Abstract
Although polyomavirus JC (JCV) is the proven pathogen of
progressive multifocal leukoencephalopathy, the fatal demyelinating
disease, this virus is ubiquitous as a usually harmless symbiote among
human beings. JCV propagates in the adult kidney and excretes its
progeny in urine, from which JCV DNA can readily be recovered. The main
mode of transmission of JCV is from parents to children through long
cohabitation. In this study, we collected a substantial number of urine
samples from native inhabitants of 34 countries in Europe, Africa, and
Asia. A 610-bp segment of JCV DNA was amplified from each urine sample,
and its DNA sequence was determined. A worldwide phylogenetic tree
subsequently constructed revealed the presence of nine subtypes
including minor ones. Five subtypes (EU, Af2, B1, SC, and CY) occupied
rather large territories that overlapped with each other at their
boundaries. The entire Europe, northern Africa, and western Asia were
the domain of EU, whereas the domain of Af2 included nearly all of
Africa and southwestern Asia all the way to the northeastern edge of
India. Partially overlapping domains in Asia were occupied by subtypes
B1, SC, and CY. Of particular interest was the recovery of JCV subtypes
in a pocket or pockets that were separated by great geographic
distances from the main domains of those subtypes. Certain of these
pockets can readily be explained by recent migrations of human
populations carrying these subtypes. Overall, it appears that JCV
genotyping promises to reveal previously unknown human migration
routes: ancient as well as recent.