One hostile little creature is causing devastation to cattle farmers in all the major livestock-production provinces of South Africa. Dr Christine Maritz-Olivier of the Department of Genetics at the University of Pretoria (UP) is leading a group of postgraduate students who are achieving success with finding a solution to alleviate and hopefully eradicate the current problem of cattle ticks. Their work includes an advisory service offered to farmers on the selection of dipping agents to which resistance has not yet been established on their farms, as well as on vaccine development against the parasite. This combination has proved to be a powerful force in combating this parasite. This service not only benefits the farmer, but also enriches the group’s research data.

The cattle tick Rhipicephalus microplus was fairly absent across most of Africa in the past, but was introduced into South Africa with the importation of cattle. This parasitic pest is not only infesting previously unaffected areas, but is also displacing less aggressive endemic tick species throughout much of eastern and southern Africa. In addition, it transmits lethal diseases like redwater and gall sickness with direct implications for farmers’ livelihoods and an indirect influence on the South African economy. Effective control of this tick, as well as its transmitted diseases, is quite difficult owing to its rapid development of resistance to chemical dipping agents. Dr Maritz-Olivier notes that farmers often do not buy the most effective dipping chemicals, but rather opt for cheaper, less effective variants.

Dr Maritz-Olivier’s team does DNA analyses on sample ticks sent to the genetic laboratory at UP to scientifically determine the DNA sequences of resistant genes, which enables them to establish which dipping agents should not be used. By including additional DNA tests they are able to study the genetic diversity of this tick species, which also contributes to their vaccine development strategy in that they can shape their vaccine to be effective against the most prominent species that occur in Southern Africa. The vaccines already developed by the UP team have shown positive results, reducing the number of ticks on cattle by at least two thirds. The vaccines are currently being improved to also inhibit the bio-ability of tick eggs, implying that once hatched, offspring are not strong enough to re-infect cattle.

Countries across the world that depend largely on cattle, like most countries in Africa, are in great need of a solution to fight R. microplus, and this UP research team is leading the way. Their research is the first to develop new genetic markers that look specifically at the genetic diversity of the species. This is valuable to international research, as the number of strains of this species remains unknown. The team, in collaboration with the global animal health company Zoetis, has patented an acaricide diagnostic test and is rolling it out to consumers.

It is encouraging to see departments across UP faculties working together in research in pursuit of better, cross-boundary results. Dr Maritz-Olivier’s group has also joined forces with two departments of the Faculty of Veterinary Sciences to ensure that they reach their five-year goal to develop an entire pipeline established for veterinarian vaccine production to fight such devastating tick species and their associated tick-borne diseases. Through interdisciplinary research, a thorough understanding of the vector, its transmitted diseases and types of treatment is becoming a reality.