Differential Expression of Immune Genes in the Rhipicephalus microplus Gut in Response to Theileria equi Infection.

is the only tick species known to serve as a biological vector of for horses and other equids in Brazil. The protozoan is one of the causal agents of equine piroplasmosis, a major threat in horse breeding systems. Vector competence is closely linked to the pathogens' ability to evade tick defense mechanisms. However, knowledge of tick immune response against infections by hemoparasites of the genus is scarce. In the present study, the expression of genes involved in immune signaling pathways of adults' guts when challenged with a high or low parasitic load of was evaluated. This research demonstrates divergences in the immune gene expression pattern linked to infection in since the Toll, IMD, and JNK signaling pathways were transcriptionally repressed in the guts of adult ticks infected with . Moreover, the results showed that different infectious doses of induce differential gene expression of key components of immune signaling cascades in gut, suggesting a link between the intensity of infection and the activation of tick immunity response. The present study adds knowledge to elucidate the gut immune signaling response of to infection. In addition, the generated data can serve as a basis for further investigations to develop strategies for controlling and preventing equine piroplasmosis.