Parasites and Vectors (2015) 8 (660) - Delineation of the population ...

Maria G. Onyango, George N. Michuki, Moses Ogugo, Gert J. Venter, Miguel A. Miranda, Nohal Elissa, Appolinaire Djikeng, Steve Kemp, Peter J. Walker and Jean-Bernard Duchemin (2015)
Delineation of the population genetic structure of Culicoides imicola in East and South Africa
Parasites and Vectors 8 (660)
Abstract:
Background
Culicoides imicola Kieffer, 1913 is the main vector of bluetongue virus (BTV) and African horse sickness virus (AHSV) in Sub-Saharan Africa. Understanding the population genetic structure of this midge and the nature of barriers to gene flow will lead to a deeper understanding of bluetongue epidemiology and more effective vector control in this region.
Methods
A panel of 12 DNA microsatellite markers isolated de novo and mitochondrial DNA were utilized in a study of C. imicola populations from Africa and an outlier population from the Balearic Islands. The DNA microsatellite markers and mitochondrial DNA were also used to examine a population of closely related C. bolitinos Meiswinkel midges.
Results
The microsatellite data suggest gene flow between Kenya and south-west Indian Ocean Islands exist while a restricted gene flow between Kenya and South Africa C. imicola populations occurs. Genetic distance correlated with geographic distance by Mantel test. The mitochondrial DNA analysis results imply that the C. imicola populations from Kenya and south-west Indian Ocean Islands (Madagascar and Mauritius) shared haplotypes while C. imicola population from South Africa possessed private haplotypes and the highest nucleotide diversity among the African populations. The Bayesian skyline plot suggested a population growth.
Conclusions
The gene flow demonstrated by this study indicates a potential risk of introduction of new BTV serotypes by wind-borne infected Culicoides into the Islands. Genetic similarity between Mauritius and South Africa may be due to translocation as a result of human-induced activities; this could impact negatively on the livestock industry. The microsatellite markers isolated in this study may be utilised to study C. bolitinos, an important vector of BTV and AHSV in Africa and identify sources of future incursions.
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Full text of article
Database assignments for author(s): Gert J. Venter, Miguel Angel Miranda

Research topic(s) for pests/diseases/weeds:
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Culicoides imicola		Kenya
	Culicoides imicola		Madagascar
	Culicoides imicola		Mauritius
	Culicoides imicola		South Africa
	Culicoides imicola		Reunion Island
	Culicoides imicola		Spain (Baleares)