Widespread Distribution of <i>chs-1</i> Mutations Associated with Resistance to Diflubenzuron Larvicide in <i>Culex pipiens</i> Across Italy, Reaching Virtual Fixation in the Venetian Lagoon

Control interventions against mosquito larvae are the primary measure to reduce the adult abundance and risk of arbovirus outbreaks in Europe. One of the most commonly used larvicides in Italy is diflubenzuron (DFB), which targets chitin synthase 1 (<i>chs-1</i>), interrupting the normal...

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Main Authors: Martina Micocci, Verena Pichler, Paola Serini, Carola Giammarioli, Chiara Malandruccolo, Chiara Virgillito, Marco Ballardini, Riccardo Paolo Lia, Daniele Arnoldi, Stefano Vettore, Davide Bonetto, Simone Martini, Andrea Drago, Alessandra della Torre, Beniamino Caputo
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Insects
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Online Access:https://www.mdpi.com/2075-4450/16/2/204
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author Martina Micocci
Verena Pichler
Paola Serini
Carola Giammarioli
Chiara Malandruccolo
Chiara Virgillito
Marco Ballardini
Riccardo Paolo Lia
Daniele Arnoldi
Stefano Vettore
Davide Bonetto
Simone Martini
Andrea Drago
Alessandra della Torre
Beniamino Caputo
author_facet Martina Micocci
Verena Pichler
Paola Serini
Carola Giammarioli
Chiara Malandruccolo
Chiara Virgillito
Marco Ballardini
Riccardo Paolo Lia
Daniele Arnoldi
Stefano Vettore
Davide Bonetto
Simone Martini
Andrea Drago
Alessandra della Torre
Beniamino Caputo
author_sort Martina Micocci
collection DOAJ
description Control interventions against mosquito larvae are the primary measure to reduce the adult abundance and risk of arbovirus outbreaks in Europe. One of the most commonly used larvicides in Italy is diflubenzuron (DFB), which targets chitin synthase 1 (<i>chs-1</i>), interrupting the normal development of larvae into adults. Recent studies identified high levels of DFB resistance in <i>Culex pipiens</i> populations from Emilia-Romagna (Italy) associated with I1043L/M/F mutations at position 1043 of the <i>chs-1</i> gene. The aim of the present study was to assess the circulation of 1043 resistance alleles in <i>Cx. pipiens</i> populations across Italy, outside Emilia-Romagna, with a focus on the Veneto region. Overall, 1032 specimens were genotyped. The 1043L allele was found in all examined Italian regions (Trentino-Alto Adige 19–36%; Veneto 0–91%; Piemonte 11%; Liguria 28%; Lazio 0–8%; Puglia 5%). The highest frequencies (up to >90%) were observed in the Venetian lagoon, where 1043M was also detected (6–11%). Overall, the relatively low frequencies of 1043 mutations despite extensive and longstanding use of DFB in Italy suggest a high fitness cost worthy of further investigations, while their extremely high frequencies in coastal touristic sites point to these sites as the most relevant for resistance monitoring and larvicide rotation.
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spelling doaj-art-adf7fa6d475c4faabaa8a3ccc78841f32025-08-20T03:12:02ZengMDPI AGInsects2075-44502025-02-0116220410.3390/insects16020204Widespread Distribution of <i>chs-1</i> Mutations Associated with Resistance to Diflubenzuron Larvicide in <i>Culex pipiens</i> Across Italy, Reaching Virtual Fixation in the Venetian LagoonMartina Micocci0Verena Pichler1Paola Serini2Carola Giammarioli3Chiara Malandruccolo4Chiara Virgillito5Marco Ballardini6Riccardo Paolo Lia7Daniele Arnoldi8Stefano Vettore9Davide Bonetto10Simone Martini11Andrea Drago12Alessandra della Torre13Beniamino Caputo14Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, ItalyDepartment of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, ItalyDepartment of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, ItalyDepartment of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, ItalyDepartment of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, ItalyDepartment of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, ItalyIstituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d’Aosta, 10154 Torino, ItalyDepartment of Veterinary Medicine, University of Bari “Aldo Moro”, 70121 Valenzano, ItalyResearch and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, 38098 Trento, ItalyEntostudio Srl, Ponte San Nicolò, 35020 Padova, ItalyEntostudio Srl, Ponte San Nicolò, 35020 Padova, ItalyEntostudio Srl, Ponte San Nicolò, 35020 Padova, ItalyEntostudio Srl, Ponte San Nicolò, 35020 Padova, ItalyDepartment of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, ItalyDepartment of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, ItalyControl interventions against mosquito larvae are the primary measure to reduce the adult abundance and risk of arbovirus outbreaks in Europe. One of the most commonly used larvicides in Italy is diflubenzuron (DFB), which targets chitin synthase 1 (<i>chs-1</i>), interrupting the normal development of larvae into adults. Recent studies identified high levels of DFB resistance in <i>Culex pipiens</i> populations from Emilia-Romagna (Italy) associated with I1043L/M/F mutations at position 1043 of the <i>chs-1</i> gene. The aim of the present study was to assess the circulation of 1043 resistance alleles in <i>Cx. pipiens</i> populations across Italy, outside Emilia-Romagna, with a focus on the Veneto region. Overall, 1032 specimens were genotyped. The 1043L allele was found in all examined Italian regions (Trentino-Alto Adige 19–36%; Veneto 0–91%; Piemonte 11%; Liguria 28%; Lazio 0–8%; Puglia 5%). The highest frequencies (up to >90%) were observed in the Venetian lagoon, where 1043M was also detected (6–11%). Overall, the relatively low frequencies of 1043 mutations despite extensive and longstanding use of DFB in Italy suggest a high fitness cost worthy of further investigations, while their extremely high frequencies in coastal touristic sites point to these sites as the most relevant for resistance monitoring and larvicide rotation.https://www.mdpi.com/2075-4450/16/2/204mosquitolarval controlinsecticide resistance<i>chs-1</i> mutation genotypingdiflubenzuron<i>Culex pipiens</i>
spellingShingle Martina Micocci
Verena Pichler
Paola Serini
Carola Giammarioli
Chiara Malandruccolo
Chiara Virgillito
Marco Ballardini
Riccardo Paolo Lia
Daniele Arnoldi
Stefano Vettore
Davide Bonetto
Simone Martini
Andrea Drago
Alessandra della Torre
Beniamino Caputo
Widespread Distribution of <i>chs-1</i> Mutations Associated with Resistance to Diflubenzuron Larvicide in <i>Culex pipiens</i> Across Italy, Reaching Virtual Fixation in the Venetian Lagoon
Insects
mosquito
larval control
insecticide resistance
<i>chs-1</i> mutation genotyping
diflubenzuron
<i>Culex pipiens</i>
title Widespread Distribution of <i>chs-1</i> Mutations Associated with Resistance to Diflubenzuron Larvicide in <i>Culex pipiens</i> Across Italy, Reaching Virtual Fixation in the Venetian Lagoon
title_full Widespread Distribution of <i>chs-1</i> Mutations Associated with Resistance to Diflubenzuron Larvicide in <i>Culex pipiens</i> Across Italy, Reaching Virtual Fixation in the Venetian Lagoon
title_fullStr Widespread Distribution of <i>chs-1</i> Mutations Associated with Resistance to Diflubenzuron Larvicide in <i>Culex pipiens</i> Across Italy, Reaching Virtual Fixation in the Venetian Lagoon
title_full_unstemmed Widespread Distribution of <i>chs-1</i> Mutations Associated with Resistance to Diflubenzuron Larvicide in <i>Culex pipiens</i> Across Italy, Reaching Virtual Fixation in the Venetian Lagoon
title_short Widespread Distribution of <i>chs-1</i> Mutations Associated with Resistance to Diflubenzuron Larvicide in <i>Culex pipiens</i> Across Italy, Reaching Virtual Fixation in the Venetian Lagoon
title_sort widespread distribution of i chs 1 i mutations associated with resistance to diflubenzuron larvicide in i culex pipiens i across italy reaching virtual fixation in the venetian lagoon
topic mosquito
larval control
insecticide resistance
<i>chs-1</i> mutation genotyping
diflubenzuron
<i>Culex pipiens</i>
url https://www.mdpi.com/2075-4450/16/2/204
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