Ayaconin, a novel inhibitor of the plasma contact system from the sand fly Lutzomyia ayacuchensis, a vector of Andean-type cutaneous leishmaniasis

•The second most abundant protein in Lutzomyia ayacuchensis saliva, designated ayaconin, was characterized.•Ayaconin inhibited the intrinsic blood coagulation pathway, targeting activation of FXII.•Binding of ayaconin to FXII was suggested to be involved in the inhibitory mechanism.•Ayaconin is considered to play an important role in blood feeding.