Functional genomics of tick vectors challenged with the cattle parasite Babesia bigemina

Ticks are obligate hematophagous ectoparasites considered as vectors of animal diseases, having a huge economic impact in cattle industry. Babesia spp. are tick-borne pathogens that cause a disease called babesiosis in a wide range of animals and in humans. Control of tick infestations is mainly based on the use of acaricides, which have limited efficacy reducing tick infestations, mostly due to wrong usage, and is often accompanied by the selection of acaricide-resistant ticks, environmental contamination, and contamination of milk and meat products. Vaccines affecting both vector and pathogens constitute new control strategies for tick and tick-borne diseases and are, therefore, a good alternative to chemical control. In this chapter we describe the identification of Rhipicephalus (Boophilus) annulatus genes differentially expressed in response to infection with B. bigemina by using suppression-subtractive hybridization (SSH), which allows the identification of differentially expressed genes. The results of the SSH studies are validated by real-time reverse transcription (RT)-PCR. Functional analyses are conducted by RNAi on selected R. annulatus genes to determine their putative role in B. bigemina-tick interactions. Gathered data may be useful for the future development of improved vaccines and vaccination strategies to control babesiosis.