Cross-immunity studies using Kenyan stocks of Cowdria ruminantium

Abstract

Heart water or cowdriaosis, caused by the rickettsia organism Cowdria ruminantium, is a disease of major economic importance in sub-Saharan Africa (Ui1enberg 1983). The disease affects domestic and wild ruminants and is transmitted trans-stadially by ticks of the genus Amblyomma. The disease is controlled by control of vector ticks through use of acaricides, treatment of sick animals or by vaccination using an infection and treatment method. The first practical vaccination approach was investigated by Neitz and Alexander (1941) using Cowdria infected sheep blood. The infection and treatment method is used because animals that recover from clinical disease are usually resistant to homologous and in most cases to heterologous challenge (Uilenberg et al 1983). There are however, same shortcomings with this method.