Genetic differentiation of the dengue vector, Aedes aegypti (Ho Chi Minh City, Vietnam) using microsatellite markers

Abstract

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.

Factors influencing the population structure of Aedes aegypti from the main cities in Cambodia

“…Temporary breeding sites disappear and a population bottleneck may have led to a reduction of polymorphism. This same pattern was very marked in populations from Ho Chi Minh City (Huber et al, 2002).…”

“…aegypti in Cambodia underlines the low level of genetic differentiation compared to that detected in Thailand (Mousson et al, 2002) or from Vietnam (Tran et al, 1999;Huber et al, 2002).…”

“…aegypti populations in four cities differing in their level of urbanisation and insecticide treatments, both of which are known to shape mosquito genetic structure (Huber et al, 2002;Mousson et al, 2002). In the present study, we addressed the following questions: (1) is the genetic structure of Ae.…”

Genetic variability and heterogeneity of Venezuelan equine encephalitis virus vector Ochlerotatus taeniorhynchus (Diptera: Culicidae) populations of the Colombian Atlantic coast, based on microsatellite loci

“…The number of alleles per locus in the populations of O. taeniorhynchus analyzed had a range of 3 to 5, being relatively low in comparison with other population genetic studies carried out in mosquitoes with microsatellite markers; thus, for example, Huber et al (2002), established for A. aegypti a range of 4 to 12 alleles per locus; Scarpassa and Conn (2007) determined for A. darlingi a range of 5 to 25 alleles per locus; Mirabello et al (2008) showed for different populations of A. darlingi from Peru and Brazil, ranges of 5 to 11 and 6 to 22 alleles per locus, respectively. However, ranges of allele numbers per locus have been established that are similar to that of the present study, as reported by Mirabello et al (2008) using the same species but in other populations of the mosquito from Belize and Guatemala, where the range was 2 to 7 alleles per locus.…”

Genetic structure of Aedes aegypti in the city of Córdoba (Argentina), a recently reinfested area

“…aegypti populations within cities have been extensively studied in Southeast Asian cities of Cambodia, Vietnam and Thailand (Tran Khanh et al 1999, Huber et al 2002, Paupy et al 2004a, b, Bosio et al 2005. In general, samples from different neighbourhoods showed significant genetic differentiation.…”