Once these microbes are transmitted to different hosts that harbor distinctly different metavirulomes, the host environment could promote colonization of these zoonotic pathogens followed by a disease state in the new host.
The microbes are transmitted from mother to offspring, and in some circumstances can provide benefits to the insects; for instance, Spiroplasma-infested flies appear to be protected against infection by some parasites.
There are increasing evidence that microbes can be transmitted and shared between people who come in close contact, family members, and even members of the same sports (Turnbaugh et al., 2009; Schwarz et al., 2008).
Certain infectious organisms are normal residents of human hands and these microbes could be transmitted to uninfected animals and quarters during milking.
For microbes to be transmitted vertically, they must inhabit seeds, an association which we have recently shown to be strongly influenced by genotype in maize [ 41].
As well as horizontal transmission from external sources (surroundings and diet), colonising microbes can also be transmitted vertically, i.e. from the mother to the baby.
Although many studies have documented antibiotic-resistant bacteria in wild animals, how these microbes arise and whether they can be transmitted to humans is poorly understood.
A wide spectrum of microbes and infectious diseases have been transmitted from domesticated and wild animals to humans for thousands of years (1 ).
Ordinarily, once epidemiologists understand the nature of a particular microbe and the way it is transmitted, they can develop effective public health responses.
In epidemiological models, microbes or viruses are considered to be transmitted from host to host.
