Culicoides arakawae (Diptera: Ceratopogonidae) efficiently blood-fed and infected with Leucocytozoon caulleryi through a natural membrane

Culicoides arakawae, the most common Culicoides sp. on chicken farms in East Asia, is an important blood-sucking insect and Leucocytozoon caulleryi vector. How parasites, in an ingested blood bolus, enter the midgut of insects and deal with this complex and biochemically hostile environment is poorly understood. However, successful blood-feeding through a membrane in C. arakawae is beneficial for studying this phenomenon. Therefore, a membrane-feeding method for C. arakawae was developed in. The blood-feeding success rates of C. arakawae fed through five different membranes were: turkey egg at 43.7+/-11.7%, chicken egg at 45.2+/-12.1%, duck egg at 38.8+/-12.0%, pig gut at 0% and chick skin at 0%. In fertility measurements, the average number of eggs produced for C. arakawae fed through egg-shell membrane, at 77.7+/-15.1 per female, was significantly higher (P<0.01) than the 46.7+/-10.6 found in C. arakawae fed on the breast skin of a live chicken. Meanwhile, in parasite infectivity tests, C. arakawae could be infected by L. caulleryi when the vector was blood-fed with infective blood cells reconstituted with specific pathogen-free (SPF) sera through an egg-shell membrane. The sporozoite average and infection rates of inoculated chicks were 166.8+/-12.5 and 100%, respectively. In conclusion, feeding C. arakawae blood through fowl-egg-shell membranes should be an efficient method for in vitro infection of midges as the engorged midges are infected by parasites and display reproductive potential. Furthermore, the method is practical for feeding a large number of midges.