Artificial systems for ticks’ feeding and infection

Ticks are hematophagous arthropods of high public health importance, since they can transmit a high number of infectious agents to humans and animals. Rearing ticks in laboratory conditions is essential to investigate their biology and vector competence to develop new control strategies. However, the long time ask for the feeding and the requirement of animals to provide the blood meal pose a strict limit to these researches, due to the ethical problems concerning animal welfare, the expensive and time-consuming animal rearing procedures, and the biosafety concerns in the presence of tick-borne pathogens (TBPs), in particular in high biocontainment conditions. The use of devices to artificially feed arthropod vectors can importantly leverage progresses in ticks’ biology and in the characterization of TBPs-vector interaction. In the last decades, several devices have been developed. The first method used capillary tubes placed over the tick mouthparts. Next, membrane-based strategies, that are more effective in mimicking the host, were developed using both natural membranes (such as animal skin) or synthetic membranes (such as silicone membrane). However, membrane base methods require the use of specific stimuli promoting ticks attachments and feeding. Regarding artificial infection, in addition to the infected animal models used to feed ticks, some animal-free strategies have been proposed. The easy approach is based on the direct injection of pathogens into the body of the tick. An alternative and easy approach requires the immersion of the tick in a solution containing the pathogen that can be internalized thorough the mouthpart. Finally, the more physiologically way to infect ticks is based on the artificial blood meal using capillaries or membrane-based approaches. The major strengths and weakness of the different procedures will be discussed and a new method under development will be presented.