Abstract

Rabbit hemorrhagic disease (RHD) is a contagious viral disease that threatens rabbit farms locally and globally. The disease causative agent is the 63-Rabbit_Haemorrhagic_Disease_Virus_Strains_Circulating_in_Rabbit_Population_RHD virus (RHDV) of the family Caliciviridae. The present study aimed to identify and characterize RHDV strains currently circulating in Upper Egypt provinces. A total of 20 suspected RHDV samples were collected from non-vaccinated rabbit flocks from January to December 2019 in Upper Egypt governorates (New Valley and Assuit), Egypt. The RHDV was confirmed through the hemagglutination test (HA) and reverse transcription-polymerase chain reaction (RT-PCR). Further characterization of selected 4 isolates was performed by nucleotide sequencing of a partial VP60 gene. All of 11 RHDV RT-PCR-positive samples were positive for HA activity against human RBCs type "O". Based on the nucleotide sequencing, the selected 4 isolates were clustered as RHDV-1 variant strains (G3-G5). The nucleotide sequence identities of the 4 isolates were 94.2-100 %, compared to available RHDV strains from GenBank. In conclusion, the presence of RHDV-1 variant strains was detected and confirmed that threatens the rabbit’s populations in New Valley and Assuit governorates.