Livestock movement and emerging zoonotic disease outbreaks: applying ecological, network, and sociocultural theories to assess the risk of Middle East respiratory syndrome from camel trade in Ethiopia and Egypt

Abstract

Background: Emerging infectious diseases are associated with complex linkages within the broader ecosystem. Studying infectious disease among hosts (animals and humans), outside of the context of their environment, ignores the complexity in which hosts interact. We aimed to formulate a framework to study the effect of large livestock movement on the ecology of emerging zoonotic infectious disease in low-income and middle-income countries. Ultimately such a framework could identify points of intervention in livestock movement chains to reduce the risk of emerging diseases. As a test case, we use camel movement and Middle East respiratory syndrome coronavirus (MERS-CoV). Methods: We reviewed grey and peer-reviewed literature on camel husbandry and interviewed key stakeholders in Egypt and Ethiopia involved in public health research, animal husbandry, the camel trade, veterinary services for camels, and physicians. A multidisciplinary team consisting of wildlife biologists, anthropologists, epidemiologists, veterinarians, geographers, modellers, virologists, and health-care professionals from the USA, Egypt, and Ethiopia was assembled to propose the framework. Findings: A framework has been developed which highlights the associations between the complex linkages within the broader ecosystem: environment (flora, climate, pollution), animals (distribution and density of animals, interaction between humans, domesticated and wildlife animals), and human behavioural systems (socio-cultural and economic structures around animal husbandry and hunting, connectivity including market trade systems). Interpretation: While there is an emphasis on interdisciplinary cooperation in the area of one health, this type of work has several challenges. A history of interdisciplinary work in zoonotic infectious disease is limited, in part, because of the lack of undergraduate and graduate curricula that provide training. Additionally the large teams required to conduct truly interdisciplinary work require sustained funding and such opportunities are rare. Funding: None.