A host shifting event occurs when a strain that was previously zoonotic begins to circulate exclusively among the new host species.Pathogen transfer is most likely to occur between species which are frequently in close contact with each other. It can also occur indirectly between species with less frequent contact if facilitated by an intermediary species; for example, a reservoir species may transfer the virus to a vector species, which in turn transfers the virus to humans. The degree of phylogenetic relatedness between host species also influences the likelihood that a pathogen is transmitted between them, likely because of the similarity of the hosts immunological defenses; for example, most human zoonotic transmissions come from other species of mammals. Pathogens of more distantly related species, on the other hand, such as plant viruses, may not be capable of infecting humans at all. Other factors influencing transmission rates include geographic proximity and intraspecies behaviors. Due to climate change and land use expansion, the risk of viral spillover is predicted to significantly increase. Prevalence and control
Cross-species transmission is the most significant cause of disease emergence in humans and other species. Wildlife zoonotic diseases of microbial origin are also the most common group of human emerging diseases, and CST between wildlife and livestock has appreciable economic impacts in agriculture by reducing livestock productivity and imposing export restrictions. This makes CST of major concern for public health, agriculture, and wildlife management.
See also
Branchial cleft cyst
Thyroglossal cyst
Lachiewicz Sibley syndrome
List of cutaneous conditions

References
Bibliography
Further reading


== External links ==