title: Rift Valley fever vector diversity and impact of meteorological and environmental factors on Culex pipiens dynamics in the Okavango Delta, Botswana.
abstract: In Northern Botswana, rural communities, livestock, wildlife and large numbers of mosquitoes cohabitate around permanent waters of the Okavango Delta. As in other regions of sub-Saharan Africa, Rift Valley Fever (RVF) virus is known to circulate in that area among wild and domestic animals. However, the diversity and composition of potential RVF mosquito vectors in that area are unknown as well as the climatic and ecological drivers susceptible to affect their population dynamics.
  
  
  
  Using net traps baited with carbon dioxide, monthly mosquito catches were implemented over four sites surrounding cattle corrals at the northwestern border of the Okavango Delta between 2011 and 2012. The collected mosquito species were identified and analysed for the presence of RVF virus by molecular methods. In addition, a mechanistic model was developed to assess the qualitative influence of meteorological and environmental factors such as temperature, rainfall and flooding levels, on the population dynamics of the most abundant species detected (Culex pipiens).
  
  
  
  More than 25,000 mosquitoes from 32 different species were captured with an overabundance of Cx. pipiens (69,39 %), followed by Mansonia uniformis (20,67 %) and a very low detection of Aedes spp. (0.51 %). No RVF virus was detected in our mosquito pooled samples. The model fitted well the Cx. pipiens catching results (ρ = 0.94, P = 0.017). The spatial distribution of its abundance was well represented when using local rainfall and flooding measures (ρ = 1, P = 0.083). The global population dynamics were mainly influenced by temperature, but both rainfall and flooding presented a significant influence. The best and worst suitable periods for mosquito abundance were around March to May and June to October, respectively.
  
  
  
  Our study provides the first available data on the presence of potential RVF vectors that could contribute to the maintenance and dissemination of RVF virus in the Okavango Delta. Our model allowed us to understand the dynamics of Cx. pipiens, the most abundant vector identified in this area. Potential predictions of peaks in abundance of this vector could allow the identification of the most suitable periods for disease occurrence and provide recommendations for vectorial and disease surveillance and control strategies.
authors: UPR AGIRs, F-34398, CIRAD, Montpellier, France. pachka.hammami@cirad.fr.|Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa. pachka.hammami@cirad.fr.|UMR CMAEE, F-34398, CIRAD, Montpellier, France. pachka.hammami@cirad.fr.
authors: Hammami
authors: H
authors: Pachka
authors: UPR AGIRs, F-34398, CIRAD, Montpellier, France.|UMR TETIS, F-34398, CIRAD, Montpellier, France.
authors: Tran
authors: T
authors: Annelise
authors: Special Pathogens Unit, NICD, Johannesburg, South Africa.
authors: Kemp
authors: K
authors: Alan
authors: Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa.|Special Pathogens Unit, NICD, Johannesburg, South Africa.
authors: Tshikae
authors: T
authors: Power
authors: Department of Veterinary Services, Ministry of Agriculture, Gaborone, Botswana.
authors: Kgori
authors: K
authors: Patrick
authors: UPR AGIRs, F-34398, CIRAD, Montpellier, France.
authors: Chevalier
authors: C
authors: Véronique
authors: Special Pathogens Unit, NICD, Johannesburg, South Africa.
authors: Paweska
authors: P
authors: Janusz
authors: UPR AGIRs, F-34398, CIRAD, Montpellier, France.|Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa.|Department of Animal Science and Production, Botswana College of Agriculture, Private bag 0037, Gaborone, Botswana.
authors: Jori
authors: J
authors: Ferran
mesh_terms: D000818:Animals; D001902:Botswana; D002417:Cattle; D002418:Cattle Diseases / Q000635:transmission / Q000821:virology*; D009033:Culicidae / Q000145:classification / Q000502:physiology / Q000821:virology*; D004777:Environment; D006801:Humans; D007303:Insect Vectors / Q000502:physiology / Q000821:virology*; D011157:Population Dynamics; D012295:Rift Valley Fever / Q000635:transmission* / Q000821:virology; D012296:Rift Valley fever virus / Q000502:physiology*; D012621:Seasons; D013696:Temperature
keywords: Botswana; Climatic factors; Culex pipiens; Flooding; Mosquito; Okavango Delta; Population dynamics modeling; Remote sensing; Rift Valley fever; Vector