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Kenne C, Mophou G, Zongo P. A nested model with boosting and waning of immunity from Tilapia Lake Virus infection with distributed resistance to pathogens carrier-state. J Math Biol 2023; 86:67. [PMID: 37009960 DOI: 10.1007/s00285-023-01906-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 02/28/2023] [Accepted: 03/16/2023] [Indexed: 04/04/2023]
Abstract
This paper proposes and analyzes an immune-structured population model of tilapia subject to Tilapia Lake Virus (TiLV) disease. The model incorporates within-host dynamics, used to describe the interaction between the pathogen, the immune system and the waning of immunity. Individuals infected with a low dose acquire a low immunity level and those infected with a high dose acquire a high level of immunity. Since individuals' immune status plays an important role in the spread of infectious diseases at the population level, the within-host dynamics are connected to the between-host dynamics in the population. We define an explicit formula for the reproductive number [Formula: see text] and show that the disease-free equilibrium is locally asymptotically stable when [Formula: see text], while it is unstable when [Formula: see text]. Furthermore, we prove that an endemic equilibrium exists. We also study the influence of the initial distribution of host resistance on the spread of the disease, and find that hosts' initial resistance plays a crucial role in the disease dynamics. This suggests that the genetic selection aiming to improve hosts' initial resistance to TiLV could help fight the disease. The results also point out the crucial role played by the inoculum size. We find that the higher the initial inoculum size, the faster the dynamics of infection. Moreover, if the initial inoculum size is below a certain threshold, it may not result in an outbreak at the between-host level. Finally, the model shows that there is a strong negative correlation between heterogeneity and the probability of pathogen invasion.
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Affiliation(s)
- Cyrille Kenne
- Department of Mathematics, Laboratoire LAMIA, Université des Antilles, Campus Fouillole, 97159, Pointe-à-Pitre, Guadeloupe.
- University of Buea, Buea, Cameroon.
| | - Gisèle Mophou
- Department of Mathematics, Laboratoire LAMIA, Université des Antilles, Campus Fouillole, 97159, Pointe-à-Pitre, Guadeloupe
- Laboratoire MAINEGE, Université Ouaga 3S, 06 BP 10347, Ouagadougou, Burkina Faso
| | - Pascal Zongo
- Laboratoire L3MA, UFR STE et IUT, Université des Antilles, 97275, Schoelcher, Martinique
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Kenne C, Zongo P, Dorville R. A mathematical model for tilapia lake virus transmission with waning immunity. JOURNAL OF BIOLOGICAL DYNAMICS 2022; 16:98-116. [PMID: 35129077 DOI: 10.1080/17513758.2022.2033860] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 01/19/2022] [Indexed: 06/14/2023]
Abstract
The goal of this paper is to investigate the influence of the waning immunity on the dynamics of Tilapia Lake Virus (TiLV) transmission in wild and farmed tilapia within freshwater. We formulate a model for which susceptible individuals can contract the disease in two ways: (i) direct mode caused by contact with infected individuals; (ii) indirect mode due to the presence of pathogenic agents in the water. We obtain an age-structured model which combines both age since infection and age since recovery. We derive an explicit formula for the reproductive number R0 and show that the disease-free equilibrium is locally asymptotically stable when, R0<1. We discuss on the form of the waning immunity parameter and show numerically that a Hopf bifurcation may occur for suitable immunity parameter values, which means that there is a periodic solution around the endemic equilibrium when, R0>1.
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Affiliation(s)
- Cyrille Kenne
- Laboratoire LAMIA, Université des Antilles, Pointe-à-Pitre, Guadeloupe (FWI), France
- Department of Mathematics, University of Buea, Buea, Cameroon
| | - Pascal Zongo
- Laboratoire L3MA, UFR STE et IUT, Université des Antilles, Schoelcher, Martinique
| | - René Dorville
- Laboratoire L3MA, UFR STE et IUT, Université des Antilles, Schoelcher, Martinique
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Paredes-Trujillo A, Mendoza-Carranza M. A systematic review and meta-analysis of the relationship between farm management, water quality and pathogen outbreaks in tilapia culture. JOURNAL OF FISH DISEASES 2022; 45:1529-1548. [PMID: 35830271 DOI: 10.1111/jfd.13679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/15/2022] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
A systematic review and meta-analysis of on farm management and water quality as risk factors triggering pathogen outbreaks in tilapia culture is presented. A total of 121 papers from 28 countries, 37 devoted to management and 84 to water quality associated with the presence of pathogens in tilapia culture were analysed. Most of research has been made on ponds, focusing on bacteria and metazoans. Meta-analysis reveals the proportion of research showing statistical inferences between management (34%), water quality (38% for bacteria and 16.2% for metazoans) and pathogen outbreaks. The most cited parameters related to pathogens outbreaks were temperature (>30°C), dissolved oxygen (<5.0 mg/L), pH (<8.0) and ammonia (1.0 >mg/L) 65, 38, 32 and 34 papers, respectively. However, statistical inference was <20%. Meta-analysis reveals tendencies between high temperatures (30-35°C), low dissolved oxygen (<5 mg/L) and high NH3 (1-5 mg/L) with pathogen outbreaks. Despite the knowledge about the relationship between management and water quality as factors for pathogen effects, most information is descriptive and empirical. Future research on tilapia culture outbreaks should be focused on the effects of multiple stressors affecting tilapia pathogen outbreaks, thereby generating strategies to prevent diseases and financial losses.
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Affiliation(s)
- Amelia Paredes-Trujillo
- Laboratorio de Sanidad Acuícola, Instituto de Ecología, Pesquerías y Oceanográfia del Golfo de México - EPOMEX, Campus 6, Universidad Autónoma de Campeche, Campeche, Mexico
| | - Manuel Mendoza-Carranza
- Laboratorio de Ecología Trófica, Instituto de Ecología, Pesquerías y Oceanográfia del Golfo de México - EPOMEX, Campus 6, Universidad Autónoma de Campeche, Campeche, Mexico
- Departamento de Ciencias de la Sustentabilidad, El Colegio de la Frontera Sur-ECOSUR, Villahermosa, Mexico
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Yang YF, Yamkasem J, Surachetpong W, Lin YJ, You SH, Lu TH, Chen CY, Wang WM, Liao CM. Assessing the effect of probiotics on tilapia lake virus-infected tilapia: Transmission and immune response. JOURNAL OF FISH DISEASES 2022; 45:1117-1132. [PMID: 35514291 DOI: 10.1111/jfd.13635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/19/2022] [Accepted: 04/21/2022] [Indexed: 06/14/2023]
Abstract
Probiotics have been used to alleviate disease transmission in aquaculture. However, there are limited studies on probiotic use in modulating tilapia lake virus (TiLV). We assessed commercially available probiotic supplements used in TiLV-infected tilapia and performed mortality and cohabitation assays. We developed a mechanistic approach to predict dose-response interactions of probiotic effects on mortality and immune gene response. We used a susceptible-infected-mortality disease model to assess key epidemiological parameters such as transmission rate and basic reproduction number (R0 ) based on our viral load dynamic data. We found that the most marked benefits of probiotics are significantly associated with immune system enhancements (~30%) and reductions in disease transmission (~80%) and R0 (~70%) in tilapia populations, resulting in a higher tolerance of farming densities (~400 fold) in aquaculture. These findings provide early insights as to how probiotic use-related factors may influence TiLV transmission and the immune responses in TiLV-infected tilapia. Our study facilitates understanding the mode of action of probiotics in disease containment and predicting better probiotic dosages in diet and supplements to achieve the optimal culturing conditions. Overall, our analysis assures that further study of rationally designed and targeted probiotics, or mechanistic modelling is warranted on the basis of promising early data of this approach.
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Affiliation(s)
- Ying-Fei Yang
- Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan
| | - Jidapa Yamkasem
- Faculty of Veterinary Medicine, Department of Veterinary Microbiology and Immunology, Kasetsart University, Chatuchak, Bangkok, Thailand
| | - Win Surachetpong
- Faculty of Veterinary Medicine, Department of Veterinary Microbiology and Immunology, Kasetsart University, Chatuchak, Bangkok, Thailand
| | - Yi-Jun Lin
- Institute of Food Safety and Health Risk Assessment, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Shu-Han You
- Institute of Food Safety and Risk Management, National Taiwan Ocean University, Keelung City, Taiwan
| | - Tien-Hsuan Lu
- Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan
| | - Chi-Yun Chen
- Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan
| | - Wei-Min Wang
- Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan
| | - Chung-Min Liao
- Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan
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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] [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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Aich N, Paul A, Choudhury TG, Saha H. Tilapia Lake Virus (TiLV) disease: Current status of understanding. AQUACULTURE AND FISHERIES 2022. [DOI: 10.1016/j.aaf.2021.04.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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An Age-Structured Model for Tilapia Lake Virus Transmission in Freshwater with Vertical and Horizontal Transmission. Bull Math Biol 2021; 83:90. [PMID: 34232396 DOI: 10.1007/s11538-021-00923-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 06/21/2021] [Indexed: 10/20/2022]
Abstract
This paper proposes a mathematical model for tilapia lake virus (TiLV) transmission in wild and farmed tilapias within freshwater. This model takes into account two routes of transmission: vertical and horizontal. This latter route integrates both the direct and indirect transmission. We define an explicit formula for the reproductive number [Formula: see text] and show by means of the Fatou's lemma that the disease-free equilibrium is globally asymptotically stable when [Formula: see text]. Furthermore, we find an explicit formula of the endemic equilibria and study its local stability as well as the uniform persistence of the disease when [Formula: see text]. Finally, a numerical scheme to solve the model is developed and some parameters of the model are estimated based on biological data. The numerical results illustrate the role of routes of transmission on the epidemic evolution.
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Surachetpong W, Roy SRK, Nicholson P. Tilapia lake virus: The story so far. JOURNAL OF FISH DISEASES 2020; 43:1115-1132. [PMID: 32829488 DOI: 10.1111/jfd.13237] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/16/2020] [Accepted: 07/17/2020] [Indexed: 05/08/2023]
Abstract
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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Affiliation(s)
- Win Surachetpong
- Department of Veterinary Microbiology and Immunology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
| | - Sri Rajiv Kumar Roy
- Department of Veterinary Microbiology and Immunology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
| | - Pamela Nicholson
- Next Generation Sequencing Platform, Institute of Genetics, Vetsuisse, University of Bern, Bern, Switzerland
- Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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