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Ticks are blood-sucking ectoparasites and can transmit various pathogens of medical and veterinary relevance. The life cycle of ticks can be completed under laboratory conditions on experimental animals, but the artificial feeding of ticks has attracted increased interest as an alternative method. This study represents the first report on the successful in vitro feeding of all life stages of two-host tick species, Hyalomma scupense and Hyalomma excavatum, and the three-host tick Hyalomma dromedarii. The attachment and engorgement rates of adults were 84% (21/25) and 76% (19/25) for H. scupense females. For adult H. excavatum and H. dromedarii, 70% (21/30) and 34.4% (11/32) of the females attached and all attached females successfully fed to repletion. The oviposition rates of the artificially fed females were 36.4%, 57.1% and 63.1% for H. dromedarii, H. excavatum and H. scupense, respectively, with a reproductive efficiency index varying between 44.3 and 60.7%. For the larvae, the attachment and engorgement rates were 44.2% (313/708) and 42.8% (303/708) for H. dromedarii, 70.5% (129/183) and 56.8% (104/183) for H. excavatum and 92.6% (113/122) and 55.7% (68/122) for H. scupense. The attachment and engorgement rates for the nymphs were 90.2% (129/143) and 47.6% (68/143) for H. dromedarii, 66.7% (34/51) and 41.2% (21/51) for H. excavatum, and 44.1% (30/68) and 36.8% (25/68) for H. scupense. Molting rates of the immature stages varied between 71.3% (216/303) and 100% (68/68) for the larvae and between 61.9% (13/21) and 96% (24/25) for the nymphs. The successful in vitro feeding of all stages of the three Hyalomma species makes this method a valuable tool for tick research, with potential applications in studies on the pathogens transmitted by these tick species such as Theileria annulata. [ABSTRACT FROM AUTHOR]

The rearing of ticks is an important technique for studies aiming to elucidate the course and pathogenesis of tick-borne diseases (TBDs). TBDs caused by protozoans (Theileria, Babesia) and bacteria (Anaplasma/Ehrlichia) impose a serious constraint upon livestock health and production in tropical and sub-tropical regions where the distributions of host, pathogen, and vector overlap. This study focuses on Hyalomma marginatum, one of the most important Hyalomma species in the Mediterranean region, being a vector of the virus that causes Crimean-Congo haemorrhagic fever in humans, together with H. excavatum, a vector of Theileria annulata, an important protozoan of cattle. The adaptation of ticks to feeding on artificial membranes allows the creation of model systems that can be put to use examining the underlying mechanisms of pathogen transmission by ticks. Silicone membranes, in particular, offer researchers the flexibility to adjust membrane thickness and content during artificial feeding. The aim of the present study was to develop an artificial feeding technique using silicone-based membranes for all developmental stages of H. excavatum and H. marginatum ticks. Attachment rates after feeding on silicone membranes for females H. marginatum and H. excavatum were 8.33% (8/96) and 7.95% (7/88), respectively. The use of cow hair as a stimulant increased the attachment rate of H. marginatum adults in comparison to other stimulants. The engorgement of H. marginatum and H. excavatum females took 20.5 and 23 days with average weights of 307.85 and 260.64 mg, respectively. Although both tick species could complete egg-laying, and this was followed by hatching of larvae; their larvae and nymphs could not be fed artificially. Taken together, the results of the present study clearly indicate that silicone membranes are suitable for feeding of H. excavatum and H. marginatum adult ticks, supporting engorgement, laying of eggs, and hatching of the larvae. They thus represent a versatile tool for studying transmission mechanisms of tick-borne pathogens. Further studies are warranted to examine attachment and feeding behaviours in order to increase the success of artificial feeding of larvae and nymphal stages. [ABSTRACT FROM AUTHOR]