Genetical Research



Variation over space and time of Aedes aegypti in Phnom Penh (Cambodia): genetic structure and oral susceptibility to a dengue virus


CHRISTOPHE PAUPY a1p1, NGAN CHANTHA a2, MARIE VAZEILLE a1, JEAN-MARC REYNES a3, FRANCOIS RODHAIN a4 and ANNA-BELLA FAILLOUX a1c1
a1 Unité des Insectes et Maladies Infectieuses, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, France
a2 National Malaria Centre, 372 boulevard Monivong, Phnom Penh, Cambodia
a3 Unité de Virologie, Institut Pasteur du Cambodge, 5 boulevard Monivong, Phnom Penh, Cambodia
a4 Ecole Pasteurienne d'Infectiologie, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, France

Article author query
paupy c   [PubMed][Google Scholar] 
chantha n   [PubMed][Google Scholar] 
vazeille m   [PubMed][Google Scholar] 
reynes j   [PubMed][Google Scholar] 
rodhain f   [PubMed][Google Scholar] 
failloux a   [PubMed][Google Scholar] 

Abstract

We studied spatial and temporal variation in 20–23 Aedes aegypti samples collected in Phnom Penh and its suburbs to estimate the population genetic structure using allozymes and the susceptibility to a dengue-2 virus. Based on seven allozyme systems, we detected low levels of genetic exchanges (i.e. high, significant FST values) between populations collected in the city centre, and different patterns of genetic structure for samples collected in the suburbs, depending on the type of environment and the date of collection. In the southern suburbs and the Chroy Chang Var Peninsula, differentiation became highly significant at the end of the dry season, whereas the opposite situation was observed for collections from the northern suburbs. Vector competence assessed by oral infections with a dengue-2 virus was lower for samples collected in the city centre than in the suburbs. A significant decrease of dengue susceptibility was observed in populations during the dry season. This study allows a model of Ae. aegypti population functioning in Phnom Penh to be suggested. Dynamics of dengue virus diffusion depend on the population genetic structure of the vector and its evolution over space and time.

(Received July 2 2003)
(Revised October 8 2003)


Correspondence:
c1 Tel: +33 1 40 61 36 17. Fax: +33 1 40 61 30 89. e-mail: afaillou@pasteur.fr
p1 Present address: Laboratoire de Microbiologie et Environnement, Institut Pasteur de La Nouvelle Calédonie, BP 61, 98845 Nouméa, New Caledonia.


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