Zoonoses Theory

Subject : Science and technology

Section: Health

Concept :

Undisclosed genetic data from a food market in Wuhan has been unearthed and is being used to support the zoonoses theory over the lab leak theory.
These findings were presented to the Scientific Advisory Group for the Origins of Novel Pathogens, an expert body constituted by the WHO.

Zoonosis

A zoonosis is an infectious disease of humans caused by a pathogen (an infectious agent, such as a bacterium, virus, parasite or prion) that can jump from a non-human (usually a vertebrate) to a human and vice versa.

Examples :

Major modern diseases such as Ebola virus disease and salmonellosis are zoonoses.
HIV was a zoonotic disease transmitted to humans in the early part of the 20th century, though it has now evolved into a separate human-only disease.
Most strains of influenza that infect humans are human diseases, although many strains of bird flu and swine flu are zoonoses. These viruses occasionally recombine with human strains of the flu and can cause pandemics such as the 1918 Spanish flu or the 2009 swine flu.

Modes of Transmission

Direct Zoonosis
Zoonoses have different modes of transmission. In direct zoonosis the disease is directly transmitted from non-humans to humans through media such as air (influenza) or through bites and saliva (rabies).
Reverse zoonosis or Anthroponosis
In contrast, transmission can also occur via an intermediate species (referred to as a vector), which carry the disease pathogen without getting sick.
When humans infect non-humans, it is called reverse zoonosisor anthroponosis.

Causes of Zoonoses

The emergence of zoonotic diseases originated with the domestication of animals.
Zoonotic transmission can occur in any context in which there is contact with or consumption of animals, animal products, or animal derivatives.
This can occur in a companionistic (pets), economic (farming, trade, butchering, etc.), predatory (hunting, butchering or consuming wild game) or research context.
According to a report from the United Nations Environment Programme and International Livestock Research Institute large part of the causes are environmental like climate change, unsustainable agriculture, exploitation of wildlife, land use change.