Ticks are obligate blood feeders. All active stages require blood as a source and, in the case of adults, for sperm or egg production. Because of the mechanical processes and salivary secretions associated with blood feeding, the tick-host parasitic interaction is complex.

Some tick species only feed on specific hosts, these are called host-specific ticks like the cattle tick Boophilus microplus, a one host tick. They are specialists.

The second category are the opportunistic ticks, which are considered as generalists. For example, Amblyomma americanum attacks mammals, birds and reptiles¹.Furthermore Ixodes ricinus is known to have a wide host-spectrum. This forms the reservoir for tick-borne diseases, including the risk to transmit new pathogens to a host, that hasn't been reported before. The most relevant ticks for companion animals are three-host-ticks. The prevalence of ticks with tick-transmitted pathogens and the prevalence of reservoir-animals increases the risk of companion animal to become infected².

Contact between ticks and hosts is regulated by at least 5 conditions at least. They consist of seasonal and daily effects (abiotic parameters) like daylength, temperature, humidity. The rest includes biotic parameters as biological processes in the tick, the biological processes in the host and interactions between these two groups³.