Dengue haemorrhagic fever emerged in the 1950s and has become a major public health
concern in most Asian countries. In Vietnam, little is known about the intraspecific
variation of the vector and its consequences on vectorial capacity. Here we report
the use of microsatellite markers to differentiate Aedes aegypti populations in Ho
Chi Minh City, a typical, overcrowded Asian city. Six microsatellite loci, with 5-14
alleles per locus, were scored in 20 mosquito samples collected in 1998 in Ho Chi
Minh City. We found substantial differentiation among Ae. aegypti populations from
the outskirts, whereas populations from the centre of the city showed less differentiation.
These results are consistent with the hypothesis that populations of Ae. aegypti in
central Ho Chi Minh City are panmictic because there are abundant larval breeding
sites and an abundance of humans for adults to feed upon. In contrast, populations
on the outskirts become differentiated largely through the processes of genetic drift
because larval breeding sites are not as abundant. These findings implicate human
activities associated with urbanization, as factors shaping the genetic structure
of Ae. aegypti populations.