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PLoS Negl Trop Dis. 2014 Aug 7;8(8):e3038. doi: 10.1371/journal.pntd.0003038. eCollection 2014 Aug.

Shifting patterns of Aedes aegypti fine scale spatial clustering in Iquitos, Peru.

Author information

1
Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America.
2
Department of Entomology, University of California Davis, Davis, California, United States of America.
3
U.S. Naval Medical Research Unit No. 6, Lima and Iquitos, Peru.
4
Department of Entomology, University of California Davis, Davis, California, United States of America; Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America.
5
Department of Global Health Systems and Development, Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana, United States of America.
6
Graduate School of Public Health, San Diego State University, San Diego, California, United States of America.
7
Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America; Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America.

Abstract

BACKGROUND:

Empiric evidence shows that Aedes aegypti abundance is spatially heterogeneous and that some areas and larval habitats produce more mosquitoes than others. There is a knowledge gap, however, with regards to the temporal persistence of such Ae. aegypti abundance hotspots. In this study, we used a longitudinal entomologic dataset from the city of Iquitos, Peru, to (1) quantify the spatial clustering patterns of adult Ae. aegypti and pupae counts per house, (2) determine overlap between clusters, (3) quantify the temporal stability of clusters over nine entomologic surveys spaced four months apart, and (4) quantify the extent of clustering at the household and neighborhood levels.

METHODOLOGIES/PRINCIPAL FINDINGS:

Data from 13,662 household entomological visits performed in two Iquitos neighborhoods differing in Ae. aegypti abundance and dengue virus transmission was analyzed using global and local spatial statistics. The location and extent of Ae. aegypti pupae and adult hotspots (i.e., small groups of houses with significantly [p<0.05] high mosquito abundance) were calculated for each of the 9 entomologic surveys. The extent of clustering was used to quantify the probability of finding spatially correlated populations. Our analyses indicate that Ae. aegypti distribution was highly focal (most clusters do not extend beyond 30 meters) and that hotspots of high vector abundance were common on every survey date, but they were temporally unstable over the period of study.

CONCLUSIONS/SIGNIFICANCE:

Our findings have implications for understanding Ae. aegypti distribution and for the design of surveillance and control activities relying on household-level data. In settings like Iquitos, where there is a relatively low percentage of Ae. aegypti in permanent water-holding containers, identifying and targeting key premises will be significantly challenged by shifting hotspots of Ae. aegypti infestation. Focusing efforts in large geographic areas with historically high levels of transmission may be more effective than targeting Ae. aegypti hotspots.

PMID:
25102062
PMCID:
PMC4125221
DOI:
10.1371/journal.pntd.0003038
[Indexed for MEDLINE]
Free PMC Article

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