Emerging Zoonoses and their Determinants

Zoonotic diseases represent one of the leading causes of illness and death from infectious disease. Worldwide, zoonotic diseases have a negative impact on commerce, travel, and economies. In most developing countries, zoonotic diseases are among those diseases of major public health significance and contribute significantly to an already overly burdened public health system. In industrialized nations, zoonotic diseases are of particular concern for at-risk groups such as the elderly, children, childbearing women, and immunocompromised individuals. The World Health Organization has defined zoonoses as, “diseases and infections naturally transmitted between nonhuman vertebrate animals and humans”, and emerging zoonotic disease as a "zoonosis that is newly recognized or newly evolved or that has occurred previously but shows an increase in incidence or expansion in geographical, host or vector range". However link between humans and animals with respect to diseases could be framed in many but slightly different ways. Strikingly, 75% of emerging infectious diseases have been identified as zoonotic in origin. Moreover if we could link the emergence of some diseases to animals, for e.g. AIDS then the number would be much higher. These agents have included some that maintain an ongoing reservoir life cycle in animals or arthropods, without the permanent establishment of a new life cycle in humans, as well as some “species jumpers” that derive from an ancient reservoir life cycle in animals but have subsequently established a new life cycle in humans that no longer involves an animal reservoir. Zoonotic diseases require rather different prevention and control strategies than diseases of etiologic agents employing only human-to-human transmission. Determinants discussed above have to be understood and dealt in proper perspective when it comes to the problem of zoonotic diseases. Different section of workers should collaborate their efforts against dreaded diseases, which are affecting mankind and animals and are continuously posing challenges. Multidisciplinary teams of ecologists, mammalogists, ornithologists, and entomologists, as well as physicians, epidemiologists, public health workers and veterinarians should join hands for intensive and sure success