A Sequence of Flushing and Drying of Breeding Habitats of Aedes aegypti (L.) Prior to the Low Dengue Season in Singapore

Seidahmed, Osama M. E.; Eltahir, Elfatih A. B.

doi:10.1371/journal.pntd.0004842

Cited by 50 publications

(55 citation statements)

References 39 publications

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“…Ehelepola et al [ 53 ] have found that regular rain favors an increase in dengue but not heavy rain. Similarly, Sarfraz [ 54 ] noted that heavy rainfalls may flush away the eggs, larvae and pupae of dengue mosquitoes, which could have consequently affected the mosquito abundance [ 55 ]. On the other hand, we have observed that moderate amount of rainfall (20–30 mm) was related to higher dengue incidences in Davao Region.…”

Section: Discussionmentioning

confidence: 99%

Meteorological factors affecting dengue incidence in Davao, Philippines

Iguchi¹,

Seposo

Honda

2018

BMC Public Health

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BackgroundDengue fever is a major public health concern in the Philippines, and has been a significant cause of hospitalizations and deaths among young children. Previous literature links climate change to dengue, and with increasingly unpredictable changing climate patterns, there is a need to understand how these meteorological variables affect dengue incidence in a highly endemic area.MethodsWeekly dengue incidences (2011–2015) in Davao Region, Philippines were obtained from the Department of Health. Same period of weekly local meteorological variables were obtained from the National Climatic Data Center (NCDC) and the National Oceanic and Atmospheric Administration (NOAA). Wavelet coherence analysis was used to determine the presence of non-stationary relationships, while a quasi-Poisson regression combined with distributed lag nonlinear model (DLNM) was used to analyze the association between meteorological variables and dengue incidences.ResultsSignificant periodicity was detected in the 7 to 14-week band between the year 2011–2012 and a 26-week periodicity from the year 2013–2014. Overall cumulative risks were particularly high for rainfall at 32 mm (RR: 1.67, 95% CI: 1.07–2.62), while risks were observed to increase with increasing dew point. On the other hand, lower average temperature of 26 °C has resulted to an increased RR of dengue (RR: 1.96, 95% CI: 0.47–8.15) while higher temperature from 27 °C to 31 °C has lower RR.ConclusionsThe observed possible threshold levels of these meteorological variables can be integrated into an early warning system to enhance dengue prediction for better vector control and management in the future.Electronic supplementary materialThe online version of this article (10.1186/s12889-018-5532-4) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Meteorological factors affecting dengue incidence in Davao, Philippines

Iguchi¹,

Seposo

Honda

2018

BMC Public Health

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“…This study explores the influence of the pattern of urban housing on dengue distribution at a neighborhood and country scales. In a previous survey in Geylang between August 2014 and August 2015, we found that Aedes aegypti breeds mainly in clogged drains close to the housing (Seidahmed & Eltahir, ). These outdoor breeding habitats are clustered in the low‐rise housing part of the Geylang.…”

Section: Introductionmentioning

confidence: 86%

“…We calculated pupal density per 1,000 population by dividing estimates of Aedes pupae found in a grid cell by the total human population in that grid. Further details on this entomological survey can be found in (Seidahmed & Eltahir, ).…”

Section: Methodsmentioning

confidence: 99%

Patterns of Urban Housing Shape Dengue Distribution in Singapore at Neighborhood and Country Scales

Seidahmed

Chong

et al. 2018

GeoHealth

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Dengue is the most important human arboviral disease in Singapore. We classified residential areas into low‐rise and high‐rise housing and investigated the influence of urban drainage on the distribution of dengue incidence and outdoor breeding at neighborhood and country scales. In Geylang area (August 2014 to August 2015), dengue incidence was higher in a subarea of low‐rise housing compared to high‐rise one, averaging 26.7 (standard error, SE = 4.83) versus 2.43 (SE = 0.67) per 1,000 people. Outdoor breeding drains of Aedes aegypti have clustered in the low‐rise housing subarea. The pupal density per population was higher in the low‐rise blocks versus high‐rise ones, 246 (SE = 69.08) and 35.4 (SE = 25.49) per 1,000 people, respectively. The density of urban drainage network in the low‐rise blocks is double that in the high‐rise ones, averaging 0.05 (SE = 0.0032) versus 0.025 (SE = 0.00245) per meter. Further, a holistic analysis at a country‐scale has confirmed the role of urban hydrology in shaping dengue distribution in Singapore. Dengue incidence (2013–2015) is proportional to the fractions of the area (or population) of low‐rise housing. The drainage density in low‐rise housing is 4 times that corresponding estimate in high‐rise areas, 2.59 and 0.68 per meter, respectively. Public housing in agglomerations of high‐rise buildings could have a positive impact on dengue if this urban planning comes at the expense of low‐rise housing. City planners in endemic regions should consider the density of drainage networks for both the prevention of flooding and the breeding of mosquitoes.

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“…The relationship between rainfall and mosquito populations is multifaceted, contributing to habitat creation and larval mortality. 32 Evidence both supports and contradicts the role of rainfall in vector establishment, especially during disease outbreaks, 33–35 where complex precipitation patterns, surface water dynamics and a diversity of time lags affect the local vector population size. 36–38 Another disputed proxy of moisture availability affecting these species is relative humidity, which is thought only to affect behavioural or survival vector changes at the extremes.…”

Section: Introductionmentioning

confidence: 99%

Determining environmental and anthropogenic factors which explain the global distribution ofAedes aegyptiandAe. albopictus

et al. 2018

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BackgroundResponsible for considerable global human morbidity and mortality, Aedes aegypti and Ae. albopictus are the primary vectors of several important human diseases, including dengue and yellow fever. Although numerous variables that affect mosquito survival and reproduction have been recorded at the local and regional scales, many remain untested at the global level, potentially confounding mapping efforts to date.MethodsWe develop a modelling ensemble of boosted regression trees and maximum entropy models using sets of variables previously untested at the global level to examine their performance in predicting the global distribution of these two vectors. The results show that accessibility, absolute humidity and annual minimum temperature are consistently the strongest predictors of mosquito presence. Both vectors are similar in their response to accessibility and humidity, but exhibit individual profiles for temperature. Their mapped ranges are therefore similar except at peripheral latitudes, where the range of Ae. albopictus extends further, a finding consistent with ongoing trapping studies. We show that variables previously identified as being relevant, including maximum and mean temperatures, enhanced vegetation index, relative humidity and population density, are comparatively weak performers.ResultsThe variables identified represent three key biological mechanisms. Cold tolerance is a critical biological parameter, controlling both species’ distribution northwards, and to a lesser degree for Ae. albopictus which has consequent greater inland suitability in North America, Europe and East Asia. Absolute humidity restricts the distribution of both vectors from drier areas, where moisture availability is very low, and increases their suitability in coastal areas. The latter is exacerbated by accessibility with increased likelihood of vector importation due to greater potential for human and trade movement.ConclusionAccessibility, absolute humidity and annual minimum temperatures were the strongest and most robust global predictors of Ae. aegypti and Ae. albopictus presence, which should be considered in control efforts and future distribution projections.

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A Sequence of Flushing and Drying of Breeding Habitats of Aedes aegypti (L.) Prior to the Low Dengue Season in Singapore

Cited by 50 publications

References 39 publications

Meteorological factors affecting dengue incidence in Davao, Philippines

Meteorological factors affecting dengue incidence in Davao, Philippines

Patterns of Urban Housing Shape Dengue Distribution in Singapore at Neighborhood and Country Scales

Determining environmental and anthropogenic factors which explain the global distribution ofAedes aegyptiandAe. albopictus

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