Abstract
BACKGROUND: An in vitro artificial feeding technique for hard ticks is quite useful for studying the tick-pathogen interactions. Here, we report a novel semi-artificial feeding technique for the adult parthenogenetic tick, Haemaphysalis longicornis, using mouse skin membrane. FINDINGS: Skin with attached adult ticks was removed from the mouse body at 4 to 5 days post-infestation for the construction of the feeding system. This system supplied with rabbit blood was kept in >95% relative humidity at 30°C during the feeding, and ticks were fully engorged (artificially engorged, AE) within 12 to 48 h. For comparison, ticks were fed to engorgement solely on rabbit or mouse for 5 days as controls (naturally engorged on rabbit, NEr, or mouse, NEm). Blood digestion-related gene expression in the midgut and reproductive fitness were compared. Body weight, egg mass weight, egg conversion ratio, and hatchability of eggs did not show any significant differences. We analyzed transcription profiles of selected genes assayed by quantitative RT-PCR and revealed similar patterns of expression between NEr and AE but some differences between NEm and AE or NEm and NEr. CONCLUSIONS: Our results demonstrate that this semi-artificial feeding technique mimics natural feeding processes of ticks and can be utilized as a standardized method to inoculate pathogens, especially Babesia protozoa, into H. longicornis and possibly other tick species as well.