Optimization of the Feeding rate of Anopheles Farauti Colony Mosquitoes in Direct Membrane Feeding Assays
Background: Direct membrane feeding assays (DMFA) are an important tool to study parasite transmission to mosquitoes. Mosquito feeding rates in these artificial systems require optimization as there are a number of factors that potentially influence the feeding rates and there are no standardized methods that apply to all Anopheline species.Methods: A range of parameters prior to and during direct membrane feeding (DMF) were evaluated for their impact on Anopheles farauti feeding rates;
... ding rates; including the starving conditions and duration of starving prior to feeding, membrane type, DMF exposure time, mosquito age, illumination level, blood volume, mosquito density and temperature of water bath. Results: The average successful DMFA feeding rate for An. farauti colony mosquitoes increased from 50 % to 85 % when assay parameters were varied. Overnight starvation and Baudruche membrane yielded the highest feeding rates but rates were also affected by blood volume in the feeder and the mosquito density in the feeding cups. Availability of water during the pre-feed starvation period did not significantly impact feeding rates, nor did the exposure duration to blood in membrane feeders nor, the age of mosquitoes (3, 5 and 7 days post-emergence), illumination during feeding or the temperature (34 °C, 38 °C, 42 °C and 46 °C) of the water bath.Conclusion: Optimal feeding conditions in An. farauti DMFA were to offer 50 female mosquitoes in a cup (with a total surface area of ~340 cm2 with 1 mosquito / 6.8 cm2) that were starved overnight 350-500 µL of blood (collected in heparin coated vacutainers) per feeder in feeders with a surface area ~5 cm2 (with a maximum capacity of 1.5 mL of blood) via a Baudruche membrane, for at least 10-20 min.