Cross-species transmission (CST), also called interspecies transmission, host jump, or spillover, is the transmission of an infectious pathogen, such as a virus, between hosts belonging to different species. Once introduced into an individual of a new host species, the pathogen may cause disease for the new host and/or acquire the ability to infect other individuals of the same species, allowing it to spread through the new host population. The phenomenon is most commonly studied in virology, but cross-species transmission may also occur with bacterial pathogens or other types of microorganisms.Steps involved in the transfer of pathogens to new hosts include contact between the pathogen and the host; the successful infection of an initial individual host, which may lead to amplification and an outbreak; and the adaptation of the pathogen, within either the original or new host, which may render it capable of spreading efficiently between individuals in populations of the new host. The concept is important in understanding and controlling emerging infectious diseases in humans, especially those caused by viruses. Most viral diseases of humans are zoonotic in origin, having been historically transmitted to human populations from various animal species; examples include SARS, Ebola, swine flu, rabies, and avian influenza.The exact mechanisms which facilitate cross-species transmission vary by pathogen, and even for common diseases are often poorly understood. It is believed that viruses with high mutation rates are able to rapidly adapt to new hosts and thereby overcome host-specific immunological defenses, allowing their continued transmission.
The Bayesian inference approach enables model averaging over several potential diffusion predictors and estimates the support and contribution of each predictor while marginalizing over phylogenetic history. For studying viral CST, the flexibility of the Bayesian statistical framework allows for the reconstruction of virus transmission between different host species while simultaneously testing and quantifying the contribution of multiple ecological and evolutionary influences of both CST spillover and host shifting. One study on rabies in bats showed geographical range overlap is a modest predictor for CST, but not for host shifts. This highlights how Bayesian inferences in models can be used for CST analysis. See also
Mathematical modelling of infectious disease
Reverse zoonosis
Spillover infection
Vector
Zoonosis
Feline zoonosis

References
External links
Theo Kypraios. "A Gentle Tutorial in Bayesian Statistics" (PDF). Retrieved 10 July 2020. {{cite journal}}: Cite journal requires |journal= (help)
Bayesian modeling book and examples available for downloading. Bayesian statistics at Wikiversity
Smith, Tara C. (2022-04-27). "What Happens When We Give Animals Our Diseases?". Quanta Magazine.