Establishment of Culex modestus in Belgium and a Glance into the Virome of Belgian Mosquito Species

Abstract

Culex modestus mosquitoes are considered to be a potential “bridge” vector, being able to transmit pathogens between birds as well as from birds to mammals, including humans. In Belgium, this mosquito species was considered absent until the finding of one larva in 2018 and subsequent evidence of a large population in 2019 to 2020 described here.

First report of kdr L1014F and ace-1 G119S insecticide resistance in Belgian Culex (Diptera: Culicidae) mosquitoes

“…Field mosquitoes were collected in Leuven and surrounding areas in urban, peri-urban, and agricultural habitats during the summer months for three consecutive years (2019-2021). Culex pipiens was the dominant species across all collection sites, a finding consistent with previous research conducted in this area (Wang et al 2021b). The majority of Culex pipiens were biotype pipiens.…”

“…The cycle conditions were as follows: initial denaturation at 95°C for 10 min, 40 cycles of denaturation at 94°C for 40 sec, elongation at 48°C for 1 min, and extension at 72°C for 1 min, and a final hold stage at 72°C for 2 min. Culex modestus and Culex torrentium mosquitoes were identified morphologically using the key of Becker (Becker et al 2010) followed by COX1 Sanger sequencing (Wang et al 2021a).…”

Intrinsic variation in the vertically transmitted core virome of the mosquito Aedes aegypti

“…The clear mosquito-associated clade present in the toti-virus like sequences (Figures 4 and 5) could represent widespread concurrent viral movement or long host coevolution (Wang et al, 2020), as is thought to be the case for Bunyaviridae, Flaviviridae, Rhabdoviridae, and Togoviridae ISVs, which are assumed to have evolved and diversified alongside their host (Vasilakis & Tesh, 2015). Historically, totiviruses were primarily fungal associated, and probably represent a viral taxon with an ancient origin (Dolja & Koonin, 2018).…”

“…In contrast, the partiti-like RdRp phylogenetic tree showed no obvious mosquito clustering, as mosquito-derived partiti-like virus sequences were dispersed throughout the tree (Figure 6). Our et al, 2016), Armigeres in China (Zhai et al, 2010), Culex in Belgium (Wang et al, 2020), Culex in California (Batson et al, 2021), Culex in Australia (Williams et al, 2020), Culex in Japan (Isawa et al, 2011), andMansonia in Brazil (de Lara Pinto et al, 2017), suggesting that toti-like viruses may be common components of core viromes among mosquito populations. Metagenomic analyses of mosquitoes from our Palmetto site collected in 2016 and 2017 also identified a totilike virus, as well as dsRNA virus environmental sample (Boyles et al, 2020), further supporting that A. aegypti mosquitoes with similar genetic backgrounds (here, representative of central Florida-based populations) share many of the same viruses, as previously reported (Konstantinidis et al, 2021;Öhlund et al, 2019;Shi et al, 2019;Wang et al, 2020).…”

“…Similarly, the Partitiviridae and partiti-like viruses have been historically associated with plants and fungi (Nibert et al, 2014) global distribution (North and South America, Africa, Asia, and Europe) (Konstantinidis et al, 2021;Öhlund et al, 2019;Shi et al, 2019;Wang et al, 2020). The low congruence between viral host phylogeny and host-range for these partiti-like viruses may suggest a recent host-switching event (Dolja & Koonin, 2018;Grubaugh et al, 2016), as the Palmetto partiti-like virus was highly divergent (<80% similarity) from other known partiti-like viruses and probably represents a novel virus.…”