Host Diversity and Origin of Zoonoses: The Ancient and the New

SIMPLE SUMMARY: There is a wide variety of diseases caused by bacteria, viruses, and parasites that are transmitted to humans by different routes from other animals. These diseases, known as zoonoses, represent 75% of new or reemerging infectious diseases. There is a considerable impact of these diseases on the economy and health at local and global levels, including zoonotic diseases caused by the ingestion of food and products derived from animals. The wide range of animal species that host these disease-causing organisms include all groups of mammals. Birds are the second significant animal group to act as hosts for zoonoses. Much progress has been made in understanding disease evolution and animal origin, with important contributions from fields such as paleopathology and analysis of DNA, applied to ancient human bone remains. The study of ancient diseases such as brucellosis and tuberculosis benefits from these approaches. More research is needed as new diseases emerge causing pandemics and some previously eradicated reemerge in some regions. Global efforts are focused, based on evidence generated by research, on the prevention of new pandemics. ABSTRACT: Bacterial, viral, and parasitic zoonotic diseases are transmitted to humans from a wide variety of animal species that act as reservoir hosts for the causative organisms. Zoonoses contribute an estimated 75% of new or reemerging infectious diseases in humans. All groups of mammals have been shown to act as hosts for transmission of different organisms that cause zoonoses, followed in importance by birds; with both wild and domestic species identified as hosts in specific cases. There has been considerable research progress leading to a better understanding of the host range, animal origin, evolution, and transmission of important zoonoses, including those caused by the ingestion of food and products derived from animals. Paleopathology studies of ancient human bone lesions, in combination with ancient DNA analysis of the causative pathogen, have contributed to our understanding of the origin of zoonotic diseases, including brucellosis and mycobacterial zoonoses. However, there are still knowledge gaps and new confirmed and potential hosts are reported locally with some frequency. Both the economic cost and burden of disease of zoonoses are substantial at local and global levels, as reflected by recent coronavirus pandemics that spread rapidly around the world. Evidence-based prevention strategies are currently a global priority increasingly recognized, especially in zoonoses-affected regions.