title: Plant resting site preferences and parity rates among the vectors of Rift Valley Fever in northeastern Kenya.
abstract: Mosquito lifespan can influence the circulation of disease causing pathogens because it affects the time available for infection and transmission. The life-cycle of mosquitoes is determined by intrinsic and environmental factors, which can include the availability of hosts and suitable resting environments that shelter mosquitoes from extreme temperature and desiccating conditions. This study determined the parity rates (an indirect measure of survival) and plant resting preference of vectors of Rift Valley fever (RVF) in northeastern Kenya.
  
  
  
  Resting mosquitoes were trapped during the rainy and the dry season using a Prokopack aspirator from vegetation, whereas general adult populations were trapped using CDC light traps. At each site, sampling was conducted within a 1 km(2) area, subdivided into 500 × 500 m quadrants and four 250 × 250 m sub-quadrants from which two were randomly selected as sampling units. In each sampling unit, plants were randomly selected for aspiration of mosquitoes. Only Aedes mcintoshi and Ae. ochraceus were dissected to determine parity rates while all mosquito species were used to assess plant resting preference.
  
  
  
  Overall, 1124 (79 %, 95 % CI = 76.8-81.1 %) mosquitoes were parous. There was no significant difference in the number of parous Ae. mcintoshi and Ae. ochraceus. Parity was higher in the rainy season than in the dry season. Daily survival rate was estimated to be 0.93 and 0.92 among Ae. ochraceus and Ae. mcintoshi, respectively. Duosperma kilimandscharicum was the most preferred plant species with the highest average capture of primary (3.64) and secondary (5.83) vectors per plant, while Gisekia africana was least preferred.
  
  
  
  Survival rate of each of the two primary vectors of RVF reported in this study may provide an indication that these mosquitoes can potentially play important roles in the circulation of diseases in northern Kenya. Resting preference of the mosquitoes in vegetation may influence their physiology and enhance longevity. Thus, areas with such vegetation may be associated with an increased risk of transmission of arboviruses to livestock and humans.
authors.affiliation: International Centre of Insect Physiology and Ecology, Nairobi, P. O. Box 30772-00100, Nairobi, Kenya. sokello@icipe.org.|Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0083, South Africa. sokello@icipe.org.
authors.forename: Samwel O
authors.initials: SO
authors.lastname: Arum
authors.affiliation: Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0083, South Africa.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Weldon
authors.affiliation: International Centre of Insect Physiology and Ecology, Nairobi, P. O. Box 30772-00100, Nairobi, Kenya.
authors.forename: Benedict
authors.initials: B
authors.lastname: Orindi
authors.affiliation: International Centre of Insect Physiology and Ecology, Nairobi, P. O. Box 30772-00100, Nairobi, Kenya.
authors.forename: Caroline
authors.initials: C
authors.lastname: Tigoi
authors.affiliation: International Centre of Insect Physiology and Ecology, Nairobi, P. O. Box 30772-00100, Nairobi, Kenya.
authors.forename: Francis
authors.initials: F
authors.lastname: Musili
authors.affiliation: International Centre of Insect Physiology and Ecology, Nairobi, P. O. Box 30772-00100, Nairobi, Kenya.
authors.forename: Tobias
authors.initials: T
authors.lastname: Landmann
authors.affiliation: International Centre of Insect Physiology and Ecology, Nairobi, P. O. Box 30772-00100, Nairobi, Kenya.
authors.forename: David P
authors.initials: DP
authors.lastname: Tchouassi
authors.affiliation: International Centre of Insect Physiology and Ecology, Nairobi, P. O. Box 30772-00100, Nairobi, Kenya.|International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), BP 320, Bamako, Mali.
authors.forename: Hippolyte D
authors.initials: HD
authors.lastname: Affognon
authors.affiliation: International Centre of Insect Physiology and Ecology, Nairobi, P. O. Box 30772-00100, Nairobi, Kenya.
authors.forename: Rosemary
authors.initials: R
authors.lastname: Sang
mesh_terms: D000330:Aedes / Q000502:physiology* / Q000821:virology; D000818:Animals; D001522:Behavior, Animal; D003465:Culex / Q000502:physiology* / Q000821:virology; D004777:Environment; D005260:Female; D005843:Geography; D006801:Humans; D007303:Insect Vectors / Q000502:physiology* / Q000821:virology; D007630:Kenya / Q000453:epidemiology; D010298:Parity; D010944:Plants; D011891:Rain; D012295:Rift Valley Fever / Q000635:transmission* / Q000821:virology; D012296:Rift Valley fever virus / Q000502:physiology*; D012621:Seasons
keywords: Parity; Resting preference; Rift Valley fever vectors; Survival; Vegetation