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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Microbiol. | doi: 10.3389/fmicb.2019.02315

Monitoring silent spillovers before emergence: a pilot study at the tick/human interface in Thailand.

 Sarah Temmam1,  Delphine Chrétien1,  Thomas Bigot2, Evelyne Dufour3, Stéphane Petres3,  Marc Desquesnes4, Elodie Devillers5, Marine Dumarest1, Léna Yousfi5, Sathaporn Jittapalapong6, Anamika Karnchanabanthoeng6, Kittipong Chaisiri7, Léa Gagnieur1, Jean-François Cosson5,  Muriel Vayssier-Taussat5,  Serge Morand8,  Sara Moutailler5 and  Marc Eloit1*
  • 1INSERM U1117 Biologie des Infections, France
  • 2USR3756 Centre de Bioinformatique, Biostatistique et Biologie Intégrative (C3BI), France
  • 3Institut Pasteur, France
  • 4Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), Réunion
  • 5INRA Biologie moléculaire et immunologie parasitaires, France
  • 6Faculty of Veterinary Medicine, Kasetsart University, Thailand
  • 7Faculty of Tropical Medicine, Mahidol university, Thailand
  • 8UMR ASTRE, CIRAD, Thailand

Emerging zoonoses caused by previously unknown agents are one of the most important challenges for human health because of their inherent inability to be predictable, conversely to emergences caused by previously known agents that could be targeted by routine surveillance programs. Emerging zoonotic infections either originate from increasing contacts between wildlife and human populations, or from the geographical expansion of hematophagous arthropods that act as vectors, this latter being more capable to impact large-scale human populations. While characterizing the viral communities from candidate vectors in high-risk geographical areas is a necessary initial step, the need to identify which viruses are able to spill over and those restricted to their hosts, have recently emerged. We hypothesized that currently unknown tick-borne arboviruses could silently circulate in specific biotopes where mammals are highly exposed to tick bites, and implemented a strategy that combined high-throughput sequencing with broad range serological techniques to both identify novel arboviruses and tick-specific viruses in a ticks/mammals interface in Thailand.
The virome of Thai ticks belonging to the Rhipicephalus, Amblyomma, Dermacentor, Hyalomma, and Haemaphysalis genera identified numerous viruses, among which several viruses could be candidates for future emergence as regards to their phylogenetic relatedness with known tick-borne arboviruses. Luciferase immunoprecipitation system targeting external viral proteins of viruses identified among the Orthomyxoviridae, Phenuiviridae, Flaviviridae, Rhabdoviridae and Chuviridae families was used to screen human and cattle Thai populations highly exposed to tick bites. Although no positive serum was detected for any of the six viruses selected, suggesting that these viruses are not infecting these vertebrates, or at very low prevalence (upper estimate 0,017% and 0,047% in humans and cattle, respectively), the virome of Thai ticks presents an extremely rich viral diversity, among which novel tick-borne arboviruses are probably hidden and could pose a public health concern if they emerge.
The strategy developed in this pilot study, starting from the inventory of viral communities of hematophagous arthropods to end by the identification of viruses able (or likely unable) to infect vertebrates, is the first step in the prediction of putative new emergences and could easily be transposed to other reservoirs/vectors/susceptible hosts interfaces.

Keywords: virome, tick, emergence, spillover, Lips

Received: 17 Jul 2019; Accepted: 23 Sep 2019.

Copyright: © 2019 Temmam, Chrétien, Bigot, Dufour, Petres, Desquesnes, Devillers, Dumarest, Yousfi, Jittapalapong, Karnchanabanthoeng, Chaisiri, Gagnieur, Cosson, Vayssier-Taussat, Morand, Moutailler and Eloit. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Marc Eloit, INSERM U1117 Biologie des Infections, Paris, France, marc.eloit@pasteur.fr