Increased pathogenicity of an Ehrlichia-like agent after passage through Amblyomma hebraeum: a preliminary report.

: After being passaged through 3 generations of Amblyomma hebraeum, an Ehrlichia-like agent isolated from an adult Hyalomma truncatum female became more pathogenic and elicited a disease in sheep indistinguishable from heartwater. Cross-immunity between this agent and several stocks of Cowdria ruminantium and high levels of antibody elicited by the agent against 2 stocks of C. ruminantium in the indirect fluorescent antibody test, confirmed its close relationship to Cowdria.

[1]  J. Olivier,et al.  The heterogenicity of Cowdria ruminantium stocks: cross-immunity and serology in sheep and pathogenicity to mice. , 1989, The Onderstepoort journal of veterinary research.

[2]  E. Camus,et al.  Heartwater serology: some problems with the interpretation of results. , 1987, The Onderstepoort journal of veterinary research.

[3]  J. Bezuidenhout.  The present state of Cowdria ruminantium cultivation in cell lines. , 1987, Onderstepoort Journal of Veterinary Research.

[4]  Jane B. Walker,et al.  The tick vectors of Cowdria ruminantium (Ixodoidea, Ixodidae, genus Amblyomma) and their distribution. , 1987, The Onderstepoort journal of veterinary research.

[5]  N. Mchardy,et al.  Cowdria ruminantium infection in the mouse: a review. , 1987, The Onderstepoort journal of veterinary research.

[6]  J. D. du Plessis,et al.  The application of the indirect fluorescent antibody test in research on heartwater. , 1987, The Onderstepoort journal of veterinary research.

[7]  H. Heyne,et al.  Rearing and infection techniques for Amblyomma species to be used in heartwater transmission experiments. , 1987, The Onderstepoort journal of veterinary research.

[8]  J. D. du Plessis,et al.  The block method of vaccination against heartwater. , 1987, The Onderstepoort journal of veterinary research.

[9]  C. Mebus,et al.  Cross-immunity between isolates of Cowdria ruminantium , 1987 .

[10]  J. Plessis.  A METHOD FOR DETERMINING THE COWDRIA RUMINANTIUM INFECTION RATE OF AMBLYOMMA HEBRAEUM: EFFECTS IN MICE INJECTED WITH TICK HOMOGENATES , 1985 .