Sudden acute respiratory syndrome

May be a rehearsal for the next influenza pandemic

News p 677

Plagues are as certain as death and taxes.1 The optimism of the 1960s and 1970s has given way to a mature realism that the relationship between human beings and microbes is neither completely predictable nor biased in favour of humans. Over the past few decades several important human viruses have emerged. Some, such as HIV, prove to be sustainable modern plagues adding to the toll of human misery. Others, such as hepatitis F, occupy a seemingly silent niche, passengers in a human caravan but contributing little to the joint relationship. Whereas viruses such as Ebola, Hantaan, and Nipah spring from an animal reservoir, destroying life but unable to sustain transmission in a new environment, others such as human metapneumovirus2 are associated with respiratory illness in young children but their contribution to adult disease remains uncertain, suggesting a balance between virus and host immune system achieved after some evolutionary negotiation. Each of these viruses has been identified through the study of human disease processes, each of which exists along a spectrum of possible outcomes between virus and host.