Biology subjects

de la Cotte, N.

Publications and source records attributed to de la Cotte, N..

3 recordsLinked to original sources

bioRxiv2024

Equine piroplasmosis in different geographical areas in France: prevalence heterogeneity of asymptomatic carriers and low genetic diversity of Theileria equi and Babesia caballi

Equine piroplasmosis is a worldwide tick-borne disease caused by the protozoan parasites Theileria equi and Babesia caballi, with significant economic and sanitary consequences. It can also limit the export of infected horses to piroplasmosis-free countries. These two parasites are genetically variable, with greater diversity observed in T. equi. This variability can potentially impact diagnostic accuracy. Our study aimed to evaluate the frequency of asymptomatic carriers of these parasites in France and describe the circulating genotypes. We used a species-specific nested PCR protocol targeting the 18S small subunit (SSU) rRNA gene and subsequent amplicon sequencing on blood samples collected from 566 asymptomatic horses across four National Veterinary Schools. The carrier frequency varied considerably, ranging from 18.7% around Paris (central-north) to 56.1% around Lyon (southeast), with an overall prevalence of 38.3%. T. equi carriers were ten times more frequent (91.7%, 209/228 isolates) compared to B. caballi carriers (8.8%, 19/228 isolates). Notably, T. equi carrier frequency was significantly lower in the northern region (Ile de France) compared to the southeastern regions. Interestingly, a strong correlation was observed between the frequencies of asymptomatic carriers and reported cases of acute piroplasmosis across all four geographic areas. Neither gender (female, gelding, or stallion) nor horse age showed a significant effect on the frequency of asymptomatic carriers. In areas with the highest carrier frequency, a substantial proportion of horses (22.2% to 37.5%) carried T. equi before the age of three, indicating high infection pressure. Genotyping of 201 T. equi isolates revealed a predominance of genotype E (98%), with only a few isolates belonging to genotype A (2%). Notably, two of the four genotype A isolates were detected in horses originating from Spain. All 19 B. caballi isolates belonged to the most common genotype A of this species. The discussion section explores the link between these results, the tick distribution and abundance, and the frequency of detection of T. equi and B. caballi in febrile cases attributed to piroplasmosis.

microbiology↗

bioRxiv2021

Transcriptome of the synganglion and characterization of the cys-loop ligand-gated ion channel gene family in the tick Ixodes ricinus.

Ticks represent a major health issue for humans and domesticated animals. Assessing the expression patterns of the ticks central nervous system, known as the synganglion, is an important step in understanding tick physiology and in managing tick-borne diseases. Neuron-specific genes like the cys-loop ligand-gated ion channels (cys-loop LGICs) are important pharmacological targets of acaricides. Here, we carried out the sequencing of transcriptomes of the I. ricinus synganglion, for adult ticks in different conditions (unfed males, unfed females, and partially-fed females). The de novo assembly of these transcriptomes allowed us to obtain a large collection of cys-loop LGICs sequences. A reference meta-transcriptome based on synganglion and whole body transcriptomes was then produced, showing high completeness and allowing differential expression analyses between synganglion and whole body. Many of the genes upregulated in the synganglion were related to biological processes or functions associated with neurotransmission and located in neurones or the synaptic membrane, including most of the cys-loop LGICs. As a first step of a functional study of cysLGICs, we cloned the predicted sequence of the resistance to dieldrin (RDL) subunit homologue, and functionally reconstituted the first GABA-gated receptor of Ixodes ricinus using a hetrologous expression approach. A phylogenetic study was performed for the nicotinic acetylcholine receptors (nAChRs) and for other cys-loop LGICs respectively, showing tick-specific expansions of some types of receptors (Histamine-gated, GluCls).

evolutionary biology↗

bioRxiv2018

First detection and molecular identification of the zoonotic Anaplasma capra in deer in France

Cervids are known to be reservoir of zoonotic tick-transmitted bacteria. The aim of this study was to perform a survey in a wild fauna reserve to characterize Anaplasma species carried by captive red deer and swamp deer. Blood from 59 red deer and 7 swamp deer was collected and analyzed over a period of two years. A semi-nested PCR that targets the 23S rRNA was performed to detect and characterise Anaplasma spp. and determine zoonotic species presence. Anaplasma phagocytophilum was identified in 14/59 deer (23.7%) but not in swamp deer. Few sequences could not be assigned to any particular species based on the 23S rRNA sequences. Nested PCR targeting 16S rRNA, gltA and groEL genes and sequencing analysis detected a recently reported zoonotic species, Anaplasma capra in red deer as well as in swamp deer. This is the first reporting of the tick-borne zoonotic bacterium A. capra in France, a species otherwise described only in China and Japan, in goats, sheep, deer and japanese serows. Even if this bacterium may have been introduced in the Park with infected imported animals, its local epidemiological cycle through tick transmission seems possible as locally born deer were found infected. Diagnostic methods, especially molecular ones, should take into account the potential infection of animals and humans with this species.

epidemiology↗