The Epidemiological Framework for Biological Invasions (EFBI): an interdisciplinary foundation for the assessment of biosecurity threats

Abstract

Emerging microparasite (e.g. viruses, bacteria, protozoa and fungi) epidemics and the introduction of non-native pests and weeds are major biosecurity threats worldwide. The likelihood of these threats is often estimated from probabilities of their entry, establishment, spread and ease of prevention. If ecosystems are considered equivalent to hosts, then compartment disease models should provide a useful framework for understanding the processes that underpin non-native species invasions. To enable greater cross-fertilisation between these two disciplines, the Epidemiological Framework for Biological Invasions (EFBI) is developed that classifies ecosystems in relation to their invasion status: Susceptible, Exposed, Infectious and Resistant. These states are linked by transitions relating to transmission, latency and recovery. This viewpoint differs markedly from the species-centric approaches often applied to non-native species. It allows generalisations from epidemiology, such as the force of infection, the basic reproductive ratio R0, super-spreaders, herd immunity, cordon sanitaire and ring vaccination, to be discussed in the novel context of non-native species and helps identify important gaps in the study of biological invasions. The EFBI approach highlights several limitations inherent in current approaches to the study of biological invasions including: (i) the variance in non-native abundance across ecosystems is rarely reported; (ii) field data rarely (if ever) distinguish source from sink ecosystems; (iii) estimates of the susceptibility of ecosystems to invasion seldom account for differences in exposure to non-native species; and (iv) assessments of ecosystem susceptibility often confuse the processes that underpin patterns of spread within -and between- ecosystems. Using the invasion of lakes as a model, the EFBI approach is shown to present a new biosecurity perspective that takes account of ecosystem status and complements demographic models to deliver clearer insights into the dynamics of biological invasions at the landscape scale. It will help to identify whether management of the susceptibility of ecosystems, of the number of vectors, or of the diversity of pathways (for movement between ecosystems) is the best way of limiting or reversing the population growth of a non-native species. The framework can be adapted to incorporate increasing levels of complexity and realism and to provide insights into how to monitor, map and manage biological invasions more effectively.

Advancing One Biosecurity to Address the Pandemic Risks of Biological Invasions

“…One Biosecurity seeks the development of a suite of more holistic risk assessment tools for the comparative assessment of biosecurity threats across the human, animal, plant, and environmental health sectors. Invasion scientists need to work with veterinarians and epidemiologists to devise a standardized quantitative approach to rapidly assess actual and potential impacts of emerging invasive alien species across all sectors, rather than being sector specific (Hulme et al 2020 ). In addition, these tools should capture both the epidemic and pandemic risk of emerging invasive alien species to present transparent and unambiguous assessments of invasive alien species that represent a Biosecurity Risk of International Concern.…”

Harmonising the fields of invasion science and forest pathology

“…The authors argue that while traditionally considered separate disciplines, many tools and conceptual frameworks underpinning pathology and entomology can and should be shared, to meet the common goal of improved forest protection. Similarly, Nunez et al (2020) proposed the strengthening of collaborations between ecologists, epidemiologists, sociologists, and biomedical researchers, to develop an expanded invasion science discipline (see also Hulme et al 2020). Such an approach, embedded in the philosophy of the "One Health" concept recognising the interrelatedness of human, animal and ecosystem health (Xie et al 2017), has the potential to make meaningful contributions to global biosecurity.…”

One Biosecurity: a unified concept to integrate human, animal, plant, and environmental health

“…These sectorial divisions appear not to recognise the fundamental similarities in the processes underpinning biological invasions whether they relate to plant, animal, or human health and this may, in part, reflect the lack of cross-disciplinary thinking among the research community [ 16 , 17 ]. Recent assessments have pointed out similar dramatic increases in the rate at which plants, animals and microorganisms have been transported around the world over the last 100 years [ 18 ].…”

“…Furthermore, the global distribution of many zoonotic livestock diseases that are infectious to humans, such as highly pathogenic avian influenza, Q fever, and anthrax, have been facilitated by human trade in poultry, cattle, pigs, and horses [ 22 ]. Thus, the global redistribution of pathogens, parasites, plants, and animals should all be viewed as biological invasions [ 19 ] and since they share many fundamental aspects of their spatial and temporal dynamics [ 16 , 23 , 24 ] a more integrated approach to biosecurity is warranted.…”

“…Data represent the results of a search for the term 'biosecurity' on 21/08/20 and have been normalised to scale between 0 and 100. [19] and since they share many fundamental aspects of their spatial and temporal dynamics [16,23,24] a more integrated approach to biosecurity is warranted.…”