Volume 16, Number 4—April 2010 Fatal Human Case of West Nile
Disease, Mexico, 2009 To the Editor: West Nile virus (WNV;
family Flaviviridae, genus Flavivirus) was first recognized in
the Western Hemisphere in 1999 during an outbreak of human,
equine, and avian encephalitis in New York (1). The virus has
since spread across the United States and Canada, where it has
caused ≈30,000 human infections and ≈1,000 deaths. Serologic
evidence has demonstrated that WNV is present throughout Mexico,
Central America, South America, and the Caribbean region (2–8).
However, WNV illness in humans and vertebrate animals in these
regions has been only sparsely reported. For instance, 7 human
cases of WNV infection have occurred in Mexico (excluding the
case described here), 3 of which were severe. All patients
survived. To our knowledge, no fatal human cases of WNV
infection have occurred in Central America, South America, or
the Caribbean region. We describe a fatal case of WNV infection
in a human in Central America. The pa