Evaluation of a semi-automated in vitro feeding system for Dermacentor reticulatus and Ixodes ricinus adults

Abstract

The long feeding duration of ixodid ticks and need for regular blood changes turns the artificial feeding of ticks into a tedious process. To reduce the number of blood changes, a semi-automated system (SAS) for the artificial feeding of hard ticks was developed and evaluated. It consisted of a glass feeding reservoir that can accommodate six tick feeding chambers. A peristaltic pump was used to pump blood through the feeding reservoir, which was changed once daily. Groups of Dermacentor reticulatus and Ixodes ricinus adults were fed simultaneously in both the SAS and a conventional in vitro feeding system. In the conventional system, feeding chambers were hung inside a glass beaker filled with blood that was replaced twice daily. Dermacentor reticulatus adults fed in the SAS obtained significantly higher engorgement weights. Although engorgement rates between both systems were comparable, significantly more SAS-fed females laid fertile egg batches. The egg batch weight of SAS-fed females was also significantly higher. In contrast, the engorgement rate and fecundity of SAS-fed I. ricinus were significantly reduced in comparison to ticks fed in the conventional system. This reduction was likely to be caused by fungal infestation, which could spread between feeding chambers in the SAS. Although the SAS reduced the workload compared to the conventional feeding system and showed promising results for the in vitro feeding of D. reticulatus adults, measures to prevent fungal infestations in the SAS should be considered in future studies.

Artificial Feeding of All Consecutive Life Stages of Ixodes ricinus

“…Over 25 years ago, the completion of the life cycle of Amblyomma hebraeum in vitro was reported [ 27 ], which until now remained the only ixodid tick species for which this was done. Although Ixodes nymphs and adults have successfully been fed in vitro using silicone-based membranes [ 19 , 28 , 32 , 33 , 37 , 38 , 39 , 40 ], only prepared animal skin membranes have previously been used for the artificial feeding of I. ricinus larvae [ 41 ]. We here report on the feeding of all consecutive I. ricinus life stages using a modified ATFS and include a comparison to I. ricinus ticks fed on calves.…”

“…This finding was most apparent in F 0 adults and correspond to previous studies on Ixodes spp. [ 28 , 38 , 40 ]. Reports on feeding duration of in vitro fed ticks are quite heterogeneous, possibly due to differences in the ATFS, blood meal diets, season, tick fitness, as well as differences between tick species and their feeding behavior.…”

“…This long duration forms a major challenge in the artificial feeding process [ 26 ], as it, in combination with temperatures of approximately 37 °C, results in a higher risk of decay of the blood meal. This results in the need for regular blood changes, making the artificial feeding a laborious process, and the addition of antibiotics in the blood meal, which may affect the tick microbiome including nutritive symbionts [ 12 , 27 , 28 , 29 , 30 ]. In addition, hard ticks also have an intricate pre-feeding behavior [ 24 , 26 ], the mimicking of which in vitro can be complicated.…”

Metazoan Parasite Vaccines: Present Status and Future Prospects

“…A major limitation in tick vaccine development for livestock is access to pre-vaccination screening tools to identify promising antigens for large-scale production and evaluation in large animal models. In this regard, artificial feeding methods have been developed (Abel et al, 2016 ; Tajeri et al, 2016 ; Krull et al, 2017 ; Böhme et al, 2018 ), offering some promise as a pre-screening approach with ticks feeding on serum derived from vaccinated hosts (Lew-Tabor et al, 2014 ; Lew-Tabor and Valle, 2016 ).…”

Evaluating Transmission Paths for Three Different Bartonella spp. in Ixodes ricinus Ticks Using Artificial Feeding

“…In order to adhere to the 3R principle (reduce, replace, refine) for humane animal research, laboratory tick feeding methods based on artificial membrane feeding have been established and used to study tick biology and conduct experimental infections with tick-borne pathogens [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ].…”