What is a biosecurity measure? A definition proposal

Introduction

Increasing demand for animal protein and the diversification of food supply chains are driving foodborne zoonotic diseases responsible for morbidity, mortality, and economic loss worldwide. This trend towards intensive farming requires improved biosecurity to control and prevent zoonotic infections in animals and humans. As part of the One Health European Joint Programme, the "Biosecurity practices for pig farming across Europe" (BIOPIGEE) project aims to establish a protocol of relevant biosecurity measures (BSMs) to reduce the occurrence of Salmonella, Hepatitis E virus (HEV) and pathogenic E. coli in pig production within the EU. While "biosecurity" is well defined, a harmonized definition of a BSM is missing. This, combined with the question of which measures can be counted as BSM, affects their understanding, acceptance, and broad, effective implementation of the concept from the farm to policy level. Therefore, the BIOPIGEE task group i) evaluated potentially relevant in- and exclusion criteria in the context of biosecurity used within BIOPIGEE and ii) screened the scientific literature for existing definitions, with the aim to propose a standard definition for the term BSM.

Methodology

In- and exclusion criteria related to biosecurity were collected from five BIOPIGEE tasks studying the effectiveness of farm and slaughterhouse biosecurity practices. The significance of each criterion for defining the term BSM was discussed; relevant criteria were summarized to propose a working definition. Concurrently, a literature scoping review was conducted with the search terms "biosecurity measures" AND (swine OR pig) in titles, abstracts, or keywords using Scopus, Pubmed, Web of Science and Google Scholar (GS) databases. As the GS search algorithm does not specify term locations, the first 300 articles sorted by relevance were selected. After removing duplicates, the remainder were processed using R-based bibliometric tools. From each database ≤25 articles explicitly related to BSMs in pig operations were extracted. A bibliometric analysis was performed on the final record subset and full-text articles were extracted by text mining tools. The records containing one of the 100 most frequent terms were included in hierarchical cluster analysis. The outcome identified research clusters among the selected articles, which were modified after an additional full-text reading.

Results

Inclusion criteria were: association to pathogen occurrence in pig operations; application of procedures (goal, pre/post conditions, timing, physical requirements, rules) or physical processes; primary and secondary biosecurity. Exclusion criteria were: factors requiring major changes of the operation (location of the buildings, size); procedures for the monitoring of, the compliance to or the effectiveness of BSMs; proficiency of personnel; description of pathogen status; tertiary biosecurity. From 926 identified records, 90 articles were retained after removal of duplicates and 34 articles remained due to considerable overlap between the databases. The scoping review did not reveal an existing definition for a BSM. Based on the final paper selection, six specific research themes were identified. We propose the following standard definition for the term BSM:

"A biosecurity measure is the active implementation of any standardized segregation, hygiene, or management procedure explicitly aimed at reducing the probability of (i) pathogen introduction into a farm/operation (external biosecurity),  (ii) pathogen spread within or out of a farm/operation (internal biosecurity)."

Discussion

Two key fragments of the proposed definition are "active implementation" and "standardized procedures" (procedure = series of actions conducted in a particular order and way). The latter is linked to various factors such as the geographical region/climate, species of pathogen/animal, production type, policy/law, and farm status (pathogen prevalence, existing biosecurity) as prerequisites. In addition, procedures are shaped by temporal conditions (short vs. long term effects for pathogen reduction), and are affected by human components related to compliance, knowledge and skills. "Active implementation" emphasizes the importance of the action itself. Assessments such as evaluating pathogen prevalence are often considered as BSMs, but whilst indispensable, cannot be considered as BSMs independently as they form part of a procedure. Tertiary biosecurity measures (e.g. vaccination) were excluded in the context of BIOPIGEE, but remain essential biosecurity measures. Although based on expertise and scientific literature from the pig sector, our proposed definition may benefit other species or production types, and improve research and communication of the best BSMs.