Methodological choices in brucellosis burden of disease assessments: A systematic review

Background Foodborne and zoonotic diseases such as brucellosis present many challenges to public health and economic welfare. Increasingly, researchers and public health institutes use disability-adjusted life years (DALYs) to generate a comprehensive comparison of the population health impact of these conditions. DALYs calculations, however, entail a number of methodological choices and assumptions, with data gaps and uncertainties to accommodate. Thisreview identifies existing brucellosis burden of disease studies and analyzes their methodological choices, assumptions, and uncertainties. It supports the Global Burden of Animal Diseases programme in the development of a systematic methodology to describe the impact of animal diseases on society, including human health. Methods/Principal findings A systematic search for brucellosis burden of disease calculations was conducted in pre-selected international and grey literature databases. Using a standardized reporting framework, we evaluated each estimate on a variety of key methodological assumptions necessary to compute a DALY. Fourteen studies satisfied the inclusion criteria (human brucellosis and quantification of DALYs). One study reported estimates at the global level, the rest were national or subnational assessments. Data regarding different methodological choices were extracted, including detailed assessments of the adopted disease models. Most studies retrieved brucellosis epidemiological data from administrative registries. Incidence data were often estimated on the basis of laboratory-confirmed tests. Not all studies included mortality estimates (Years of Life Lost) in their assessments due to lack of data or the assumption that brucellosis is not a fatal disease. Only two studies used a model with variable health states and corresponding disability weights. The rest used a simplified singular health state approach. Wide variation was seen in the duration chosen for brucellosis, ranging from 2 weeks to 4.5 years, irrespective of the whether a chronic state was included. Conclusion Available brucellosis burden of disease assessments vary widely in their methodology and assumptions. Further research is needed to better characterize the clinical course of brucellosis and to estimate case-fatality rates. Additionally, reporting of methodological choices should be improved to enhance transparency and comparability of estimates. These steps will increase the value of these estimates for policy makers

Feeding the Worlth Healthily: the Challenge of Measuring the effects of Agriculture on Health

Agricultural production, food systems and population health are intimately linked. While there is a strong evidence base to inform our knowledge of what constitutes a healthy human diet, we know little about actual food production or consumption in many populations and how developments in the food and agricultural system will affect dietary intake patterns and health. The paucity of information on food production and consumption is arguably most acute in low- and middle-income countries, where it is most urgently needed to monitor levels of under-nutrition, the health impacts of rapid dietary transition and the increasing ‘double burden’ of nutrition-related disease. Food availability statistics based on food commodity production data are currently widely used as a proxy measure of national-level food consumption, but using data from the UK and Mexico we highlight the potential pitfalls of this approach. Despite limited resources for data collection, better systems of measurement are possible. Important drivers to improve collection systems may include efforts to meet international development goals and partnership with the private sector. A clearer understanding of the links between the agriculture and food system and population health will ensure that health becomes a critical driver of agricultural change

A systematic review of zoonoses transmission and livestock/wildlife interactions: Preliminary findings

Around 60% of all human pathogens are zoonoses and domestic animals and wildlife are of equal importance as reservoir hosts. Moreover, most emerging infectious diseases are zoonoses and most emerge from wildlife. There have been several recent initiatives to categorize zoonoses and their reservoirs but their socio-economic impact remains poorly defined and previous reviews lacked both poverty and gender perspectives. We present the initial findings of a multi-disciplinary, systematic review commissioned by the Department for International Development (UK) to synthesize best available scientific knowledge about zoonotic disease transmission through direct or indirect domestic livestock/wildlife interaction, with emphasis on risk factors, drivers and trajectories of transmission, and promising interventions for controlling important zoonoses based on managing domestic livestock/wildlife interaction. The review covers: zoonoses transmission and relative importance of the wildlife/livestock route; wildlife pathogens capable of recombining with analogous organisms in domestic livestock; risk factors and drivers for zoonoses transmission at the human/livestock/wildlife interface; historical changes in transmission and trends; livestock production systems as primary drivers of zoonotic disease load in the environment and role of wildlife as amplifiers, spill-over/indicator hosts and reservoirs; socio-economic, institutional and political factors influencing risk of transmission between wildlife and domestic livestock and from wildlife/livestock to people; risk management and control interventions and their success or failure with emphasis on interventions based on managing interaction between hosts (wildlife/livestock/humans). This review summarizes best evidence on livestock/wildlife interactions and zoonoses transmission

Zoonoses (Project 1): Wildlife/domestic livestock interactions

The objective of this study was to synthesise the best available scientific knowledge about zoonotic disease transmission through livestock and wildlife interaction (direct or indirect), with emphasis on risk factors, drivers and trajectories of transmission, as well as promising interventions for controlling important zoonoses, based on managing the interaction between domestic livestock and wildlife. A multi-disciplinary team from the International Livestock Research Institute, Kenya, and the Royal Veterinary College, United Kingdom, with expertise in zoonoses, epidemiology, socio-economics, and wildlife, undertook the review. A database of important zoonoses was compiled and used to develop a list of priority zoonoses with a livestock-wildlife interface for developing countries. Spatial relationships between important zoonoses and land use and human population density were explored. A systematic review was carried out focussing on: disease transmission routes, risk factors for disease transmission, drivers of wildlife-livestock interactions, pathogens of wildlife capable of recombining with organisms in livestock, wildlife species that are potential sources of zoonotic pathogens, production and socio-economic factors influencing the risk of transmission, and risk management and control interventions

Livestock trade networks for guiding animal health surveillance

BACKGROUND: Trade in live animals can contribute to the introduction of exotic diseases, the maintenance and spread endemic diseases. Annually millions of animals are moved across Europe for the purposes of breeding, fattening and slaughter. Data on the number of animals moved were obtained from the Directorate General Sanco (DG Sanco) for 2011. These were converted to livestock units to enable direct comparison across species and their movements were mapped, used to calculate the indegrees and outdegrees of 27 European countries and the density and transitivity of movements within Europe. This provided the opportunity to discuss surveillance of European livestock movement taking into account stopping points en-route. RESULTS: High density and transitivity of movement for registered equines, breeding and fattening cattle, breeding poultry and pigs for breeding, fattening and slaughter indicates that hazards have the potential to spread quickly within these populations. This is of concern to highly connected countries particularly those where imported animals constitute a large proportion of their national livestock populations, and have a high indegree. The transport of poultry (older than 72 hours) and unweaned animals would require more rest breaks than the movement of weaned animals, which may provide more opportunities for disease transmission. Transitivity is greatest for animals transported for breeding purposes with cattle, pigs and poultry having values of over 50%. CONCLUSIONS: This paper demonstrated that some species (pigs and poultry) are traded much more frequently and at a larger scale than species such as goats. Some countries are more vulnerable than others due to importing animals from many countries, having imported animals requiring rest-breaks and importing large proportions of their national herd or flock. Such knowledge about the vulnerability of different livestock systems related to trade movements can be used to inform the design of animal health surveillance systems to facilitate the trade in animals between European member states. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12917-015-0354-4) contains supplementary material, which is available to authorized users

Defining and averting syndemic pathways in aquaculture: a major global food sector

Aquaculture now provides half of all aquatic protein consumed globally—with most current and future production occurring in low- and middle-income countries (LMICs). Concerns over the availability and application of effective policies to deliver safe and sustainable future supply have the potential to hamper further development of the sector. Creating healthy systems must extend beyond the simple exclusion of disease agents to tackle the host, environmental, and human drivers of poor outcomes and build new policies that incorporate these broader drivers. Syndemic theory provides a potential framework for operationalizing this One Health approach.</jats:p

Exploring local knowledge and perceptions on zoonoses among pastoralists in northern and eastern Tanzania

Background: Zoonoses account for the most commonly reported emerging and re-emerging infectious diseases in Sub-Saharan Africa. However, there is limited knowledge on how pastoral communities perceive zoonoses in relation to their livelihoods, culture and their wider ecology. This study was carried out to explore local knowledge and perceptions on zoonoses among pastoralists in Tanzania. Methodology and principal findings: This study involved pastoralists in Ngorongoro district in northern Tanzania and Kibaha and Bagamoyo districts in eastern Tanzania. Qualitative methods of focus group discussions, participatory epidemiology and interviews were used. A total of 223 people were involved in the study. Among the pastoralists, there was no specific term in their local language that describes zoonosis. Pastoralists from northern Tanzania possessed a higher understanding on the existence of a number of zoonoses than their eastern districts' counterparts. Understanding of zoonoses could be categorized into two broad groups: a local syndromic framework, whereby specific symptoms of a particular illness in humans concurred with symptoms in animals, and the biomedical framework, where a case definition is supported by diagnostic tests. Some pastoralists understand the possibility of some infections that could cross over to humans from animals but harm from these are generally tolerated and are not considered as threats. A number of social and cultural practices aimed at maintaining specific cultural functions including social cohesion and rites of passage involve animal products, which present zoonotic risk. Conclusions: These findings show how zoonoses are locally understood, and how epidemiology and biomedicine are shaping pastoralists perceptions to zoonoses. Evidence is needed to understand better the true burden and impact of zoonoses in these communities. More studies are needed that seek to clarify the common understanding of zoonoses that could be used to guide effective and locally relevant interventions. Such studies should consider in their approaches the pastoralists' wider social, cultural and economic set up

Defining and averting syndemic pathways in aquaculture: a major global food sector

Aquaculture now provides half of all aquatic protein consumed globally—with most current and future production occurring in low- and middle-income countries (LMICs). Concerns over the availability and application of effective policies to deliver safe and sustainable future supply have the potential to hamper further development of the sector. Creating healthy systems must extend beyond the simple exclusion of disease agents to tackle the host, environmental, and human drivers of poor outcomes and build new policies that incorporate these broader drivers. Syndemic theory provides a potential framework for operationalizing this One Health approach

Approximating the global economic (market) value of farmed animals

Understanding the global economic importance of farmed animals to society is essential as a baseline for decision making about future food systems. We estimated the annual global economic (market) value of live animals and primary production outputs, e.g., meat, eggs, milk, from terrestrial and aquatic farmed animal systems. The results suggest that the total global market value of farmed animals ranges between 1.61 and 3.3 trillion USD (2018) and is expected to be similar in absolute terms to the market value of crop outputs (2.57 trillion USD). The cattle sector dominates the market value of farmed animals. The study highlights the need to consider other values of farmed animals to society, e.g., finance/insurance value and cultural value, in decisions about the sector's future