Cultural contexts of swine-related infections in Polynesia

Policies to prevent zoonotic spillover: a systematic scoping review of evaluative evidence

BACKGROUND

Emerging infectious diseases of zoonotic origin present a critical threat to global population health. As accelerating globalisation makes epidemics and pandemics more difficult to contain, there is a need for effective preventive interventions that reduce the risk of zoonotic spillover events. Public policies can play a key role in preventing spillover events. The aim of this review is to identify and describe evaluations of public policies that target the determinants of zoonotic spillover. Our approach is informed by a One Health perspective, acknowledging the inter-connectedness of human, animal and environmental health.

METHODS

In this systematic scoping review, we searched Medline, SCOPUS, Web of Science and Global Health in May 2021 using search terms combining animal health and the animal-human interface, public policy, prevention and zoonoses. We screened titles and abstracts, extracted data and reported our process in line with PRISMA-ScR guidelines. We also searched relevant organisations' websites for evaluations published in the grey literature. All evaluations of public policies aiming to prevent zoonotic spillover events were eligible for inclusion. We summarised key data from each study, mapping policies along the spillover pathway.

RESULTS

Our review found 95 publications evaluating 111 policies. We identified 27 unique policy options including habitat protection; trade regulations; border control and quarantine procedures; farm and market biosecurity measures; public information campaigns; and vaccination programmes, as well as multi-component programmes. These were implemented by many sectors, highlighting the cross-sectoral nature of zoonotic spillover prevention. Reports emphasised the importance of surveillance data in both guiding prevention efforts and enabling policy evaluation, as well as the importance of industry and private sector actors in implementing many of these policies. Thoughtful engagement with stakeholders ranging from subsistence hunters and farmers to industrial animal agriculture operations is key for policy success in this area.

CONCLUSION

This review outlines the state of the evaluative evidence around policies to prevent zoonotic spillover in order to guide policy decision-making and focus research efforts. Since we found that most of the existing policy evaluations target 'downstream' determinants, additional research could focus on evaluating policies targeting 'upstream' determinants of zoonotic spillover, such as land use change, and policies impacting infection intensity and pathogen shedding in animal populations, such as those targeting animal welfare.

Field application of a combined pig and poultry market chain and risk pathway analysis within the Pacific Islands region as a tool for targeted disease surveillance and biosecurity

Limited resources are one of the major constraints in effective disease monitoring and control in developing countries. This paper examines the pig and poultry market chains of four targeted Pacific Island countries and territories (PICTs): Fiji, Papua New Guinea, Solomon Islands and Vanuatu and combines them with a risk pathway analysis to identify the highest risk areas (risk hotspots) and risky practices and behaviours (risk factors) of animal disease introduction and/or spread, using highly pathogenic avian influenza (HPAI) and foot-and-mouth disease (FMD) as model diseases because of their importance in the region. The results show that combining a market chain analysis with risk pathways is a practical way of communicating risk to animal health officials and improving biosecurity. It provides a participatory approach that helps officials to better understand the trading regulations in place in their country and to better evaluate their role as part of the control system. Common risk patterns were found to play a role in all four PICTs. Legal trade pathways rely essentially on preventive measures put in place in the exporting countries while no or only limited control measures are undertaken by the importing countries. Legal importations of animals and animal products are done mainly by commercial farms which then supply local smallholders. Targeting surveillance on these potential hotspots would limit the risk of introduction and spread of animal diseases within the pig and poultry industry and better rationalize use of skilled manpower. Swill feeding is identified as a common practice in the region that represents a recognized risk factor for dissemination of pathogens to susceptible species. Illegal introduction of animals and animal products is suspected, but appears restricted to small holder farms in remote areas, limiting the risk of spread of transboundary animal diseases along the market chain. Introduction of undeclared goods hidden within a legal trade activity was identified as a major risk pathway. Activities such as awareness campaigns for pig and poultry farmers regarding disease reporting, biosecurity measures or danger of swill feeding and training of biosecurity officers in basic animal health and import-associated risks are recommended to prevent and limit the spread of pathogens within the PICTs.

The history of brucellosis in the Pacific Island Countries and Territories and its re-emergence

There are few publications on brucellosis within the Pacific Island Countries and Territories (PICTs). The reason is possibly because the cattle population has been reportedly free of the disease for many years until a re-emergence occurred in the Fiji Islands (Viti Levu) in 2009. This paper reports on the outbreak of brucellosis in Fiji and its progression between 2009 and 2013 in the context of an overview of brucellosis in the Pacific Island community. Review of the literature found only 28 articles with the oldest record of brucellosis being in 1965 in Papua New Guinea (PNG) and from human cases in Tonga in 1980. The Fiji outbreak of Brucella abortus occurred in cattle in 2009 (Wainivesi basin) in the Tailevu province. Prior to the outbreak, Fiji declared freedom from B. abortus to OIE in 1996 after a successful eradication campaign. During the course of the outbreak investigation, serum samples were collected from between 9790 and 21,624 cattle per annum between 2009 and 2013 from 87 farms on the main island of Fiji (Viti Levu). Blood samples were tested for brucellosis using the Rose Bengal Test (RBT) in 2009 and the indirect ELISA test in subsequent years. At the time of the outbreak in Fiji (2009) the apparent prevalence in cattle was 1.50% and this has fluctuated since the outbreak. The True Prevalence (TP) for the main island in Fiji for the indirect ELISA tests was 2.40% in 2010, reached a peak of 3.49% in 2011 then reduced to 0.12% by 2013. The significant reduction in prevalence compared to 2010 is most likely due to the control programs being implemented in Fiji. The re-emergence of B. abortus in Fiji could be attributed to the lack of monitoring for the disease until 2009 combined with inadequate management of exposed animals, thus illustrating how important it is for authorities not to become complacent. Continued awareness and monitoring for brucellosis is essential if future outbreaks are to be avoided.