to know how an infection may have spread. For example, after
sparked a major outbreak in 2003, scientists identified the virus in
palm civets, a small mongoose-like animal. Maybe the disease had
been routinely circulating in civets before spilling over into the human
population?
Analysis of different viruses suggested otherwise. Human
and civet viruses were closely related, indicating that both were
relatively new hosts for the virus. had potentially jumped from
civets into humans a few months before the outbreak started. In
contrast, the virus had been circulating in bats for much longer,
making its way into civets sometime around 1998. Based on the
evolutionary history of the different viruses, civets were probably just
a brief stepping stone for as it made its way into humans.[3]
During Richard Schmidt’s trial, the prosecution used similar
phylogenetic evidence to show that it was plausible that Trahan’s
infection had come from the patient who’d visited Schmidt.
Evolutionary biologist David Hillis and his colleagues compared the
viruses isolated from the pair with other viruses found in patients
in Lafayette. In his testimony, Hillis said the viruses found in
Schmidt’s patient and Trahan were ‘the most closely related
sequences in the analysis, and as closely related to sequences
isolated that two individuals could be’. Although it wasn’t conclusive
proof that Trahan’s infection had come from Schmidt’s patient, it
undermined the defence’s claim that the cases were unrelated.
Eventually, Schmidt was found guilty and sentenced to fifty years in
prison. As for Trahan, she remarried and continued to live with ,
celebrating her twentieth wedding anniversary in 2016.[4]