# First Molecular Detection of Rickettsia conorii and Rickettsia helvetica in Ticks from Dogs in Luxembourg

## TL;DR

This study reports the first detection of Rickettsia conorii and Rickettsia helvetica in ticks from dogs in Luxembourg, highlighting a potential public health risk.

## Contribution

The first molecular detection of Rickettsia spp. in ticks from domestic animals in Luxembourg.

## Key findings

- Rickettsia helvetica and Rickettsia conorii subsp. raoultii were detected in Ixodes ricinus ticks from dogs in Luxembourg.
- Phylogenetic analysis showed high genetic similarity to known European and Asian Rickettsia strains.
- 4.9% of ticks tested positive for Rickettsia spp., indicating a potential risk of tick-borne diseases in the region.

## Abstract

Vector-borne diseases, particularly those caused by Rickettsia species, pose a significant public health threat in Europe. Despite extensive research on tick-borne pathogens in various European countries, Luxembourg has yet not been studied for Rickettsia spp. in ticks infesting domestic animals. This study aimed to fill this gap by investigating the presence of Rickettsia spp. in Ixodes ricinus ticks collected from domestic dogs in Luxembourg between April 2023 and April 2024. A total of 61 ticks were examined using molecular techniques, including PCR amplification of the outer membrane protein B (ompB), outer membrane protein A (ompA), and citrate synthase (gltA) genes. Results revealed the presence of R. helvetica and R. conorii subsp. raoultii, with 4.9% of ticks testing positive for Rickettsia spp. Phylogenetic analysis confirmed the high genetic identity of the sequences obtained with previously described strains from Europe and Asia. This study highlights the potential risk of emerging tick-borne diseases in Luxembourg and emphasizes the need for ongoing surveillance to better understand the spread of Rickettsia spp. in Europe, particularly as climate change may facilitate the expansion of tick populations and their associated pathogens.