Viral Metagenomic Analysis of Aedes albopictus Mosquitos from Southern Switzerland

Abstract

A metagenomic study was performed on 498 female and 40 male Aedes albopictus mosquitos collected in August and September 2019 in Ticino, a region in southern Switzerland, to address the question regarding the risk of the local transmission of zoonotic viruses. A total of 13 viruses from seven different virus families and several unclassified viral taxa were identified. Reads of insect-specific flaviviruses were present in all pools, and a complete genome of aedes flavivirus was assembled and phylogenetically analysed. The most abundant virus was Wenzhou sobemo-like virus, assembled from 1.3 × 10⁵ to 3.6 × 10⁶ reads in each pool. In a pool of male mosquitos, a complete genome of aedes Iflavi-like virus was detected and phylogenetically analysed. Most importantly, genomes of human pathogenic viruses were not found. This is the first study to determine the virome of Ae. albopictus from Switzerland and forms a baseline for future longitudinal investigations concerning the potential role of Ae. albopictus as a vector of clinically relevant viruses.

Keywords: Aedes albopictus; metagenomic; virome.

Figure 1

Locations of mosquito collection. Detailed coordinates and sample descriptions are given in Table 1.

Figure 2

The phylogenetic tree of Aedes flaviviruses constructed using the maximum likelihood method and Kimura 2-parameter model. The percentage of replicate trees in which the associated taxa clustered together in the bootstrap test (1000 replicates) are shown next to the branches. The black dot indicates the genome sequenced in this study.

Figure 3

The phylogenetic tree of Aedes iflavi-like virus constructed using the maximum likelihood method and Kimura 2-parameter model. The percentage of replicate trees in which the associated taxa clustered together in the bootstrap test (1000 replicates) are shown next to the branches. The black dot indicates the genome sequenced in this study.

Figure 4

The phylogenetic tree of Wenzhou sobemo-like virus constructed using Table 2. parameter model. The percentage of replicate trees in which the associated taxa clustered together in the bootstrap test (1000 replicates) are shown next to the branches. The black dot indicates the genome sequenced in this study.