A new evidence brief, based on a study by the Juno Evidence Alliance conducted in collaboration with CABI’s One Health Hub, has highlighted that a One Health approach is needed in research into zoonotic disease risks around the world.

The study, an evidence synthesis carried out by the Juno Evidence Alliance with Newcastle University and funded by UK International Development, did not find published research on zoonoses risks linked to agrifood systems for 46% of low- and middle-income countries (LMICs), which could point to an uneven distribution of research resources.

It adds that several key areas related to zoonotic disease occurrence remain underexplored in the published research. These include evidence from certain food system contexts using One Health perspectives, wild animal hosts, and how exposure to wild animals may influence occurrence in humans and domesticated animals.

Zoonotic diseases pose significant threats to human health and wellbeing, with around 60% of known human infectious diseases and 75% of newly emerging infections originating from animals.

Decision-makers lack evidence-based linkages

Dr Marie McIntyre, Fellow in Translational Food Safety at Newcastle University and lead subject expert of the study, said, “Zoonoses are responsible for 2.5 billion cases of human illness and 2.7 million human deaths globally each year. Agrifood systems play an integral part in the emergence of zoonotic diseases.

“Factors such as land use change, intensifying livestock production and wildlife trade all contribute to disease risks. Meanwhile, the impacts of climate change may pose further challenges.

“However, despite growing recognition of these relationships, our research shows that decision-makers lack evidence-based linkages connecting specific practices to the emergence of zoonotic diseases.”

The research presents the current evidence base on factors influencing zoonotic disease occurrence in agrifood systems in LMICs.

Researchers conducted systematic mapping and searching of five bibliographic databases and 17 organizational websites. In total, 7839 of the 49,038 unique publications were identified as potentially relevant using manual screening and machine learning. A 14% random sample (1034 publications) were screened at full text, and 424 of these were included in the map.

The four most investigated categories of factors were exposure to potential hosts or vector species, particularly livestock (featuring in 53% of publications), social and economic factors (47%), physical and environmental factors, including land use, climate and weather (46%), and domesticated animal practices (38%).

Zoonotic diseases linked to agrifood systems represent a significant risk

Dr Hazel Cooley, co-lead author of the study, said, “Zoonotic diseases linked to agrifood systems represent a significant risk to global health, but the factors behind their rise are not fully understood.

“While certain areas are well studied, knowledge gaps exist in other areas such as within certain food system contexts, geographic regions, and One Health perspectives.

“By advocating for systems-based research and policies to address these gaps, decision-makers can prioritize resources, improve preparedness, and reduce the risk of diseases spreading from animals to humans.”

Several recommendations

The study presents several recommendations for researchers, policymakers and decision-makers.

They include emphasis on understanding the transmission processes across the food chain. These include food processing, distribution and consumption systems. Research that focuses on an integrated, systems-based approach is vital, the researchers say. This will detail how changes in farming, land use, and food demand interact across agrifood systems.

Other recommendations include supporting international collaboration, particularly with LMICs to address country-specific research gaps and increase understanding of zoonotic risks.

Creating dialogue around One Health research

The findings from the Zoonoses Systematic Map contributes to a One Health research roadmap, published by CABI’s One Health Hub.
The FAO’s One Health Knowledge Nexus (OHKN) will be hosting a webinar to discuss these findings and their implications for global One Health research. The event will be held as part of the OHKN’s Community of Practice on ‘Drivers of Emerging Plant and Animal Pests and Diseases, including Zoonotic Spillover’.

The webinar will take place on 2 December at 14:00 GMT / 15:00 CET. Participants may register on: https://fao.zoom.us/webinar/register/WN_oo_-R9vyTmui-3V2an9nzw#/registration