Structural Characterization of Open Reading Frame-Encoded Functional Genes from Tilapia Lake Virus (TiLV)

Acharya, Varsha; Chakraborty, Hirak Jyoti; Rout, Ajaya Kumar; Balabantaray, Sucharita; Behera, Bijay Kumar; Das, Basanta Kumar

doi:10.1007/s12033-019-00217-y

Cited by 37 publications

(27 citation statements)

References 51 publications

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“…Although the structure of TiLV genome contains conserved complementary sequences at the 5’ and 3’ termini which is a typical genomic organization found in other orthomyxoviruses, most of the segments have no homology to any other known viruses, except segment 1 which shares a weak sequence homology to the RNA‐dependent RNA polymerase (RdRp) subunit of PB1 of influenza C virus (Bacharach et al., 2016). Recent research discovered that there are 14 functional genes responsible for the production of 14 viral proteins from these 10 TiLV gene segments (Acharya et al, 2019). Initially, due to TiLV being a negative‐sense, single‐stranded RNA virus with various genomic structures like other orthomyxoviruses, it was touted as being an “orthomyxo‐like virus.” However, based on sequence analysis, TiLV has been assigned as a new species, Tilapia tilapinevirus , under genus Tilapinevirus and family Amnoonviridae (Adams et al., 2017).…”

Section: Tilv Characteristicsmentioning

confidence: 99%

Tilapia lake virus: The story so far

Surachetpong

Roy

Nicholson

2020

Journal of Fish Diseases

107

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Tilapia lake virus (TiLV) is a highly contagious pathogen that has detrimental effects on tilapia farming. This virus was discovered in 2014 and has received tremendous global attention from the aquaculture sector due to its association with high fish mortalities and its strong economic impact on the tilapia aquaculture industry. Currently, TiLV has been reported in 16 countries, and this number is continuing to rise due to improved diagnostic assays and surveillance activities around the world. In this review, we summarize the up-to-date knowledge of TiLV with regard to TiLV host species, the clinical signs of a TiLV infection, the affected tissues, pathogenesis and potential disease risk factors. We also describe the reported information concerning the virus itself: its morphology, genetic make-up and transmission pathways. We review the current methods for virus detection and potential control measures. We close the review of the TiLV story so far, by offering a commentary on the major TiLV research gaps, why these are delaying future TiLV research and why the TiLV field needs to come together and proceed as a more collaborative scientific community if there is any hope limiting the impact of this serious virus.

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Section: Tilv Characteristicsmentioning

confidence: 99%

Tilapia lake virus: The story so far

Surachetpong

Roy

Nicholson

2020

Journal of Fish Diseases

107

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“…Segment 1 encodes a protein with weak homology to the influenza C polymerase PB1 subunit [7], and so is thought to encode the TiLV RNA polymerase, responsible for viral replication and transcription. Although in silico analysis predicted fourteen TiLV proteins in total, six of which have transmembrane helix regions [8], the proteins encoded by segments 2-10 have no relatives in reference databases, and so their functions are unknown [7].…”

Section: (A)mentioning

confidence: 99%

“…As early as 2009, huge losses of cultured tilapia were reported in Israel, and the causative agent, tilapia lake virus (TiLV), was formally identified in 2014 [6]. TiLV is an enveloped virus with a 10 segment, negative-sense RNA genome [7] encoding 14 predicted proteins [8], initially proposed to belong to the family Orthomyxoviridae due to similarities in the structure of its segment termini [7], but subsequently placed in a new family, Amnoonviridae, in the same order as the Orthomyxoviridae (Articulavirales) [9]. It appears to infect tilapia at all growth stages, including fertilised eggs, egg yolk larvae, fry and fingerlings [10].…”

Section: Introductionmentioning

confidence: 99%

The Segment Matters: Probable Reassortment of Tilapia Lake Virus (TiLV) Complicates Phylogenetic Analysis and Inference of Geographical Origin of New Isolate from Bangladesh

Chaput

Bass

Alam

et al. 2020

Viruses

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Tilapia lake virus (TiLV), a negative sense RNA virus with a 10 segment genome, is an emerging threat to tilapia aquaculture worldwide, with outbreaks causing over 90% mortality reported on several continents since 2014. Following a severe tilapia mortality event in July 2017, we confirmed the presence of TiLV in Bangladesh and obtained the near-complete genome of this isolate, BD-2017. Phylogenetic analysis of the concatenated 10 segment coding regions placed BD-2017 in a clade with the two isolates from Thailand, separate from the Israeli and South American isolates. However, phylogenetic analysis of individual segments gave conflicting results, sometimes clustering BD-2017 with one of the Israeli isolates, and splitting pairs of isolates from the same region. By comparing patterns of topological difference among segments of quartets of isolates, we showed that TiLV likely has a history of reassortment. Segments 5 and 6, in particular, appear to have undergone a relatively recent reassortment event involving Ecuador isolate EC-2012 and Israel isolate Til-4-2011. The phylogeny of TiLV isolates therefore depends on the segment sequenced. Our findings illustrate the need to exercise caution when using phylogenetic analysis to infer geographic origin and track the movement of TiLV, and we recommend using whole genomes wherever possible.

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“…Tilapia lake virus is a negative sense, segmented, single-stranded RNA virus. The virus has a diameter ranging from 55 – 90 nm, containing 10 genome segments with predicted 14 encoded proteins (Acharya et al, 2019; Bacharach et al, 2016a; del-Pozo et al, 2017; Eyngor et al, 2014). It has been demonstrated that TiLV can be horizontally transmitted from fish to fish through cohabitant studies (Eyngor et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Efficacy of heat-killed and formalin-killed vaccines againstTilapia tilapinevirusin juvenile Nile tilapia (Oreochromis niloticus)

Mai

Kayansamruaj

Taengphu

et al. 2021

Preprint

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Tilapia tilapinevirus (also known as tilapia lake virus, TiLV) is considered to be a new threat to the global tilapia industry. The objective of this study was to develop simple cell culture-based heat-killed (HKV) and formalin-killed (FKV) vaccines for the prevention of disease caused by TiLV. The fish were immunized with 100 μL of either HKV or FKV by intraperitoneal injection with each vaccine containing 1.8 × 106 TCID50 inactivated virus. A booster vaccination was carried out at 21-day post vaccination (dpv) using the same protocol. The fish were then challenged with a lethal dose of TiLV at 28 dpv. The expression of five immune genes (IgM, IgD, IgT, CD4 and CD8) in the head kidney and spleen of experimental fish was assessed at 14 and 21 dpv and again after the booster vaccination at 28 dpv. TiLV-specific IgM responses were measured by ELISA at the same time points. The results showed that both vaccines conferred significant protection, with relative percentage survival (RPS) of 71.3% and 79.6% for HKV and FKV, respectively. Significant up-regulation of IgM and IgT was observed in the head kidney of fish vaccinated with HKV at 21 dpv, while IgM, IgD and CD4 expression increased in the head kidney of fish receiving FKV at the same time point. After booster vaccination, IgT and CD8 transcripts were significantly increased in the spleen of fish vaccinated with the HKV, but not with FKV. Both vaccines induced a specific IgM response in both serum and mucus. In summary, this study showed that both HKV and FKV are promising injectable vaccines for the prevention of disease caused by TiLV in Nile tilapia.

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Structural Characterization of Open Reading Frame-Encoded Functional Genes from Tilapia Lake Virus (TiLV)

Cited by 37 publications

References 51 publications

Tilapia lake virus: The story so far

Tilapia lake virus: The story so far

The Segment Matters: Probable Reassortment of Tilapia Lake Virus (TiLV) Complicates Phylogenetic Analysis and Inference of Geographical Origin of New Isolate from Bangladesh

Efficacy of heat-killed and formalin-killed vaccines againstTilapia tilapinevirusin juvenile Nile tilapia (Oreochromis niloticus)

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