Induction of long-lived potential aestivation states in laboratory An. gambiae mosquitoes

Abstract Background How anopheline mosquitoes persist through the long dry season in Africa remains a gap in our understanding of these malaria vectors. To span this period in locations such as the Sahelian zone of Mali, mosquitoes must either migrate to areas of permanent water, recolonize areas as...

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Main Authors: Benjamin J. Krajacich, Margery Sullivan, Roy Faiman, Laura Veru, Leland Graber, Tovi Lehmann
Format: Article
Language:English
Published: BMC 2020-08-01
Series:Parasites & Vectors
Subjects:
Online Access:http://link.springer.com/article/10.1186/s13071-020-04276-y
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spelling doaj-d30d52d9947749f3be1f3631e8da6ab52020-11-25T03:46:11ZengBMCParasites & Vectors1756-33052020-08-0113111010.1186/s13071-020-04276-yInduction of long-lived potential aestivation states in laboratory An. gambiae mosquitoesBenjamin J. Krajacich0Margery Sullivan1Roy Faiman2Laura Veru3Leland Graber4Tovi Lehmann5Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthLaboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthLaboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthLaboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthLaboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthLaboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthAbstract Background How anopheline mosquitoes persist through the long dry season in Africa remains a gap in our understanding of these malaria vectors. To span this period in locations such as the Sahelian zone of Mali, mosquitoes must either migrate to areas of permanent water, recolonize areas as they again become favorable, or survive in harsh conditions including high temperatures, low humidity, and an absence of surface water (required for breeding). Adult mosquitoes surviving through this season must dramatically extend their typical lifespan (averaging 2–3 weeks) to 7 months. Previous work has found evidence that the malaria mosquito An. coluzzii, survives over 200 days in the wild between rainy seasons in a presumed state of aestivation (hibernation), but this state has so far not been replicated in laboratory conditions. The inability to recapitulate aestivation in the lab hinders addressing key questions such as how this state is induced, how it affects malaria vector competence, and its impact on disease transmission. Methods In effort to induce aestivation, we held laboratory mosquitoes in climate-controlled incubators with a range of conditions that adjusted humidity (40–85% RH), temperature (18–27 °C), and light conditions (8–12 h of light) and evaluated their survivorship. These conditions were chosen to mimic the late rainy and dry seasons as well as relevant extremes these mosquitoes may experience during aestivation. Results We found that by priming mosquitoes in conditions simulating the late wet season in Mali, and maintaining mosquitoes in reduced light/temperature, mean mosquito survival increased from 18.34 ± 0.65 to 48.02 ± 2.87 days, median survival increased from 19 (95% CI 17–21) to 50 days (95% CI 40–58), and the maximum longevity increased from 38 to 109 days (P-adj < 0.001). While this increase falls short of the 200 + day survival seen in field mosquitoes, this extension is substantially higher than previously found through environmental or dietary modulation and is hard to reconcile with states other than aestivation. This finding will provide a platform for future characterization of this state, and allow for comparison to field collected samples.http://link.springer.com/article/10.1186/s13071-020-04276-yAestivationDry seasonAnophelesMalaria
collection DOAJ
language English
format Article
sources DOAJ
author Benjamin J. Krajacich
Margery Sullivan
Roy Faiman
Laura Veru
Leland Graber
Tovi Lehmann
spellingShingle Benjamin J. Krajacich
Margery Sullivan
Roy Faiman
Laura Veru
Leland Graber
Tovi Lehmann
Induction of long-lived potential aestivation states in laboratory An. gambiae mosquitoes
Parasites & Vectors
Aestivation
Dry season
Anopheles
Malaria
author_facet Benjamin J. Krajacich
Margery Sullivan
Roy Faiman
Laura Veru
Leland Graber
Tovi Lehmann
author_sort Benjamin J. Krajacich
title Induction of long-lived potential aestivation states in laboratory An. gambiae mosquitoes
title_short Induction of long-lived potential aestivation states in laboratory An. gambiae mosquitoes
title_full Induction of long-lived potential aestivation states in laboratory An. gambiae mosquitoes
title_fullStr Induction of long-lived potential aestivation states in laboratory An. gambiae mosquitoes
title_full_unstemmed Induction of long-lived potential aestivation states in laboratory An. gambiae mosquitoes
title_sort induction of long-lived potential aestivation states in laboratory an. gambiae mosquitoes
publisher BMC
series Parasites & Vectors
issn 1756-3305
publishDate 2020-08-01
description Abstract Background How anopheline mosquitoes persist through the long dry season in Africa remains a gap in our understanding of these malaria vectors. To span this period in locations such as the Sahelian zone of Mali, mosquitoes must either migrate to areas of permanent water, recolonize areas as they again become favorable, or survive in harsh conditions including high temperatures, low humidity, and an absence of surface water (required for breeding). Adult mosquitoes surviving through this season must dramatically extend their typical lifespan (averaging 2–3 weeks) to 7 months. Previous work has found evidence that the malaria mosquito An. coluzzii, survives over 200 days in the wild between rainy seasons in a presumed state of aestivation (hibernation), but this state has so far not been replicated in laboratory conditions. The inability to recapitulate aestivation in the lab hinders addressing key questions such as how this state is induced, how it affects malaria vector competence, and its impact on disease transmission. Methods In effort to induce aestivation, we held laboratory mosquitoes in climate-controlled incubators with a range of conditions that adjusted humidity (40–85% RH), temperature (18–27 °C), and light conditions (8–12 h of light) and evaluated their survivorship. These conditions were chosen to mimic the late rainy and dry seasons as well as relevant extremes these mosquitoes may experience during aestivation. Results We found that by priming mosquitoes in conditions simulating the late wet season in Mali, and maintaining mosquitoes in reduced light/temperature, mean mosquito survival increased from 18.34 ± 0.65 to 48.02 ± 2.87 days, median survival increased from 19 (95% CI 17–21) to 50 days (95% CI 40–58), and the maximum longevity increased from 38 to 109 days (P-adj < 0.001). While this increase falls short of the 200 + day survival seen in field mosquitoes, this extension is substantially higher than previously found through environmental or dietary modulation and is hard to reconcile with states other than aestivation. This finding will provide a platform for future characterization of this state, and allow for comparison to field collected samples.
topic Aestivation
Dry season
Anopheles
Malaria
url http://link.springer.com/article/10.1186/s13071-020-04276-y
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