Location: Livestock Arthropod Pests Research
Project Number: 3094-32000-038-030-I
Project Type: Interagency Reimbursable Agreement
Start Date: Oct 1, 2016
End Date: Sep 30, 2019
Objective:
To devise innovative methods for the suppression of insects that transmit diseases to U.S. military deployed abroad.
Approach:
Devise innovative methods for the suppression of insects that transmit diseases to U.S. military deployed abroad. Continue studies of acetylcholinesterase biochemistry and structure expressing additional mutations reported in mosquitoes or other fly species. Continue efforts (initiated in 2015) to determine if AChE is present in sand fly and mosquito saliva. Continue bioassays for insecticidal, attractant and repellant activity on a variety of compounds including FIFRA 25(b) conditionally exempt compounds that, if effective, may provide opportunity for field deployment. Utilize the PCR-based assays we developed to assess the occurrence of the sand fly G119S mutation in nature. The codon variant (GGC) giving rise to the G119S mutation exists in our fly colony and in sand flies collected from Africa, strongly suggesting the G119S mutation is likely to occur in nature. Investigate neonicotinoids interaction with OP-resistance resulting from mutations in AChE. Conduct further study of neonicotinoid potential use for sand fly and mosquito control, and may conduct initial biochemical assays using our recombinant PpAChEs if time, safety considerations and availability allow selection of appropriate compounds for testing. Anticipate testing new insecticide compounds against sandflies if they become available (Zyrox bait, Syngenta; tolfenpyrad, Bayer; c8910 fatty acids, neonicotinoids). Test developed novel arthropod repellants and conduct additional studies expected to focus on chemical identification (mass spectrometry) of sex-specific cuticular markers that may communicate information relating to reproduction, location of food sources, or other activities. Quantitative PCR will be utilized to assess degree of silencing for selected targets using oral administration of RNAi, including neural, gut, and housekeeping gene targets in addition to selected miRNAs (miRNa-8, reported in literature to be essential for mosquito reproduction). Evaluate possible modifications of sand fly larval medium by inoculation of autoclaved medium with bacteria and yeast as preliminary results suggest the modifications can eliminate the presence of nematodes and other entomopathogens that were problematic in 2015. Investigate development of sand fly larval phagostimulation/phagoinhibition assays to assist in improving larval medium preparation and formulation. Investigate potential development of isothermal PCR assays for field-based genetic testing of insects (resistance, epidemiology, etc.).
