A cross section through mosquitoes of Bosnia and Herzegovina: Barcodes, blood meals and pathogens

Mosquitoes are important vectors of human and animal pathogens, yet data on their diversity and vector potential remain scarce for the central Balkan country Bosnia and Herzegovina. This study aimed to assess mosquito species composition, associated pathogens, and the potential public health risks in BIH. Adult mosquitoes were collected with light traps, identified morphologically and by barcoding, and screened molecularly for various pathogens, including West Nile virus (WNV), <i>Dirofilaria</i> spp., <i>Trypanosoma</i> spp., and <i>Plasmodium</i> spp. A total of 2691 mosquitoes of 17 species were identified, with <i>Culex pipiens</i>/<i>torrentium</i> being most abundant and new records of <i>Aedes albopictus</i> and <i>Ae. japonicus japonicus</i>. The first detection of WNV (lineage 2) RNA in mosquitoes in BIH highlights the potential risk of circulation in the region, aligning with findings from neighboring countries. In addition, DNA of filarioid nematodes (<i>Dirofilaria immitis</i>, <i>D. repens,</i> and <i>Setaria tundra</i>) were detected, underscoring their role as potential vectors of zoonotic dirofilariasis. Also, <i>Trypanosoma</i> and <i>Plasmodium</i> DNA was detected, warranting further investigation into the possible involvement of mosquitoes in their transmission. The detection of invasive <i>Aedes</i> species and mosquito-borne pathogens emphasize the need for strengthened vector surveillance in southeastern Europe, particularly in BIH. This study provides the first barcode inventory of 17 mosquito species and novel molecular evidence of mosquito-borne pathogens in BIH, offering valuable baseline data for future epidemiological assessments and sustained entomological surveillance.