosquitoes revealed that competent vector species were dominant in dengue endemic and sporadic villages.Conclusions/significanceOur data suggested that the utility of traditional larvae indices, which continue to be used in many dengue endemic countries, should be re-evaluated locally. The results highlight the need for validation of risk indicators and control strategies across DENV affected areas here and perhaps elsewhere in SE Asia.

Forest cover and climate as potential drivers for dengue fever in Sumatra and Kalimantan 2006–2016: a spatiotemporal analysis

“…The ENSO event also influenced inter-annual rainfall variability [44], with Sumatra, Kalimantan and Malaysia being most affected [45]. This phenomenon is similar to ENSO 1992-2001 [46] and was also recorded in Taiwan in 2016 [47][48][49][50]. Notably, other causes of inter-annual variation in DF incidence have been reported in the literature, including varying levels of population immunity [51][52][53][54][55][56].…”

Dengue viruses circulating in Indonesia: A systematic review and phylogenetic analysis of data from five decades

“…Changes in epidemiological aspects include that outbreak trend of dengue haemorrhagic fever (DHF) has become irregular, with a high interepidemic background, increasing mean age of DHF cases, increasing annual DHF incidence, and decreasing case fatality rate . Studies have been conducted to assess the plausible determinants associated with increased dengue incidence or outbreaks, including meteorological data, vector activities, and socio‐economic and environmental factors . However, missing from this literature is a review of the dynamics of DENV transmission in Indonesia by means of a chronological overview and assessment of whether changes in DENV circulation may be associated with an increase in dengue incidence.…”

Dengue Outbreak in Mombasa City, Kenya, 2013–2014: Entomologic Investigations

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