The next generation vaccine for East Coast fever (EFC), an important cattle disease was the discussion agenda in a 2.5 day workshop organized by the International Livestock Research Institute (ILRI), United States Department of Agriculture Agricultural-Research Service (USDA-ARS) and Global Alliance for Livestock Veterinary Medicines (GALVmed) on April 16-18. Stakeholders from Nairobi-ILRI, USA, UK, Belgium, Malawi and South Africa met at ILRI Nairobi to share research experiences, discuss interdisciplinary approaches and build linkages. In his opening remark, Baty Ndungu the director for research and development at GALVmed emphasized that the workshop objectives were to take stock of our current knowledge on ECF and to explore new research opportunities that could be harnessed to develop a modern day vaccine for the control of this killer disease.
ECF is an important cattle disease that occurs in 11 countries in Eastern and Southern Africa. The disease is caused by a protozoa, Theileria parva and puts millions of cattle at mortality risk in addition to causing production losses. Current control measures for the disease are: tick control with acaricides, treatment of sick animals and the live vaccine: Infection and treatment method (ITM).
In an attempt to fill in the various gaps that exist in ECF research and come up with a coordinated and linked research effort, workshop participants presented their findings and experiences on ECF research. Discussions were held on the ITM vaccine, which is the only commercial vaccine available for EFC and has been shown to provide good protection despite manufacturing and delivery limitations such as, a long batch production cycle, cold chain storage, large dose size per pack and cost. The participants went on to discuss anti-sporozoite based subunit vaccines like p67 that have been shown in some but not all field trials to offer protection against the disease, as well as other different aspects of ECF including a potential role for tick based vaccines. Progress made in understanding the molecular basis of the protective cellular immune response elicited by ITM was presented and the scientific challenge of routinely inducing a similar response by vaccination was debated. The latter is a technical challenge to the global human and veterinary vaccine development community.
Bringing together interested partners with a huge focus on learning from each other led to an increased understanding of ECF, mechanisms that contribute to immunity and assessment of past vaccine trials. There was agreement that ITM remains the gold standard and that it was important to continue working on improving this vaccine. In the medium to longer term there are good opportunities to work on anti-sporozoite based subunit vaccines and on T cell-mediated immunity, which targets the schizont stage. There was also agreement that it would be useful to standardize experimental approaches and reagents in order to compare results across different laboratories, to promote information and knowledge exchange while at the same time building capacity for younger scientists in this particular research field.