LEARNING FROM THE PAST: INFERRING THE EVOLUTIONARY AND EPIDEMIC HISTORIES OF EMERGING AND POTENTIALLY EMERGENT VIRUSES

In recent decades there has been an increase in so-called ‘emerging’ infections, most notably those caused by viruses that have their origins in animal populations. Important recent examples include HIV, dengue virus, avian influenza virus, SARS coronavirus, and west nile virus. In addition to their direct effects on the health of human populations, their associated morbidity and mortality have a substantial indirect social and economic impact. Conversely, the emergence of infectious diseases in human populations is a direct consequence of demographic and societal changes that alter natural ecosystems. Disease emergence may also be precipitated by genetic changes in pathogens that affect transmissibility, host range and virulence. If we are to prevent or control disease in human populations, or to identify those that are potentially emergent, an understanding of the evolutionary and ecological factors involved in viral emergence, patterns of dispersal and mechanisms of maintenance is crucial. The use of phylogenetic and other bioinformatic techniques based on Bayesian coalescent theory to infer the evolutionary and epidemic histories of viruses from their genomic sequences will be presented using examples from our recent work on dengue and other mosquito-borne viruses, and on coronaviruses in bats