Zoonoses and the Human-Animal-Ecosystems Interface
Any disease or infection that is naturally transmissible from vertebrate animals to humans and vice-versa is classified as a zoonosis according to the PAHO publication "Zoonoses and communicable diseases common to man and animals". Zoonoses have been recognized for many centuries, and over 200 have been described. They are caused by all types of pathogenic agents, including bacteria, parasites, fungi, and viruses.
Reducing public health risks from zoonoses and other health threats at the human-animal-ecosystems interface (such as antimicrobial resistance) is not straightforward. Management and reduction of these risks must consider the complexity of interactions among humans, animals, and the various environments they live in, requiring communication and collaboration among the sectors responsible for human health, animal health, and the environment.
The WHO is engaging in an ever-increasing number of cross sectoral activities to address health threats at the human-animal-ecosystem interface. These threats include existing and emerging zoonoses as well as antimicrobial resistance, food-borne zoonoses, and other threats to food safety.
Some examples of zoonoses, classified according to the type of causative agent, are given hereafter.
Zoonoses still represent significant public health threats, but many of them are neglected, i.e. they are not prioritized by health systems at national and international levels. They affect hundreds of thousands of people especially in developing countries, although most of them can be prevented.