Identification and molecular characterization of 18 paramyxoviruses isolated from snakes

Viral agents from 18 different snake species (families Colubridae., Viperid ae, and Crotalidae) showing respiratory symptoms and neuronal disease were identified as paramyxoviruses by typical cytopathogenic effect (CPE), elect ron microscopy. and hemagglutination inhibition. Detailed molecular charact erization of the viruses was performed by partial L- and F-gene-specific re verse transcription polymerase chain reaction (RT-PCR) and sequencing, nucl eotide and amino acid sequence alignment, and phylogenetic analysis (PHYLIP ). RT-PCR of the partial L-gene (566 nt) was successful for all 18 viruses, amplicons of the partial F-gene (918 nt) could be obtained in 16 cases. F- and L-sequence alignment revealed similarities to Fer de Lance virus (FDLV ) ranging from 79 to 88% on a nucleotide basis, and 94 to 99% on an amino a cid basis. Phylogenetic analysis of the ophidian paramyxoviruses resulted i n three clusters for the L-gene sequence and corresponding clusters for the F-gene sequence, indicating no species specificity, We analyzed the F-prot ein of the snake paramyxoviruses. which proved to have an identical conserv ed motif of heptad repeat A and predicted a furin cleavage site. This unifo rmity distinguishes the snake virus group from the other type species of th e subfamily Paramyxovirinae. For further classification., we aligned the se quences of the ophidian paramyxoviruses and members of the Paramyxoviridae, such as Sendai virus (genus Respirovirus), mumps virus (genus Rubulavirus) , measles virus (genus Morbillivirus), human respiratory syncytial virus (g enus Pneumovirus) (Van Regenmortel and 10 co-authors, 2000) and Hendra viru s. which have recently been suggested as type species of the genus Henipavi rus (Wang et al., 2000). Maximum sequence similarity was found to the parti al L-gene of Sendai virus, with 56% nucleotide and 61% amino acid identity. The FDLV and Sendai virus cluster in the phylogenetic analysis Of L- and F -protein regarding the Paramyxovirus type species and Hendra virus and show the closest relationship. Regarding the biological properties, the antigen ic distance. and particularly the low homology of available sequences, we p ropose a new genus for the reptilian paramyxoviruses within the Paramyxovir idae. (C) 2001 Elsevier Science B.V. All rights reserved.