Emergent virus in the context of "Eradication of infectious diseases"

A zoonosis (/zoʊˈɒnəsɪs, ˌzoʊəˈnoʊsɪs/ ; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a virus, bacterium, parasite, fungi, or prion) that can jump from a non-human vertebrate to a human. When humans infect non-humans, it is called reverse zoonosis or anthroponosis.

Major modern diseases such as Ebola 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. Human infection with animal influenza viruses is rare, as they do not transmit easily to or among humans. However, avian and swine influenza viruses in particular possess high zoonotic potential, and these occasionally recombine with human strains of the flu and can cause pandemics such as the 2009 swine flu. Zoonoses can be caused by a range of disease pathogens such as emergent viruses, bacteria, fungi and parasites; of 1,415 pathogens known to infect humans, 61% were zoonotic. Most human diseases originated in non-humans; however, only diseases that routinely involve non-human to human transmission, such as rabies, are considered direct zoonoses.

Wildlife trade refers to the exchange of products derived from non-domesticated animals or plants usually extracted from their natural environment or raised under controlled conditions. It can involve the trade of living or dead individuals, tissues such as skins, bones or meat, or other products. Legal wildlife trade is regulated by the United Nations' Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which currently has 184 member countries called Parties. Illegal wildlife trade is widespread and constitutes one of the major illegal economic activities, comparable to the traffic of drugs and weapons.

Wildlife trade is a serious conservation problem, has a negative effect on the viability of many wildlife populations and is one of the major threats to the survival of vertebrate species. The illegal wildlife trade has been linked to the emergence and spread of new infectious diseases in humans, including emergent viruses. Global initiatives like the United Nations Sustainable Development Goal 15 have a target to end the illegal supply of wildlife.

The bat virome is the group of viruses associated with bats. Bats host a diverse array of viruses, including all seven types described by the Baltimore classification system: (I) double-stranded DNA viruses; (II) single-stranded DNA viruses; (III) double-stranded RNA viruses; (IV) positive-sense RNA viruses; (V) negative-sense RNA viruses; (VI) positive-sense RNA viruses that replicate through a DNA intermediate; and (VII) double-stranded DNA viruses that replicate through a single-stranded RNA intermediate. The greatest share of bat-associated viruses identified as of 2020 are of type IV, in the family Coronaviridae.

Bats harbor many viruses and a few of them are zoonotic, or capable of infecting humans and causing disease, thus, are considered important emerging viruses. These zoonotic viruses include the rabies virus, SARS-CoV, MERS-CoV, Marburg virus, Nipah virus, and Hendra virus. While research strongly indicates that SARS-CoV-2 originated in bats, it is unknown how it was transmitted to humans, or if an intermediate host was involved. It has been speculated that bats may have a role in the ecology of Ebola virus, though this is unconfirmed. A closely-related ebolavirus, Bombali ebolavirus, has been detected in insectivorous bats. While transmission of rabies from bats to humans usually occurs from bites or scratches, most other zoonotic bat viruses are transmitted by direct contact with infected bat fluids like urine, guano, or saliva, or through contact with an infected, non-bat intermediate host. There is no firm evidence that butchering or consuming bat meat can lead to viral transmission, though this has been speculated because such activity causes aerosols that may facilitate respiratory transmission.