Risk assessment of wild fish as environmental sources of red sea bream iridovirus (RSIV) outbreaks in aquaculture.

Red sea bream iridovirus (RSIV) causes substantial economic damage to aquaculture. In the present study, RSIV in wild fish near aquaculture installations was surveyed to evaluate the risk of wild fish being an infection source for RSIV outbreaks in cultured fish. In total, 1102 wild fish, consisting of 44 species, were captured from 2 aquaculture areas in western Japan using fishing, gill nets, and fishing baskets between 2019 and 2022. Eleven fish from 7 species were confirmed to harbor the RSIV genome using a probe-based real-time PCR assay. The mean viral load of the RSIV-positive wild fish was 101.1 ± 0.4 copies mg-1 DNA, which was significantly lower than that of seemingly healthy red sea bream Pagrus major in a net pen during an RSIV outbreak (103.3 ± 1.5 copies mg-1 DNA) that occurred in 2021. Sequencing analysis of a partial region of the major capsid protein gene demonstrated that the RSIV genome detected in the wild fish was identical to that of the diseased fish in a fish farm located in the same area in which the wild fish were captured. Based on the diagnostic records of RSIV in the sampled area, the RSIV-infected wild fish appeared during or after the RSIV outbreak in cultured fish, suggesting that RSIV detected in wild fish was derived from the RSIV outbreak in cultured fish. Therefore, wild fish populations near aquaculture installations may not be a significant risk factor for RSIV outbreaks in cultured fish.

Assessment of transmission risk in WSSV-infected shrimp Litopenaeus vannamei upon cooking.

White spot syndrome virus has been a threat to the global shrimp industry since it was discovered in Taiwan in 1992. Thus, shrimp-producing countries have launched regulations to prevent import of WSSV-infected commodity shrimp from endemic areas. Recently, cooked shrimp that is infected with WSSV tested positive by PCR. However, there is no study to determine the infectivity of WSSV in cooked shrimp that tested positive by PCR. In the present study, WSSV-infected shrimp were cooked at boiling temperature for different times including 0, 1, 3, 5, 10 and 30 min. Upon exposure to boiling temperature, WSSV-infected shrimp were fed to SPF shrimp (Litopenaeus vannamei). The result showed experimentally challenged shrimp from 0-min treatment (positive control) indeed got infected with WSSV. However, experimentally challenged shrimp that were fed tissues boiled at 1, 3, 5, 10 and 30 min were not infected with WSSV. Mortality data showed that only the positive control (0-min) treatment displayed high mortality, whereas no mortality was observed in any other treatment category. These findings suggest that cooking shrimp at boiling temperature for at least 1 min might prevent any potential spread of WSSV from endemic countries to other geographical areas where WSSV has not yet been reported.

Assessment of prevalence and load of torquetenovirus viraemia in a large cohort of healthy blood donors.

OBJECTIVES: Torquetenovirus (TTV) is an emerging marker of functional immune competence with the potential to predict transplant-related adverse events. A large-scale epidemiological study was performed to understand how basal values vary in healthy individuals according to age and gender. METHODS: We tested plasma from 1017 healthy blood donors aged 18-69 years. The presence and load of TTV were determined by a real-time PCR assay. A sub-cohort of 384 donors was tested for anti-cytomegalovirus IgG antibodies, and 100 participants were also tested for TTV viraemia on a paired whole blood sample. RESULTS: The overall prevalence of TTV was 65% (657/1017) with a mean (±SD) growth of 5 ± 4% every 10 years of age increase, but stably higher in males (465/690, 67%) than in females (192/327, 59%). Mean (±SD) TTV load was 2.3 ± 0.7 Log copies/mL with no sex difference. TTV viraemia showed modest increases along 10-year age intervals (mean ± SD: 0.3 ± 0.1). TTV viraemia in donors sampled 2 years later remained stable (mean ± SD: 2.3 ± 0.8 versus 2.2 ± 0.7 Log copies between samples). Twenty-six per cent (9/34) of blood donors with TTV-negative plasma scored positive when whole blood was tested, and the donors with positive plasma showed a mean (±SD) 1.4 ± 0.5 Log increase in copy numbers when whole blood was tested. CONCLUSIONS: This study establishes the mean value of TTV viraemia in plasma in healthy blood donors and suggests that ageing causes only minimal increases in TTV viraemia.

Quantitative risk assessment of WSSV transmission through partial harvesting and transport practices for shrimp aquaculture in Mexico.

This quantitative risk assessment provided an analytical framework to estimate white spot syndrome virus (WSSV) transmission risks in the following different scenarios: (1) partial harvest from rearing ponds and (2) post-harvest transportation, assuming that the introduction of contaminated water with viral particles into shrimp culture ponds is the main source of viral transmission risk. Probabilities of infecting shrimp with waterborne WSSV were obtained by approaching the functional form that best fits (likelihood ratio test) published data on the dose-response relationship for WSSV orally inoculated through water into shrimp. Expert opinion defined the ranges for the following uncertain factors: (1) the concentrations of WSSV in the water spilled from the vehicles transporting the infected shrimp, (2) the total volume of these spills, and (3) the dilution into culture ponds. Multiple scenarios were analysed, starting with a viral load (VL) of 1×102mL-1 in the contaminated water spilled that reached the culture pond, whose probability of infection of an individual shrimp (Pi) was negligible (1.7×10-7). Increasing the VL to 1×104.5mL-1 and 1×107mL-1 yielded results into very low (Pi=5.3×10-5) and high risk (Pi=1.6×10-2) categories, respectively. Furthermore, different pond stocking density (SD) scenarios (20 and 30 post-larvae [PL]/m2) were evaluated, and the probability of infection of at least one out of the total number of shrimp exposed (PN) was derived; for the scenarios with a low VL (1×102mL-1), the PN remained at a negligible risk level (PN, 2.4×10-7 to 1.8×10-6). For most of the scenarios with the moderate VL (1×104.5mL-1), the PN scaled up to a low risk category (PN, 1.1×10-4 to 5.6×10-4), whereas for the scenarios with a high VL (1×107mL-1), the risk levels were high (PN, 2.3×10-2 to 3.5×10-2) or very high (PN, 1.1×10-1 to 1.6×10-1) depending on the volume of contaminated water spilled in the culture pond (VCWSCP, 4 or 20L). In the sensitivity analysis, for a SD of 30 PL/m2, it was shown that starting with a VL of 1×105mL-1 and a VCWSCP of 12L, the PN was moderate (1.05×10-3). This was the threshold for greater risks, given the increase in either the VCWSCP or VL. These findings supported recommendations to prevent WSSV spread through more controlled transportation and partial harvesting practices.

Vivências e necessidades de saúde de homens no período pós-nascimento de um filho / Experiences and health needs of men in the period post-birth of a child / Experiencias y necesidades de salud de los hombres en el período post-nacimiento de un hijo

Esta pesquisa aborda percepções de homens sobre suas experiências e necessidades de saúde no pós-nascimento. Objetiva-se distinguir analiticamente, a partir de uma perspectiva de gênero, necessidades de saúde relativas ao evento, experimentadas, expressas e/ou negadas pelos homens. Trata-se de um estudo exploratório-descritivo, qualitativo, realizado em dois territórios de saúde de Cuiabá, Mato Grosso, mediante entrevista semiestruturada e análise temática dos dados. Participaram oito homens que vivenciavam o pós-nascimento de um filho. Estes manifestaram, sobretudo, a necessidade de provimento de segurança financeira à família, destacando também a necessidade de bem estar do filho, acessando o retorno afetivo que a experiência traz. Não se reconheciam com necessidades de saúde no pós-nascimento. O apoio dos serviços locais de saúde é importante para que os homens se percebam na vivência da paternidade e a sua relação com aspectos socioculturais, para que distingam necessidades próprias, valorizem o cuidado de si e adotem uma perspectiva equânime de gênero.

This research addresses men’s perceptions about their experiences and health needs in the post-birth period. The goal is to distinguish analytically and from a gender perspective the health needs related to the event, experienced, expressed and/or denied by men. This is an exploratory, descriptive and qualitative study carried out in two municipal health areas of Cuiabá, state of Mato Grosso, using a semi structured interview and thematic analysis of the data. The participants were eight men who were experiencing the post-birth period of a child. Above all, they expressed the need to provide financial security to the family, emphasizing also the need of their children’s well-being, with the affective return that this experience brings. They did not perceive themselves with health needs during the post-birth period. The support provided by local health services is important so that men can understand the experience of parenthood and its relationship with social and cultural aspects in order to distinguish their own needs, appreciate self-care, and adopt a gender equity perspective.

Esta investigación aborda las percepciones de hombres acerca de sus experiencias y necesidades de salud en el período postparto. El objetivo es distinguir analíticamente, desde una perspectiva de género, las necesidades de salud relacionadas al evento, experimentadas, expresadas y/o negadas por los hombres. Se trata de un estudio exploratorio, descriptivo y cualitativo llevado a cabo en dos áreas municipales de salud de Cuiabá, Estado de Mato Grosso, mediante entrevista semiestructurada y análisis temático de los datos. Participaron ocho hombres que experimentaban el período postparto de un hijo. Ellos expresaron, sobre todo, la necesidad de proveer seguridad económica a la familia, destacando también la necesidad del bienestar de los hijos, con el retorno afectivo que esa experiencia proporciona. No se reconocían con necesidades de salud en el período postparto. El apoyo de los servicios locales de salud es importante para que los hombres entiendan la experiencia de la paternidad y su relación con aspectos socioculturales, para que distingan las necesidades, valoren el cuidado de sí mismos y adopten una perspectiva de equidad de género.

Development of a loop-mediated isothermal amplification assay for rapid detection of iridovirus in the Chinese giant salamander.

The Chinese giant salamander (Andrias davidianus) iridovirus (GSIV) is an emerging infectious pathogen responsible for severe hemorrhagic disease and high mortality in cultured Chinese giant salamanders. A loop-mediated isothermal amplification (LAMP) assay based on the major caspid protein (MCP) gene has been developed to detect this virus. Primer pairs for the LAMP assay were designed based on the GSIV MCP gene sequence. Amplification results indicate that under optimized conditions the LAMP assay has the ability to specifically detect the virus in both diseased animals and infected epithelioma papilloma cyprinid (EPC) cells. The assay was shown to be 10-fold more sensitive than nested PCR and was able to detect concentrations of 10(-9) (approximately 0.01 pg/µL). The LAMP assay is relatively easy to perform in situ and the amplification products can be observed directly under UV light or via staining with SYBR Green I. The LAMP assay is also rapid and cost-effective. This study establishes the use of a LAMP assay for rapid detection of GSIV, which is a novel and important tool for the diagnosis of GSIV infection in laboratory or farmed Chinese giant salamanders.

A model to approximate lake temperature from gridded daily air temperature records and its application in risk assessment for the establishment of fish diseases in the UK.

Ambient water temperature is a key factor controlling the distribution and impact of disease in fish populations, and optimum temperature ranges have been characterised for the establishment of a number important aquatic diseases exotic to the UK. This study presents a simple regression method to approximate daily average surface water temperature in lakes of 0.5-15 ha in size across the UK using 5 km(2) gridded daily average air temperatures provided by the UK Meteorological Office. A Geographic information system (GIS) is used to present thematic maps of relative risk scores established for each grid cell based on the mean number of days per year that water temperature satisfied optimal criteria for the establishment of two economically important pathogens of cyprinid fish (koi herpesvirus (KHV) and spring viraemia of carp virus (SVCV)) and the distribution and density of fish populations susceptible to these viruses. High-density susceptible populations broadly overlap the areas where the temperature profiles are optimal for KHV (central and south-east England); however, few fish populations occur in areas where temperature profiles are most likely to result in the establishment of spring viremia of carp (SVC) (namely northern England and Scotland). The highest grid-cell risk scores for KHV and SVC were 7 and 6, respectively, out of a maximum score of 14. The proportion of grid cells containing susceptible populations with risk scores of 5 or more was 37% and 5% for KHV and SVC, respectively. This work demonstrates a risk-based approach to inform surveillance for exotic pathogens in aquatic animal health management, allowing efficient use of resources directed towards higher risk animals and geographic areas for early disease detection. The methodology could be used to examine the change in distribution of high-risk areas for both exotic and endemic fish diseases under different climate change scenarios.

Prevalence and assessment of role of SEN virus in acute and chronic hepatitis in India.

BACKGROUND AND AIM: SEN virus (SENV), is a recently discovered single-stranded DNA virus of Annelloviridae family and is believed may play a role in non A-E hepatitis. We conducted this study to identify the prevalence and clinical association of SENV with acute and chronic hepatitis. METHODS: 135 liver disease patients were studied. Extent of liver damage was assessed using the Model for End Stage Liver Disease (MELD) score. A-E viruses and HIV were detected by enzyme immunoassay. Nested PCR was performed for detection of SENV and its genotypes D and H. RESULTS: 34 cases (25.18%) were positive for SEN virus DNA, a statistically significant finding (p < 0.01) of which 22 (64%) had acute viral hepatitis, 4 (11.76%) had chronic viral hepatitis, 3 (8.82%) fulminant hepatic failure and 5 (14.70%) cirrhosis. Mean AST was 47.85 IU/L, ALT 51.2 IU/L and INR 1.73, mean MELD score was 18.38 (11 to 24). 17.64% had severely deranged MELD score. SENV-D genotype was detected in 13 (38%) and SENV-H in 19 (58%) cases. SENV-H occurred in both acute (53%) and chronic hepatitis (47%). SENV-D was strongly associated with acute hepatitis (85%). Cirrhotic and FHF cases were SENV-H positive. 12 (44.11%) were co-infected with HBV, 5 (14.7%) with TTV, 4(11.76%) with HEV, 2 (5.88%) with HCV and 5 (14.4%) with HIV. CONCLUSION: Significant prevalence of SENV in hepatitis patients was observed. On the basis of clinical findings and abnormal liver function tests, we conclude that SENV appears to be not only hepatotropic but also capable of liver damage. Higher prevalence of SENV-H in cirrhotics may point to its possible role in the development of cirrhosis.

Discovery of a novel Torque teno sus virus species: genetic characterization, epidemiological assessment and disease association.

The study describes a novel Torque teno sus virus (TTSuV) species, provisionally named Torque teno sus virus k2b (TTSuVk2b), originally found in commercial pig sera by applying the rolling-circle amplification technique. Full-length sequences of TTSuVk2b were obtained, annotated and used in the phylogenetic analyses, which revealed that TTSuVk2b is a novel Anellovirus species within the genus Kappatorquevirus of the family Anelloviridae. Quantitative PCR techniques were developed to determine total TTSuV DNA quantities as well as the prevalence and viral DNA quantities of TTSuV1, TTSuVk2a and TTSuVk2b. The mean total TTSuV load in seven commercial sera was determined at 6.3 log(10) DNA copies ml(-1) of serum, with TTSuVk2b loads being the lowest at 4.5 log(10) DNA copies ml(-1) of serum. Subsequently, prevalence and loads of TTSuVs were determined in pig sera from 17 countries. TTSuVk2b prevalence ranged from 0 to 100 % with viral loads from 3.3 to 4.6 log(10) copies ml(-1) of sera. TTSuVk2a, so far the only species in the genus Kappatorquevirus, has been linked to an economically important swine disease, namely post-weaning multisystemic wasting syndrome (PMWS). Considering the grouping of TTSuVk2b in the same genus as TTSuVk2a, TTSuVk2b prevalence and viral DNA load were determined in PMWS-affected animals and healthy counterparts. This revealed that TTSuVk2a and TTSuVk2b are not only genetically related, but also that their viral loads in serum are elevated in PMWS animals compared with those of healthy pen mates. In summary, the present work describes a novel TTSuV species including its genetic characterization, epidemiological assessment and potential disease association.

Two amphibian diseases, chytridiomycosis and ranaviral disease, are now globally notifiable to the World Organization for Animal Health (OIE): an assessment.

The global trade in amphibians entails the transport of tens of millions of live animals each year. In addition to the impact harvesting wild animals can have on amphibian populations, there is mounting evidence that the emerging pathogens Batrachochytrium dendrobatidis and ranaviruses, the aetiological agents of chytridiomycosis and ranaviral disease, respectively, are spread through this trade. The link between these pathogens and amphibian declines and extinctions suggests that the epidemiological impact of the trade is significant and may negatively affect conservation and trade economics. Here we present a brief assessment of the volume of the global trade in live amphibians, the risk of individuals harboring infection, and information on the recent listing by the World Organization for Animal Health (OIE) of chytridiomycosis and ranaviral disease in the OIE Aquatic Animal Health Code. This listing made chytridiomycosis and ranaviral disease internationally notifiable diseases and thus subject to OIE standards, which aim to assure the sanitary safety of international trade in live amphibians and their products.

Genetic 'budget' of viruses and the cost to the infected host: a theory on the relationship between the genetic capacity of viruses, immune evasion, persistence and disease.

The nature of the pathogen-host relationship is recognized as being a dynamic coevolutionary process where the immune system has required ongoing adaptation and improvement to combat infection. Under survival pressure from sophisticated immune responses, adaptive processes for microbes, including viruses, have manifested as immune evasion strategies. This paper proposes a theory that virus immune evasion can be broadly classified into 'acquisition' or 'erroneous replication' strategies. Acquisition strategies are characteristic of large genome dsDNA viruses, which (i) replicate in the cell nucleus; (ii) have acquired host genes that can be used to directly manipulate responses to infection; (iii) are often latent for the lifetime of the host; and (iv) have little or no serious impact on health. Alternatively, erroneous replication strategies are characteristic of small genome RNA viruses, which are recognized as being the cause of many serious diseases in humans. It is proposed that this propensity for disease is due to the cytoplasmic site of replication and truncated temporal relationship with the host, which has limited or removed the evolutionary opportunity for RNA viruses to have acquired host genes. This has resulted in RNA viruses relying on error-prone replication strategies which, while allowing survival and persistence, are more likely to lead to disease due to the lack of direct viral control over potentially host-deleterious inflammatory and immune responses to infection.

Further observations on the epidemiology and spread of epizootic haematopoietic necrosis virus (EHNV) in farmed rainbow trout Oncorhynchus mykiss in southeastern Australia and a recommended sampling strategy for surveillance.

Epizootic haematopoietic necrosis virus (EHNV) is an iridovirus confined to Australia and is known only from rainbow trout Oncorhynchus mykiss and redfin perch Perca fluviatilis. Outbreaks of disease caused by EHNV in trout populations have invariably been of low severity, affecting only 0+ post-hatchery phase fingerlings < 125 mm in length. To date the virus has been demonstrated in very few live in-contact fish, and anti-EHNV antibodies have not been found in survivors of outbreaks, suggesting low infectivity but high case fatality rates in trout. During an on-going study on an endemically infected farm (Farm A) in the Murrumbidgee River catchment of southeastern New South Wales, EHNV infection was demonstrated in 4 to 6 wk old trout fingerlings in the hatchery as well as in 1+ to 2+ grower fish. During a separate investigation of mortalities in 1+ to 2+ trout on Farm B in the Shoalhaven River catchment in southeastern New South Wales, EHNV infection was demonstrated in both fingerlings and adult fish in association with nocardiosis. A 0.7% prevalence of antibodies against EHNV was detected by ELISA in the serum of grower fish at this time, providing the first evidence that EHNV might not kill all infected trout. EHNV infection on Farm B occurred after transfer of fingerlings from Farm C in the Murrumbidgee river catchment. When investigated, there were no obvious signs of diseases on Farm C. 'Routine' mortalities were collected over 10 d on Farm C and EHNV was detected in 2.1% of 190 fish. Tracing investigations of sources of supply of fingerlings to Farm B also led to investigation of Farm D in Victoria, where the prevalence of anti-EHNV antibodies in 3+ to 4+ fish was 1.3%. The results of this study indicate that EHNV may be found in trout in all age classes, need not be associated with clinically detectable disease in the population, can be transferred with shipments of live fish, can be detected in a small proportion of 'routine' mortalities and may be associated with specific antibodies in a small proportion of older fish. Sampling to detect EHNV for certification purposes should be based on examination of 'routine' mortalities rather than random samples of live fish. Antigen-capture ELISA can be used as a cost effective screening test to detect EHNV on a farm provided that sampling rates conform with statistical principles.