Accurate understanding of the global spread of emerging viruses is critical for public health
responses and for anticipating and preventing future outbreaks. Here we elucidate when, …

Since the first reports of a novel severe acute respiratory syndrome (SARS)-like coronavirus
in December 2019 in Wuhan, China, there has been intense interest in understanding how …

RNA viruses deserve their reputation as Nature’s swiftest evolvers. Their high rates of mutation
and replication (Holland et al., 1982) allow them to move through sequence space at a …

In March and early April 2009, a new swine-origin influenza A (H1N1) virus (S-OIV) emerged
in Mexico and the United States 1 . During the first few weeks of surveillance, the virus …

Background A large number of dry-preserved insect specimens exist in collections around
the world that might be useful for genetic analyses. However, until now, the recovery of …

Some key questions lie at the heart of investigations into the origin of the COVID-19 pandemic,
including what is known about the earliest COVID-19 cases in Wuhan, China, and what …

The source, timing, and geographical origin of the 1918–1920 pandemic influenza A virus
have remained tenaciously obscure for nearly a century, as have the reasons for its unusual …

Understanding how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged
in 2019 is critical to preventing future zoonotic outbreaks before they become the next …

Human immunodeficiency virus type 1 (HIV-1) sequences that pre-date the recognition of
AIDS are critical to defining the time of origin and the timescale of virus evolution 1 , 2 . A viral …

Understanding the circumstances that lead to pandemics is important for their prevention.
We analyzed the genomic diversity of severe acute respiratory syndrome coronavirus 2 (SARS-…