Tick vaccine
Tick vaccine - Beef CRC - Beef Genetic Technologies
 The Beef CRC will identify several vaccine candidates which can be used by a commercial company to develop a suitable tick vaccine to protect cattle in northern Australia with at least 90 per cent efficacy based on an annual booster vaccination. Why does industry want a tick vaccine? A vaccine against ticks is considered a high priority for industry. It will reduce losses, increase productivity and reduce the chemical residues in cattle. Complete genetic resistance to tick infestation is unlikely to be achieved. Therefore sustainable tick control will most likely involve a combination of genetic and non-genetic interventions. It is estimated the beef industry in Australia incurs losses of approximately $175 million each year due to the impact of ticks and tick-borne diseases and the costs of treatment to ensure compliance with regulatory protocols for stock movement. These costs and the growing concern about the use of chemicals on food safety and the environment are why the cattle industry and governments worldwide have identified the development of a tick vaccine with 12 months immunity duration and 90 per cent efficacy as a high priority. |
| How will industry benefit from a tick vaccine? |
| The current tick vaccine TickGARD®Plus is based on a concealed tick gut antigen but is not effective against all stages of the ticks’ life cycle. It also appears to have hugely variable effects in different geographical locations. As this vaccine is poorly immunogenic and initially required two injections and an annual booster, it was not widely adopted. Based on the assumption of a 75 per cent adoption rate within 5 to 10 years, the economic benefit is estimated to be a total of $32.5m. In the medium to long term (10-15 years) the economic benefit is estimated to be a total of $50m. Several commercial companies have already expressed interest in developing, testing and marketing the new vaccine in Australia and the rest of the world. |
| Progress |
| An ideal vaccine would incorporate the concealed antigen approach while inducing an anamnestic or ‘remembered’ response following natural infestations thus eliminating the need for repeat vaccination. Molecules released during tick attachment and feeding stimulate innate and acquired immune responses. The ability of the host to respond to these molecules results in different levels of resistance. Researchers are using a ‘reverse vaccinolgy’ approach in which computer software screens newly available tick (Rhipicephalus (Boophilus) microplus) genome sequence data (13,643 genes) to identify tick vaccine candidates which are then evaluated in laboratory models and cattle trials. Currently, out of ~200 candidates, the team is selecting 80 for laboratory screening. The team have also undertaken tick immunity cattle trials which have provided the reagents for screening vaccine candidates in the laboratory (cells, sera). Once vaccine candidates are identified, they will be passed on to a pharmaceutical company for development of a commercial vaccine. Development, registration and proof of efficacy of the vaccine will likely take a further 8-10 years to progress through the various registration processes. |
