Chapter 6 - Sapro-Zoonotic Risks Posed by Wild Birds in Agricultural Landscapes

Abstract

There are over 1400 catalogued human pathogens, with approximately 62% classified as zoonotic. Because humans generally do not have direct contact with wild birds, exposure to pathogens is via indirect routes, that is, environmental. This chapter explores the risks wild birds pose to the contamination of field crops and the risk such contamination poses to human health. It presents a few studies that document the role wild birds have in contaminating field crops and subsequent acquisition of pathogens and onset of disease by humans. Most of the evidence in the literature focuses on relatively few commensally wildlife species in urbanized environments, or at best, general wildlife surveillance and monitoring efforts. This means that there is no direct evidence. Therefore, this chapter summarizes the circumstantial evidence, relying mostly on the characterization of host range of pathogens, similarities of virulence traits of animal and human pathogens, and habitat use patterns of wild birds in agricultural and urban landscapes. It calls for more directed studies to form a more informed assessment as to what actual human pathogen contamination risks wild birds pose to field crops, and by implication, to human health. Finally, it touches upon the mitigation efforts that might be undertaken to reduce risks of pathogen transmission by wild birds.