Compositions and methods for preventing hematophagous infestation of
cattle are provided, directed at isolated proteins with antithrombin activity and
nucleotide sequences encoding the proteins. The protein named thrombostasin is
isolated from the salivary glands of Haematobia irritans. The compositions
are useful as veterinary vaccines in prevention of blood-feeding in cattle by the
infesting horn fly. The proteins of the invention are also useful in treatment
of thrombosis.
