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Testing heartwater vaccine n Friesian cattle


Testing heartwater vaccine in Friesian cattle


Testing of various formulations of an attenuated heartwater vaccine in Friesian cattle. Test heartwater attenuated Welgevonden stock vaccine in cattle


Industry Sector: Cattle and Small Stock

Research focus area: Animal Health and Welfare

Research Institute: ARC-Animal Production Institute Northern Cape Department of Agriculture, Land Reform and Rural Development and University of the Free State
 
Researcher: Dr Helena Steyn D Tech

Research Team: Ms A.I. Josemans Nat. Dipl. Vet. Tech, Dr E. Zweygarth PhD, Dr A. Latif PhD, Mr C. Troskie Nat. Dipl. Vet. Tech.


Final report approved: 26 February 2013


Aims of the project

  • To formulate an effective attenuated heartwater vaccine for cattle witch is easy to administer
  • To determine the optimum dose and route of attenuated Welgevonden vaccine in Holstein cattle
  • To determine duration of immunity
  • To field challenge the immunized cattle in a heartwater endemic region

Executive Summary


Ehrlichia ruminantium is the causative agent of heartwater and it is transmitted to ruminants by the Amblyomma hebraeum tick. An experimental cell-derived attenuated E. ruminantium (Welgevonden) vaccine was developed at ARC-OVI. This attenuated Welgevonden does not cause heartwater in sheep and goats but induces complete protection when administered either intravenously (IV) or intramuscularly (IM) (subcutaneous route was less effective) against a lethal needle challenge dose with the homologous stock. Previously a preliminary experiment indicated that when the attenuated Welgevonden vaccine was tested in Friesian cattle with the IV route only one animal required treatment after challenge with the Gardel stock. Further optimisation of the attenuated vaccine regarding dose, route and challenge was thus required for use in cattle.

This project showed that a dose of 1x10e6 CFU/2ml of the attenuated vaccine via the IM route can induced 100 % protection when administered to cattle (n=5) challenged with ten ticks infected with the Welgevonden strain. Accurate, reproducible and immediate determination of the attenuated vaccine dose after thawing and before administration is however required before this vaccine can be taken to the next level.

 


Please contact the Primary Researcher if you need a copy of the comprehensive report of this project –
Helena Steyn on steynh@arc.agric.za