Newly discovered viruses

Although humans are affected by an enormous range of microorganisms, almost all newly discovered emerging pathogens are viruses that are often zoonotic or vector-borne. These emerging viruses often have high baseline mutation rates, allowing them to adapt relatively easily to new hosts and enabling them to take advantage of new epidemiological opportunities provided by the changing environment. A range of apparently new human viral pathogens has been reported increasingly in international outbreak information over the last few years. How they will influence global public health remains to be seen.

Emerging viruses that may be of particular public health importance include (1) respiratory SARS-like coronaviruses; (2) Garissa and Ngari viruses, Alkhurma virus and Lujo virus—discovered during investigations of haemorrhagic fever; (3) KI and WU human polyomaviruses, new human coronaviruses, human bocavirus, human parechovirus, and mimivirus—causing predominantly respiratory disease; (4) Toscana and, Usutu viruses—causing viral meningitis and encephalitis; (5) Merkel cell polyomavirus—with oncogenic potential. The human pathogenicity of other emerging viruses, e.g. Vesivirus, Ljungan virus, Aichi virus, Titi Monkey adenovirus, gamma-retrovirus, and Saffold virus is less certain.