First detection of one of the tick-borne lymphadenopathy (TIBOLA) etiological agent in ticks from a highly frequented sub-urban forest near Paris, France

Abstract

In the context of global changes including climate, environmental and socio-economic modifications, the surveillance of tick populations in term of species distribution and harboured pathogens is an absolute necessity. With this aim in view, ticks were collected in May 2022 in an highly frequented suburban forest located near Paris, France. The objective was to identify tick species and tick-borne pathogens that may warrant long-term monitoring, as well as to assess added value of metatranscriptomic Next Generation Sequencing (mNGS) for the detection of known and possibly new pathogens in ticks. Both Dermacentor reticulatus and Ixodes ricinus were collected. In addition to expected pathogens detected in I. ricinus (i.e., Anaplasma, Babesia, and Borrelia species), we report the detection of Rickettsia conorii subsp. raoultii, a zoonotic bacterium never identified in the region before and transmitted by a tick species on the rise: D. reticulatus.

Fig 1. Phylogenetic tree of 23S rRNA sequence of Rickettsia species, including the R. conorii subsp. raoultii collected in Sénart forest (highlighted in red).

Branch support values above 70 are indicated above each branch. The tree is represented with midpoint rooting. The clades with high support values are collapsed where possible and the species or subspecies are indicated next to the clades. In the R. conorii subsp. raoultii clade, identical sequences are omitted for visualization purposes. The non-collapsed tree is available in S2 Fig.