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Tran TH, Nguyen VTH, Bui HCN, Tran YBT, Tran HTT, Le TTT, Vu HTT, Ngo TPH. Tilapia Lake Virus (TiLV) from Vietnam is genetically distantly related to TiLV strains from other countries. J Fish Dis 2022; 45:1389-1401. [PMID: 35696542 DOI: 10.1111/jfd.13669] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 05/29/2022] [Accepted: 06/01/2022] [Indexed: 06/15/2023]
Abstract
Tilapia Lake Virus (TiLV) is reported as a threat to tilapia aquaculture in 16 countries on four continents with outbreaks causing up to 90% mortality. This research is one of the first studies on TiLVs from Vietnam. We propagated successfully one TiLV isolate HB196-VN-2020 from a diseased tilapia sample using an E-11 cell line and evaluated its virulence in two different weights of red hybrid tilapia and three serial 10-fold diluted viral titers. Smaller fish (4.5 ± 1.98 g) were proved to be more susceptible to TiLV infection at the viral titre of 9.1 × 105 TCID50 fish-1 than larger fish (20.8 ± 7.5 g) with the mortalities of 92.5% and 12.5%, respectively. Reassortant detection analysis revealed seven potential reassortment events among 23 TiLV genomes, indicating the mixed infection of multiple TiLV isolates at the farms and the fish movement among different regions. Seven maximum likelihood phylogenetic trees based on the individual segments or the concatenated coding regions of some segments showed the genetically distant relationship of the Southern Vietnamese isolate RIA2-VN-2019 with the 21 reference isolates, and suggest the different origins of two Vietnamese TiLV isolates (RIA2-VN-2019 and HB196-VN-2020). However, additional sequences from various sampling locations and times are required to better understand the impacts of genetic diversity and reassortments on the evolution, migration and natural selection of TiLVs in Vietnam and other countries.
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Affiliation(s)
- Triet Hanh Tran
- Division of Aquacultural Biotechnology, Biotechnology Center of Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Vy Thuy Hoang Nguyen
- Division of Aquacultural Biotechnology, Biotechnology Center of Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Hieu Chi Nguyen Bui
- Division of Aquacultural Biotechnology, Biotechnology Center of Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Yen Binh Thi Tran
- Department of Genetics, Faculty of Biology and Biotechnology, University of Science, Vietnam National University Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Huong Thanh Thi Tran
- Division of Aquacultural Biotechnology, Biotechnology Center of Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Thao Thu Thi Le
- Division of Aquacultural Biotechnology, Biotechnology Center of Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Huong Thanh Thi Vu
- Division of Aquacultural Biotechnology, Biotechnology Center of Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Thao Phuong Huynh Ngo
- Division of Aquacultural Biotechnology, Biotechnology Center of Ho Chi Minh City, Ho Chi Minh City, Vietnam
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Chengula AA, Mugimba KK, Tal S, Levi RT, Dubey S, Mutoloki S, Dishon A, David L, Evensen Ø, Munang'andu HM. Efficiency, sensitivity and specificity of a quantitative real-time PCR assay for Tilapia Lake virus (TiLV). J Virol Methods 2022; 307:114567. [PMID: 35709972 DOI: 10.1016/j.jviromet.2022.114567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 11/30/2022]
Abstract
Tilapia lake virus (TiLV) is an emerging viral pathogen of tilapiines worldwide in wild and farmed tilapia. TiLV is an orthomyxo-like, negative sense segmented RNA virus, belonging to genus Tilapinevirus, family Amnoonviridae. Here we developed a quantitative real-time PCR (qRT-PCR) assay testing primer sets targeting the 10 segments of TiLV. Sensitivity, specificity, efficiency and reproducibility of these assays were examined. Detection sensitivity was equivalent to 2 TCID50/ml when tested on supernatants from cell culture-grown TiLV. Specificity tests showed that all primer sets amplified their respective TiLV segments, and standard curves showed linear correlation of R2 > 0.998 and amplification efficiencies between 93 % and 98 %. Intra- and inter-assay coefficients of variation (CV %) were in the range of 0.0 %- 2.6 % and 0.0 %- 5.9 %, respectively. Sensitivity tests showed that primer sets targeting segments 1, 2, 3 and 4 had the highest detection sensitivities (100.301 TCID50/ml). The qRT-PCR used for detection of viral genome in TiLV infected organs gave virus titers equivalent to 3.80 log10, 3.94 log10 and 3.52 log10 TCID50/ml for brain, kidney and liver tissues, respectively as calculated on the basis of Ct values. These findings suggest that primer optimization for qPCR should not only focus on attaining high amplification efficiency but also sensitivity comparison of primer sets targeting different viral segments in order to develop a method with the highest sensitivity.
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Affiliation(s)
- Augustino Alfred Chengula
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Department of Paraclinical Sciences, PO Box 5003, N-1432 Ås, Norway; Sokoine University of Agriculture, College of Veterinary Medicine and Biomedical Sciences, Department of Microbiology, Parasitology and Biotechnology, P.O. Box 3019, Morogoro, Tanzania
| | - Kizito Kahoza Mugimba
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Department of Paraclinical Sciences, PO Box 5003, N-1432 Ås, Norway; Makerere University, College of Veterinary Medicine Animal Resources and Biosecurity, Department of Biotechnical and Diagnostic Sciences, Kampala, Uganda
| | - Shlomit Tal
- Phibro Animal Health Corporation, R&D Vaccines, Ha'melacha St. 3, POB 489, West Industrial Zone, Beit-Shemesh 99100, Israel
| | - Roni Tadmor Levi
- Department of Animal Sciences, R.H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 7610001, Israel
| | - Saurabh Dubey
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Department of Paraclinical Sciences, PO Box 5003, N-1432 Ås, Norway
| | - Stephen Mutoloki
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Department of Paraclinical Sciences, PO Box 5003, N-1432 Ås, Norway
| | - Arnon Dishon
- Phibro Animal Health Corporation, R&D Vaccines, Ha'melacha St. 3, POB 489, West Industrial Zone, Beit-Shemesh 99100, Israel
| | - Lior David
- Department of Animal Sciences, R.H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 7610001, Israel
| | - Øystein Evensen
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Department of Paraclinical Sciences, PO Box 5003, N-1432 Ås, Norway
| | - Hetron Mweemba Munang'andu
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Department of Paraclinical Sciences, PO Box 5003, N-1432 Ås, Norway; Department of Biosciences and Aquaculture, Nord University, PB 1490, 8049 Bodø, Norway.
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