title: Delineation of the population genetic structure of Culicoides imicola in East and South Africa.
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.
authors.affiliation: CSIRO Health and Biosecurity, Australian Animal Health Laboratory, 5 Portalington Road, Geelong, VIC, 3220, Australia. Maria.Onyango@csiro.au.|School of Medicine, Deakin University, 75 Pidgons Road, Waurn Ponds, VIC, 3216, Australia. Maria.Onyango@csiro.au.
authors.forename: Maria G
authors.initials: MG
authors.lastname: Onyango
authors.affiliation: International Livestock Research Institute, P.O. Box 30709, 00100, Nairobi, Kenya. mgngondi@gmail.com.
authors.forename: George N
authors.initials: GN
authors.lastname: Michuki
authors.affiliation: International Livestock Research Institute, P.O. Box 30709, 00100, Nairobi, Kenya. m.ogugo@cgiar.org.
authors.forename: Moses
authors.initials: M
authors.lastname: Ogugo
authors.affiliation: ARC-Onderstepoort Veterinary Institute, Private bag X5, Onderstepoort, 0110, South Africa. VenterG@arc.agric.za.
authors.forename: Gert J
authors.initials: GJ
authors.lastname: Venter
authors.affiliation: Laboratoria de Zoologia, University of the Balearic Islands, Palma de Mallorca, CP: 07122, Spain. ma.miranda@uib.es.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Miranda
authors.affiliation: Institut Pasteur of Madagascar, B.P. 1274 Ambatofotsikely, 101, Antananarivo, Republic of Madagascar. nelissa@pasteur.mg.
authors.forename: Nohal
authors.initials: N
authors.lastname: Elissa
authors.affiliation: International Livestock Research Institute, P.O. Box 30709, 00100, Nairobi, Kenya. A.Djikeng@cgiar.org.|Biosciences eastern and central Africa - ILRI Hub (BecA-ILRI Hub), ILRI, PO Box 30709, 00100, Nairobi, Kenya. A.Djikeng@cgiar.org.
authors.forename: Appolinaire
authors.initials: A
authors.lastname: Djikeng
authors.affiliation: International Livestock Research Institute, P.O. Box 30709, 00100, Nairobi, Kenya. s.kemp@cgiar.org.
authors.forename: Steve
authors.initials: S
authors.lastname: Kemp
authors.affiliation: CSIRO Health and Biosecurity, Australian Animal Health Laboratory, 5 Portalington Road, Geelong, VIC, 3220, Australia. Peter.Walker@csiro.au.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Walker
authors.affiliation: CSIRO Health and Biosecurity, Australian Animal Health Laboratory, 5 Portalington Road, Geelong, VIC, 3220, Australia. Jean-Bernard.Duchemin@csiro.au.
authors.forename: Jean-Bernard
authors.initials: JB
authors.lastname: Duchemin
mesh_terms: D000351:Africa, Eastern; D000818:Animals; D002519:Ceratopogonidae / Q000145:classification* / Q000235:genetics* / Q000254:growth & development; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics; D051456:Gene Flow; D005828:Genetics, Population; D006239:Haplotypes; D007303:Insect Vectors / Q000145:classification / Q000235:genetics; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D058974:Phylogeography; D017422:Sequence Analysis, DNA; D013019:South Africa
chemical_list: D004272:DNA, Mitochondrial