Infectious pancreatic necrosis virus in Scottish Atlantic salmon farms, 1996-2001. (Research).The rapid growth of aquaculture aquaculture, the raising and harvesting of fresh- and saltwater plants and animals. The most economically important form of aquaculture is fish farming, an industry that accounts for an ever increasing share of world fisheries production. has provided opportunities for the emergence of diseases. Programs designed to monitor these pathogens are useful for analysis of regional variation and trends, provided methods are standardized. Data from an official monitoring program were used to analyze the emergence of infectious pancreatic necrosis virus in Scottish salmon farms from 1996 to 2001. An annual increase in the prevalence of this virus was found in saltwater (10%) and freshwater sites (2% to 3%), with a much faster increase (6.5%) in Shetland's freshwater sites. No significant increase in the virus was detected in the marine farms of southern mainland Scotland. However, the virus had become very prevalent at marine sites and was almost ubiquitous in Shetland by 2001. The prevalence of this virus at marine sites may be underestimated. Because several diseases have emerged or are emerging in fish farming Fish farming is the principal form of aquaculture, while other methods may fall under mariculture. It involves raising fish commercially in tanks or enclosures, usually for food. , aquaculture surveillance programs represent a rich potential source of data on emerging diseases. ********** The growth of the aquaculture industry provides a rich environment in which to study emergence of pathogens (1,2). New fish species are being cultivated, and production has risen rapidly. For example, from 1996 to 2001, Scottish farmed salmon production doubled to 158,000 metric tons (3). Shipping is extensive, and stock movement between farms is substantial (4). Thus, both host populations and contact opportunities are high, the ideal theoretical conditions for disease transmission (5). Indeed, an array of pathogens that affect farmed salmon have emerged (6). Because of the disease threat, official (6,7) and industry (8) surveillance for pathogens is extensive. This surveillance is designed to find pathogens, and thus may bias estimates of true pathogen prevalence. Sampling may be biased to farms perceived to be at risk or to specific times of year. The number of fish in a sample may vary. Similarly, sampling methods have detection limits, which may result in substantial numbers of asymptomatic infections being undetected (9,10). Nevertheless, a continuous centrally organized national survey exists for pathogens in an environment where pathogens are emerging. This survey has the potential to throw detailed light on patterns of pathogen emergence, even if absolute prevalence may be biased. Infectious pancreatic necrosis (IPN IPN Instant Payment Notification (PayPal) IPN Instituto Politecnico Nacional (México) IPN Infectious Pancreatic Necrosis IPN Interplanetary Internet (JPL) ) is considered the most serious viral disease in terms of its impact on Atlantic salmon Atlantic salmon Oceanic trout species (Salmo salar), a highly prized game fish. It averages about 12 lbs (5.5 kg) and is marked with round or cross-shaped spots. Found on both sides of the Atlantic Ocean, it enters streams in the fall to spawn. (Salmo salar) production in the European Union European Union (EU), name given since the ratification (Nov., 1993) of the Treaty of European Union, or Maastricht Treaty, to the European Community (11); the disease occurs on four continents (7). The problem is increasing as the disease continues to emerge (12). IPN is caused by the Infectious pancreatic necrosis virus (IPNV IPNV Infectious Pancreatic Necrosis Virus IPNV Input Parameter Not Valid (Alcatel) ; genus Aquabirnavirus) (13,14). Presence of IPNV is a necessary, but not sufficient, condition for IPN; disease also depends upon viral strain (15), environment (12), and age of the fish (12, 13). In nondiseased fish, IPNV may be present in small quantities (13,16); virus in such carrier fish may be difficult to detect, which leads to underreporting (9,10). IPN has been known for decades. It was first described in North America North America, third largest continent (1990 est. pop. 365,000,000), c.9,400,000 sq mi (24,346,000 sq km), the northern of the two continents of the Western Hemisphere. in freshwater trout in the 1950s (17), although indications of the disease were reported in 1940 (16). IPN was first reported in the United Kingdom in 1971 (18) in rainbow trout rainbow trout Species (Oncorhynchus mykiss) of fish in the salmon family (Salmonidae) noted for spectacular leaps and hard fighting when hooked. It has been introduced from western North America to many other countries. , Oncorhynchus mykiss, a North American North American named after North America. North American blastomycosis see North American blastomycosis. North American cattle tick see boophilusannulatus. species. Early reports of IPN in salmonids were associated with deaths of fry (recently hatched fishes) in freshwater hatcheries (13), but since the 1980s, deaths have also been increasingly reported among smolts (2-year-old salmon) shortly after transfer to seawater seawater Water that makes up the oceans and seas. Seawater is a complex mixture of 96.5% water, 2.5% salts, and small amounts of other substances. Much of the world's magnesium is recovered from seawater, as are large quantities of bromine. (15,12). IPNV-positive salmon smolts are estimated to have a mortality rate five times higher than IPNV-negative smolts (14). IPN is also associated with less easily quantified losses such as loss of appetite loss of appetite Medtalk Anorexia, see there and therefore of production (19). Methods Fisheries Research Services Fisheries Research Services (FRS) is an Executive Agency of the Scottish Executive, part of the Scottish Executive Environment and Rural Affairs Department. FRS is responsible for scientific and technical research into the marine and freshwater fisheries and aquaculture, and the (FRS FRS abbr. Fellow of the Royal Society FRS, n “flexed rotated side-bent,” an osteopathic abbreviation used to describe vertebral position in cases of spinal dysfunction. ) fisheries inspectors have sampled fish from throughout Scotland for pathogens, including IPNV, for many years. The inspectorate is based in Aberdeen (Figure 1), distant from salmon farming areas on the west coast and Northern Isles (3). This central organization is important for the sampling structure because the same persons collected samples from different regions using standard operating procedures standard operating procedure Medtalk A technique, method or therapy performed 'by the book,' using a standard protocol meeting internally or externally defined criteria; a formal, written procedure that describes how specific lab operations are to be performed. , and a single laboratory then processed these samples. [FIGURE 1 OMITTED] The IPNV diagnosis used cell culture on Chinook salmon chinook salmon or king salmon Prized North Pacific food and sport fish (Oncorhynchus tshawytscha) of the salmon family. The average weight is about 22 lbs (10 kg), but individuals of 50–80 lbs (22–36 kg) are not unusual. embryo cell lines in plates containing 24 wells (7). Virus identification was undertaken with enzyme-linked immunosorbent assay enzyme-linked immunosorbent assay n. ELISA. Enzyme-linked immunosorbent assay (ELISA) A diagnostic blood test used to screen patients for AIDS or other viruses. (7). The standard sample from 30 fish was divided into six pools, each containing material from five kidneys; occasionally 30 pools from individual kidneys were sampled. However, some samples did not contain 30 fish, depending upon opportunity, and varied from 1 to 150 fish kidneys; pool size also varied. Any positive pool generated a positive result at the sample level. Because samples with smaller numbers of fish are less likely to contain virus than are large ones (20), IPNV may be missed in small samples. In addition, limits of test sensitivity mean that fish with low IPNV titers may escape detection (9,10), although if samples are large enough to contain several infected fish, test sensitivity is likely to be less important in detecting IPNV at the sample level (20). Small samples from biased locations and test detection limits mean that errors may exist in the absolute prevalence estimates, but with standard methods and centralized personnel, trends and relative regional prevalence can be determined. FRS scientists have been testing for IPNV since the 1970s (18); standard methods approved by the Office International des Epizooties (7) were used through the 1990s. In freshwater, sonication sonication /son·i·ca·tion/ (son?i-ka´shun) exposure to sound waves; disruption of bacteria by exposure to high-frequency sound waves. son·i·ca·tion n. has been applied to tissue homogenate homogenate /ho·mog·e·nate/ (ho-moj´in-at) material obtained by homogenization. homogenate material obtained by homogenization. since 1993 to disrupt cells and release virus; in saltwater, this process was not begun until 2001. Thus, sensitivity of detection may have been slightly improved for marine samples in the last year and was generally better in freshwater. Data available for 1996-2001 have been used to find underlying patterns in the distribution of prevalence of IPNV in Scottish salmon farms. Fish were sampled at all stages of the production cycle, although many more samples were collected in summer than in winter, leading to potential biases. Also, inspectors preferentially take moribund fish because these are of most concern and could indicate a disease outbreak. Most sites were only sampled at most once in a given year, but a minority (8.5% in 1996, 12.3% in 1997, 7.9% in 1998, 15% in 1999, 26% in 2000, and 31% in 2001) were sampled on two or more occasions in a single year. All farms are sampled at least once every 2 years. Data are insufficient to systematically analyze variation at sites. The mean prevalence of IPNV was calculated for classes of samples, e.g., marine salmon farms in Shetland in 1996. (Prevalence was the proportion of samples that were IPNV positive for the class of site examined.) The use of prevalence removed the bias associated with different sampling frequencies. Confidence intervals were determined from the probability values for which distribution intercepts with observations, for the number of observations available. For a more formal test of when regional means deviated significantly from the overall mean, we used the [chi square chi square (kī), n a nonparametric statistic used with discrete data in the form of frequency count (nominal data) or percentages or proportions that can be reduced to frequencies. ] test, because the data were binomially distributed. Site samples were not fully independent, but most sites were not sampled more than once in a year and thus were semi-independent. Clumping of samples could also have occurred for sites within hydrodynamically well-mixed environments (e.g., farms in the same sea loch). Regional patterns exist for IPN; Shetland has a particularly serious problem (16). Regional variation in IPN-induced deaths is also apparent in Norway (12). Regional prevalence patterns are therefore examined by separating out salmon production sites into regions based on a United Kingdom ordnance survey Ordnance Survey Noun the British government organization that produces detailed maps of Britain and Ireland Noun 1. Ordnance Survey - the official cartography agency of the British government 100-[km.sup.2] grid. The regions identified are Shetland, Orkney, the Outer Hebrides Outer Hebrides, Scotland: see Hebrides, the. , and mainland Scotland. Mainland Scotland was divided into northern and southern regions by using the 800-km north line of the United Kingdom ordnance survey's national grid national grid Noun Brit & NZ 1. a network of high-voltage power lines linking major electric power stations 2. the arrangement of vertical and horizontal lines on an ordnance survey map system (Figure 1). The interannual changes in IPNV prevalence have been examined at salmon production sites within the regions identified above. Multilevel Model Multilevel models are known by several names: hierarchical linear models, generalized linear mixed models, nested models, mixed models (in biostatistics), random coefficient or random-effects models (in econometrics), random parameter models, and split-plot designs. Both space and time play roles in determining variance in the observations. Simple multilevel models of the variance in the observations allow determination of the relative contributions of these components. These models, based on normal or binomial binomial (bī'nō`mēəl), polynomial expression (see polynomial) containing two terms, for example, x+y. The binomial theorem, or binomial formula, gives the expansion of the nth power of a binomial (x+ assumptions, were constructed by using the package MLwiN (21). The model was constructed with binomial variance distributed according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. a logistic function A logistic function or logistic curve models the S-curve of growth of some set P. The initial stage of growth is approximately exponential; then, as saturation begins, the growth slows, and at maturity, growth stops. IPNV = [1 + exp[(-[beta])].sup.-1]. This model determined a mean [beta] = -1.138 ([+ or -] 0.517), which gave a mean prevalence of 0.242 (24%). The logistic function was used because it varies from 0 to 1 and therefore covers the range of situations when IPNV is absent to situations when it is present in all samples within a group. The model was then used to determine the contributions of the different levels in the model to the variance about this mean. The highest level of the model is the split between saltwater and freshwater environments. These salmon production sites are fundamentally different in nature (3), with different age classes of fish and routes of infection. Inclusion does add uncertainty to the model's output because environment has only two classes. However, because saltwater and freshwater sites are related at other levels in different ways, this split in variance is explicitly modeled, rather than added as a fixed effect. The second level is the region; at this level, different climates, environments, and local organizations (e.g., the Orkney Fish Farmers Association) exist. The third level at which variance is resolved is that of year: because IPNV's prevalence is increasing, prevalence changes over time. Seasonal data are also included because most IPNV cases occur in summer. Seasonal effect was analyzed by using three seasons of 4 months' duration (January-April, May-August, and September-December) because individual months in winter are often poorly sampled. Results Mean IPNV prevalence was determined by region, and a [chi square] test of deviation from the overall Scottish mean was conducted (Table 1). High IPNV levels stood out in Shetland for both freshwater and seawater sites. Northern mainland Scotland and the Outer Hebrides showed a particularly low relative prevalence of IPNV in the marine sites and marginally significant low prevalence in freshwater. Orkney also had a low prevalence of IPNV in freshwater; however, because we obtained fewer data from Orkney, this finding was not significant. In marine sites, IPNV prevalence showed different temporal patterns in different regions (Figure 2). In most areas, IPNV prevalence appeared to have increased from 1996 to 2001 at approximately 10% per year (Table 2); the trends in these regions were not significantly different from each other or from the national mean. Analysis methods changed slightly in 2001; however, the trend of increasing prevalence was apparent throughout the entire 1996-2001 period. In southern mainland Scotland, IPNV prevalence was not statistically significant. If anything, it declined, although variation occurred from year to year. Linear increase in IPNV prevalence in Shetland became difficult to sustain once prevalence exceeded 80% in 1999, so the increase reached a saturation point saturation point n. 1. Chemistry The point at which a substance will receive no more of another substance in solution. 2. The point at which no more can be absorbed or assimilated. (Figure 2). [FIGURE 2 OMITTED] In freshwater production sites, interannual variation in IPNV prevalence increased approximately 2% to 3% per year (Figure 3, Table 2). However, in Shetland, the increase was faster at 6.5% year, which is significantly different from other regressions at 90% confidence. The analysis used has not changed for freshwater since 1993. In northern Scotland Northern is an administrative division of Scotland used for police and fire services. It consists of Highland, the Orkney Islands, the Shetland Islands and the Western Isles. , no significant increase has occurred, although since 1999, prevalence has increased. As noted earlier, prevalence of IPNV in Shetland in freshwater is higher than in other areas and is increasing more rapidly. [FIGURE 3 OMITTED] Differences between regions have decreased in recent years in spite of increasing prevalence (Figure 4). The regions are becoming less distinct with respect to IPNV prevalence as the IPNV-positive regions converge. [FIGURE 4 OMITTED] The multilevel model has been used to determine how much different components contribute to the variation in model results from the overall mean of 24% (Table 3). The contribution is distributed, as expected from the observations described earlier. Most variance is accounted for at level 2, between regions. A substantial amount of variance is at the top level between saltwater and freshwater environments, but, because only two categories exist, the degree of this variance is uncertain. Since slightly more sensitive methods were used to sample IPNV in freshwater than in saltwater, this difference may be underestimated. A similar amount of variance is accounted for at the interannual level but with less uncertainty. Very little variation is due to season. Discussion Our analysis systematically shows that variation exists in the distribution of IPNV in Scotland and allows a detailed picture of changes in distribution to be derived. The emergence of IPNV has been documented, with IPNV prevalence increasing from very low levels to high levels, even to near ubiquity in Shetland salmon farms. IPNV prevalence has typically increased annually by 10% in saltwater and by 2% to 3% in freshwater. In freshwater in Shetland, the annual increase was 6.5%. In spite of IPNV's emergence in most of Scotland, the virus's prevalence did not change significantly in southern areas; if anything, it declined. The reasons for this are unclear, but the pattern suggests that controlling the emergence of IPNV may be possible. In Sweden, IPNV is controlled by culling culling removal of inferior animals from a group of breeding stock. The removal is premature, i.e. before completion of its life span, disposal of an animal from a herd or other group. , and the virus is officially absent from that country in spite of very high levels in neighboring Norway (11). Notably, in 1999 or 2000 in many areas of Scotland, marine IPNV prevalence declined, or at least increased less rapidly. This decline followed a period of fallowing, which in turn followed widespread culling to control the outbreak of infectious salmon anemia Infectious salmon anemia or anaemia (ISA) is a viral disease of Atlantic Salmon (Salmo salar) that affects fish farms in Canada, Norway, and Scotland, causing severe losses to infected farms. of 1998-99 (22,4). Multilevel modeling shows that the regional pattern dominates the structure of variation in IPNV's prevalence in salmon farms, overshadowing even the difference between marine and freshwater sites, although this could be slightly underestimated. The strength of this regional pattern is due to the extremely high prevalence of IPNV in Shetland and its low prevalence in the Outer Hebrides in both freshwater and saltwater sites. The regional variation is in decline for marine salmon farms, however. As IPNV approaches ubiquity in Shetland, the virus has reached the saturation point; in many other areas, the increase remains rapid. In the Outer Hebrides, where prevalence was lowest, the increase has been the most rapid. As a result, IPNV prevalence levels are converging, and the standard deviation In statistics, the average amount a number varies from the average number in a series of numbers. (statistics) standard deviation - (SD) A measure of the range of values in a set of numbers. among regional means has declined. As the regions have become increasingly similar, regional differentiation in control policy becomes less useful. Our analysis is not intended to describe the absolute prevalence of IPNV in Scotland. Detection limits (9,10) and, on occasion, small numbers of fish (19) may mean that infection may not always be detected at an infected site; thus, the true prevalence of IPNV within samples is probably higher than reported. Uncertainty in test results is also a fundamental limitation (10) and would apply to the results of a survey specifically designed to determine viral prevalence as much as it applies to these monitoring data. Sample site selection is not random but is based on the need to monitor for IPNV, which may also lead to biases. However, with a centralized organization that collects data by standardized methods, trends and regional variation may be analyzed in relative terms. Improved analysis methods may have contributed to increases in reported IPNV prevalence in marine water in 2001; however, this increase continues a trend and reflects an increase in clinical IPN cases (11,15). Increased experience per se is unlikely to be a factor in increased detection during the study period since the FRS Marine Laboratory has been sampling for IPNV since the 1970s (18) and has contributed to the development of standard tests (9). Moreover, prevalence shows different temporal patterns in different areas, in spite of centrally controlled methods and personnel. These increases therefore cannot be explained in terms of improvements in methods, nor can differences in methodology be used to explain regional differences in prevalence. In addition, sampling methods used in freshwater may be slightly more sensitive than those used for marine sites, which could mean the difference in prevalence between fresh and marine waters is even larger than reported here. Because IPNV has a wide variety of host species (7,13), persistent carriers among recovered hosts (23), and the ability to be carried by piscivorous piscivorous fisheating; said of birds. bird vectors (24), the virus is difficult to eradicate, once established. Given IPNV prevalence increases of approximately 10% per year, effective control would have to be reestablished very soon if IPNV is not to become as ubiquitous in most areas as it is in Shetland. Owing to owing to prep. Because of; on account of: I couldn't attend, owing to illness. owing to prep → debido a, por causa de limitations in detection methods, IPNV prevalence in samples may be even higher than reported (10). IPNV prevalence has been held steady in southern areas of Scotland, indicating that an increase is not inevitable; Sweden has maintained IPNV-free status. In freshwater sites in Scotland, IPNV is less prevalent, and the prevalence is increasing at lower rates; therefore, control can likely be reasserted in freshwater. IPNV is one of a series of emerging pathogens causing serious economic damage to aquaculture in Scotland (6,22) and around the world (1,2). Although data collected from programs to monitor these pathogens are not always statistically unbiased, they form a valuable resource on emerging and established (8) diseases. As further fish species are cultivated (e.g., cod Gadus morhua [3,7]), such data are required to design a sustainable industry.
Table 1. Mean prevalence of infectious pancreatic necrosis virus by
region for all 1996-2001 data, and [chi square] probability that
prevalence is significantly different from the all-Scotland mean
Saltwater Freshwater
[chi [chi
Region % Prevalence square] p % Prevalence square] p
All Scotland 49.6 N/A 10.6 N/A
North 41.1 0.001 5.5 0.1
South 55.5 -- 11.1 --
Shetland 77.0 0.001 35.3 0.001
Orkney 48.5 -- 6.7 --
Outer Hebrides 31.3 0.001 6.7 0.1
Table 2. Trends in annual average prevalence of infectious
pancreatic necrosis virus for all Scotland and by regions with
regression 90% confidence intervals, probability, and [r.sup.2a]
% Annual
Region increase 90% CI p [r.sup.2]
Marine sites
All Scotland 6.2 [+ or -] 3.1 0.012 0.82
South Mainland -3.4 [+ or -] 6.2 0.306 0.26
North Mainland 8.7 [+ or -] 5.4 0.026 0.75
Shetland 7.4 [+ or -] 3.7 0.014 0.82
Orkney 11.5 [+ or -] 3.7 0.003 0.91
Outer Hebrides 10.6 [+ or -] 7.1 0.013 0.71
Freshwater Sites
All Scotland 2.0 [+ or -] 1.5 0.051 0.66
South Mainland 1.9 [+ or -] 1.3 0.039 0.69
North Mainland 0.4 [+ or -] 1.9 0.663 0.05
Shetland 6.5 [+ or -] 3.9 0.026 0.75
Orkney 2.4 [+ or -] 2.3 0.097 0.54
Outer Hebrides 3.0 [+ or -] 2.2 0.041 0.69
(a) IPNV, infectious pancreatic necrosis virus; CI, confidence
intervals; p, probability; [r.sup.2], coefficient of determination for
bivariate analysis
Table 3. Variance in the error terms obtained in a multilevel model
with binomial assumptions regarding infectious pancreatic necrosis
virus distribution
Level of model Variance + standard error Component
1 0.333 [+ or -] 0.474 Saltwater/freshwater
2 0.582 [+ or -] 0.341 Region
3 0.362 [+ or -] 0.111 Year
4 0.042 [+ or -] 0.055 Season
Acknowledgments We thank the Fisheries Research Services Marine Laboratory's fisheries health inspectors for their data on infectious pancreatic necrosis virus. Use of trade names is for identification only and does not imply endorsement by the Public Health Service or by the U.S. Department of Health and Human Services Noun 1. Department of Health and Human Services - the United States federal department that administers all federal programs dealing with health and welfare; created in 1979 Health and Human Services, HHS . References (1.) Garrett ES, dosSantos CL, Jahnecke ML. Public, animal and environmental health implications of aquaculture. Emerg Infect Dis 1997;3:453-7. (2.) Harvell CD, Kim K, Burkholder JM, Colwell RR, Epsteine PR, Grimes DJ, et al. Emerging marine diseases--climate links and anthropogenic an·thro·po·gen·ic adj. 1. Of or relating to anthropogenesis. 2. Caused by humans: anthropogenic degradation of the environment. factors. Science 1999;285:1505-10. (3.) Stagg RM, Allan CET CET abbr. Central European Time CET Central European Time CET n abbr (= Central European Time) → hora de Europa central CET abbr . Scottish fish farms annual production survey, 2000. Aberdeen (Scotland): Scottish Executive FRS Marine Laboratory; 2001 (4.) Murray AG, Smith RJ, Stagg RM. Shipping and the spread of infectious salmon anemia in Scottish aquaculture. Emerg Infect Dis 2002;8:1-5. (5.) Anderson RM, May RM. Population biology of infectious diseases: part 1. Nature 1979;280:361-7. (6.) Hill BJ. National legislation in Great Britain for control of fish diseases. Rev Sci Tech Int Off Epiz 1996;15:633-45. (7.) Office International des Epizooties. Chapter 2.2.3. Infectious pancreatic necrosis. In: Diagnostic manual for aquatic animal diseases, 3rd edition. Paris: The Office; 2000. p. 74-81. (8.) Revie CW, Gettinby G, Treasurer JW, Rae GH, Clark N. Temporal, environmental and management factors influencing the epidemiological patterns of sea lice (Lepeophtheirus salmonis) infestations on farmed Atlantic salmon (Salmo salar) in Scotland. Pest Manag Sci 2002;58:576-84. (9.) Aguis C, Mangunwiyro H, Johnson RH, Smail DA. A more sensitive technique for isolating infectious pancreatic necrosis virus from asymptomatic carrier asymptomatic carrier, n an individual who serves as host for an infectious agent but who does not show any apparent signs of the illness; may serve as a source of infection for others. rainbow trout, Salmo gairdneri Richardson. Journal of Fish Diseases 1982;5:285-92. (10.) Bruneau NN, Thorburn MA, Stevenson RMW RMW Read-Modify-Write RMW Regulated Medical Waste RMW RM Williams (Holding Limited) RMW Radioactive Mixed Waste(s) RMW Robert Mondavi Winery RMW Rock My World . Use of the Delphi panel method to assess expert perceptions of screening test systems for infectious pancreatic necrosis virus and infectious hematopoietic necrosis virus Infectious hematopoietic necrosis virus (IHNV), is a negative-sense single-stranded RNA virus that is a member of the Rhabdoviridae family, and from the genus Novirhabdovirus. . Journal of Aquatic Animal Health 1999;11:139-47. (11.) Ariel E, Olesen NJ. Finfish finfish fish with fins, that is teleosts, elasmobranches, holocephalids, agnathids and cephalochordates; also a fish marketer's term used to include that section of marketable fish which is neither shellfish nor molluscs. in aquaculture and their diseases--a retrospective view on the European community. Bulletin of the European Association of fish Pathologists 2002;22:72-83. (12.) Jarp J, Gjevre AG, Olsen AB, Bruheim T. Risk factors for furunculosis furunculosis /fu·run·cu·lo·sis/ (fu-rung?ku-lo´sis) 1. the persistent sequential occurrence of furuncles over a period of weeks or months. 2. the simultaneous occurrence of a number of furuncles. , infectious pancreatic necrosis and mortality in post-smolt of Atlantic salmon, Salmo salar L. Journal of Fish Diseases 1994;18:67-78. (13.) Hill BJ. Infectious pancreatic necrosis virus and its virulence. In: Roberts RJ, editor. Microbial microbial pertaining to or emanating from a microbe. microbial digestion the breakdown of organic material, especially feedstuffs, by microbial organisms. diseases of fish. New York New York, state, United States New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of : Academic Press; 1982. p. 91-114. (14.) Jarp J. Epidemiological aspects of viral diseases in the Norwegian farmed Atlantic salmon (Salmo salar L.) Bulletin of the European Association of Fish Pathologists 1999;19:240-4. (15.) Small DA, Bruno DW, Dear G, McFarlane LA, Ross K. Infectious pancreatic necrosis (IPN) virus sp serotype serotype /se·ro·type/ (ser´o-tip) the type of a microorganism determined by its constituent antigens; a taxonomic subdivision based thereon. se·ro·type n. See serovar. v. in farmed Atlantic salmon, Salmo salar L., post-smolts associated with mortality and clinical disease. Journal of Fish Diseases 1992;15:77-83. (16.) Smail DA, McFarlane LA, Bruno DW, McVicar AH. The pathology of an IPN-Sp sub-type (Sh) in farmed Atlantic salmon, Salmo salar L, post-smolts in the Shetland Isles, Scotland. Journal of Fish Diseases 1995;18:631-8. (17.) Wood EM, Snieszko SF, Yasutake WT. Infectious pancreatic necrosis of brook trout brook trout or speckled trout Popular freshwater game fish (Salvelinus fontinalis), a variety of char, that is valued for its flavour and its fighting qualities when hooked. The brook trout is a native of the northeastern U.S. . AMA (Automatic Message Accounting) The recording and reporting of telephone calls within a telephone system. It includes the calling and called parties and start and stop times of the call. Arch Pathol 1955;60:26-8. (18.) Ball HJ, Munro ALS Als (äls), Ger. Alsen, island, 121 sq mi (313 sq km), Sønderjylland co., S Denmark, in the Lille Bælt, separated from the mainland by the narrow Alensund. , Ellis A, Elson KGR KGR Key Generator Receiver KGR Kukup Golf Resort (Malaysia) KGR Kristal Golf Resort (Malaysia) , Hodgkiss W, McFarlane LS. Infectious pancreatic necrosis in rainbow trout in Scotland. Nature 1971;234:417-8. (19.) Damsgard B, Mortensen A, Sommer Sommer is a surname, from the German and Danish word for the season "summer". It may refer to:
(20.) Thorburn MA. Apparent prevalence of fish pathogens in asymptomatic salmonid salmonid a member of the fish family Salmonidae. Includes salmon, trout, char. populations and its effect on misclassifying population infection status. Journal of Aquatic Animal Health 1996;8:271-7. (21.) Rasbash J, Browne W, Goldstein H, Yang M, Plewis I, Healy M, et al. A user's guide to MLwiN, Version 2.1. London: Institute of Education, University of London For most practical purposes, ranging from admission of students to negotiating funding from the government, the 19 constituent colleges are treated as individual universities. Within the university federation they are known as Recognised Bodies ; 2000. (22.) Stagg RM, Bruno DW, Cunnigham CO, Raynard RS, Munro PD, Murray AG, et al. Epizootiological investigations into and outbreak of infectious salmon anaemia anaemia see anemia. (ISA (1) (Instruction Set Architecture) See instruction set. (2) (Interactive Services Association) See Internet Alliance. (3) (Internet Security and Acceleration) See .NET. ) in Scotland. Report No 13/01. Aberdeen (Scotland): FRS Marine Laboratory; 2001. (23.) Smail DA, Munro ALS. Infectious pancreatic necrosis virus persistence in fanned Atlantic salmon (Salmo salar) In: Ellis AE, editor. Fish and shellfish pathology. New York: Academic Press; 1985. p. 277-88. (24.) McAlister PE, Owens WJ. Recovery of infective pancreatic necrosis virus from the faeces of wild piscivorous birds. Aquaculture 1992;106:222-32. Address for correspondence: A.G. Murray, FRS Marine Laboratory, Victoria Road, Aberdeen AB11 9DB, U.K.; fax: 01224 295511; email: murrays@marlab.ac.uk Dr. Murray is a senior research fellow at the Fisheries Research Services Marine Laboratory The Fisheries Research Services (FRS) Marine Laboratory is situated in Aberdeen, Scotland. It is an agency of the Scottish Executive Environment and Rural Affairs Department. FRS provides advice to the Scottish Executive and UK Government on fishing and other marine issues. , Aberdeen, Scotland, and the Department of Zoology zoology, branch of biology concerned with the study of animal life. From earliest times animals have been vitally important to man; cave art demonstrates the practical and mystical significance animals held for prehistoric man. , University Aberdeen. His research interests include the modeling of diseases and parasites of farmed and wild fish and other aquatic organisms. Alexander G. Murray, * ([dagger]) Corina D. Busby, * and David W. Bruno * * Fisheries Research Services Marine Laboratory, Victoria Road, Aberdeen, Scotland; and ([dagger]) Department of Zoology, University of Aberdeen The University of Aberdeen is an ancient university founded in 1495, in Old Aberdeen, Scotland and a world-renowned centre for teaching and research. It is the fifth oldest university in the United Kingdom and the wider English-speaking world. , Aberdeen, Scotland |
|
||||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion