Swine flu in the context of "2009 flu pandemic"

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.

Shark liver oil is an oil obtained from the livers of sharks. It has been used for centuries as a folk remedy to promote the healing of wounds and as a remedy for respiratory tract and digestive system problems. It is still promoted as a dietary supplement, and additional claims have been made that it can treat other maladies such as cancer, HIV, radiation sickness, swine flu, and the common cold. To date, none of these claims has been medically validated and shark liver oil (alone) is not a medication prescribed or utilized by American physicians. However, it is a component of some moisturizing skin lotions and hemorrhoid medications.