Vaccination against Rhipicephalus microplus: an alternative to chemical control?

Abstract

Rhipicephalus (Boophilus) microplus is a hard tick endemic in livestock-growing regions and causes economic losses in the largest beef-producing countries, including Brazil, Mexico, Argentina, Australia and Uruguay. The use of chemical acaricides is still the main strategy to control R. microplus infestations. Nevertheless, immunological control of R. microplus with an anti-tick vaccine is a suitable alternative and has manifold advantages because it can avoid drug-resistance and the presence of acaricide residues in milk, beef and in the environment. Indeed, vaccines based on the Bm86 antigen have had relative commercial and technical success to control R. microplus in some regions. Although, the efficacy of such vaccines varies among tick populations and is insufficient to provide an acceptable level of protection. Therefore, the need to search for better antigens is impelling. This review focused on the restrictions imposed on the use of acaricides in Brazil and in the European Union, as well as on the impacts of Bm86-based vaccines on R. microplus control. The efficacy of experimental anti-tick vaccines (based on subolesin, glutathione S-transferase, ferritin 2; voltage-dependent anion channel; aquaporin, 60 S acidic ribosomal protein, metalloprotease and trypsin) that can elicit an immune response against the physiological functions of various ticks is discussed.