Development of simulium blackfly trap for monitoring and control of onchecerciasis in Burkina Faso : mission report to Banfora, 02 to 09 June 2014

Development of Simulium blackfly trap for monitoring and control of onchocerciasis in Burkina Faso Mission Report to Banfora I. Introduction The project had shown substantial progress in developing a trap platform to replace human landing collections. A simple inexpensive trap platform, called the Esperanza Window Trap (EWT), which when baited with organically produced carbon dioxide and human scent (a dirry shirt or trousers) collects equivalent numbers of S. damnosum to those collected by a human collector. In 2013, the APOC team conducted behavioral Y-tube bioassays in Banfora, Burkina Faso with S.damnosum s.l. The results were enough informative, in term of repellence and attractive selection of compounds, there is still a need to test the mixture of the best performing compounds. Given the encouraging results achieved, it was recommended to deploy traps into countries, as it is expected to combine human bait capture and trapping system in the onchocerciasis transmission assessment planned this year. It is therefore necessary to have a critical mass of facilitators to allow an efficient transfer of traps. In addition to the trap deployment process, ongoing research work aiming at optimizing the performance of traps will be conducted in parallel. II. Objective of the mission The present field trip aims at carrying different experiments including Evaluation of blackflies response to sweat compounds: Ammonium bicarbonate in a Y-tube; Evaluation of blackflies response to the mixture of the best performing compounds; Training of the personnel of the laboratory on the deployment and monitoring of the traps. A field trip in Burkina Faso (R6gion des Cascades) is organized in collaboration with the Programme National de Lutte contre l'onchocercose (PNLO) of Burkina Faso. The mission will take place from June2 to 9,2014. III. Evaluation of blackllies response to sweat compounds: Ammonium bicarbonate in a Y-tube Objective: to determine the activity of S.damnosum flies exposed to Ammonium bicarbonate in Y-Tube. A total of 1250 black flies - Simulium damnosum s.l - were collected in Bodajugu during 5 days by fly collectors, and sent to our local field laboratory in the regional hospital at Banfora. The experimentations were performed within 24 hours after collection. Behavioral bioassays were conducted in a Y-tube olfactometer following the same protocol used for the first experiments. Each testing group use twenty host seeking flies. The tests were conducted using 0.1 % and l0Z ammonium bicarbonate. Four duplicates were run for each concentration. During the experimentation, the attraction response was measured for each test run replicate and the values inserted in an excel datasheet. Laurent TOE : 02 to 09 June 2014 The data obtained was sent to Pr Unnasch for analysis (See Annex). The preliminary analysis is showing a satisfactory result when using the loh ammonium bicarbonate. IV.Evaluation of blackflies response to the mixture of the best performing compounds IV. a Purpose: To test attractiveness of selected combinations of chemical compounds to host seeking S. damnosum females utilizing our own delivery methods. In this trial chemicals found attractive to S. damnosumwere incorporated into the lure and perform paired evaluations, until the most effective lure is found. The lures are compared on the EWT to Human Vector Collector. IV.b Detailed methods: Both sides of the EWT are coated with Tanglefoot adhesive, replenished every three days (or after heavy rains). Black flies were recovered from the traps once daily (between 1l-12 AM). Six EWT were used in total, all of which will utilize yeast-generated CO2. The 6 EWT were divided into 2 lots for the field trials. One lot of traps were placed at Bodajugu Peulh along, Como6 River. The second lot was place at Bodajugu Barridre. Each trap position was 15-25 m apart Two EW-traps plus organic CO2 were baited with the "home-made lure" and run for six days (June 3 to June 8,2014) on the catching points of Bodajugu Peulh and Barridre. The vector collector team was working in this experiment at a similar distance. The EWtraps were run from I PM until 1 PM (24 hours of collection) of the following day over a total of 6 days. Collections were retrieved once daily. Tangle foot was removed from flies caught in the traps using odorless mineral spirit. IV.c Results 600 1"' ,oo I ''. ooo ".1' . 300 200 100 0 I Seriel "_*- __ I BW BlcLr/Noir r co2 BW Blcu/Noir t CO2 +Test Lure I P.rrrtalon BW Bleu/Noir t CO2 rllL Figure 1: Catches of S. damnosum exposed to different type of lures In the present conditions at Bodajugu, the Espranza window trap baited With Human lure was more attractive than tha EW baited with the "damnosum lure". We recommend that this experiment be repeated during a longer time to confirm this result. 450 400 350 300 250 200 150 100 50 0 I BodJjugLr Barridrc I Bod"tjug,u Pcr,rlh .*"--"-""*--*"f^""--r""*-""r-"e Figure 2 z S. damnosum collection by vector collectors during the study p6riod at bodajugu Peulh and barri6re Conditions of work at Bodajugu barridre and peulh were different. The Number of flies collected by the human landing collectors were different More flies were collected at Bodajugu peulh even when weather condition turned to rains. V. Training of the personnel of the laboratory on the deployment and monitoring of the traps. The personnel of laboratory extensively learned the following: - Factors of attractiveness among the blackflies (visual and olfactory stimuli) - Preparation of odorous compounds based on chemical and organic inputs - The assembling and disassembly of EWT - The positioning of the EWT on a collection site of blackflies, depending on the distance breeding site, the river flow direction and the location of voluntary catchers - Harvesting and sorting of insects on the trap - Sensitization and training of community stakeholders in the management of EWT. VI.Conclusion a. The tests of attractiveness of ammonium bicarbonate on S.damnosum have given satisfactory results. Other concentrations should be tested. b. The field test of "damnosum lures" should be continued during a longer time. c. The personnel of laboratory were trained to the use of the Esperanza window trap. They are now ready to conduct the deployment of the trap in the endemic countries.