Validation of ELISA for the detection of African horse sickness virus antigens and antibodies

Summary

The mortality rate in susceptible populations of horses during an epizootic of African horse sickness (AHS) may be in excess of 90%. Rapid and reliable assays are therefore essential for the confirmation of clinical diagnoses and to enable control strategies to be implemented without undue delay. One of the major objectives of a recent European Union funded project was the validation of newly developed diagnostic assays which are rapid, sensitive, highly reproducible and inexpensive, for the detection of African horse sickness virus (AHSV) antigens and antibodies. The Laboratorio de Sanidad y Produccion Animal (LSPA) in Algete, Spain was charged with the responsibility of co-ordinating and supplying samples of viruses and antisera to the participating laboratories in Spain, France and the United Kingdom. The panels comprised 76 antigen samples for assay by indirect sandwich ELISAs and 53 serum samples for antibody detection by either indirect or competitive ELISAs. Results generated by ELISA for each laboratory were analysed in LSPA in terms of their relative sensitivities and specificities. There was a good agreement between the ELISAs used for either antigen or antibody detection. The participating groups agreed that any field sample giving a doubtful result would always be retested by ELISA and an alternative assay.