High impact and effectiveness of Gavac™ vaccine in the national program for control of bovine ticks Rhipicephalus microplus in Venezuela

Abstract The 80% of the world's cattle population (approximately 1281 million), 80% are at risk for ticks and tick-borne diseases. Over a decade ago, the estimated global costs of control measures and productivity losses amounted to $7.0 billion USD annually (7 USD/head/years). Tick control in livestock remains, to a large extent, based on chemical acaricides, but their use in combination with anti-tick vaccines and utilization of host resistance to ticks should reduce dependency on chemical tick control. Currently the only effective vaccine in the market to control tick populations is Gavac™. The immunogen Bm86 used to produce Gavac™ had already been tested in controlled experiments and field trials demonstrating its effectiveness. In this study Gavac™ vaccine was used for the first time in a national program, namely the integrated program for bovine tick control, which included more than 1.9 million bovines, spread over 18 states of the Republic of Venezuela. After two years of implementation of the program, 38835 cattle farms were included, and 83.7% of chemical acaricide were reduced. The program had a major impact, saving 81.5% of the estimated cost of the traditional chemical tick control treatments. A reduction of more than 260 t of chemical acaricides was attained. These results strongly support the use of vaccine for tick control in integrated control programs.