Finn Phillips Blog Post 2

 

    The past two weeks, I have been working to help finish up the PCRs for the kdr mutations in Aedes aegypti from a thermal project that is being done in the Saavedra Lab, and with this project's work being wrapped up, my focus has switched over to the RaHP surveillance project.  This has meant a lot more mosquito identification work, which is more difficult now that there is not primarily Aedes Vexans in our overnight CO2 traps. We are finally starting to get a good amount of Culex Tarsalis in our traps, which is the primary focus of our surveillance, although we are also conducting bottle bioassays on Culex Pipiens simply because of the number of individuals we have been able to trap.

    We have had mixed results from traps and sometimes will have up to 90% of the individuals in the trap being Tarsalis, and other times only a few individuals in the trap being Tarsalis, which has made conducting consistent bioassay trials with sufficient replicates difficult. As a part of our surveillance, we also are working on being able to have a positive control using some of the susceptible culex tarsalis that is kept in the insectary, but due to the stage of maintenance of the colonies, we are going to have to wait until next week, as the mosquitos were blood-fed this week and eggs were being collected so we were unable to use any.

Despite the difficulties, we have been able to conduct two successful bioassays on Culex Tarsalis from two different collections at sites in the Fort Collins area, each bioassay done with more than 3 replicates of 15+ individuals, and an acetone control. The data was recorded, and we then fit the recorded data to a logarithmic regression to ensure that the progression of knockdown is consistent with expected results. This allows us to calculate an LT50 and an LT90.

    In both trials so far, the knockdown time has been longer than expected according to CDC diagnostic times, but both trials ended with 100% knockdown after 60 minutes. The interesting thing is that after a 24-hour incubation period, we observed up to 50% recovery in replicates. This result is unexpected, and without a positive control, we are unable to tell whether the recovery is due to kdr mutation within the mosquitoes or if there was an error in the bioassay. We plan on trapping every day of the work week to conduct as many trials as possible and add a positive control to the trials.

    One aspect of the project I am somewhat proud of is my implementation of an application called Epicollect 5, which is a free and easy-to-use tool for data collection of trap data. We are using it to log where, when, and what we catch in our traps, as part of our goal for the project is also to do a full surveillance of the Fort Collins area, analyzing differences found in natural versus residential or agricultural areas. I think this is also something that people in other labs will be using as they are starting to do collections now.

    I am excited for the coming week and hope our trapping can be successful and efficient so we can begin to get complete data from our assays.