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Abstract BackgroundCache Valley virus (CVV) is an understudiedOrthobunyaviruswith a high spillover transmission potential due to its wide geographical distribution and large number of associated hosts and vectors. Although CVV is known to be widely distributed throughout North America, no studies have explored its geography or employed computational methods to explore the mammal and mosquito species likely participating in the CVV sylvatic cycle. MethodsWe used a literature review and online databases to compile locality data for CVV and its potential vectors and hosts. We linked location data points with climatic data via ecological niche modeling to estimate the geographical range of CVV and hotspots of transmission risk. We used background similarity tests to identify likely CVV mosquito vectors and mammal hosts to detect ecological signals from CVV sylvatic transmission. ResultsCVV distribution maps revealed a widespread potential viral occurrence throughout North America. Ecological niche models identified areas with climate, vectors, and hosts suitable to maintain CVV transmission. Our background similarity tests identifiedAedes vexans,Culiseta inornata, andCulex tarsalisas the most likely vectors andOdocoileus virginianus(white-tailed deer) as the most likely host sustaining sylvatic transmission. ConclusionsCVV has a continental-level, widespread transmission potential. Large areas of North America have suitable climate, vectors, and hosts for CVV emergence, establishment, and spread. We identified geographical hotspots that have no confirmed CVV reports to date and, in view of CVV misdiagnosis or underreporting, can guide future surveillance to specific localities and species. Graphical Abstract 

Abstract BackgroundVector-borne diseases (VBDs) are important contributors to the global burden of infectious diseases due to their epidemic potential, which can result in significant population and economic impacts. Oropouche fever, caused by Oropouche virus (OROV), is an understudied zoonotic VBD febrile illness reported in Central and South America. The epidemic potential and areas of likely OROV spread remain unexplored, limiting capacities to improve epidemiological surveillance. MethodsTo better understand the capacity for spread of OROV, we developed spatial epidemiology models using human outbreaks as OROV transmission-locality data, coupled with high-resolution satellite-derived vegetation phenology. Data were integrated using hypervolume modeling to infer likely areas of OROV transmission and emergence across the Americas. ResultsModels based on one-support vector machine hypervolumes consistently predicted risk areas for OROV transmission across the tropics of Latin America despite the inclusion of different parameters such as different study areas and environmental predictors. Models estimate that up to 5 million people are at risk of exposure to OROV. Nevertheless, the limited epidemiological data available generates uncertainty in projections. For example, some outbreaks have occurred under climatic conditions outside those where most transmission events occur. The distribution models also revealed that landscape variation, expressed as vegetation loss, is linked to OROV outbreaks. ConclusionsHotspots of OROV transmission risk were detected along the tropics of South America. Vegetation loss might be a driver of Oropouche fever emergence. Modeling based on hypervolumes in spatial epidemiology might be considered an exploratory tool for analyzing data-limited emerging infectious diseases for which little understanding exists on their sylvatic cycles. OROV transmission risk maps can be used to improve surveillance, investigate OROV ecology and epidemiology, and inform early detection. 

Abstract BackgroundThe term virus ‘spillover’ embodies a highly complex phenomenon and is often used to refer to viral transmission from a primary reservoir host to a new, naïve yet susceptible and permissive host species. Spillover transmission can result in a virus becoming pathogenic, causing disease and death to the new host if successful infection and transmission takes place. Main textThe scientific literature across diverse disciplines has used the terms virus spillover, spillover transmission, cross-species transmission, and host shift almost indistinctly to imply the complex process of establishment of a virus from an original host (source/donor) to a naïve host (recipient), which have close or distant taxonomic or evolutionary ties. Spillover transmission may result in unsuccessful onward transmission, if the virus dies off before propagation. Alternatively, successful viral establishment in the new host can occur if subsequent secondary transmission among individuals of the same novel species and among other sympatric susceptible species occurred. As such, virus spillover transmission is a common yet highly complex phenomenon that encompasses multiple subtle stages that can be deconstructed to be studied separately to better understand the drivers of disease emergence. Rabies virus (RABV) is a well-documented viral pathogen which still inflicts heavy impact on humans, companion animals, wildlife, and livestock throughout Latin America due substantial spatial temporal and ecological—natural and expansional—overlap with several virus reservoir hosts. Thereby, the rabies disease system represents a robust avenue through which the drivers and uncertainties surrounding spillover transmission can be unravel at its different subtle stages to better understand how they may be affected by coarse, medium, and fine scale variables. ConclusionsThe continued study of viral spillover transmission necessitates the elucidation of its complexities to better assess the cross-scale impacts of ecological forces linked to the propensity of spillover success. Improving capacities to reconstruct and predict spillover transmission would prevent public health impacts on those most at risk populations across the globe. Graphical Abstract: 

Abstract In North America, the rodent‐borne hantavirus pulmonary syndrome is predominantly caused by the Sin Nombre virus, typically associated with the deer mousePeromyscus maniculatus. Utilizing data from the National Ecological Observatory Network (NEON) hantavirus program, we assessed factors that may influence the spatial and temporal distribution of hantavirus in rodent populations across the United States. Between 2014 and 2019, the NEON hantavirus program conducted 104,379 small mammal captures and collected 14,004 blood samples from 49 species at 45 field sites. Our study identified 296 seropositive samples across 15 rodent species, including 8Peromyscusspecies. We describe six new species with hantavirus seropositive samples not previously reported as hantavirus hosts. The highest number of seropositive samples was obtained fromPe. maniculatus(n = 116; 2.9% seroprevalence), followed byPeromyscus leucopus(n = 96; 2.8%) andMicrotus pennsylvanicus(n = 33; 4.2%). Hantavirus seroprevalence showed an uneven spatial distribution, with the highest seroprevalence found in Virginia (7.8%, 99 seropositive samples), Colorado (5.7%,n = 37), and Texas (4.8%,n = 19). Hantavirus seropositive samples were obtained from 32 sites, 10 of which presented seropositive samples in species other thanPe. maniculatusorPe. leucopus. Seroprevalence was inconsistent across years but showed intra‐annual bimodal trends, and inPe. maniculatusandPe. leucopus, the number of captures correlated with seroprevalence in the following months. Seroprevalence was higher in adult males, with only one seropositive sample obtained from a juvenilePeromyscus truei. Higher body mass, presence of scrotal testes, and nonpregnant status were associated with higher seropositivity. The NEON dataset, derived from a multiyear and structured surveillance system, revealed the extensive distribution of hantavirus across broad taxonomic and environmental ranges. Future research should consider winter season surveillance and continued analyses of stored samples for a comprehensive spatiotemporal study of hantavirus circulation in wildlife. Global changes are expected to affect the dynamics of rodent populations by affecting their availability of resources and demography and, consequently, may modify transmission rates of rodent‐borne zoonotic pathogens such as hantavirus. This study can be considered a baseline to assess hantavirus patterns across host taxa, geographies, and seasons in the United States. 

ABSTRACT BackgroundIn Latin America, there is a high incidence of vampire bat‐transmitted rabies in cattle causing increased mortality of livestock, which heavily impacts the agricultural sector. Anticoagulants‐based control methods for the common vampire bat (Desmodus rotundus) have been employed continuously since the 1970s with various methods of application, presentations, doses and active ingredients. Studies from half a century ago still serve as a reference for the current use of anticoagulants for bat‐borne rabies control in Latin America. The objective of this study was to structurally and bibliometrically review literature on the use of anticoagulants for the control ofD. rotundusas a means of rabies control. Materials & MethodsScientific literature on the use of anticoagulant products forD. rotunduscontrol was obtained, reviewed and analysed. Articles were retrieved from Scopus and Web of Science databases. Research articles from 1971 to 2021 in Spanish, English and Portuguese were included in the review. Results were visualised using RStudio, Bibliometrix and VOSviewer. ResultsThe body of literature indicates effectiveness of up to 100% in the use of anticoagulants to induce bat mortality. The effectiveness of anticoagulants for rabies control, however, remains uncertain. No evidence was found to support or refute the use of anticoagulants for rabies control. DiscussionInstead, literature suggests that disturbing bat colonies increases rabies prevalence. This finding suggests that anticoagulants may have the opposite intended effect on rabies control and highlights the importance of further research on the practical methods for bat‐borne rabies prevention. ConclusionField experimental studies that include control groups over areas and periods that account forD. rotundusecology are needed to determine the effectiveness of anticoagulants for rabies control in livestock. In conclusion, the use of anticoagulants for rabies control is questionable. 

Abstract Pathogen spillover corresponds to the transmission of a pathogen or parasite from an original host species to a novel host species, preluding disease emergence. Understanding the interacting factors that lead to pathogen transmission in a zoonotic cycle could help identify novel hosts of pathogens and the patterns that lead to disease emergence. We hypothesize that ecological and biogeographic factors drive host encounters, infection susceptibility, and cross‐species spillover transmission. Using a rodent–ectoparasite system in the Neotropics, with shared ectoparasite associations as a proxy for ecological interaction between rodent species, we assessed relationships between rodents using geographic range, phylogenetic relatedness, and ectoparasite associations to determine the roles of generalist and specialist hosts in the transmission cycle of hantavirus. A total of 50 rodent species were ranked on their centrality in a network model based on ectoparasites sharing. Geographic proximity and phylogenetic relatedness were predictors for rodents to share ectoparasite species and were associated with shorter network path distance between rodents through shared ectoparasites. The rodent–ectoparasite network model successfully predicted independent data of seven known hantavirus hosts. The model predicted five novel rodent species as potential, unrecognized hantavirus hosts in South America. Findings suggest that ectoparasite data, geographic range, and phylogenetic relatedness of wildlife species could help predict novel hosts susceptible to infection and possible transmission of zoonotic pathogens. Hantavirus is a high‐consequence zoonotic pathogen with documented animal‐to‐animal, animal‐to‐human, and human‐to‐human transmission. Predictions of new rodent hosts can guide active epidemiological surveillance in specific areas and wildlife species to mitigate hantavirus spillover transmission risk from rodents to humans. This study supports the idea that ectoparasite relationships among rodents are a proxy of host species interactions and can inform transmission cycles of diverse pathogens circulating in wildlife disease systems, including wildlife viruses with epidemic potential, such as hantavirus.