Development of innovative tools for the identification and classification of arthropods

Les arthropodes ont une grande importance en santé humaine et animale. La surveillance épidémiologique des vecteurs, leur identification et la détection des microorganismes associés, demeurent des éléments clés dans les stratégies de lutte et de contrôle des maladies vectorielles. Nos travaux de thèse ont porté dans un premier temps sur l’identification des arthropodes en faisant appel à plusieurs méthodes d’identification : Morphologique, moléculaire et spectrométrie de masse (MALDI-TOF MS pour l’identification des poux). En second lieu, nous nous sommes penchés sur l’étude des microorganismes associés aux arthropodes (poux, tiques et puces) et/ou leurs hôtes. Ainsi, au cours de nos investigations, nous avons pu après une identification morphologique et moléculaire mettre au point l’identification par MALDI-TOF MS des poux humains d’élevage et de 13 espèces de poux d’animaux collectés en France et dans plusieurs régions d’Algérie. La recherche par la suite des microorganismes associés aux poux par les outils de biologie moléculaire a permis de révéler le portage de plusieurs bactéries. Ensuite, nous avons travaillé sur la détection des microorganismes chez des petits mammifères (Rongeurs) et leurs ectoparasites associés (Tiques dures et molles) et des puces. Les résultats des travaux de cette thèse ont confirmé pour la première fois l’efficacité et la précision du MALDI-TOF MS a identifié correctement et rapidement plusieurs espèces de poux. Aussi, cette étude a contribué à enrichir et compléter le répertoire des microorganismes chez plusieurs arthropodes.Arthropods are of great importance in human and animal health. Epidemiological surveillance of vectors, their identification and the detection of associated microorganisms remain key elements in vector disease control strategies. Our thesis work focused initially on the identification of arthropods using several identification methods: Morphological, molecular and mass spectrometry (MALDI-TOF MS for the identification of lice). Secondly, we focused on the study of microorganisms associated with arthropods (lice, ticks and fleas) and/or their hosts. Thus, during our investigations, we were able after a morphological and molecular identification, to develop the identification by MALDI-TOF MS of human lice and 13 species of animal lice collected in France and in several regions of Algeria. Subsequent research for microorganisms associated with lice using molecular biology tools revealed the carriage of several bacteria. Then, we worked on the detection of microorganisms in small mammals (Rodents) and their associated ectoparasites (Hard and soft ticks) and fleas. The results of this thesis work confirmed for the first time the efficiency and accuracy of MALDI-TOF MS to correctly and rapidly identify several species of lice. Also, this study has contributed to enrich and complete the repertoire of microorganisms in several arthropods

Detection of Rickettsia raoultii in Dermacentor reticulatus and Haemaphysalis inermis ticks in Slovakia

International audienceTicks are vector arthropods responsible for the transmission of several pathogenic agents that affect both human and animal health worldwide. In this study our objective was to analyse, using molecular tools, the bacterial community of Dermacentor reticulatus and Haemaphysalis inermis ticks collected in south-eastern Slovakia. Using real-time PCR, we identified the presence of Rickettsia spp. DNA at levels of 14/59 (23.72 %) and 29/173 (16.76 %) in D. reticulatus and H. inermis , respectively. In addition, using standard PCR and sequencing, we identified the presence of Rickettsia raoultii DNA in 13 ticks belonging to the two investigated species. Rickettsia raoultii blast results revealed an average identification percentage of 99.62 %. Following the results of this molecular study there is a possibility that D. reticulatus and H. inermis play a potential role in the transmission of R. raoultii . To prove the possibility of validity of this hypothesis, we suggest performing experimental models in future studies. Our results can serve as preliminary data for future transmission models

Lice and lice-borne diseases in humans in Africa: A narrative review

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Molecular detection of microorganisms in lice collected from farm animals in Northeastern Algeria

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Development of MALDI-TOF mass spectrometry for the identification of lice isolated from farm animals

International audienceMatrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is now routinely used for the rapid identification of microorganisms isolated from clinical samples and has been recently successfully applied to the identification of arthropods. In the present study, this proteomics tool was used to identify lice collected from livestock and poultry in Algeria. The MALDI-TOF MS spectra of 408 adult specimens were measured for 14 species, including Bovicola bovis, B. ovis, B. caprae, Haematopinus eurysternus, Linognathus africanus, L. vituli, Solenopotes capillatus, Menacanthus stramineus, Menopon gallinae, Chelopistes meleagridis, Goniocotes gallinae, Goniodes gigas, Lipeurus caponis and laboratory reared Pediculus humanus corporis. Good quality spectra were obtained for 305 samples. Spectral analysis revealed intra-species reproducibility and inter-species specificity that were consistent with the morphological classification. A blind test of 248 specimens was performed against the in-lab database upgraded with new spectra and validated using molecular tools. With identification percentages ranging from 76% to 100% alongside high identification scores (mean = 2.115), this study proposes MALDI-TOF MS as an effective tool for discriminating lice species.La Spectrométrie de Masse à Temps de Vol par Désorption/Ionisation Laser Assistée après Matrice est maintenant utilisée pour l’identification rapide des microorganismes isolés à partir d’échantillons cliniques et a récemment été appliquée avec succès pour l’identification des arthropodes. Dans cette étude, cet outil protéomique a été utilisé pour identifier les poux prélevés sur le bétail et la volaille en Algérie. Les spectres MALDI-TOF MS de 408 spécimens adultes ont été mesurés pour 14 espèces, dont Bovicola bovis, B. ovis, B. caprae, Haematopinus eurysternus, Linognathus africanus, L. vituli, Solenopotes capillatus, Menacanthus stramineus, Menopon gallinae, Chelopistes meleagridis, Goniocotes gallinae, Goniodes gigas, Lipeurus caponis et Pediculus humanus corporis élevé en laboratoire. Des spectres de bonne qualité ont été obtenus pour 305 échantillons. L’analyse spectrale a révélé une reproductibilité intra-espèce et une spécificité inter-espèces qui concordaient avec la classification morphologique. Un test à l’aveugle de 248 échantillons a été effectué par rapport à la base de données de notre laboratoire mise à niveau avec de nouveaux spectres et validée à l’aide d’outils moléculaires. Avec des pourcentages d’identification allant de 76 à 100 % et des scores d’identification élevés (moyenne : 2,115), cette étude propose MALDI-TOF MS comme un outil efficace pour distinguer les espèces de poux

Identification of Lice Stored in Alcohol Using MALDI-TOF MS

International audienceAbstract Lice pose major public and veterinary health problems with economic consequences. Their identification is essential and requires the development of an innovative strategy. MALDI-TOF MS has recently been proposed as a quick, inexpensive, and accurate tool for the identification of arthropods. Alcohol is one of the most frequently used storage methods and makes it possible to store samples for long periods at room temperature. Several recent studies have reported that alcohol alters protein profiles resulting from MS analysis. After preliminary studies on frozen lice, the purpose of this research was to evaluate the influence of alcohol preservation on the accuracy of lice identification by MALDI-TOF MS. To this end, lice stored in alcohol for variable periods were submitted for MS analysis and sample preparation protocols were optimized. The reproducibility and specificity of the MS spectra obtained on both these arthropod families allowed us to implement the reference MS spectra database (DB) with protein profiles of seven lice species stored in alcohol. Blind tests revealed a correct identification of 93.9% of Pediculus humanus corporis (Linnaeus, 1758) and 98.4% of the other lice species collected in the field. This study demonstrated that MALDI-TOF MS could be successfully used for the identification of lice stored in alcohol for different lengths of time

The Trick of the Hedgehog: Case Report and Short Review About Archaeopsylla erinacei (Siphonaptera: Pulicidae) in Human Health

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Pathogen Detection in Ornithodoros sonrai Ticks and Invasive House Mice Mus musculus domesticus in Senegal

Ornithodoros sonrai (O. sonrai) ticks are the only known vectors of Borrelia crocidurae, an agent of tick-borne relapsing fever (TBRF) borreliosis. Rodents serve as principal natural reservoirs for Borrelia. Our research objective was to detect TBRF Borrelia and other zoonotic bacterial infections in ticks and in house mice Mus musculus domesticus, an invasive species currently expanding in rural northern Senegal. Real-time and conventional PCR were utilized for detecting Borrelia and other bacterial taxa. The analyses were performed on 253 specimens of O. sonrai and 150 samples of brain and spleen tissue from rodents. Borrelia crocidurae was found in one O. sonrai tick and 18 Mus musculus domesticus samples, with prevalences of 0.39 percent and 12 percent, respectively, as well as Ehrlichia sp. in one Mus musculus domesticus. Further, we were able to detect the presence of a potentially infectious novel species belonging to the Anaplasmataceae family for the first time in O. sonrai ticks. More attention should be paid to the house mouse and O. sonrai ticks, as they can be potential hosts for novel species of pathogenic bacteria in humans

Vaccine hesitancy among general practitioners in Southern France and their reluctant trust in the health authorities

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