María José Tolsá-García

The international wildlife trade is a major global activity, involving billions of live animals and wildlife-derived products being exchanged annually across the world (Smith et al. 2009; Gippet an...

Coronavirus (CoV) spillover from wildlife to humans is increasing and has caused major global epidemics, facilitated by human-induced habitat alteration that promotes zoonotic emergence. This highlights the need for sustained surveillance and a better understanding of circulation patterns within wildlife reservoirs. Although Neotropical bats harbour a highly diverse CoV community, how host traits and ecological factors shape CoV circulation and virus–host associations remains poorly characterized. During 2021–3, we conducted extensive bat sampling across 12 localities along an anthropogenic land-use gradient in the Yucatan Peninsula, Mexico, to characterize bat community diversity. We then screened bats for CoVs and evaluated the association between CoV detection and host traits and ecological variables. Detected CoVs were subsequently sequenced and phylogenetically characterized. Using publicly available databases and host phylogenetic diversity metrics, we further analysed the putative host range of each identified CoV taxon and their distribution along the gradient. Bat diversity was significantly lower in urban sites. Although overall CoV positivity was low (3.2%), we identified eight divergent CoV taxa, including two novel Alphacoronavirus sequences, one of which represents the first CoV reported from Lophostoma brasiliense. Juvenile bats were more likely to be CoV-positive, a pattern particularly pronounced in Sturnira parvidens but absent in Artibeus jamaicensis. We found variation in putative host breadth among the identified CoV taxa, supported by differences in host phylogenetic distances. Notably, CoV taxa detected at sites with lower bat diversity were associated with a greater number of reported host species and higher host phylogenetic diversity. Our findings expand the known diversity of Neotropical bat CoVs and reveal distinct patterns in CoV detection and virus–host associations across viral taxa. Sustained viral surveillance, complemented by broader genomic studies and deeper investigation into variation within and among CoV taxa, is needed to clarify these patterns, guide research priorities in the Neotropical CoVs, and help mitigate the risk of future zoonotic emergence.

Human activities and land use changes have a major impact on the distribution and diversity of mosquito vectors and their associated viruses. This study describes the diversity and differential abundance of viruses associated with mosquito species from four habitats of the Yucatan Peninsula, Mexico. Using next-generation sequencing (NGS), we analyzed 61 genomic libraries belonging to 20 mosquito species to characterize the viral community. A total of 16 viral species were identified, representing 14 different viral families. Most identified viruses were associated with insects, plants, and fungi. Additionally, vertebrate associated viral families, including Herpesviridae, Peribunyaviridae, Nairoviridae, and Arenaviridae, were detected in mosquitoes from urban habitats. Notably, insect-associated viruses like Hubei mosquito virus 4 and Hubei virga-like virus 2 were identified, along with the first report of Mercadeo virus in Mexico. Variations in viral community composition were primarily driven by mosquito species, with species of the same genus maintaining similar viromes despite occupying different habitats. These findings reinforce that intrinsic traits of mosquito species play a key role in shaping viral community composition. To our knowledge, this is the first study that describes the viral community in mosquitoes in Yucatan Peninsula, Mexico. This study provides essential baseline data for the surveillance of mosquitoes and associated viruses from a biodiverse tropical region that faces strong land use modifications.

The composition of host communities is pivotal for pathogen persistence and transmission. We present a community competence index (CCI), based on the Amplification Fraction framework, and applied it to the West Nile virus (WNV) system, and its avian and mosquito hosts, using field data from France, Germany, and Mexico across several land-use types. Our results showed that urban areas exhibited significantly higher AF and CCI values compared to rural and natural habitats. These findings suggest that the lower diversity distinctive of urban communities is associated with higher average community competence, supporting the hypothesis of the dilution effect hypothesis, in which high richness can dilute pathogen transmission. The CCI provides a versatile and integrative tool for estimating pathogen transmission capacity at the community level, complementing existing strategies for the early prevention, surveillance, and risk assessment of zoonotic diseases.

Mosquito-borne flaviviruses (MBFVs) are of public and animal health concern because they cause millions of human deaths annually and impact domestic animals and wildlife globally. MBFVs are phylogenetically divided into two clades, one is transmitted by Aedes mosquitoes (Ae-MBFVs) associated with mammals and the other by Culex mosquitoes (Cx-MBFVs) associated with birds. However, this assumption has not been evaluated. Here, we synthesized 79 published reports of MBFVs from wild mammals, estimating their host. Then, we tested whether the host specificity was biased to sampling and investigation efforts or to phylogenetic relationships using a viral phylogenetic tree drawn from analyzing whole flavivirus genomes obtained in GenBank. We found in total 18 flaviviruses, nine related to Aedes spp. and nine to Culex spp. infecting 129 mammal species. Thus, this supports that vectors are transmitting MBFV across available host clades and that ornithophilic mosquitoes are readily infecting mammals. Although most of the mosquito species are generalists in their host-feeding preferences, we also found a certain degree of MBFV’s specificity, as most of them infect closely related mammal species. The present study integrates knowledge regarding MBFVs, and it may help to understand their transmission dynamics between viruses, vectors, and mammal hosts.

Zoonotic diseases transmitted by wildlife affect biological conservation, public and animal health, and the economy. Current research efforts are aimed at finding wildlife pathogens at a given location. However, a meta-analytical approach may reveal emerging macroecological patterns in the host–pathogen relationship at different temporal and spatial scales. West Nile virus (WNV) is a pathogen with worldwide detrimental impacts on bird populations. To understand macroecological patterns driving WNV infection, we aimed to recognize unknown competent reservoirs using three disease metrics—serological prevalence (SP), molecular prevalence (MP) and mortality (M)—and test if these metrics are correlated with the evolutionary history, geographical origin of bird species, viral strain, time–space and methodology. We performed a quantitative review of field studies on birds sampled for WNV. We obtained 4945 observations of 949 species from 39 countries. Our analysis supported the idea that MP and M are good predictors of reservoir competence, and allowed us to identify potential competent reservoirs. Furthermore, results indicated that the variability of these metrics was attributable to phylogeny, time–space and sample size. A macroecological approach is needed to recognize susceptible species and competent reservoirs, and to identify other factors driving zoonotic diseases originating from wildlife.