Dirofilaria immitis and Dirofilaria repens in mosquitoes from Corsica Island, France

Laidoudi Younes (1, 2, 3) , Hélène Barré-Cardi (4) , Samia Bedjaoui (5) , Nazli Ayhan (6) , Marie Varloud (7) , Oleg Mediannikov (1, 2) , Domenico Otranto (8, 2) , Bernard Davoust (1, 2)

1 MEPHI - Microbes évolution phylogénie et infections
2 IHU Marseille - Institut Hospitalier Universitaire Méditerranée Infection
3 UNIBA - Università degli studi di Bari Aldo Moro = University of Bari Aldo Moro
4 Office de l'environnement de la Corse
5 Higher National Veterinary School
6 UVE - Unité des Virus Emergents
7 Laboratoire Vétérinaire Pharmaceutique - CEVA Santé Animale [Libourne, France]
8 Bu-Ali Sina University

Background Dirofilaria immitis and Dirofilaria repens are the main causative agents of heartworm disease and subcutaneous dirofilariasis in domestic and wild canids, respectively. Both pathogens have zoonotic potential and are transmitted by mosquitoes. The present study aimed to determine the transmission period, prevalence and diversity of Dirofilaria spp. vectors from endemic areas of Corsica (France). Methods A monthly point data model based on average temperature recorded by four meteorological stations during 2017 was used to calculate the Dirofilaria transmission period. From June to September 2017, female mosquitoes ( n = 1802) were captured using Biogents ® Sentinel 2 traps lured with carbon dioxide and BG-Lure™ or octanol. Mosquitoes were identified to species level, pooled accordingly, and screened using multiplex real-time qPCR to detect D. immitis and D. repens . Results The monthly point data model showed the possible transmission of Dirofilaria spp. from the third week in May to the last week in October in the studied area. Mosquitoes were identified as Ochlerotatus caspius ( n = 1432), Aedes albopictus ( n = 199), Culex pipiens sensu lato ( n = 165) and Aedes vexans ( n = 6) and were grouped into 109 pools (from 1 to 27 specimens, mean 11.4 ± 0.7), of which 16 scored positive for Dirofilaria spp. (i.e., n = 13; estimated infection rate [EIR] = 1.1% for D. immitis and n = 3; EIR = 0.2% for D. repens ). Specifically, 6 (i.e., EIR = 3.8%) of 15 pools of Ae. albopictus were positive for D. immitis , 2 of 14 of Cx. pipiens s.l. were positive for D. immitis and D. repens , respectively, and 8 of 77 pools of Oc. caspius were positive for D. immitis (i.e., n = 6; EIR = 0.4%) and D. repens (i.e., 2; EIR = 0.1%). The highest mosquito infection rate was recorded in July (EIR = 2.5%), then in June (EIR = 1.3%) and September (EIR = 0.6%). Conclusions The data suggest that both Dirofilaria species are endemic and occur possibly in sympatry in the studied area in Corsica, highlighting the need to implement preventive chemoprophylaxis and vector control strategies to reduce the risk of these filarioids in dog and human populations. Graphical Abstract

Mots clés: Dirofilaria immitis; Dirofilaria repens; Mosquitoes; Transmission suitability; Corsica

Domaines: Bactériologie; Virologie; Parasitologie; Cardiologie et système cardiovasculaire; Maladies émergentes; Maladies infectieuses

Laidoudi Younes, Hélène Barré-Cardi, Samia Bedjaoui, Nazli Ayhan, Marie Varloud, et al.. Dirofilaria immitis and Dirofilaria repens in mosquitoes from Corsica Island, France. Parasites & Vectors, 2021, 14 (1), ⟨10.1186/s13071-021-04931-y⟩. ⟨hal-03429636⟩