Co-infection of bacteria and protozoan parasites in Ixodes ricinus nymphs collected in the Alsace region, France Nebbak, A. Dahmana, H. Almeras, L. Raoult, D. Boulanger, N. Jaulhac, B. /Mediannikov, Oleg Parola, P. Ixodes ricinus Co-infection Bacterial pathogens Protozoan parasites MALDI-TOF MS Fifty nymphal Ixodes ricinus ticks collected in Alsace, France, identified by morphological criteria and using MALDI-TOF MS, were tested by PCR to detect tick-associated bacteria and protozoan parasites. Seventy percent (35/50) of ticks contained at least one microorganism; 26% (9/35) contained two or more species. Several human pathogens were identified including Borrelia burgdorferi s.s. (4%), Borrelia afzelii (2%), Borrelia garinii (2%), Borrelia valaisiana (4%), Borrelia miyamotoi (2%), Rickettsia helvetica (6%) and "Babesia venatorum" (2%). Bartonella spp. (10%) and a Wolbachia spp. (8%) were also detected. The most common co-infections involved Anaplasmataceae with Borrelia spp. (4%), Anaplasmataceae with Bartonella spp. (6%) and Anaplasmataceae with Rickettsia spp. (6%). Co-infection involving three different groups of bacteria was seen between bacteria of the family Anaplasmataceae, Borrelia spp. and Bartonella spp. (2%). Results highlight the panel of infectious agents carried by Ixodes ricinus. Co-infection suggests the possibility of transmission of more than one pathogen to human and animals during tick blood feeding. 2019 text https://www.documentation.ird.fr/hor/fdi:010077009 fdi:010077009 Nebbak A., Dahmana H., Almeras L., Raoult D., Boulanger N., Jaulhac B., Mediannikov Oleg, Parola P.. Co-infection of bacteria and protozoan parasites in Ixodes ricinus nymphs collected in the Alsace region, France. 2019, 10 (6), art. 101241 [5 p.] EN FRANCE ALSACE