The Crimean‐Congo haemorrhagic fever tick vectorHyalomma marginatumin the south of France: Modelling its distribution and determination of factors influencing its establishment in a newly invaded area

• DOI: 10.1111/tbed.14578
• Publication Date: 2022-05-05T15:43:40Z
• Authors: Madiou Thierno Bah; Vladimir Grosbois; Frédéric Stachurski; Facundo Muñoz; Maxime Duhayon; Ignace Rakotoarivony; Anaïs Appelgren; Clément Calloix; Liz Noguera; Théo Mouillaud; Charlotte Andary; Renaud Lancelot; Karine Huber; Claire Garros; Agnès Leblond; Laurence Vial
• Keywords: 570; 550; Ixodidae; [SDV]Life Sciences [q-bio]; Hyalomma marginatum; distribution des populations; 910; http://aims.fao.org/aos/agrovoc/c_49865; correlative distribution modelling; 0403 veterinary science; 03 medical and health sciences; Ticks; 0302 clinical medicine; vecteur de maladie; 11. Sustainability; http://aims.fao.org/aos/agrovoc/c_3081; Animals; Horses; modélisation; http://aims.fao.org/aos/agrovoc/c_6113; http://aims.fao.org/aos/agrovoc/c_230ab86c; U10 - Informatique, mathématiques et statistiques; espèce envahissante; Original Articles; 04 agricultural and veterinary sciences; fièvre hémorragique de Crimée-Congo; [SDV] Life Sciences [q-bio]; http://aims.fao.org/aos/agrovoc/c_ac826b92; Hemorrhagic Fever Virus, Crimean-Congo; http://aims.fao.org/aos/agrovoc/c_8164; Hemorrhagic Fever, Crimean; Horse Diseases; France; L72 - Organismes nuisibles des animaux; Tick

For the first time we built a correlative model for predicting the distribution of H. marginatum, one of the main vector of Crimean-Congo Haemorrhagic fever virus (CCHFV), at high resolution in a recently colonized area, namely south of France. Field tick collections were conducted on horses from 2016 to 2021 in 14 French southern departments, which resulted in a first map of H. marginatum on the national territory. Such updated presence/absence data, as well as the mean number of H. marginatum per examined animal (mean parasitic load) as a proxy of the tick abundance, were correlated to multiple parameters that described the climate and habitats characterizing each collection site, as well as movements of horses as a possible source of tick diffusion and new establishment. Our model highlighted the importance of warm temperatures all along the year, as well as dry conditions during summer and moderate annual humidity for the establishment of H. marginatum. A predominance of open natural habitats in the environment was also identified as a supporting factor, in opposition to artificial and humid habitats that were determined as unsuitable. Based on this model, we predicted the current suitable areas for the establishment of the tick H. marginatum in South of France, with a relatively good accuracy using internal and external validation methods. Concerning tick abundance, some correlative relationships were similar than in the occurrence model but the type of horse movements were also pointed out as an important factor explaining the mean parasitic load, leading to differential exposure to ticks. The limitations of estimating and modelling H. marginatum abundance in a correlative model are discussed.