Prevention and Control of Viral Diseases of Salmonids

1976 ◽  
Vol 33 (4) ◽  
pp. 1059-1066 ◽  
Author(s):  
Donald F. Amend
Keyword(s):  
Disease Resistance ◽  
Selective Breeding ◽  
Infected Fish ◽  
Stress Conditions ◽  
Viral Diseases ◽  
Environmental Manipulation ◽  
Infectious Hematopoietic Necrosis ◽  
Elevated Water ◽  
And Control ◽  
Reducing Stress

Three viral diseases of salmonids are of worldwide concern: infectious pancreatic necrosis (IPN) viral hemorrhagic septicemia (VHS), and infectious hematopoietic necrosis (IHN). Six principal approaches are being used to prevent or control these diseases: 1) preventing contact o the pathogen with the host, 2) environmental manipulation, 3) immunization, 4) chemotherapy, 5 selective breeding for disease resistance, and 6) reducing stress conditions which augment disease conditions. Preventing the introduction of a pathogen into a new stock of fish has been accomplished mainly by implementing stringent laws to prevent transport of infected fish into uninfected areas. Stocks of fish already infected are sometimes destroyed, and the hatchery is disinfected and restocked with fish free of specific pathogens. Environmental manipulation (elevated water temperature) has been successfully used to control IHN. Chemotherapeutics such as povidone-iodine for IPN and benzipyrene for IHN show promise of controlling mortalities; however, the practicality of using these drugs to eliminate the carrier fish has not been evaluated. Salmonids are capable of developing immune responses to viruses; however, development of effective vaccines, selective breeding for disease resistance, and identification of stress conditions which augment disease are still in the experimental phase.

scholarly journals Experimental Parasite Infection Causes Genome-Wide Changes in DNA Methylation

2020 ◽  
Vol 37 (8) ◽  
pp. 2287-2299 ◽  
Author(s):  
Kostas Sagonas ◽  
Britta S Meyer ◽  
Joshka Kaufmann ◽  
Tobias L Lenz ◽  
Robert Häsler ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Infected Fish ◽  
Parasite Infection ◽  
Control Fish ◽  
Regulatory Processes ◽  
Neuropeptide Ff ◽  
Genome Wide ◽  
Parasite Infections ◽  
And Shifts ◽  
And Control

Abstract Parasites are arguably among the strongest drivers of natural selection, constraining hosts to evolve resistance and tolerance mechanisms. Although, the genetic basis of adaptation to parasite infection has been widely studied, little is known about how epigenetic changes contribute to parasite resistance and eventually, adaptation. Here, we investigated the role of host DNA methylation modifications to respond to parasite infections. In a controlled infection experiment, we used the three-spined stickleback fish, a model species for host–parasite studies, and their nematode parasite Camallanus lacustris. We showed that the levels of DNA methylation are higher in infected fish. Results furthermore suggest correlations between DNA methylation and shifts in key fitness and immune traits between infected and control fish, including respiratory burst and functional trans-generational traits such as the concentration of motile sperm. We revealed that genes associated with metabolic, developmental, and regulatory processes (cell death and apoptosis) were differentially methylated between infected and control fish. Interestingly, genes such as the neuropeptide FF receptor 2 and the integrin alpha 1 as well as molecular pathways including the Th1 and Th2 cell differentiation were hypermethylated in infected fish, suggesting parasite-mediated repression mechanisms of immune responses. Altogether, we demonstrate that parasite infection contributes to genome-wide DNA methylation modifications. Our study brings novel insights into the evolution of vertebrate immunity and suggests that epigenetic mechanisms are complementary to genetic responses against parasite-mediated selection.

scholarly journals Evolutionary Understanding of Metacaspase Genes in Cultivated and Wild Oryza Species and Its Role in Disease Resistance Mechanism in Rice

Genes ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1412
Author(s):  
Ruchi Bansal ◽  
Nitika Rana ◽  
Akshay Singh ◽  
Pallavi Dhiman ◽  
Rushil Mandlik ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Wild Rice ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Resistance Mechanism ◽  
Regulatory Elements ◽  
Stress Conditions ◽  
Pcr Analysis ◽  
North East ◽  
Wild Rice Species

Metacaspases (MCs), a class of cysteine-dependent proteases found in plants, fungi, and protozoa, are predominately involved in programmed cell death processes. In this study, we identified metacaspase genes in cultivated and wild rice species. Characterization of metacaspase genes identified both in cultivated subspecies of Oryza sativa, japonica, and indica and in nine wild rice species was performed. Extensive computational analysis was conducted to understand gene structures, phylogenetic relationships, cis-regulatory elements, expression patterns, and haplotypic variations. Further, the haplotyping study of metacaspase genes was conducted using the whole-genome resequencing data publicly available for 4726 diverse genotype and in-house resequencing data generated for north-east Indian rice lines. Sequence variations observed among wild and cultivated rice species for metacaspase genes were used to understand the duplication and neofunctionalization events. The expression profiles of metacaspase genes were analyzed using RNA-seq transcriptome profiling in rice during different developmental stages and stress conditions. Real-time quantitative PCR analysis of candidate metacaspase genes in rice cultivars Pusa Basmati-1 in response to Magnaporthe oryzae infection indicated a significant role in the disease resistance mechanism. The information provided here will help to understand the evolution of metacaspases and their role under stress conditions in rice.

scholarly journals Antioxidant role and immunological function of Excoecaria agallocha in Amphiprion sebae against Vibrio alginolyticus

2019 ◽  
pp. 50-64
Author(s):  
Nagarajan Balachandran Dhayanithi ◽  
Thipramalai Thankappan Ajithkumar ◽  
Gunapathy Devi ◽  
Chellam Balasundaram ◽  
Harikrishnan Ramasamy
Keyword(s):  
Immune Response ◽  
Disease Resistance ◽  
Innate Immune Response ◽  
Control Diet ◽  
Bacterial Count ◽  
Infected Fish ◽  
Vibrio Alginolyticus ◽  
Innate Immune ◽  
Excoecaria Agallocha ◽  
High Bacterial Count

The efficacy of supplementation diet with 0, 2.5, 5, and 10 g kg-1 of Excoecaria agallocha aqueous leaf extract on innate immune response, survival, and disease resistance was reported in clownfish, Amphiprion sebae against Vibrio alginolyticus. The mean weight gain (MWG), specific growth rate (SGR), and protein efficiency ratio (PER) did not significantly vary with any supplementation diet except with 5 g kg-1 diet on weeks 6 and 8. The white blood cell (WBC) level significantly increased with any supplementation diets on weeks 6 and 8. The phagocytic activity, alternate complement activity, and lysozyme activity increased significantly with 5 and 10 g kg-1 diet on weeks 6 and 8 whereas the respiratory burst activity significantly increased with any supplementation diets on weeks 6 and 8. The cumulative mortality with the 2.5 and 10 g kg-1 supplementation diets were 10% against V. alginolyticus whereas with 5 g kg-1 supplementation diet only 5%. V. alginolyticus count was high in infected fish fed with control diet as well as the infected fish fed with 2.5 g kg-1 diet had high bacterial count (cfu/g) in kidney, blood, and spleen (1.4 x 102, 1.1 x 103, and 1.2 x 103) whereas it was low with 10 g kg-1 diet in blood, spleen, and kidney (0.6 x 101, 0.2 x 101, and 0.2 x 101). The present results indicate that infected fish fed diet containing 5 and 10 g kg-1 of E. agallocha positively enhance the innate immune response and reduce the mortality in A. sebae against V. alginolyticus infection. Keywords: Disease resistance; Excoecaria agallocha; Innate immune parameter; Mortality; Vibrio alginolyticus

scholarly journals Emerging epidemics: is the Zanzibar healthcare system ready to detect and respond to mosquito-borne viral diseases?

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Fatma Saleh ◽  
Jovin Kitau ◽  
Flemming Konradsen ◽  
Leonard E.G. Mboera ◽  
Karin L. Schiøler
Keyword(s):  
Healthcare System ◽  
Health Management ◽  
Public Awareness ◽  
Disease Outbreaks ◽  
Viral Disease ◽  
Health Facilities ◽  
Effective Control ◽  
Viral Diseases ◽  
District Health ◽  
And Control

Abstract Background Effective control of emerging mosquito-borne viral diseases such as dengue, chikungunya, and Zika requires, amongst other things, a functional healthcare system, ready and capable of timely detection and prompt response to incipient epidemics. We assessed the readiness of Zanzibar health facilities and districts for early detection and management of mosquito-borne viral disease outbreaks. Methods A cross-sectional study involving all 10 District Health Management Teams and 45 randomly selected public and private health facilities in Zanzibar was conducted using a mixed-methods approach including observations, document review, and structured interviews with health facility in-charges and District Health Management Team members. Results The readiness of the Zanzibar healthcare system for timely detection, management, and control of dengue and other mosquito-borne viral disease outbreaks was critically low. The majority of health facilities and districts lacked the necessary requirements including standard guidelines, trained staff, real-time data capture, analysis and reporting systems, as well as laboratory diagnostic capacity. In addition, health education programmes for creating public awareness and Aedes mosquito surveillance and control activities were non-existent. Conclusions The Zanzibar healthcare system has limited readiness for management, and control of mosquito-borne viral diseases. In light of impending epidemics, the critical shortage of skilled human resource, lack of guidelines, lack of effective disease and vector surveillance and control measures as well as lack of laboratory capacity at all levels of health facilities require urgent attention across the Zanzibar archipelago.

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