ABSTRACT
The genome and structural organization of a novel insect-specific orthomyxovirus, designated Sinu virus, is described. Sinu virus (SINUV) was isolated in cultures of C6/36 cells from a pool of mosquitoes collected in northwestern Colombia. The virus has six negative-sense ssRNA segments. Genetic analysis of each segment demonstrated the presence of six distinct ORFs encoding the following genes: PB2 (Segment 1), PB1, (Segment 2), PA protein (Segment 3), envelope GP gene (Segment 4), the NP (Segment 5), and M-like gene (Segment 6). Phylogenetically, SINUV appears to be most closed related to viruses in the genus Thogotovirus.
Subject(s)
Culicidae/virology , Evolution, Molecular , Orthomyxoviridae/isolation & purification , Amino Acid Sequence , Animals , Colombia , Genome, Viral , Models, Molecular , Molecular Sequence Data , Orthomyxoviridae/chemistry , Orthomyxoviridae/classification , Orthomyxoviridae/genetics , Phylogeny , Thogotovirus/chemistry , Thogotovirus/classification , Thogotovirus/genetics , Thogotovirus/isolation & purification , Viral Proteins/chemistry , Viral Proteins/genetics , Viral Proteins/metabolismABSTRACT
UNLABELLED: Tilapia are an important global food source due to their omnivorous diet, tolerance for high-density aquaculture, and relative disease resistance. Since 2009, tilapia aquaculture has been threatened by mass die-offs in farmed fish in Israel and Ecuador. Here we report evidence implicating a novel orthomyxo-like virus in these outbreaks. The tilapia lake virus (TiLV) has a 10-segment, negative-sense RNA genome. The largest segment, segment 1, contains an open reading frame with weak sequence homology to the influenza C virus PB1 subunit. The other nine segments showed no homology to other viruses but have conserved, complementary sequences at their 5' and 3' termini, consistent with the genome organization found in other orthomyxoviruses. In situ hybridization indicates TiLV replication and transcription at sites of pathology in the liver and central nervous system of tilapia with disease. IMPORTANCE: The economic impact of worldwide trade in tilapia is estimated at $7.5 billion U.S. dollars (USD) annually. The infectious agent implicated in mass tilapia die-offs in two continents poses a threat to the global tilapia industry, which not only provides inexpensive dietary protein but also is a major employer in the developing world. Here we report characterization of the causative agent as a novel orthomyxo-like virus, tilapia lake virus (TiLV). We also describe complete genomic and protein sequences that will facilitate TiLV detection and containment and enable vaccine development.
Subject(s)
Fish Diseases/mortality , Fish Diseases/virology , Orthomyxoviridae Infections/veterinary , Orthomyxoviridae/isolation & purification , Tilapia/virology , Amino Acid Sequence , Animals , Ecuador/epidemiology , Fish Diseases/epidemiology , Israel/epidemiology , Open Reading Frames , Orthomyxoviridae/chemistry , Orthomyxoviridae/classification , Orthomyxoviridae/genetics , Orthomyxoviridae Infections/epidemiology , Orthomyxoviridae Infections/mortality , Orthomyxoviridae Infections/virology , Sequence Alignment , Viral Proteins/chemistry , Viral Proteins/geneticsABSTRACT
We described here the complete nucleotide sequence of the L RNA segment of Oropouche virus (genus Orthobunyavirus, family Bunyaviridae). We found the L RNA segment is 6846 nucleotides long and encodes a putative RNA polymerase of 2250 amino acids. Phylogenetic analysis showed that ORO virus cluster to the Orthobunyavirus genus confirming the serological classification. It also showed that Bunyamwera and California viruses, from the Orthobunyavirus genus, are more closely related to each other than to ORO virus. Sequence comparisons performed between the L proteins of 15 bunyaviruses and the PB1 proteins of 3 influenza viruses revealed that ORO L protein contains the 3 regions characteristic of arenaviruses and bunyaviruses. These comparisons also showed the existence of an additional fourth conserved region in the L protein of bunyaviruses that contains at least two active sites.