Shrimp and Fish Diseases

It is believed by many that parasites are only as important as the fish they infect. Parasites are ubiquitous, primarily surviving in a dynamic equilibrium with their host(s) and they are often overlooked in fish health assessments. Changes in the environment, both anthropogenic and environmental, can alter the parasite/host equilibrium and cause disease or mortality in fish. Therefore it is imperative that we have knowledge of both parasites and parasitic communities within a given population. When fish kills occur, it can often be associated with changes in parasite density and community composition. Often the damage associated with these fish is relative to the rate of infestation with the parasite; a fish that is lightly infected will show few signs of the parasite, while a heavily infected fish may become physiologically impaired and even die. Parasites can cause mechanical damage (fusion of gill lamellae, tissue replacement), physiological damage (cell proliferation, immunomodulation, detrimental behavioral responses, altered growth) and reproductive damage. As parasitism is the most common lifestyle on the planet, understanding its role in the environment may help researchers understand changes in a given fish population or stream ecosystem.

Flavobacterium columnare is the aetiological agent of columnaris disease and severely affects various freshwater aquaculture fish species worldwide. The objectives of this study were to determine the phenotypic characteristics and genetic variability among F. columnare isolates isolated from red tila-pia in Thailand. Forty-four F. columnare isolates were recovered from diseased fish in different geographical locations. The isolates exhibited homologous phenotypic characteristics but exhibited genetic diversity. One isolate was assigned to genomovar I, and the remainder were assigned to genomovar II, indicating the coexistence of these genomovars but predominance of genom-ovar II. Phylogenetic analysis of the 16S-23S ISR sequences revealed that a subset of the Thai isolates (n = 25) contained a smaller intergenic spacer region (ISR) (523–537 bp) and formed a unique ISR phylogenetic group. Phylogenetic analysis of the 16S rRNA gene supported the unique cluster of Thai isolates. This is the first description of the phenotypic and molecular characteristics of F. columnare isolated from red tilapia in Thailand as well as five isolates of F. columnare derived from other fish species including Nile tilapia, koi carp and striped catfish.

The Litopenaeus vannamei is one of the most important economical shell fish in throughout the world. Mineral
deposition is a continuous problem in Litopenaeus vannamei culture pond in world wild. The current study to
compares the water quality parameters, shrimp growth biomass, and mortality rates during harvest between three
ponds. Experimental setup was selected three different ponds (brackish water pond, bore well pond, and bore well
resevoir pond) were seeded with the same density of the Litopenaeus vannamei at Pennar River Andhra Pradesh,
south India. The primary differences between the ponds were as the water source; one pond was filled from the
estuary, estuarine-water was fed to the pond, the second one was taken from bore wells with high alkalinity, and
there’d one filled from bore well resevoir pond. Temperature in three ponds was varied and it reached up to 29.6°C
after 125 days of culture. Dissolved oxygen (DO) levels were varied within the acceptable range although levels
in the alkaline pond were as near the lower limit in the last 90 days before harvest. Salinity levels were varied in
three ponds, above optimal levels and increased over the 120 days. Alkalinity in the estuarine water was typically
<100 ppm and whereas (275-399 ppm) in the alkaline pond. In the alkaline pond, beginning on 75th day the mineral
deposits was observed all parts of shrimp over the body and it’s including the eye and the inner gill chambers after
harvest, 42% of the shrimp showed this coating. The initial stages of the mineral deposits on shrimps showed
pale yellow colour. Elemental analysis identified the major constituents was present in the sample as Manganese,
Sodium, Chlorine, Magnesium, Aluminium, Silica, Iron and Calcium. Survival rates of shrimps in the estuarine-water-
fed pond was 92% with a total pond biomass at harvest was 1.65 tons ha-1 compared to survival rates of 79% in the
alkaline pond and a biomass at harvest was 1.020 tons ha-1. When quality water may be used, its alkalinity should
be monitored and diluted with water from other sources.

Earthen pond rearing system is the most prevalent type of aquaculture facilities in Egypt due to low construction costs. Such facilities are characterized by open nature which allows large numbers of imposing factors to interact with cultured fishes during the production cycle. Aquatic invasive species (i.e., red swamp cray fish: Procambrus  clarkii), migratory birds, wild amphibians and reptiles are staggering examples for such interacting factors, which impose severe deleterious impacts on the fish production cycle. The active nature and vast distribution of these species will ultimately violate the rearing regime of the fish farming facility through the establishment, proliferation and spread of pathogens by mechanical, biological and direct infectious routes. Further, the wet nature of aquaculture operations, frequent introduction of new broodstocks, fish meal, reuse of agricultural drainage water and faulty use of animal manure as well as movement of fish from different localities offers a multitude of opportunities for pathogen entry to fish farming operations. Once introduced, pathogens can easily proliferate within the systems leading to potent disease issues, sometimes leading to a complete collapse in production, or more intermittent outbreaks affecting output reliability. Therefore, this study is designated to examine the key role played by invasive species, vectors and reservoirs responsible for pathogen introduction into fish farms. Moreover, the essential needs were discussed for development of practical methods to limit pathogen introduction, spread and proliferation at any level of fish production cycle parallel with the adoption of Good Aquaculture Practice (GAP) and Hazard Analysis and Critical Control Points (HACCP) in Egyptian fish farms.

Several species of Vibrio are the causative agent of gastroenteritis in humans. In aquaculture , Vibrio harveyi (Vh) and V. parahaemolyticus (Vp) have long been considered as shrimp pathogens in freshwater, brackish and marine environments. Here we show by using scanning electron microscopy (SEM) that Penaeus monodon orally inoculated with each of these two pathogens via an Artemia diet had numerous bacteria attached randomly across the stomach surface, in single and in large biofilm-like clusters 6 h post-infection. A subsequent marked proliferation in the number of V. harveyi within the biofilm-like formations resulted in the development of infections in the stomach, the upper and middle midgut, but neither in the posterior midgut nor the hindgut. SEM also revealed the induced production of peritrichous pili-like structures by the Vp attaching to the stomach lining, whilst only a single polar fibre was seen forming an apparent physical bridge between Vh and the host's epithe-lium. In contrast to these observations, no such adherences or linkages were seen when trials were conducted with non-pathogenic Vibrio spp. or with Micrococcus luteus, with no obvious resultant changes to the host's gut surface. In naive shrimp, the hindgut was found to be a favorable site for bacteria notably curved, short-rod shaped bacteria which probably belong to Vibrio spp. Data from the current study suggests that pathogens of P. monodon must be able to colonize the digestive tract, particularly the stomach, where chitin is present, and then they use an array of virulent factors and enzymes to infect their host resulting in disease. Oral infection is a better way of mimicking natural routes of infection; investigating the host-bacteria interactions occurring in the digestive tract may lead to new strategies for the prevention or control of bacterial infections in penaeids.

This review was conducted to investigate the significance, underlying causes and negative effects of nutritional diseases of fish on aquaculture production and health safety. Information were collected from different secondary sources and then arranged chronologically. Investigation reveals that, Aquaculture is the largest single animal food producing agricultural sector that is growing rapidly all over the world. Nutritional disease is one of most devastating threats to aquaculture production because it is very difficult to identify nutritional diseases. Production cost get increased due to investment lost, fish mortality, treatment cost and decreased yield quality and quantity. Public health hazards are also in dangerous situation due to frequent disease outbreak and treatment involving synthetic drugs. It is very essential to control nutritional diseases to increase fish supply through aquaculture production. This study will be helpful to provide basic knowledge on nutritional diseases management in aquaculture and to raise awareness among the farmers fisheries management. Abstract Abbreviations EPA: Eicosa-pentaenoic Acid; DHA: Docosahexaenoic Acid; UFA: Unsaturated Fatty Acid; EFA: Essential Fatty Acids.

The first time the white spot disease (WSD) and IHHNV were reported in Iran was in 2004
and  2008,  respectively  in  Bushehr  Province. In Sistan and Balochestan  province  only the
WSD  was  reported  in  2008.The  aim  of  this  study  was detecting  these two  viral  diseases  in
these provinces, during December 2009 to April 2010. A total of 364 samples were collected
according to  suspected gross  signs  from  hatcheries  and  shrimp  farms  in  Bushehr  and  Sistan
and Blochestan  provinces  (I.R.  Iran)  respectively, including  larvae  (72,  43  samples),  post
larvae  (48,  37  samples),  juveniles  (57,  32  samples),  sub  adults  (39,  22  samples)  and
broodstock (29, 13 samples) of Litopenaus vannamei . WSD was detected from juveniles (23
samples),  sub  adults (14  samples),  and  broodstock  (14  samples),  and IHHNV was  also
detected  from  juveniles (16  samples),  sub  adults (9  samples)  and  broodstock  (5 samples)
based  on  gross  signs,  PCR and histopathological  changes  from  Bushehr  province  but  from
Sistan and Blochestan  province  only  WSD  was  detected  from  juveniles (26  samples),  sub
adults (18  samples)  and  broodstock  (7  samples). Histopathological  observations  of  WSSV
showed basophilic Cowdry type A inclusion bodies in all tissues such as gills, haematopoietic
tissue, cuticle epithelium, lymphoid organ and connective tissue. However histologically, the
hepatopancreas  tissue  showed  vacuolization  of  B  cells,  without  inclusion  bodies,  but
histopatholgical changes caused by IHHNV including eosinophilic Cowdry type A inclusion
bodies which were ectodermal, mesodermal and rarely endodermal.

Polymerase Chain Reaction (PCR) technique allows the detection  of the most enterovirulent Escherichia coli
strains: enterotoxigenic (ETEC), enteroinvasive (EIEC), enterohaemorrhagic (EHEC) and enteropathogenic
(EPEC). However, PCR efficiency depends on the primer design, target samples and environmental factors. The aim
of the present study was  therefore  to  detect enterovirulent strains of E. coli in the four different shrimp farms of
Dumuria, Khulna, Bangladesh. Water, sediment and shrimp  were examined from each farm. Six pairs of
oligonucleotide  specific  primers were  used for the amplification and thereby detection of target genes viz. the
alkaline phophatase (phoA), the heat-labile toxin1 (hlt1), heat-labile toxin2 (hlt2), heat-stable toxin1(hst1),
verotoxin (vt) and attachment and effacement (eae) virulence genes. Finally, PCR products were analyzed and
detection of different strains was confirmed by agarose gel electrophoresis using DNA markers. The results revealed
the presence of  phoA gene, hlt1 and hlt2 genes of ETEC in the shrimp and water samples of two different farms. At
the same time,  vt  gene of EHEC was found especially in the shrimp body. One farm was completely free of EEC
strains, which might be due to sanitation.  Moreover, enterovirulent E. coli strains were absent in the sediment of all of the experimental farms. These findings of the study suggest that the PCR method is a highly sophisticated and
useful tool to analyze the dynamics of fecal bacteria in shrimp farms

The aquatic veterinary practice have witnessed the publication of many diagnostic manuals that mainly focused on specific species , specific group of fishes , specific group of pathogens or specific diagnostic procedures. However, comprehensive forms of diagnostic manuals are relatively scarce. Thereby, a wide scope of clinical and laboratory procedures have been addressed in the current manual. The manual contain detailed information about the finfish anatomy, farm visits, fish reflexes/ behavior , possible etiologies / description of the lesions of the most common finfish diseases, transportation, anesthesia , sampling , laboratory bacteriological and parasitological examination. The last chapter of the manual is a briefed colored atlas of fish anatomy.

The shrimp aquaculture is one of the most important livelihoods in the Philippines.  Although there is an observed boost in the production of shrimps in the Philippines, there are remaining problems that are needed to be resolved.  Bacterial and viral infections in shrimps have significantly affected its mortality, resulting in lower production and yield.  In order to prevent or lessen this effect, various researches have been made to increase the resistance of shrimps against infections.  In this study, a probiotic microorganism, Lactobacillus salivarius was used as a dietary supplementation for Macrobrachium rosenbergii and see its influence on the antioxidant biomarkers and temperature stress tolerance of the shrimp. Three concentrations of L. salivarius (1.0x107, 1.0x108, and 1.0x109 cells/g) were initially tested for its effect towards the oxidative stress tolerance and the oxygen consumption of the shrimp.  The study involved the use of various antioxidant biomarkers, including total glutathione (tGSH), catalase enzyme activity, and lipid peroxidation. Results showed that 1.0x108 cell/g of L. salivarius was the most effective concentration of probiotic micro organism per weight of feeds in improving the metabolic rate of the shrimp. Oxidative stress tolerance levels were observed to be increasing in terms of the catalase reaction (12.46 and 21.74 nmole/min) and lipid peroxidation (1.4x10-7 and 1.49x10-7 nmole MDA/mg protein) on both hepatopancreas and muscles tissues when the shrimp was fed with supplemented feeds. Also, high oxidant stress biomarkers were more evident on the hepatopancreas than the muscles.

A problem often faced by grouper fish exporters is the high mortality rate (97%) of the fish due to stress during transport. The present study was conducted to analyzethe effect of clove oil on blood glucose levels and the number of erythrocyte during close transport system. This experimental design used complete randomized design (CRD). The data obtained in the study were analyzed using statistical test ANOVA (Analysis of Variance) to determine whether there were differences among the treatments, followed by Duncan's multiple range test. Results of the study showed blood glucose value of P< 0.05, indicating significant difference in the treatment of clove oil. Duncan's multiple range test showed that there were significant differences among the treatments P2 (MS-222 70 ppm) with P1 (negative control), P3 (clove oil 5 ppm), P4 (clove oil 10 pp) and P5 (clove oil 15 ppm). Total erythrocyte estimation shows the value of p>0.05, indicating no significant difference in clove oil treatment. In this study,Duncan's multiple range test showed no significant differences among treatments.

White spot Baculovirus (WSBV) infection of shrimp is characterized by high mortality of tiger shrimp Penaeus monodon. The gross signs of moribund shrimp are present of white spot, initially circular, inside cuticle, sometimes accompanied by overall red body coloration. The 5 major protein were isolated from WSBV are 15 kDa (VP15), 19 kDa (VP19), 24 kDa (VP24), 26 kDa (VP26) and 28 kDa (VP28). The isolated protein were then purified and characterized to be VP19, VP24, and VP28. Purified protein injected to shrimp to detect whether they have a protective immunity against WSBV infection. The result showed protection of infected shrimp against WSBV after administration of VP19, VP24 and VP28 are 20%, 0% and 60%, respectively. VP28 injected shrimp have a high production of phenoloxidase 24.1822 U/min/mg and after WSBV challenged 44.6067 U/min/mg. Based on the result suggest that VP28 of WSBV is potentially to increase immune response in penaeid shrimp.

Eighty fresh samples of Oreochromis niloticus of family Cichildae were collected from Jable
Aulia dam – Al shagara farm, University farm – Wad Al Mamon farm, (40 from the Nile and 40
from the farms), during the period April to July 2009.The spacemen’s were examined for the
presence of fungal contamination, based on the generic names of the isolated organisms.
The density of contamination of the total samples was found to be 54% while the density of
contamination in fishes collected from Jable aulia dam 70% (which represent the natural
environment) Alshagara farm 38% Sudan University farm 47% and Wad Al Mamon farm 42%
(which represent the culture environment the density of contamination was found to be 42%).
The fungal organism was identified as Saprolegnia spp, Aphanomyces spp, Achlaya spp,
Asperigulus niger, pencilium spp and Rhizopupus species.

En el presente trabajo se determinó la prevalencia, abundancia e intensidad promedio de los parásitos encontrados en el intestino de juveniles de Litopenaeus schmitti en las localidades de Curarire (Municipio Cañada de Urdaneta) y Santa Rita (Municipio Santa Rita), Lago de Maracaibo, Estado Zulia, Venezuela. El diagnóstico parasitológico se hizo mediante el examen microscópico en fresco de intestino. La identificación y clasificación se realizó según Levine et al. (1980) y Hutton et al. (1959). Se reporta la gregarina Nematopsis sp (Protozoa: Apicomplexa) en diferentes etapas de desarrollo y una larva de eucestodo (Cestoda: Lecanicephallidae) libres en el lúmen intestinal. Los valores más altos de prevalencia (P= 24,24%), abundancia (A= 4,06 Nematopsis/camarón) e intensidad promedio (IP= 16,75 Nematopsis/camarón) de Nematopsis sp, se observaron en los ejemplares de menor talla (20-35 mm LT), procedentes de la localidad de Curarire. El mayor porcentaje de ejemplares parasitados fueron hembras. Los valores más altos de prevalencia (P= 52,78%), abundancia (A= 63,39 larvas/camarón) e intensidad promedio (IP= 136,50 larvas/camarón) de la larva de eucéstodo (Metazoa: Lecanicephallidae), se registraron en ejemplares de menor talla (55-85 mm LT), procedentes de Santa Rita. En éste caso el mayor porcentaje de ejemplares parasitados fueron machos. No se observaron lesiones ni reacción inflamatoria en el tejido epitelial intestinal que representen un efecto dañino de los parásitos reportados en los ejemplares silvestres de Litopenaeus schmitti.

Background and Aim: There has been continuous effort to search for alternative medicinal plants that are applicable to ameliorate viral disease on shrimp pond. This study aimed to examine the effect of Acanthus ilicifolius leaf extract on clinical symptoms and non-specific immune response of black tiger shrimp (Penaeus monodon).

Materials and Methods: A total of 330 shrimps were equally assigned into three extract forms (crude extract, ethyl acetate extract, and n-butanol extract, respectively) in which three levels were provided for each extract. Negative control (without leaf extract) and positive control (with oxytetracycline at 0.05 mg/mL) were used, giving a total of 11 experimental treatments.

Results: The results showed that shrimps induced into all form of leaf extracts had significantly higher survival rates, clinical symptoms, and pathological anatomy than those negative control (C–) and positive control (C+). Total hemocyte cells, granulocytes, percentage of phagocytic, and prophenoloxidase activity were similar among leaf extract treatments (p>0.05), but those groups were significantly higher than those of C– and C+ (p<0.05).

Conclusion: n-butanol leaf extract at 300 mg/L is suggested to be the most effective treatment since it showed the highest efficacy on the parameters observed. Thus, it is possible to use the leaf extract of A. ilicifolius on-farm as a strategy to enhance bacterial disease resistance and prevent mortality.

Several bacteriological surveys were performed from 1994 to 1996 at different Litopenaeus vannamei hatcheries (in Ecuador) and shrimp farms (in Mexico). Samples were taken from routine productions of healthy and diseased L. vannamei larvae, postlarvae, and their culture environment and from healthy and diseased juveniles and broodstock. In Ecuador, the dominant bacterial flora associated with shrimp larvae showing symptoms of zoea 2 syndrome, mysis mold syndrome, and bolitas syndrome has been determined. Strains were characterized by Biolog metabolic fingerprinting and identified by comparison to a database of 850 Vibrio type and reference strains. A selection of strains was further genotypically fine typed by AFLP. Vibrio alginolyticus is predominantly present in all larval stages and is associated with healthy nauplius and zoea stages. AFLP genetic fingerprinting shows high genetic heterogeneity among V. alginolyticus strains, and the results suggest that putative probiotic and pa...

Seaweeds can play an essential role in controlling antibiotic resistance for bacterial diseases. Three extracts of two brown seaweeds Padina tetrastromatica and Sargassum ilicifolium were investigated as growth promoters and to provide immune protection against Vibrio parahaemolyticus. Extracts of the two seaweeds were administered at 2.5 and 5 g kg À1 with food for 45 days to Penaeus monodon juveniles. The maximum weight gain (6.28 and 7.08 g), specific growth rate (3.39 and 3.32%), and survival rate (78.45 and 82.45%) of the juvenile tiger shrimp were obtained at a dose of 5 g kg À1 with P. tetrastromatica extracted by methanol and ethanol, respectively; which was significantly higher than the other solvents and control group (p < .01). On the other hand, methanol extract of both seaweeds had maximal antibacterial activity against V. parahaemolyticus with zones of inhibition ranging between 20.25 ± 1.00 and 22.00 ± 0.50 mm. The minimal time required for haemolymph clotting was with methanol extracted of P. tetrastromatica at 5 g kg À1 , which was significantly lower than the other groups (p < .05). After challenging with V. parahaemolyticus, the total haemocyte count (THC) in P. monodon treated with methanol-extract of P. tetrastromatica diet at 5 g kg À1 was higher (5.42 Â 10 5 cells mL À1) but not significantly different than the other diets (p > .05). However, the administration of 5 g kg À1 methanol and ethanol extract of P. tetrastromatica improved growth performance and the immune capacity of P. monodon by increasing their phenoloxidase activity, superoxide anion concentration, and resistance against V. parahaemolyticus. HIGHLIGHTS The maximum growth performance and survival of juvenile tiger shrimps obtained with Padina tetrastromatica extract at a dose of 5 g kg À1. The methanol extract of P. tetrastromatica and Sargassum ilicifolium had maximal antibacterial activity against V. parahaemolyticus. The administration of 5 g kg À1 methanol and ethanol extract of P. tetrastromatica improved growth performance and the immune capacity of P. monodon.

Se describen algunas pruebas realizadas en una larvicultura comercial de camarón Penaeus vannamei con el uso de ácidos orgánicos, incluyendo su efecto sobre los microorganismos (inhibición microbiana, conteos de colonias), así como su efecto sobre las postlarvas (sobrevivencia, productividad). Se concluye que el empleo de estos productos resulta en mejoras significativas de los parámetros de producción de un laboratorio.

Aim: The present study investigated hemocytes profile of black tiger shrimp (Penaeus monodon) induced with Xylocarpus granatum leaves extract to protect against Vibrio harveyi infection. Materials and Methods: X. granatum leaves were chopped into small size, air-dried, and extracted with one of the following solvents: Ethanol, distilled water, and seawater, whereas each solvent was given in three different concentrations (750 ppm, 1.000 ppm, and 1.250 ppm, respectively). Extracts were induced to 60 post-larvae shrimp in each treatment (three replicates, 20 shrimp for each) by immersing method and subsequently challenged with V. harveyi. Results: This study demonstrated different effectiveness among solvents used to extract X. granatum leaves, in which distilled water showed the most effective solvent as can be seen from the lowest percentage on anorexia, lethargic, and weakened reflex of shrimp compared with another solvent, positive and negative controls. Pathological symptoms for ...

Several bacteriological surveys were performed from 1994 to 1996 at different Litopenaeus vannamei hatcheries (in Ecuador) and shrimp farms (in Mexico). Samples were taken from routine productions of healthy and diseased L. vannamei larvae, postlarvae, and their culture environment and from healthy and diseased juveniles and broodstock. In Ecuador, the dominant bacterial flora associated with shrimp larvae showing symptoms of zoea 2 syndrome, mysis mold syndrome, and bolitas syndrome has been determined. Strains were characterized by Biolog metabolic fingerprinting and identified by comparison to a database of 850 Vibrio type and reference strains. A selection of strains was further genotypically fine typed by AFLP. Vibrio alginolyticus is predominantly present in all larval stages and is associated with healthy nauplius and zoea stages. AFLP genetic fingerprinting shows high genetic heterogeneity among V. alginolyticus strains, and the results suggest that putative probiotic and pathogenic strains each have specific genotypes. V. alginolyticus was found to be associated with larvae with the zoea 2 syndrome and the mysis mold syndrome, while different Vibrio species (V. alginolyticus and V. harveyi) are associated with the bolitas syndrome. V. harveyi is associated with diseased postlarvae, juveniles, and broodstock. The identities of the strains identified as V. harveyi by the Biolog system could not be unambiguously confirmed by AFLP genomic fingerprinting. Vibrio strain STD3-988 and one unidentified strain (STD3-959) are suspected pathogens of only juvenile and adult stages. V. parahaemolyticus, Photobacterium damselae, and V. mimicus are associated with juvenile and adult stages.

This study aimed to estimate the genotype-by-environment interaction for body weight (BW) and harvest survival (HS), in the presence and absence of White Spot Disease (WSD) in two genetic lines of Penaeus vannamei (Growth-GRO-and resistance to WSD-RES-). The heritability for BW in the GRO line was 0.05 ± 0.16 in the presence of WSD and 0.35 ± 0.15 in the absence, while for the RES line it was 0.26 ± 0.07 and 0.49 ± 0.08 in the presence and absence of WSD, respectively. The genetic correlations for BW between environments were-0.17 ± 0.60 for GRO and 0.89 ± 0.09 for RES. The heritability for HS in GRO was 0.01 in both environments and the genetic correlation was not estimable, while, for RES, the heritabilities were 0.06 ± 0.04 and 0.11 ± 0.06 in the absence and presence of WSD, respectively, additionally, the genetic correlation it was not significant. Although the linear model suggests a genotype-by-environment interaction, the estimates propose independence of the same characteristic between environments, and the correlations between characteristics for the resistance line propose to independently select the characteristics when WSD is present.

La acuicultura ha mostrado un crecimiento vertiginoso en los últimos años y se espera que esa tendencia se sostenga. El cultivo de camarones es uno de los renglones más vigorosos dentro del subsector, particularmente en Venezuela. Las amenazas más significativas para el potencial acuícola están constituidas por las enfermedades. En tal sentido, a nivel global está tomando fuerza la implementación de programas de bioseguridad en las instalaciones acuícolas, procurando evitar la ocurrencia de patologías. A pesar del peligro siempre presente de enfermedades, no se conoce de trabajos previos en el país que consideren los riesgos existentes para organismos en una facilidad de producción acuícola. Por esta razón, se concibió desarrollar un estudio de los peligros sanitarios presentes para la operación de una camaronera comercial situada en la isla de Coche, Venezuela. Se realizaron visitas semanales a la granja por espacio de un año. Se recabó información pertinente por medio de instrumentos de encuestas y levantamiento directo, y se analizó a la luz de literatura científica relacionada. Como resultado, fueron evidentes numerosas prácticas y condiciones que constituyen peligros en el ámbito sanitario. De la misma forma, se identificaron 40 elementos de riesgo para la salud de los camarones (11 virales, diez bacterianos, cuatro micóticos, uno asociado a microalgas, seis protistas, tres helmínticos, un cnidario y cuatro abióticos. Entre ellos, ocho con riesgo moderado por lo cual se propone un plan de bioseguridad para la empresa el cual se recomienda abordar a la brevedad para prevenir problemas patológicos.

ABSTRACT Objective: Acute hepatopancreatic necrosis disease is an emerging infectious disease of Penaeus species. The causative agent is Vibrio species, which dispels binary toxin similar to pirA and pirB, which causes mortality in infected shrimp. The aim of this research was to investigate the evolutionary relationship of pirA and pirB homologous genes present in this Asia and Costa Rica in silico. Materials and methods: The sequences for in silico analysis were all retrieved from the Basic Local Alignment Search Tool Nucleotide (BLASTN) tool of the National Center for Biotechnology Center. For pirA, a total of 25 sequences submitted from different Asian countries and Costa Rica were retrieved for analysis. Meanwhile, for pirB, a total of 11 sequences submitted from five Asian countries were retrieved. Sequences were aligned using the CLUSTAL W alignment tool under Molecular Evolutionary Genetics Analysis (MEGA) 7 software. The evolutionary history was then estimated using the Unweighted Pair Group Method with Arithmetic mean (UPGMA) method, whereas the evolutionary distances were determined using the maximum composite likelihood model with 1,000 bootstrap replications. Results and Discussion: The results show that, among 27 DNA sequences analyzed for pirA gene, three groups were generated, while for pirB, 13 DNA sequences yielded only one group. The analysis revealed low genetic variation among isolates for both pirA and pirB genes. Conclusion: This result suggests that the low frequency of polymorphism and geographic location cannot be attributed to the differences in V. parahaemolyticus isolates in Asian countries relative to Costa Rican isolates in pirA and pirB genes. ARTICLE HISTORY