Holis-Tick : Identification and control of vector-borne diseases by ticks in Corsica

Les dernières années témoignent du fardeau en santé publique de l’émergence des maladies vectorielles à tiques. Ces arthropodes parasites hématophages stricts sont aujourd’hui, les premiers vecteurs de maladies chez les humains dans l’hémisphère nord, et les premiers chez les animaux dans le monde avant les moustiques. La Corse possède un environnement de choix pour l’étude des maladies vectorisées par les tiques, notamment un climat chaud subtropical de façade ouest, des microclimats du a de nombreuses stratifications géologiques et végétales, de nombreuses corridor de migration aviaire, ainsi que de nombreux échange du a son héritage culturelle et au tourisme de masse, entre la faune sauvage, les animaux domestiques et les populations humaines. Ces caractéristiques font de l’ile un environnement favorable à une diversité de tiques importante. De plus, des espèces de tiques présentes en Corse, ont déjà commencé à migrer vers l’Europe grâce aux changements climatiques. L’objectif est d’utiliser la Corse comme espaces sentinelles pour se préparer aux épidémies des maladies transmises par les tiques. En effet, en identifiant et en se préparant aux épidémies que peuvent causer les pathogènes transmis par les tiques en Corse, notamment par la création d’outils de diagnostic déployable rapidement. Nos résultats ont montré que la Corse possède une diversité de tiques importante, qui se répercute sur la diversité de pathogène bactérien et viral retrouvé. Nous avons identifié 8 espèces de tiques différentes porteuses d’une dizaine de pathogènes bactériens des genres Rickettsia spp. Anaplasma spp, Ehrlichia spp et borrelia spp. La collecte de plus de 8 000 tiques testé au virus de la Fièvre Hémorragique Crimée-Congo, nous a permis de conclure que la Corse n’est pas un Hotpost pour ce virus, malgré la présence de sa tique vectrice. Nous avons détecté le Jingmen Tick virus, nouveaux virus associes avec des symptômes fébriles chez les humains et crée un système de détection rapide capable de détecter tous les virus du groupe Jingmen Tick virus group. Nous avons pu caractériser un nouveau virus, appartenant lui-même a un nouveau groupe des Phlébovirus, dans le genre Uukuvirus, des analyses sont en cours pour comprendre ces mécanismes et sa pathogénicité. Grace à cette thèse nous établissons les bases d’une réponse générique qui pourra être mise en œuvre dans la lutte contre les épidémies futures à l’échelle Européen.Recent years have witnessed the public health burden of the emergence of tick-borne diseases. These strict hematophagous arthropod parasites are currently the primary vectors of disease in humans in the northern hemisphere, and the primary vectors of diseases in animals worldwide before mosquitoes. Corsica has a privileged environment for the study of tick-borne diseases, including a warm subtropical climate on the western side, micro-climates due to numerous geological and vegetation stratification, numerous avian migration corridors, as well as numerous exchanges due to its cultural heritage and mass tourism, between wild fauna, domestic animals and human populations. These characteristics provide a favourable environment for a wide variety of ticks. Moreover, some tick species present in Corsica have already started to migrate to Europe due to global climate change. The objective of this initiative is to make use of Corsica as a sentinel area to prepare for epidemics of tick-borne diseases. Indeed, by identifying and preparing for epidemics that may be caused by tick-borne pathogens in Corsica, notably by creating rapidly deployed diagnostic tools. Our results showed that Corsica possesses a high diversity of ticks, which is reflected in the diversity of bacterial and viral pathogens found. We recognised 8 different species of ticks carrying about 10 bacterial pathogens of the genus Rickettsia spp. Anaplasma spp, Ehrlichia spp and Borrelia spp. The collection of more than 8,000 ticks tested for Crimean-Congo Haemorrhagic Fever virus, allowed us to conclude that Corsica is not a Hotpost for this virus, despite the presence of its vector tick. We have detected the Jingmen Tick virus, a new virus associated with febrile symptoms in humans, and created a rapid detection system able to detect all the viruses of the Jingmen Tick virus group.We were therefore able to characterise a new virus, itself belonging to a new group of Phleboviruses, in the genus Uukuvirus, and analyses are underway to understand its mechanisms and pathogenicity. Through this thesis we are establishing the basis for a generic response that can be implemented in the fight against future epidemics on a European scale

Holis-Tick : Identification et maitrise des maladies vectorielles transmises par les tiques en Corse

Recent years have witnessed the public health burden of the emergence of tick-borne diseases. These strict hematophagous arthropod parasites are currently the primary vectors of disease in humans in the northern hemisphere, and the primary vectors of diseases in animals worldwide before mosquitoes. Corsica has a privileged environment for the study of tick-borne diseases, including a warm subtropical climate on the western side, micro-climates due to numerous geological and vegetation stratification, numerous avian migration corridors, as well as numerous exchanges due to its cultural heritage and mass tourism, between wild fauna, domestic animals and human populations. These characteristics provide a favourable environment for a wide variety of ticks. Moreover, some tick species present in Corsica have already started to migrate to Europe due to global climate change. The objective of this initiative is to make use of Corsica as a sentinel area to prepare for epidemics of tick-borne diseases. Indeed, by identifying and preparing for epidemics that may be caused by tick-borne pathogens in Corsica, notably by creating rapidly deployed diagnostic tools. Our results showed that Corsica possesses a high diversity of ticks, which is reflected in the diversity of bacterial and viral pathogens found. We recognised 8 different species of ticks carrying about 10 bacterial pathogens of the genus Rickettsia spp. Anaplasma spp, Ehrlichia spp and Borrelia spp. The collection of more than 8,000 ticks tested for Crimean-Congo Haemorrhagic Fever virus, allowed us to conclude that Corsica is not a Hotpost for this virus, despite the presence of its vector tick. We have detected the Jingmen Tick virus, a new virus associated with febrile symptoms in humans, and created a rapid detection system able to detect all the viruses of the Jingmen Tick virus group.We were therefore able to characterise a new virus, itself belonging to a new group of Phleboviruses, in the genus Uukuvirus, and analyses are underway to understand its mechanisms and pathogenicity. Through this thesis we are establishing the basis for a generic response that can be implemented in the fight against future epidemics on a European scale.Les dernières années témoignent du fardeau en santé publique de l’émergence des maladies vectorielles à tiques. Ces arthropodes parasites hématophages stricts sont aujourd’hui, les premiers vecteurs de maladies chez les humains dans l’hémisphère nord, et les premiers chez les animaux dans le monde avant les moustiques. La Corse possède un environnement de choix pour l’étude des maladies vectorisées par les tiques, notamment un climat chaud subtropical de façade ouest, des microclimats du a de nombreuses stratifications géologiques et végétales, de nombreuses corridor de migration aviaire, ainsi que de nombreux échange du a son héritage culturelle et au tourisme de masse, entre la faune sauvage, les animaux domestiques et les populations humaines. Ces caractéristiques font de l’ile un environnement favorable à une diversité de tiques importante. De plus, des espèces de tiques présentes en Corse, ont déjà commencé à migrer vers l’Europe grâce aux changements climatiques. L’objectif est d’utiliser la Corse comme espaces sentinelles pour se préparer aux épidémies des maladies transmises par les tiques. En effet, en identifiant et en se préparant aux épidémies que peuvent causer les pathogènes transmis par les tiques en Corse, notamment par la création d’outils de diagnostic déployable rapidement. Nos résultats ont montré que la Corse possède une diversité de tiques importante, qui se répercute sur la diversité de pathogène bactérien et viral retrouvé. Nous avons identifié 8 espèces de tiques différentes porteuses d’une dizaine de pathogènes bactériens des genres Rickettsia spp. Anaplasma spp, Ehrlichia spp et borrelia spp. La collecte de plus de 8 000 tiques testé au virus de la Fièvre Hémorragique Crimée-Congo, nous a permis de conclure que la Corse n’est pas un Hotpost pour ce virus, malgré la présence de sa tique vectrice. Nous avons détecté le Jingmen Tick virus, nouveaux virus associes avec des symptômes fébriles chez les humains et crée un système de détection rapide capable de détecter tous les virus du groupe Jingmen Tick virus group. Nous avons pu caractériser un nouveau virus, appartenant lui-même a un nouveau groupe des Phlébovirus, dans le genre Uukuvirus, des analyses sont en cours pour comprendre ces mécanismes et sa pathogénicité. Grace à cette thèse nous établissons les bases d’une réponse générique qui pourra être mise en œuvre dans la lutte contre les épidémies futures à l’échelle Européen

First molecular detection of Rickettsia africae in a tropical bont tick, Amblyomma variegatum, collected in Corsica, France

International audienc

First detection of Ehrlichia minasensis in Hyalomma marginatum ticks collected from cattle in Corsica, France

International audienc

Molecular Detection of Spotted-Fever Group Rickettsiae in Ticks Collected from Domestic and Wild Animals in Corsica, France

International audienceTo obtain a better understanding of the current magnitude of tick-borne rickettsioses in Corsica, we used molecular methods to characterize the occurrence of Rickettsia spp. in ixodid ticks collected from domestic and wild animals. The presence of Rickettsia spp. was evaluated using real-time polymerase chain reaction targeting the gltA gene and by sequencing of gltA and ompA partial genes for species identification and phylogenetic analysis. Infection rates were calculated as the maximum-likelihood estimation (MLE) with 95% confidence intervals (CI). In total, 1117 ticks belonging to four genera (Rhipicephalus, Hyalomma, Ixodes, and Dermacentor) were collected from cattle, sheep, wild boars, and companion animals during July-August 2017 and July 2018-January 2019. Overall, Rickettsia DNA was detected in 208 of 349 pools of ticks (MLE = 25.6%, 95% CI: 22.6-28.8%). The molecular analysis revealed five different rickettsial species of the spotted-fever group (SFG). We highlighted the exclusive detection of Candidatus Ri. barbariae in R. bursa and of Ri. aeschlimanii in H. marginatum. Rickettsia slovaca was detected in D. marginatus collected from wild boars. This study provides the first evidence of the presence of Ri. monacensis in I. ricinus ticks isolated from a dog in Corsica. In conclusion, our data revealed wide dispersal of SFG Rickettsiae and their arthropod hosts in Corsica, highlighting the need for surveillance of the risk of infection for people living and/or working close to infected or infested animals

Lack of Evidence for Crimean–Congo Hemorrhagic Fever Virus in Ticks Collected from Animals, Corsica, France

This study has been funded in part by the European Virus Archive Global Project, which has received funding from the European Union's Horizon 2020-INFRAIA-2019 research and innovation programme (grant agreement no. 871029) and by the European Union-Cepheid Innovative Medicines Initiative Joint Undertaking (as part of the Viral Haemorrhagic Fever: Modern Approaches For Developing Bedside Rapid Diagnostics [VHFMoDRAD] under grant no. 823666).International audienceIn Corsica, France, 9.1% of livestock serum samples collected during 2014-2016 were found to have antibodies against Crimean-Congo hemorrhagic fever virus (CCH-FV), an emerging tickborne zoonotic disease. We tested 8,051 ticks for CCHFV RNA and Nairovirus RNA. The results indicate that Corsica is not a hotspot for CCHFV

Molecular detection of parapoxvirus in Ixodidae ticks collected from cattle in Corsica, France

International audienceBackground: Several viruses belonging to the family Poxviridae can cause infections in humans and animals. In Corsica, livestock farming (sheep, goats, pigs, and cattle) is mainly mixed, leading to important interactions between livestock, wildlife, and human populations. This could facilitate the circulation of zoonotic diseases, and makes Corsica a good example for studies of tick-borne diseases.Objectives: To gain understanding on the circulation of poxviruses in Corsica, we investigated their presence in tick species collected from cattle, sheep, horses, and wild boar, and characterized them through molecular techniques.Methods: Ticks were tested using specific primers targeting conserved regions of sequences corresponding to two genera: parapoxvirus and orthopoxvirus.Results: A total of 3555 ticks were collected from 1549 different animals (687 cattle, 538 horses, 106 sheep, and 218 wild boars). They were tested for the presence of parapoxvirus DNA on one hand and orthopoxvirus DNA on the other hand using Pangeneric real-time TaqMan assays. Orthopoxvirus DNA was detected in none of the 3555 ticks. Parapoxvirus DNA was detected in 6.6% (36/544) of ticks collected from 23 cows from 20 farms. The remaining 3011 ticks collected from horses, wild boars, and sheep were negative. The infection rate in cow ticks was 8.0% (12/148) in 2018 and 6.0% (24/396) in 2019 (p = 0.57). Parapoxvirus DNA was detected in 8.5% (5/59) of Hyalomma scupense pools, 8.2% (15/183) of Hyalomma marginatum pools, and 6.7% (16/240) of Rhipicephalus bursa pools (p = 0.73). We successfully amplified and sequenced 19.4% (7/36) of the positive samples which all corresponded to pseudocowpox virus.Conclusions: Obviously, further studies are needed to investigate the zoonotic potential of pseudocowpox virus and its importance for animals and public health