Location: Arthropod-borne Animal Diseases Research2012 Annual Report
1a. Objectives (from AD-416):
Arthropod vectored disease transmission is dependent on insects becoming infected by feeding on diseased hosts. The objective of this project is to test if mosquitoes and flies are more attracted to diseased animals than infected ones. If there is a quantifiable preference for diseased animals, the increased feeding may be associated with behavioral or physiological changes in the host.
1b. Approach (from AD-416):
The feeding preferences of the mosquitoes and flies will be quantified to determine if infected animals are preferentially fed upon. If this is found, then the odor volatiles from infected animals will be collected and compared to healthy animals. Differences in odor volatile profiles will be tested with electro-antennal detection (EAD) to determine the mosquito or flies attraction to the specific components of the odor profile.
3. Progress Report:
The goal of disease vector surveillance is to have the monitoring trap captures as close as possible to the vector population within the trapping environment. Therefore more efficient traps that sample a larger proportion of the population’s habitat should improve vector surveillance sensitivity and efficacy. This project on biting midge disease vector attractants was done in collaboration with Kansas State University researcher Tom Phillips and ARS scientists. The objective is to collect and analyze volatiles to identify compounds that elicit positive taxis. The three projects consist of: 1) Identifying possible attractive volatiles present in organically produced carbon dioxide from sugar, water and three types of fermenting yeasts (baker’s, wine, and that used for industrial ethanol production). Carbon dioxide and other volatiles were collected in Tedlar bags, concentrated before identification using gas chromatography-mass spectrometery (GC-MS). 2) Collecting sex-specific volatiles from 1 day old virgin male and female Culicoides placed glass aeration chambers for 24 hour periods using Poropak-Q adsorbent. Hexane was used to elute the compounds from the Poropak, which were then concentrated before injection on the GCMS to and identify potential pheromones. 3) Identifying attractive compounds on the cuticular surface. The fly bodies were washed with hexane to extract cuticular surface compounds. This wash was then analyzed using the GCMS to identify possible semiochemicals. All three projects are ongoing and the compounds are being identified for future behavioral studies using Y-tube olfactometers. The goal is to identify and patent a chemo-attractant that will improve disease vector monitoring in domestic and rural environments in the event of an outbreak of epizootic hemorrhagic disease virus, bluetongue, vesicular stomatitis virus or a Schmallenberg virus introduction to the United States.