Foot-and-mouth disease virus (FMDV) is one of the few veterinary pathogens that defines policy and global trade in animal products. Its prominence necessitates approaches to control that integrate the multiple factors contributing to the disease’s biology and transmission characteristics. Central to this concept is the epidemiological FMD status (endemic or FMD-free, with or without vaccination) of a territory, which defines access to export markets. FMD epidemiology is complex, insufficiently understood, and intertwined with the biology of the virus (multiple serotypes and subtypes), global distribution (distinct regional virus pools), pathogenesis (subclinical infections and species differences), and host range (broad range of susceptible domestic and wild animals). Despite steady advances, critical knowledge gaps persist in FMD epidemiology that undermine the optimal control of FMD. This review summarizes the distinct thematic compartments of FMD epidemiology and presents the critical knowledge gaps that continue to limit the effectiveness of global, regional, and national initiatives to control and eradicate FMD.

Vesicular stomatitis (VS) is a vector-borne livestock disease caused by vesicular stomatitis New Jersey virus (VSNJV) or vesicular stomatitis Indiana virus (VSIV). The disease circulates endemically in northern South America, Central America, and Mexico and only occasionally causes outbreaks in the United States. Over the past 20 years, VSNJV outbreaks in the southwestern and Rocky Mountain regions occurred with incursion years followed by virus overwintering and subsequent expansion outbreak years. Regulatory response by animal health officials is deployed to prevent spread from lesioned animals. The 2019 VS incursion was the largest in 40 years, lasting from June to December 2019 with 1144 VS-affected premises in 111 counties in eight states (Colorado, Kansas, Nebraska, New Mexico, Oklahoma, Texas, Utah, and Wyoming) and was VSIV serotype, last isolated in 1998. A subsequent expansion occurred from April to October 2020 with 326 VS-affected premises in 70 counties in eight states (Arizona, Arkansas, Kansas, Missouri, Nebraska, New Mexico, Oklahoma, and Texas). The primary serotype in 2020 was VSIV, but a separate incursion of VSNJV occurred in south Texas. Summary characteristics of the outbreaks are presented along with VSV-vector sampling results and phylogenetic analysis of VSIV isolates providing evidence of virus overwintering.

Foot-and-mouth disease (FMD) continues to be one of the most important diseases of livestock globally based upon both biological features and regulatory aspects. Few pathogens have had comparable impact on global livestock production and regulation of international trade in animal-derived products. The pathogenesis (interaction between pathogen and host) is central to the importance of the disease ranging from how the causal pathogen, FMD virus (FMDV), transmits between hosts and is maintained in populations. Key accomplishments over the last decade include description of the primary sites of infection in domestic species, delineating critical differences in temporo-anatomic progression in different host species and emphasizing that knowledge gained regarding FMDV pathogenesis in one host cannot necessarily be extrapolated and applied to a different host. Host responses to infection and viral genomics have been characterized with ever-increasing granularity. Yet, the numerous knowledge gaps that remain in understanding FMDV pathogenesis impede advancements in FMD control and eradication. For instance, it remains unclear if long-term asymptomatic FMDV carriers are biologically relevant (contagious) and the manner in which host genomics and transcriptomics affect pathogenesis during different phases of infection. The characterization of neoteric subclinical infection as a disease stage that is distinct from the persistent “FMDV carrier state” has emphasized the importance of sample collection from clinically unaffected animals for FMDV surveillance. Similarly, incorporating a phase of pre-clinical infectiousness in simulation modeling can dramatically improve prediction of FMD outbreaks in non-endemic regions. The outcome of FMDV infection with regards to viral persistence differs between host species as well as between individuals of the same species. Yet, we lack a satisfactory explanation of the host factors that drive the FMDV carrier state divergence. This review was based upon a gap-analysis workshop organized by the Global Foot-and-Mouth Disease Research Alliance (GFRA) in Buenos Aires, Argentina, in December of 2022. The purpose of this work is to summarize the current understanding of the distinct compartments of FMD pathogenesis with an emphasis on progress made within the last decade and present the critical knowledge gaps that continue to limit FMD control and eradication.

Aim: Estimating the distribution and abundance of wildlife is an essential task in species conservation, wildlife management and habitat prioritization. Although a host of methods and tools have been proposed to accomplish this undertaking, several challenges remain in accurately forecasting occurrence and abundance for highly mobile species. Exhibiting extensive geographic ranges with seasonally varying local occupancy, migratory ducks are exemplar highly mobile species and are foci for waterfowl conservation and management globally. With the goal of informing species conservation and management, our aim was to leverage citizen science data to estimate occurrence and relative abundance for ten dabbling duck species across the continental United States.Location: Conterminous United States.Methods: We applied spatially and temporally explicit Bayesian hierarchical modelling to jointly estimate season‐specific occurrence and relative abundance for ten dabbling duck species in the GenusAnas. Our conditionally dependent model design enabled relative abundance estimates to be informed by occurrence probability while accounting for cumulative spatial and temporal errors across shared model components.Results: Outcomes suggest that although dabbling duck distributions show little inter‐annual variability at the continental scale, local relative abundances may differ year to year. Commensurate with being highly mobile migratory species, estimates indicate considerable intra‐annual variation with occurrence probability, local abundance and habitat preferences differing by season and species.Main conclusions: Our approach offers a powerful and flexible framework for quantifying intra‐/inter‐annual duck occurrence and relative abundance while accounting for spatial, temporal and data collection biases. We believe that model produced maps can be applied to inform waterfowl conservation and management throughout the continental United States.

Avian influenza (AI) affects wild aquatic birds and poses hazards to human health, food security, and wildlife conservation globally. Accordingly, there is a recognized need for new methods and tools to help quantify the dynamic interaction between wild bird hosts and commercial poultry. Using satellite-marked waterfowl, we applied Bayesian joint hierarchical modeling to concurrently model species distributions, residency times, migration timing, and disease occurrence probability under an integrated animal movement and disease distribution modeling framework. Our results indicate that migratory waterfowl are positively related to AI occurrence over North America such that as waterfowl occurrence probability or residence time increase at a given location, so too does the chance of a commercial poultry AI outbreak. Analyses also suggest that AI occurrence probability is greatest during our observed waterfowl northward migration, and less during the southward migration. Methodologically, we found that when modeling disparate facets of disease systems at the wildlife-agriculture interface, it is essential that multiscale spatial patterns be addressed to avoid mistakenly inferring a disease process or disease-environment relationship from a pattern evaluated at the improper spatial scale. The study offers important insights into migratory waterfowl ecology and AI disease dynamics that aid in better preparing for future outbreaks.