Occurrence of putative Culicoides biting midge vectors (Diptera: Ceratopogonidae) inside and outside barns in Germany and factors influencing their activity

Abstract Background After several years without bluetongue disease, a ruminant illness caused by Culicoides-borne bluetongue virus (BTV), two new autochthonous cases were reported in 2018 in Germany. By contrast, Schmallenberg virus (SBV), another Culicoides-borne virus pathogenic to ruminants, has...

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Main Authors: Sarah Groschupp, Helge Kampen, Doreen Werner
Format: Article
Language:English
Published: BMC 2023-08-01
Series:Parasites & Vectors
Subjects:
Online Access:https://doi.org/10.1186/s13071-023-05920-z
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author Sarah Groschupp
Helge Kampen
Doreen Werner
author_facet Sarah Groschupp
Helge Kampen
Doreen Werner
author_sort Sarah Groschupp
collection DOAJ
description Abstract Background After several years without bluetongue disease, a ruminant illness caused by Culicoides-borne bluetongue virus (BTV), two new autochthonous cases were reported in 2018 in Germany. By contrast, Schmallenberg virus (SBV), another Culicoides-borne virus pathogenic to ruminants, has continuously circulated in Germany since its first emergence in 2011. The disease outbreaks have triggered numerous studies on the biology of the Culicoides vectors, but many ecological details are still obscure. Methods Culicoides biting midge species were collected with UV-light traps on 10 farms in Germany, with one trap inside and one trap outside barns on each of the farms. Traps were run once a week for 24 h from January to December 2019. Collected biting midges were morphologically identified, counted and statistically evaluated, with a focus on the Obsoletus Group and the Pulicaris Complex of the ceratopogonid genus Culicoides, which are believed to contain the major virus vectors. Temperature and relative humidity recorded at each trap were linked to the quantity of caught Culicoides. Correlations between relative Culicoides abundance and presence of livestock or type of husbandry were also investigated. Results A total of 38,886 Culicoides biting midges were trapped, with most of them belonging to the Obsoletus Group (51.0%) and the Pulicaris Complex (38.8%). The majority of captured specimens were collected in traps inside the barns. Obsoletus Group individuals were caught from late January to the last week of December while Pulicaris Complex individuals were captured from the end of March to early December. The lowest average temperatures at which members of the two groups were collected were 10.7 °C and 12.8 °C, respectively. While temperature had a statistically significant effect on the activity of both the Obsoletus Group and the Pulicaris Complex, relative humidity only significantly affected the activity of the latter. The presence of livestock significantly influenced the number of captured Obsoletus Group, but not of Pulicaris Complex specimens. Inside the barns, no statistical difference was found between numbers of caught Obsoletus Group and Pulicaris Complex specimens in livestock holdings with deep litter and manure scraper or slatted floor husbandry systems. Conclusions The almost year-round presence of Obsoletus Group biting midges and the demonstrated high relative abundance of other potential Culicoides vector species inside barns suggest a high risk of indoor virus transmission to ruminants should BTV or SBV circulate locally. Appropriate structural, organisational and vector control measures to reduce biting midge exposure should be implemented. Graphical Abstract
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spelling doaj.art-be51d4a7e0454c4481d49c33ebdd2aea2023-11-26T12:29:33ZengBMCParasites & Vectors1756-33052023-08-0116111310.1186/s13071-023-05920-zOccurrence of putative Culicoides biting midge vectors (Diptera: Ceratopogonidae) inside and outside barns in Germany and factors influencing their activitySarah Groschupp0Helge Kampen1Doreen Werner2Research Area 2 “Landscape Use and Governance”, Leibniz Centre for Agricultural Landscape Research (ZALF)Friedrich-Loeffler-Institut–Federal Research Institute for Animal HealthResearch Area 2 “Landscape Use and Governance”, Leibniz Centre for Agricultural Landscape Research (ZALF)Abstract Background After several years without bluetongue disease, a ruminant illness caused by Culicoides-borne bluetongue virus (BTV), two new autochthonous cases were reported in 2018 in Germany. By contrast, Schmallenberg virus (SBV), another Culicoides-borne virus pathogenic to ruminants, has continuously circulated in Germany since its first emergence in 2011. The disease outbreaks have triggered numerous studies on the biology of the Culicoides vectors, but many ecological details are still obscure. Methods Culicoides biting midge species were collected with UV-light traps on 10 farms in Germany, with one trap inside and one trap outside barns on each of the farms. Traps were run once a week for 24 h from January to December 2019. Collected biting midges were morphologically identified, counted and statistically evaluated, with a focus on the Obsoletus Group and the Pulicaris Complex of the ceratopogonid genus Culicoides, which are believed to contain the major virus vectors. Temperature and relative humidity recorded at each trap were linked to the quantity of caught Culicoides. Correlations between relative Culicoides abundance and presence of livestock or type of husbandry were also investigated. Results A total of 38,886 Culicoides biting midges were trapped, with most of them belonging to the Obsoletus Group (51.0%) and the Pulicaris Complex (38.8%). The majority of captured specimens were collected in traps inside the barns. Obsoletus Group individuals were caught from late January to the last week of December while Pulicaris Complex individuals were captured from the end of March to early December. The lowest average temperatures at which members of the two groups were collected were 10.7 °C and 12.8 °C, respectively. While temperature had a statistically significant effect on the activity of both the Obsoletus Group and the Pulicaris Complex, relative humidity only significantly affected the activity of the latter. The presence of livestock significantly influenced the number of captured Obsoletus Group, but not of Pulicaris Complex specimens. Inside the barns, no statistical difference was found between numbers of caught Obsoletus Group and Pulicaris Complex specimens in livestock holdings with deep litter and manure scraper or slatted floor husbandry systems. Conclusions The almost year-round presence of Obsoletus Group biting midges and the demonstrated high relative abundance of other potential Culicoides vector species inside barns suggest a high risk of indoor virus transmission to ruminants should BTV or SBV circulate locally. Appropriate structural, organisational and vector control measures to reduce biting midge exposure should be implemented. Graphical Abstracthttps://doi.org/10.1186/s13071-023-05920-zArbovirusBiting midgesBluetongue virusCulicoidesObsoletus GroupPulicaris Complex
spellingShingle Sarah Groschupp
Helge Kampen
Doreen Werner
Occurrence of putative Culicoides biting midge vectors (Diptera: Ceratopogonidae) inside and outside barns in Germany and factors influencing their activity
Parasites & Vectors
Arbovirus
Biting midges
Bluetongue virus
Culicoides
Obsoletus Group
Pulicaris Complex
title Occurrence of putative Culicoides biting midge vectors (Diptera: Ceratopogonidae) inside and outside barns in Germany and factors influencing their activity
title_full Occurrence of putative Culicoides biting midge vectors (Diptera: Ceratopogonidae) inside and outside barns in Germany and factors influencing their activity
title_fullStr Occurrence of putative Culicoides biting midge vectors (Diptera: Ceratopogonidae) inside and outside barns in Germany and factors influencing their activity
title_full_unstemmed Occurrence of putative Culicoides biting midge vectors (Diptera: Ceratopogonidae) inside and outside barns in Germany and factors influencing their activity
title_short Occurrence of putative Culicoides biting midge vectors (Diptera: Ceratopogonidae) inside and outside barns in Germany and factors influencing their activity
title_sort occurrence of putative culicoides biting midge vectors diptera ceratopogonidae inside and outside barns in germany and factors influencing their activity
topic Arbovirus
Biting midges
Bluetongue virus
Culicoides
Obsoletus Group
Pulicaris Complex
url https://doi.org/10.1186/s13071-023-05920-z
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AT helgekampen occurrenceofputativeculicoidesbitingmidgevectorsdipteraceratopogonidaeinsideandoutsidebarnsingermanyandfactorsinfluencingtheiractivity
AT doreenwerner occurrenceofputativeculicoidesbitingmidgevectorsdipteraceratopogonidaeinsideandoutsidebarnsingermanyandfactorsinfluencingtheiractivity