Vector Specificity of Arbovirus Transmission

Abstract

More than 25% of human infectious diseases are vector-borne diseases (VBDs). These diseases, caused by pathogens shared between animals and humans, are a growing threat to global health with more than 2.5 million annual deaths. Mosquitoes and ticks are the main vectors of arboviruses including flaviviruses, which greatly affect humans. However, all tick or mosquito species are not able to transmit all viruses, suggesting important molecular mechanisms regulating viral infection, dissemination, and transmission by vectors. Despite the large distribution of arthropods (mosquitoes and ticks) and arboviruses, only a few pairings of arthropods (family, genus, and population) and viruses (family, genus, and genotype) successfully transmit. Here, we review the factors that might limit pathogen transmission: internal (vector genetics, immune responses, microbiome including insect-specific viruses, and coinfections) and external, either biotic (adult and larvae nutrition) or abiotic (temperature, chemicals, and altitude). This review will demonstrate the dynamic nature and complexity of virus-vector interactions to help in designing appropriate practices in surveillance and prevention to reduce VBD threats.

Keywords: arbovirus; host–pathogen interactions; mosquito; tick; vectorial transmission.

FIGURE 1

Global distributions of mosquito genera of medical importance (A) and arboviruses transmitted by the three main mosquito genera (B). (A) The three mosquito genera reported on the map are the most prevalent ones around the world representing the principal vectors of arboviruses (Aedes and Culex spp.) and parasites (Anopheles spp.) of human health importance. The pink, blue, and green areas represent respective presence of Aedes spp., Anopheles spp., and Culex spp. mosquitoes. The hatched areas represent the distribution of Aedes spp. and Anopheles spp. mosquitoes in the same countries. (B) Map of the main arboviruses transmitted by Aedes, Culex, and Anopheles spp. including the flaviviruses (YFV, JEV, DENV, ZIKV, and WNV), the alphaviruses chikungunya (CHIKV) and O’nyong’nyong virus (ONNV), and the phlebovirus Rift valley fever virus (RVFV) (Tiwari et al., 2012; Hanley et al., 2013; Reisen, 2013; Fredericks and Fernandez-Sesma, 2014; Houe et al., 2019; Noorbakhsh et al., 2019; Pezzi et al., 2019; Centers for Disease Control and Prevention, 2020a,c; European Centre for Disease Prevention and Control, 2021). The maps were built using the open source map site https://cmap.comersis.com/cartes-Monde-WORLD.html.

FIGURE 2

Global distributions of tick genera of medical and veterinary importance (A) and arboviruses transmitted by ticks (B). (A) The five tick genera reported on the map, namely, Ornithodoros, Ixodes, Rhipicephalus, Dermacentor, and Hyalomma spp., are the most prevalent ones around the world representing the principal vectors of arboviruses. (B) Map of the main arboviruses transmitted by ticks. The yellow, orange, green, blue, and pink areas represent respective presence of the tick-borne flaviviruses, namely, tick-borne encephalitis virus (TBEV), Louping ill virus (LIV), and Powasan virus (POWV); the Asfivirus, namely, African swine fever virus (ASFV); and the Orthonairovirus, namely, Crimean-Congo hemorrhagic fever virus (CCHFV) (Myers, 2015; Dupraz et al., 2016; Diuk-Wasser et al., 2016; DW Akademie, 2016; de la Fuente et al., 2017; Frant et al., 2017; Galgani et al., 2017; Bakkes et al., 2018; Lindqvist et al., 2018; Andersen et al., 2019; Burrow et al., 2019; Kemenesi and Banyai, 2019; Wang et al., 2019; Centers for Disease Control and Prevention, 2020b; Gaudreault et al., 2020; World Health Organization, 2020). The map was built using the open source map site https://cmap.comersis.com/cartes-Monde-WORLD.html.

FIGURE 3

Vector immune pathways to fight against viral infections. The vector immune responses to pathogen infections, composed of four different pathways, allow vectors to neutralize entomopathogens, such as fungi, bacteria, or virus, and are involved in viral infection, replication, dissemination, and transmission along vector life cycle. siRNA (in green), JAK/STAT (in pink), IMD (in orange), and Toll (in blue) immune pathways are represented (Schonhofer et al., 2016; Terradas et al., 2017; Lee et al., 2019). Created with BioRender.com.

FIGURE 4

Overview of factors influencing the vectorial system. Vector capacity results from complex interactions of multiple factors influencing pathogen transmission by a vector. Internal factors like genetic, evolution, immunity, or interactions with other microorganisms are modulated by external parameters such as abiotic (like climate or topography) and biotic (like nutrition or hosts) factors (Lefevre et al., 2013). Created with Flaticon.com.