Open Access Research

Phenetic and genetic structure of tsetse fly populations (Glossina palpalis palpalis) in southern Ivory Coast

Dramane Kaba1, Sophie Ravel2, Geneviève Acapovi-Yao3, Philippe Solano4, Koffi Allou3, Henriette Bosson-Vanga1, Laetitia Gardes2, Eliezer Kouakou N’Goran3, Christopher John Schofield5, Moussa Koné1 and Jean-Pierre Dujardin6*

Author Affiliations

1 Institut Pierre Richet / Institut National de Santé Publique, BP V 47 Abidjan, Côte d’Ivoire

2 IRD UMR 177, Laboratoire de Recherche et de Coordination sur les Trypanosomoses IRD-CIRAD, Campus International de Baillarguet, 34398 Montpellier cedex 5, France

3 Laboratoire de Zoologie, Université d’Abidjan-Cocody, 22 BP 582, Abidjan 22, Côte d’Ivoire

4 IRD/CIRDES, UMR 177 IRD/CIRAD INTERTRYP, BP 454, 01 Bobo-Dioulasso, Burkina Faso

5 LSHTM (ITD), London WC1E7HT, UK

6 IRD, UMR 5090 MIVEGEC, Avenue Agropolis, IRD, Montpellier, France

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Parasites & Vectors 2012, 5:153  doi:10.1186/1756-3305-5-153

Published: 30 July 2012

Abstract

Background

Sleeping sickness, transmitted by G. p. palpalis, is known to be present in the Ivory Coast. G. p. palpalis has recently been reported to occur in several places within the town of Abidjan, including: (i) the Banco forest, (ii) the Abobo Adjamé University campus and (iii) the zoological park. Could these three places be treated sequentially, as separate tsetse populations, or should they be taken as one area comprising a single, panmictic population?

Methods

The amount of gene flow between these places provides strategic information for vector control. It was estimated by the use of both microsatellite DNA and morphometric markers. The idea was to assess the interest of the faster and much less expensive morphometric approach in providing relevant information about population structure. Thus, to detect possible lack of insect exchange between these neighbouring areas of Abidjan, we used both genetic (microsatellite DNA) and phenetic (geometric morphometrics) markers on the same specimens.

Using these same markers, we also compared these samples with specimens from a more distant area of south Ivory Coast, the region of Aniassué (186 km north from Abidjan).

Results

Neither genetic nor phenetic markers detected significant differentiation between the three Abidjan G. p. palpalis samples. Thus, the null hypothesis of a single panmictic population within the city of Abidjan could not be rejected, suggesting the control strategy should not consider them separately. The markers were also in agreement when comparing G. p. palpalis from Abidjan with those of Aniassué, showing significant divergence between the two sites.

Conclusions

Both markers suggested that a successful control of tsetse in Abidjan would require the three Abidjan sites to be considered together, either by deploying control measures simultaneously in all three sites, or by a continuous progression of interventions following for instance the "rolling carpet" principle. To compare the geometry of wing venation of tsetse flies is a cheap and fast technique. Agreement with the microsatellite approach highlights its potential for rapid assessment of population structure.