Cattle provide the main source of protein for the people living in Uganda, where its production stretches from northeast to southwest along what is known as the “Cattle Corridor”. However, as in other tropical and subtropical regions of the world, tick infestations significantly affect livestock health and production, negatively impacting the economy and welfare of Ugandan livestock keepers. On the other hand, to combat ticks and the diseases they transmit, it is common to use chemical acaricides, which pollute the environment and to which ticks are increasingly resistant. Consequently, vaccine research and biotechnological development is a priority in countries like Uganda.
Scientists from the Health and Biotechnology Research Group (SaBio) of the Hunting Resources Research Institute (IREC – CSIC, UCLM, JCCM), in collaboration with the National Livestock Resources Research Institute (NaLIRRI/NARO, Uganda) and the Basque Institute of Agricultural Research and Development (NEIKER), have developed the formulation of a vaccine that combines tick antigens with mycobacterial antigens.
Specifically, the Subolesina (SUB, also known as 4D8) is a tick antigen that has shown efficacy in vaccine formulations for the control of ectoparasite infestations and pathogen infection/transmission. For its part, recent research by the IREC SaBio Group in collaboration with NEIKER, the Veterinary Health Surveillance Center (VISAVET) of the Complutense University of Madrid and the University of Córdoba, among others, have shown that heat-inactivated mycobacteria (IV) they constitute a powerful activator of the non-specific so-called “trained immunity”.
Following some proof of concept, researchers conducted a controlled trial in Uganda using an oral formulation combining SUB with inactivated mycobacteria (SUB+IV) for the control of cattle tick infestations. The efficacy of the SUB+IV vaccine (E) on the tick life cycle was compared with IV and SUB alone and with unvaccinated controls. The efficacy for the control of infestations by different species of ticks was maximum for the SUB+IV combination (E > 95%). In addition, protection was also found using each of the products separately. Antibody titers and serum levels of biomarkers correlated with protection confirmed the findings and demonstrated the activation of multiple immune mechanisms.
The findings of this work as a whole support the application of oral vaccine formulations with SUB+IV for the control of ticks in cattle to improve animal health and reduce dependence on acaricides, and suggest the potential use of combined oral vaccines for the simultaneous control of different endemic diseases.
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