Project Number: 5410-32000-014-11
Project Type: Specific Cooperative Agreement

Start Date: Apr 15, 2006
End Date: Apr 14, 2011

Objective:
The main objective of this project is to study the genetics of known Rift Valley Fever Virus (RVFV) vectors in Kenya. We will determine rates of gene flow among populations of known RVFV mosquitoes. Individual mosquitoes will be assayed for virus to look at natural infection rates. Vector competence studies will be conducted when possible. We will attempt to colonize some of the vector species to establish colonies for future studies on the various genetic factors that affect vector competence and transovarial transmission of the virus.

Approach:
Collection sites will include past RVF outbreak sites and areas known to be endemic for the RVFV as well as sites indicated to be at risk by a model developed by colleagues in Florida. Distinct genetic differences and/or restrictions to gene flow among populations of mosquitoes found in endemic/outbreak/virus-free areas of the country will be examined. Mosquitoes will be collected as adults, larvae, and eggs. Immature stages will be raised to adulthood. Individual insects will be ground and one aliquot assayed for RVFV using RT-PCR, and another aliquot used to analyze variation in a mitochondrial gene by SSCP or fragment analysis on an ABI sequencer. Vector competence studies will be completed when enough mosquitoes are captured and if they will feed on an artificial membrane feeder. Mosquitoes will be given a RVFV infectious blood meal and assayed for RVFV after the EIP. Rodents will be trapped, bled and tested for antibody to RVFV using ELISA.