RESUMO
A case of juvenile red tilapia (Oreochromis sp.) showing body deformity due to spinal curvature was investigated. Approximately 20% of the crop (4,000 fish/crop) was affected. Bacterial isolation from the kidney and tissue surrounding the spinal lesion of the affected fish was negative. Histopathology revealed granulomatous inflammation and Gram-positive cocci in connective tissues around the bone and notochord. PCR assay confirmed the presence of S. agalactiae in the spinal tissue lesion. Spinal deformity in red tilapia observed in our study may be associated with the inflammatory process and granuloma that compress the skeleton structure. The present study highlights chronic streptococcosis in tilapia culture that may be unnoticed.
Assuntos
Ciclídeos , Doenças dos Peixes , Infecções Estreptocócicas , Tilápia , Animais , Ciclídeos/microbiologia , Doenças dos Peixes/microbiologia , Infecções Estreptocócicas/microbiologia , Streptococcus agalactiae , Tilápia/microbiologiaRESUMO
BACKGROUND: The majority of infectious diseases of cultured fish is caused by bacteria. Rapid identification of bacterial pathogens is necessary for immediate management. The present study developed a custom Main Spectra Profile (MSP) database and validate the method using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for rapid identification of fish bacterial pathogens. Streptococcus agalactiae, Streptococcus iniae, Aeromonas hydrophila, Aeromonas veronii, and Edwardsiella tarda obtained from diseased fish were used as representative bacterial pathogens in this study. Bacterial peptides were extracted to create a Main Spectra Profile (MSP), and the MSPs of each bacterial species was added into the MALDI Biotyper database. Fifteen additional isolates of each bacterial species were tested to validate the utilized technique. RESULTS: The MSPs of all field isolates were clearly distinguishable, and the MSPs of the same species were clustered together. The identification methodology was validated with 75 bacterial isolates. The reliability and specificity of the method were determined with MALDI Biotyper log score values and matching results with 16 s rDNA sequencing. The species identification using the public MALDI Biotyper library (Bruker MALDI Biotyper) showed unreliable results (log score < 2.000) with 42.67% matching result with the reference method. In contrast, accurate identification was obtained when using the custom-made database, giving log score > 2.115, and a 100% matching result. CONCLUSION: This study demonstrates an effective identification of fish bacterial pathogens when a complete custom-made MSP database is applied. Further applications require a broad, well-established database to accommodate prudent identification of many fish bacterial pathogens by MALDI-TOF MS.
Assuntos
Infecções Bacterianas/veterinária , Proteínas de Bactérias/química , Bases de Dados de Proteínas , Doenças dos Peixes/microbiologia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/veterinária , Animais , Aquicultura , Infecções Bacterianas/microbiologia , Análise por Conglomerados , Peixes , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodosRESUMO
In June 2017, mass mortalities were reported at whiteleg shrimp Penaeus vannamei farms in Texas, USA. PCR testing for OIE-listed and non-listed pathogens detected the pirA and pirB toxin genes associated with acute hepatopancreatic necrosis disease (AHPND). DNA sequence analyses of cloned pirA and pirB genes showed them to be identical to those detected in other AHPND-causing Vibrio sp. Amplicons generated using PCR tests targeted to the toxR gene showed the Pir toxin genes to be associated with a V. parahaemolyticus type more similar to a genotype found in Mexico compared to that found in Asia. Histology detected masses of bacteria and hemocytic infiltrations as well as extensive necrosis and sloughing of epithelial cells in hepatopancreatic tubules pathognomonic of AHPND. The data support AHPND as the cause of the mortalities. Given that US companies produce shrimp broodstock for farms in Asia and Latin America, the further spread of AHPND in the USA needs to be prevented to avoid serious economic consequences to these industries.
Assuntos
Hepatopâncreas/patologia , Vibrioses/diagnóstico , Vibrio parahaemolyticus/isolamento & purificação , Doença Aguda , Animais , Humanos , Necrose , Penaeidae/microbiologia , Texas , Vibrio parahaemolyticus/genéticaRESUMO
White feces syndrome (WFS) is an emerging problem for penaeid shrimp farming industries in SE Asia countries, Thailand, Malaysia, Vietnam, Indonesia, China, and in India. This occurrence of this syndrome is usually first evidenced by the appearance of white fecal strings floating on surface of the shrimp ponds. The gross signs of affected shrimp include the appearance of a whitish hindgut and loose carapace, and it is associated with reduced feeding and growth retardation. To investigate the nature of the white feces syndrome, samples of white feces and shrimp hepatopancreas tissue were collected from Penaeus vannamei in affected farms in Indonesia, and these were examined histologically. Within the white feces, we found densely packed spores of the microsporidian Enterocytozoon hepatopenaei (abbreviated as EHP) and relatively fewer numbers of rod-shaped bacteria. From WFS ponds, hepatopancreas samples form 30 individual shrimp were analyzed by histology and in situ hybridization. The results showed that all of the shrimp examined were infected with EHP accompanied by septic hepatopancreatic necrosis (SHPN). Midgut epithelial cells were also infected and this increased the number of tissue types being affected by EHP. By PCR, EHP was detected in all the samples analyzed from WFS-affected ponds, but not in those sampled from healthy shrimp ponds. To determine the modes of transmission for this parasite, we performed feeding and cohabitation bioassays, the results showed that EHP can be transmitted through per os feeding of EHP-infected hepatopancreas tissue to healthy shrimp and through cohabitation ofinfected and healthy shrimp. In addition, we found the use of Fumagillin-B, an antimicrobial agent, was ineffective in either reducing or eliminating EHP in infected shrimp.
Assuntos
Penaeidae/parasitologia , Frutos do Mar/parasitologia , Animais , Aquicultura , Enterocytozoon , Fezes/microbiologia , Reação em Cadeia da PolimeraseAssuntos
Enterite , Doenças dos Peixes , Perciformes , Animais , Infecções Assintomáticas , Enterite/veterinária , Streptococcus iniaeRESUMO
Over the past 2 decades, shrimp aquaculture in Thailand has been impacted by white spot disease (WSD) caused by white spot syndrome virus (WSSV). Described here are results of a survey of 157 intensive shrimp farms in Chanthaburi province, Thailand, to identify potential farm management and location risk factors associated with the occurrence of WSD outbreaks. Logistic regression analysis of the survey responses identified WSD risks to be associated with farms sharing inlet water and culturing shrimp year round and with a single owner operating more than 1 farm. The analysis also showed WSD risks to be reduced at farms that used probiotics and applied lime to pond bottoms when fallow to neutralize acidity and kill microorganisms. Regression modeling identified no association of geographical location with WSD. The data should assist shrimp farms in mitigating the effects of WSD in Thailand.
Assuntos
Criação de Animais Domésticos/métodos , Penaeidae/virologia , Animais , Aquicultura , Interações Hospedeiro-Patógeno , Tailândia , Vírus da Síndrome da Mancha Branca 1RESUMO
Plastic waste has emerged as a major environmental concern in recent years. As plastic waste discharged into the marine environment, it undergoes a breakdown process, eventually accumulating in aquatic organisms in the form of microplastics (MPs). To date, reduced food intake, nutritional absorption, and impaired immune system are known adverse effects of MPs-exposed aquatic organisms. This study aims to investigate whether MP exposure accelerated white spot syndrome virus (WSSV) infection in Pacific white shrimp (Penaeus vannamei) via laboratory tests. Briefly, experimental shrimp were divided into four groups; WSSV (group 1); MP (group 2); WSSV + MP (group 3); and Control (group 4). No mortality was observed in group 2, group 4, and even in group 1. However, group 3 showed a cumulative mortality of 50% during the experimental period. The PCR assay results showed no WSSV in the other three groups (groups 1, 2, and 4), but the dead and alive shrimp collected from group 3 were confirmed to be infected with the virus. Histopathological examination revealed normal structures in the hepatopancreas, gill, and muscle tissues of group 4, whereas numerous abnormally shaped nuclei were detected in the gill tissue of group 2. Moreover, group 1 showed minor WSSV-related lesions with few basophilic inclusion bodies in the gills, interestingly, group 3 exhibited severe lesions with numerous basophilic inclusion bodies in the gills. In conclusion, this study confirmed the correlation between the viral disease of shrimp and MPs, which can cause significant economic losses to the shrimp aquaculture industry.
RESUMO
The increasing economic losses associated with growth retardation caused by Enterocytozoon hepatopenaei (EHP), a microsporidian parasite infecting penaeid shrimp, require effective monitoring. The internal transcribed spacer (ITS)-1 region, the non-coding region of ribosomal clusters between 18S and 5.8S rRNA genes, is widely used in phylogenetic studies due to its high variability. In this study, the ITS-1 region sequence (~600-bp) of EHP was first identified, and primers for a polymerase chain reaction (PCR) assay targeting that sequence were designed. A newly developed nested-PCR method successfully detected the EHP in various shrimp (Penaeus vannamei and P. monodon) and related samples, including water and feces collected from Indonesia, Thailand, South Korea, India, and Malaysia. The primers did not cross-react with other hosts and pathogens, and this PCR assay is more sensitive than existing PCR detection methods targeting the small subunit ribosomal RNA (SSU rRNA) and spore wall protein (SWP) genes. Phylogenetic analysis based on the ITS-1 sequences indicated that the Indonesian strain was distinct (86.2% nucleotide sequence identity) from other strains collected from Thailand and South Korea, and also showed the internal diversity among Thailand (N = 7, divided into four branches) and South Korean (N = 5, divided into two branches) samples. The results revealed the ability of the ITS-1 region to determine the genetic diversity of EHP from different geographical origins.
Assuntos
DNA Espaçador Ribossômico , Enterocytozoon , Microsporidiose , Penaeidae , Filogenia , Reação em Cadeia da Polimerase , Enterocytozoon/genética , Enterocytozoon/isolamento & purificação , Enterocytozoon/classificação , Penaeidae/microbiologia , Penaeidae/parasitologia , Animais , DNA Espaçador Ribossômico/genética , Reação em Cadeia da Polimerase/métodos , Microsporidiose/microbiologia , Microsporidiose/diagnóstico , DNA Fúngico/genética , Primers do DNA/genética , Fezes/microbiologia , Fezes/parasitologia , Análise de Sequência de DNA , TailândiaRESUMO
Juvenile Asian seabass (Lates calcarifer) (body weight 10 ± 0.7 g) were intraperitoneally injected with 1012 CFU fish-1 of formalin-killed Streptococcus iniae. The protective efficacy of the vaccine on survival and infection rate was assessed upon challenge at 4, 8, 12, 20, and 28 weeks post-vaccination. The results revealed that the challenged vaccinated fish showed no mortality at all time points, and the control fish presented 10-43.33% mortality. The infection rate at 2 weeks post-challenge was 0-13.33% in the vaccinated fish and 30-82.35% in the control group. At 8 weeks post-vaccination, the vaccinated fish showed comparable ELISA antibody levels with the control; however, the antibody levels of the vaccinated fish increased significantly after the challenge (p < 0.05), suggesting the presence of an adaptive response. Innate immune genes, including MHC I, MHC II, IL-1ß, IL-4/13B, and IL-10, were significantly upregulated at 12 h post-challenge in the vaccinated fish but not in the control. In summary, vaccination with S. iniae bacterin provided substantial protection by stimulating the innate and specific immune responses of Asian seabass against S. iniae infection.
RESUMO
We developed a qPCR assay based on the ß-tubulin gene sequence for the shrimp microsporidian parasite Enterocytozoon hepatopenaei (EHP). This assay reacted with the hepatopancreas (HP) of EHP-infected shrimps, and the highest copy numbers were found in HP and feces samples from Southeast Asian countries (106-108 copies mg-1), while HP samples from Latin America, Artemia, and EHP-contaminated water showed lower amounts (101-103 copies mg-1 or mL-1 of water). No false positive was found with the normal shrimp genome, live feeds, or other parasitic diseases. This tool will facilitate the management of EHP infection in shrimp farms.
RESUMO
We report here the complete genome sequence of Vibrio campbellii, isolated from Penaeus vannamei cultured in a Latin American country. The Tn3-like transposon and pirAB genes were encoded on the plasmid pLA16-2. These data support the geographical variations in the virulence plasmid found among acute hepatopancreatic necrosis disease (AHPND)-causing Vibrio isolates from Latin America and Asia.