Indirect ELISA for analysis of malignant catarrhal fever virus-specific antibodies in a range of species.

The culture-attenuated alcelaphine herpesvirus 1 (AlHV-1) C500 strain can be grown to high titre and has been used successfully as a candidate vaccine for wildebeest-associated malignant catarrhal fever (MCF). This vaccine virus was also used to develop an indirect ELISA to allow monitoring of virus-specific antibodies in vaccinated cattle. However the extraction method was expensive and time-consuming, and the resulting test was not suitable for use in sheep. Here we describe an improved antigen extraction method that also broadens the application of the assay, allowing its application to sheep samples. The updated assay was tested using control samples from cattle and sheep, and showed a high level of accuracy in both species. This novel assay should prove to be a useful tool in MCF diagnosis and in evaluation of MCF vaccine responses.