EGYPTIAN NON-HEMAGGLUTINATING ISOLATES OF RABBIT HEMORRHAGIC DISEASE VIRUS CAN CHANGE TO VARIABLE HA PROFILE

Dalia A.M. Abd El-Moaty1, Gabr F.El-Bagoury2, Seham A.R. El-Zeedy1, Owees G.A.Salman1

Abstract

Rabbit Hemorrhagic Disease Virus (RHDV) is highly contagious and fatal disease. Many researches about circulating RHDV isolates in the different Egyptian governorates showed the existence of HA negative as well as HA positive isolates. For the first time we report the presence of RHDV isolates with variable HA profile in Egypt as many HA negative isolates changed into positive after passage on susceptible rabbits that were confirmed by RT/PCR technique for the variable region (C-E) of VP60 gene. In conclusion, HAT is not reliable in diagnosis or typing of RHDV field isolates as there is no correlation between the HA activity and genetic typing of RHDV either classical or variant strains. However, for tracking the genetic evolution of Egyptian isolates, further investigations at molecular level will be needed depending on sequence and phylogenetic analysis of highly variable region of VP60 gene.

Key words

RHDV, HA properities, Rabbit, Egyptian isolates