Abstract
Background Among hematophagous arthropods, ticks transmit the greater variety of pathogens of public health and veterinary importance whose (re)-emergence is recognized worldwide. However, the epidemiological situation of the Caribbean area with regard to tick-borne diseases is poorly documented, mainly focusing on livestock pathogens such as Ehrlichia ruminantium, Babesia (bovis and bigemina) and Anaplasma marginale. These observations underline the need to undertake new large-scale epidemiological surveys to better assess the distribution of tick-borne pathogens and anticipate the risk of (re)-emergence of tick-borne diseases in these areas. To ease and reduce the cost of such large-scale surveys, the development of a fast and cheap high-throughput detection technics is desirable.
Methods In this study, we first implemented a high-throughput microfluidic real-time PCR (BioMark™ dynamic arrays, Fluidigm Corporation) adapted for the large-scale screening of tick-borne pathogens. The system developed here includes 57 designs allowing both the screening of bacteria and protozoans potentially circulating in the West Indies (5 bacterial genera, 30 bacterial species, 1 protozoan phylum, 2 protozoan genera and 17 protozoan species), and the molecular identification of three tick species mainly involved in tick-borne pathogens transmission in the Caribbean (Amblyomma variegatum, Rhipicephalus microplus and Rhipicephalus sanguineus sensu lato). Then, using the new high-throughput microfluidic real-time PCR system, we performed an exploratory epidemiological study on 132 specimens of Amblyomma variegatum and 446 Rhipicephalus microplus collected in Guadeloupe and Martinique.
Results We successfully detected tick-borne pathogens expected to be present in the area – Ehrlichia ruminantium, Rickettsia africae, Anaplasma marginale, Babesia bigemina, Babesia bovis, Theileria velifera and Theileria mutans – as well as unsuspected pathogens and microorganisms belonging to the genera Anaplasma, Ehrlichia, Borrelia, and Leishmania.
Conclusions We demonstrated the ability of the Biomark system to give a rapid overview of the pathogens/microorganisms diversity present in ticks, thus opening new research perspectives on tick-borne pathogens epidemiology in the Caribbean. Our study demonstrated how high-throughput microfluidic real-time PCR technology is a major improvement in large-scale epidemiological studies, giving a rapid overview of the tick-borne pathogens and microorganisms present in ticks in a given area.
Footnotes
Please note that this paper has already been published online as a preprint on bioRxiv: https://doi.org/10.1101/532457
Section results and discussion revised