2004 Life, Science and Health: Diseases Across Species
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THE ACCIDENTAL HOST: Animal Diseases in Humans
Zoonoses are human diseases that can be acquired from vertebrate animals. Humans are "accidental" hosts in that human infection is not required for propagation of the infectious agent in nature. Humans have become ill from zoonoses for as long as we have hunted or domesticated animals, and most newly emerging infectious diseases are zoonotic in origin. The causative agents of zoonotic disease can be viruses, bacteria, parasites or prions (the agents associated with "mad cow disease"). The ways that we get infected (modes of transmission) are numerous and complex. Sometimes we infect animals with our own diseases, for example tuberculosis. Animals in which an infectious agent can be propagated, often without significant effect on the animal, are known as reservoirs. It is when we come in contact with these reservoirs, either directly or indirectly, that transmission occurs. The principal factors that enhance the emergence of zoonotic diseases include climatic and ecological changes, the movement of pathogens, vectors and animals into new areas, change and adaptation in the pathogens themselves, and human behavior and demographics.
Harry Taber, Ph.D.
As director of the Division of Infectious Disease, Dr. Taber oversees a broad range of research, clinical and environmental programs in zoonoses and other disease entities. Laboratories within the division include not only the Laboratory of Zoonotic Disease and Clinical Virology, but also the Laboratories of Bacterial Disease, Viral Disease, Mycobacterial Disease, and Fungal and Parasitic Disease. Research and diagnostic programs within the division thus cover the full gamut of human infectious disease. Dr. Taber's own laboratory focuses on genotyping and molecular epidemiology of tuberculosis, and he works closely with the Health Department's Tuberculosis Control unit and with the Centers for Disease Control and Prevention in tracking the spread of tuberculosis. He participates in national public health committees involved with infectious disease diagnostic problems. His long-standing research interests include bacterial resistance to antimicrobial agents, mechanisms of uptake of these agents, and regulation of gene expression in bacteria.