Cargando…

The importance of accounting for larval detectability in mosquito habitat-association studies

BACKGROUND: Mosquito habitat-association studies are an important basis for disease control programmes and/or vector distribution models. However, studies do not explicitly account for incomplete detection during larval presence and abundance surveys, with potential for significant biases because of...

Descripción completa

Detalles Bibliográficos
Autores principales: Low, Matthew, Tsegaye, Admasu Tassew, Ignell, Rickard, Hill, Sharon, Elleby, Rasmus, Feltelius, Vilhelm, Hopkins, Richard
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4855760/
https://www.ncbi.nlm.nih.gov/pubmed/27142303
http://dx.doi.org/10.1186/s12936-016-1308-4
_version_ 1782430407989395456
author Low, Matthew
Tsegaye, Admasu Tassew
Ignell, Rickard
Hill, Sharon
Elleby, Rasmus
Feltelius, Vilhelm
Hopkins, Richard
author_facet Low, Matthew
Tsegaye, Admasu Tassew
Ignell, Rickard
Hill, Sharon
Elleby, Rasmus
Feltelius, Vilhelm
Hopkins, Richard
author_sort Low, Matthew
collection PubMed
description BACKGROUND: Mosquito habitat-association studies are an important basis for disease control programmes and/or vector distribution models. However, studies do not explicitly account for incomplete detection during larval presence and abundance surveys, with potential for significant biases because of environmental influences on larval behaviour and sampling efficiency. METHODS: Data were used from a dip-sampling study for Anopheles larvae in Ethiopia to evaluate the effect of six factors previously associated with larval sampling (riparian vegetation, direct sunshine, algae, water depth, pH and temperature) on larval presence and detectability. Comparisons were made between: (i) a presence-absence logistic regression where samples were pooled at the site level and detectability ignored, (ii) a success versus trials binomial model, and (iii) a presence-detection mixture model that separately estimated presence and detection, and fitted different explanatory variables to these estimations. RESULTS: Riparian vegetation was consistently highlighted as important, strongly suggesting it explains larval presence (−). However, depending on how larval detectability was estimated, the other factors showed large variations in their statistical importance. The presence-detection mixture model provided strong evidence that larval detectability was influenced by sunshine and water temperature (+), with weaker evidence for algae (+) and water depth (−). For larval presence, there was also some evidence that water depth (−) and pH (+) influenced site occupation. The number of dip-samples needed to determine if larvae were likely present at a site was condition dependent: with sunshine and warm water requiring only two dips, while cooler water and cloud cover required 11. CONCLUSIONS: Environmental factors influence true larval presence and larval detectability differentially when sampling in field conditions. Researchers need to be more aware of the limitations and possible biases in different analytical approaches used to associate larval presence or abundance with local environmental conditions. These effects can be disentangled using data that are routinely collected (i.e., multiple dip samples at each site) by employing a modelling approach that separates presence from detectability. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12936-016-1308-4) contains supplementary material, which is available to authorized users.
format Online
Article
Text
id pubmed-4855760
institution National Center for Biotechnology Information
language English
publishDate 2016
publisher BioMed Central
record_format MEDLINE/PubMed
spelling pubmed-48557602016-05-05 The importance of accounting for larval detectability in mosquito habitat-association studies Low, Matthew Tsegaye, Admasu Tassew Ignell, Rickard Hill, Sharon Elleby, Rasmus Feltelius, Vilhelm Hopkins, Richard Malar J Research BACKGROUND: Mosquito habitat-association studies are an important basis for disease control programmes and/or vector distribution models. However, studies do not explicitly account for incomplete detection during larval presence and abundance surveys, with potential for significant biases because of environmental influences on larval behaviour and sampling efficiency. METHODS: Data were used from a dip-sampling study for Anopheles larvae in Ethiopia to evaluate the effect of six factors previously associated with larval sampling (riparian vegetation, direct sunshine, algae, water depth, pH and temperature) on larval presence and detectability. Comparisons were made between: (i) a presence-absence logistic regression where samples were pooled at the site level and detectability ignored, (ii) a success versus trials binomial model, and (iii) a presence-detection mixture model that separately estimated presence and detection, and fitted different explanatory variables to these estimations. RESULTS: Riparian vegetation was consistently highlighted as important, strongly suggesting it explains larval presence (−). However, depending on how larval detectability was estimated, the other factors showed large variations in their statistical importance. The presence-detection mixture model provided strong evidence that larval detectability was influenced by sunshine and water temperature (+), with weaker evidence for algae (+) and water depth (−). For larval presence, there was also some evidence that water depth (−) and pH (+) influenced site occupation. The number of dip-samples needed to determine if larvae were likely present at a site was condition dependent: with sunshine and warm water requiring only two dips, while cooler water and cloud cover required 11. CONCLUSIONS: Environmental factors influence true larval presence and larval detectability differentially when sampling in field conditions. Researchers need to be more aware of the limitations and possible biases in different analytical approaches used to associate larval presence or abundance with local environmental conditions. These effects can be disentangled using data that are routinely collected (i.e., multiple dip samples at each site) by employing a modelling approach that separates presence from detectability. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12936-016-1308-4) contains supplementary material, which is available to authorized users. BioMed Central 2016-05-04 /pmc/articles/PMC4855760/ /pubmed/27142303 http://dx.doi.org/10.1186/s12936-016-1308-4 Text en © Low et al. 2016 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Low, Matthew
Tsegaye, Admasu Tassew
Ignell, Rickard
Hill, Sharon
Elleby, Rasmus
Feltelius, Vilhelm
Hopkins, Richard
The importance of accounting for larval detectability in mosquito habitat-association studies
title The importance of accounting for larval detectability in mosquito habitat-association studies
title_full The importance of accounting for larval detectability in mosquito habitat-association studies
title_fullStr The importance of accounting for larval detectability in mosquito habitat-association studies
title_full_unstemmed The importance of accounting for larval detectability in mosquito habitat-association studies
title_short The importance of accounting for larval detectability in mosquito habitat-association studies
title_sort importance of accounting for larval detectability in mosquito habitat-association studies
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4855760/
https://www.ncbi.nlm.nih.gov/pubmed/27142303
http://dx.doi.org/10.1186/s12936-016-1308-4
work_keys_str_mv AT lowmatthew theimportanceofaccountingforlarvaldetectabilityinmosquitohabitatassociationstudies
AT tsegayeadmasutassew theimportanceofaccountingforlarvaldetectabilityinmosquitohabitatassociationstudies
AT ignellrickard theimportanceofaccountingforlarvaldetectabilityinmosquitohabitatassociationstudies
AT hillsharon theimportanceofaccountingforlarvaldetectabilityinmosquitohabitatassociationstudies
AT ellebyrasmus theimportanceofaccountingforlarvaldetectabilityinmosquitohabitatassociationstudies
AT felteliusvilhelm theimportanceofaccountingforlarvaldetectabilityinmosquitohabitatassociationstudies
AT hopkinsrichard theimportanceofaccountingforlarvaldetectabilityinmosquitohabitatassociationstudies
AT lowmatthew importanceofaccountingforlarvaldetectabilityinmosquitohabitatassociationstudies
AT tsegayeadmasutassew importanceofaccountingforlarvaldetectabilityinmosquitohabitatassociationstudies
AT ignellrickard importanceofaccountingforlarvaldetectabilityinmosquitohabitatassociationstudies
AT hillsharon importanceofaccountingforlarvaldetectabilityinmosquitohabitatassociationstudies
AT ellebyrasmus importanceofaccountingforlarvaldetectabilityinmosquitohabitatassociationstudies
AT felteliusvilhelm importanceofaccountingforlarvaldetectabilityinmosquitohabitatassociationstudies
AT hopkinsrichard importanceofaccountingforlarvaldetectabilityinmosquitohabitatassociationstudies