Table 1.

Recent virus emergence events and their ecological circumstances

Virus	Family	First reported outbreak	Location	Original host	New host	Transmission route	Factors contributing to emergence	References
Bluetongue virus	Reoviridae	1998	Europe	Ruminants	Ruminants, especially sheep	Culicoides midges	Warmer temperatures in Europe	41, 42
Chikungunya virus	Togaviridae	2005	India	Nonhuman primates	Humans	Aedes albopictus	Vector switch	21, 25
East African cassava mosaic virus (Uganda variant)	Geminiviridae	1988	Uganda	Cassava plant	Cassava plant	Whiteflies	Recombination between coinfecting strains	43, 44
Ebola virus	Filovirdae	1976	Congo, Sudan	Fruit bats	Humans	Contact with body fluids	Encroachment into wildlife habitat	45, 46
Human immunodeficiency virus	Retroviridae	Early 20th century	Cameroon	Chimpanzees, gorillas, sooty mangabeys	Humans	Contact with body fluids	Exposure to primate body fluid	47, 48
Influenza A virus H1N1	Orthomyxoviridae	2009	Mexico	Swine	Humans	Airborne, fomites	Reassortment of virus segments	49, 50
Nipah virus	Paramyxoviridae	1998	Malaysia	Fruit bats	Swine, humans	Pig consumption of fruit pulp, droplet transmission to humans	Changing agricultural patterns	51, 52
Parvovirus	Parvoviridae	1978	Europe	Cats, raccoons	Canines	Oral contact with feces, fomites	Rapid evolution	53, 54
SARS coronavirus	Coronaviridae	2003	China	Bats	Humans	Handling of contaminated animals	Encroachment of wildlife habitat	55, 56
Sin Nombre virus	Bunyaviridae	1993	Southwestern United States	Mice	Humans	Contact with fomites, feces	El Niño–driven increases in rodent populations	57, 58
West Nile virus	Flaviviridae	1999	New York City	Birds	Humans	Culex mosquitoes	Broad host range, bird migration	59, 60

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