Assuntos
Transtorno Autístico , Criança , Humanos , Lactente , Transtorno Autístico/diagnóstico , Anestesia GeralRESUMO
The success of acute stroke treatment is first and foremost time-dependent, and the need for improvement in acute stroke management is demonstrated by the fact that only a minority of patients gain access to treatment - in particular, intravenous recombinant tissue plasminogen activator (IV tPA) - within the necessary time window. Standards of acute stroke care vary widely both regionally and nationally; consequently, various healthcare organizations have undertaken initiatives to measure and improve quality of care. To date, most quality measures have been process-based, focusing primarily on metrics of patient care in the acute hospital-based setting (e.g., time to recombinant tPA administration). Therefore, there remains a need for metrics designed to assess how improvements in process translate into patient outcomes. A global forum was convened to share best practice and provide consensus recommendations on core metrics for measuring improvements in access to care and patient outcomes. Recommendations for core metrics of patient outcomes include hospital-based outcomes (e.g., neurological status at 24 h, ambulatory status at discharge) and post-discharge outcomes (e.g., modified Rankin Scale score at 30 and/or 90 days). Recommendations for best practice relating to aspects of people, process, and technology involved in the stroke treatment pathway that may help provide improvements in these core outcome measures are also outlined.
Assuntos
Acidente Vascular Cerebral/terapia , Determinação de Ponto Final , Humanos , Proteínas Recombinantes/administração & dosagem , Ativador de Plasminogênio Tecidual/administração & dosagem , Resultado do TratamentoRESUMO
The serological reactivity between strains of each of the six currently genetically defined subtypes of salmonid alphavirus (SAV) was examined by comparison of homologous and heterologous virus neutralization titres on sera from experimentally infected fish. With the exception of the level of SAV subtype 6 neutralization by heterologous sera, good cross-neutralization was detected between all subtypes, albeit with variation in geometric mean titres when each subtype-specific serum set was tested against the panel of virus subtypes. A similar pattern was evident with field sera, except that heterologous neutralization of the SAV6 strain was more evident. In only 23% of available pairwise comparisons was the homologous titre recorded with an experimentally derived serum fourfold or greater than the heterologous titre, and in only two instances was this difference demonstrated in both directions. No virus strains consistently met the old serology-based criteria (Sub-committee on Inter-relationships Among Catalogued Alphaviruses) to be considered separate subtypes within an alphavirus species. Only when testing with an SAV subtype-2-specific monoclonal antibody was a major difference between homologous and heterologous neutralization capacity evident. These results provide new direct or indirect information in terms of SAV classification, vaccine efficacy and the selection and validation of reagents for serological and immunological diagnostic purposes.
Assuntos
Infecções por Alphavirus/veterinária , Alphavirus/classificação , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Especificidade de Anticorpos , Doenças dos Peixes/virologia , Alphavirus/genética , Infecções por Alphavirus/imunologia , Infecções por Alphavirus/virologia , Animais , Anticorpos Monoclonais , Doenças dos Peixes/imunologia , Testes de Neutralização , Salmo salar/sangueRESUMO
PURPOSE: The internet has revolutionised the way we search for information. We determined the level of internet use by parents of children attending general surgical services and identified trends in online information-seeking behaviour. METHODS: A questionnaire based on the work by Boston and Tassone was distributed to parents attending both the day surgical units and surgical outpatients department in a paediatric tertiary referral centre. RESULTS: There were 214 (82.3 %) questionnaires returned, with 82 (38.3 %) of respondents having searched the internet regarding their child's surgical issue. Access to a smartphone, a university education and private health insurance were factors that positively influenced online searching (p < 0.005). Of those respondents who searched the internet, 42 (51 %) felt that information they found online was understandable, while only 14 (17 %) admitted to online sourced information influencing the treatment decisions they had made for their children. When asked to rank information sources on Likert-type scales in terms of importance; parents ranked the surgeon as most important (mean = 4.73), whilst the internet ranked lowest (mean = 3.02). CONCLUSION: We demonstrated significant use of the internet amongst those attending paediatric general surgical services. Clinician sourced information remains important, however we should engage with patients to utilise this vast resource effectively.
Assuntos
Comportamento de Busca de Informação , Internet/estatística & dados numéricos , Pais , Pediatria , Procedimentos Cirúrgicos Operatórios , Adolescente , Adulto , Idoso , Procedimentos Cirúrgicos Ambulatórios/estatística & dados numéricos , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pacientes Ambulatoriais/estatística & dados numéricos , Inquéritos e Questionários , Adulto JovemRESUMO
BACKGROUND AND PURPOSE: Incidental findings are discovered in neuroimaging research, ranging from trivial to life-threatening. We describe the prevalence and characteristics of incidental findings from 16,400 research brain MRIs, comparing spontaneous detection by nonradiology scanning staff versus formal neuroradiologist interpretation. MATERIALS AND METHODS: We prospectively collected 16,400 brain MRIs (7782 males, 8618 females; younger than 1 to 94 years of age; median age, 38 years) under an institutional review board directive intended to identify clinically relevant incidental findings. The study population included 13,150 presumed healthy volunteers and 3250 individuals with known neurologic diagnoses. Scanning staff were asked to flag concerning imaging findings seen during the scan session, and neuroradiologists produced structured reports after reviewing every scan. RESULTS: Neuroradiologists reported 13,593/16,400 (83%) scans as having normal findings, 2193/16,400 (13.3%) with abnormal findings without follow-up recommended, and 614/16,400 (3.7%) with "abnormal findings with follow-up recommended." The most common abnormalities prompting follow-up were vascular (263/614, 43%), neoplastic (130/614, 21%), and congenital (92/614, 15%). Volunteers older than 65 years of age were significantly more likely to have scans with abnormal findings (P < .001); however, among all volunteers with incidental findings, those younger than 65 years of age were more likely to be recommended for follow-up. Nonradiologists flagged <1% of MRIs containing at least 1 abnormality reported by the neuroradiologists to be concerning enough to warrant further evaluation. CONCLUSIONS: Four percent of individuals who undergo research brain MRIs have an incidental, potentially clinically significant finding. Routine neuroradiologist review of all scans yields a much higher rate of significant lesion detection than selective referral from nonradiologists who perform the examinations. Workflow and scan review processes need to be carefully considered when designing research protocols.
Assuntos
Encefalopatias , Encéfalo , Masculino , Feminino , Humanos , Adulto , Encéfalo/patologia , Encefalopatias/diagnóstico por imagem , Encefalopatias/epidemiologia , Achados Incidentais , Imageamento por Ressonância Magnética , Neuroimagem , VoluntáriosRESUMO
Sequence data from salmonid alphavirus (SAV) strains obtained from farmed marine Atlantic salmon, Salmo salar L. , over a 20-year period between 1991 and 2011 was reviewed to examine the geographical distribution of the genetically defined SAV subtypes in twelve regions across Ireland and Scotland. Of 160 different Atlantic salmon SAV strains examined, 62 belonged to subtype 1, 28 to subtype 2, 34 to subtype 4, 35 to subtype 5 and 1 to subtype 6. SAV subtypes 1, 4 and 6 were found in Ireland, while subtypes 1, 2, 4 and 5 were found in Scotland. In the majority of regions, there was a clear clustering of subtypes, with SAV subtype 1 being the dominant subtype in Ireland overall, as well as in Argyll and Bute in Scotland. SAV subtype 2 predominated in the Shetland and Orkney Islands. The emergence in Atlantic salmon of subtype 2 strains typically associated with sleeping disease in rainbow trout in Argyll and Bute, strongly suggesting transmission of infection between these species, was noted for the first time. SAV subtype 4 was the most common subtype found in the southern Western Isles, while SAV subtype 5 predominated in the northern Western Isles and north-west mainland Scotland. No single strain was dominant on sites in the western Highlands, with a number of sites in this region in particular having more than one subtype detected in different submissions. The significance of these results in relation to aspects of the epidemiology of infection, including transmission, biosecurity and wildlife reservoirs are discussed and knowledge gaps identified.
Assuntos
Infecções por Alphavirus/veterinária , Alphavirus/genética , Doenças dos Peixes/virologia , Salmo salar/virologia , Alphavirus/classificação , Infecções por Alphavirus/virologia , Animais , Irlanda , Filogenia , Escócia , Proteínas do Envelope Viral/genéticaRESUMO
A comparative challenge study of six marine isolates representing subtypes 1-6 of salmonid alphavirus (salmon pancreas disease virus, Genus Alphavirus, Family Togaviridae) was conducted in Atlantic salmon in a fresh water cohabitation trial. Histopathological lesions typical of pancreas disease were observed with all subtypes, and virus was re-isolated from serum of cohabitant fish in each case. Using a virus neutralization (VN) test neutralizing salmonid alphavirus (SAV) subtype 1 strain F93-125, VN antibodies were detected in all challenge groups, consistent with serological cross-reactivity between these subtypes. Using real-time RT-PCR, SAV RNA was detected in heart tissue from 2 to 3 weeks post-challenge (wpc) in all cohabitant groups excluding controls. The results obtained suggested differences in the dynamics of infection between strains of SAV and potentially between subtypes. Results for SAV subtypes 1 and 3 suggested essentially synchronous infection of cohabitant fish. These two study groups also had the highest virus load in heart tissue as measured by quantitative RT-PCR and also had the most extensive histopathological changes. In contrast, results for SAV subtypes 2 and 6 strains were consistent with asynchronous infection in the cohabitant fish and were characterized by slow spread, low virus loads and mild histopathological changes. The SAV subtype 4 and 5 strains occupied an intermediate position in this regard. Despite the use of concentration procedures, it was not possible to detect SAV RNA in water samples from selected study tanks. However, testing of faeces from the SAV subtypes 1, 3 and 6 challenge groups found positive signals in each beginning at 1-3 wpc and remaining detectable for a further 2-3 weeks. Parallel testing of mucus samples found these became positive at 2-3 wpc and remained positive for a further 1-3 weeks. These results demonstrate for the first time that shedding and transmission of virus may occur by both these routes and suggest that dispersal in these matrices should be included in any disease transmission models.
Assuntos
Infecções por Alphavirus/veterinária , Alphavirus/genética , Alphavirus/imunologia , Doenças dos Peixes/virologia , Pancreatopatias/veterinária , Salmo salar/virologia , Alphavirus/isolamento & purificação , Alphavirus/patogenicidade , Infecções por Alphavirus/patologia , Infecções por Alphavirus/transmissão , Infecções por Alphavirus/virologia , Animais , Anticorpos Antivirais/sangue , Feminino , Doenças dos Peixes/patologia , Doenças dos Peixes/transmissão , Água Doce , Coração/virologia , Masculino , Músculo Esquelético/patologia , Músculo Esquelético/virologia , Miocárdio/patologia , Pâncreas/patologia , Pâncreas/virologia , Pancreatopatias/patologia , Pancreatopatias/virologia , RNA Viral/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Salmo salar/fisiologiaRESUMO
Prospective longitudinal studies of two outbreaks of pancreas disease in Atlantic salmon (AS), Salmo salar L., in Ireland were conducted. Both outbreaks occurred during the marine phase of production, with one caused by salmonid alphavirus subtype 1 (SAV1) and the other by SAV4. In addition to screening a range of tissues by real-time reverse transcriptase polymerase chain reaction (RRT-PCR), virological, serological and histopathological examinations were performed along with partial genome sequencing and results were related to environmental and production data and farm history. On Farm 1 (marine sampling only), infection was detected within 3 weeks of smolts being placed on the farm, while on Farm 2 (freshwater and marine sampling), infection was first detected 315 days after transfer to sea. In both outbreaks, RRT-PCR signals were detected in a range of tissues including gill, heart, kidney, pancreas/pyloric caeca, brain and serum. Persistence of signal was longest in gill and heart (> or =265 days on both farms) and shortest in serum. Mortalities on the two farms varied from 10.9% to 30%. In both cases, partial genome sequence of the causative viruses were identical to SAV strains detected in previous populations of AS on each of the study farms, including populations with which the study populations overlapped in time and space.
Assuntos
Infecções por Alphavirus/veterinária , Alphavirus/fisiologia , Doenças dos Peixes/epidemiologia , Pesqueiros , Salmo salar/virologia , Alphavirus/isolamento & purificação , Infecções por Alphavirus/epidemiologia , Infecções por Alphavirus/mortalidade , Infecções por Alphavirus/patologia , Animais , Anticorpos Antivirais/sangue , Doenças dos Peixes/mortalidade , Doenças dos Peixes/patologia , Doenças dos Peixes/virologia , Irlanda , Estudos Longitudinais , RNA Viral/sangue , Reação em Cadeia da Polimerase Via Transcriptase Reversa , TemperaturaRESUMO
Attention deficit hyperactivity disorder (ADHD) is a common childhood psychiatric condition that is effectively treated by catecholaminergic drugs with a variety of different mechanisms and the SH rat is frequently used as a model of this disorder. In vivo microdialysis in freely-moving rats has been employed extensively to provide a better understanding of the pharmacodynamics of drugs at their sites of action. In this review, these three topics are brought together to explore the contribution of in vivo microdialysis studies in spontaneously hypertensive (SH) rats to our understanding of the neurochemical deficits in this rat strain and the actions of ADHD drugs on catecholaminergic function in the prefrontocortex (PFC), striatum and nucleus accumbens. What is revealed is that basal efflux of norepinephrine in the PFC is attenuated, whilst striatal and mesolimbic dopaminergic neurotransmission is hyperfunctional; the latter observation fits closely with the hyperactive phenotype of the SH rat. Furthermore, experiments performed with the enantiomers of amphetamine and threo-methylphenidate demonstrate that pharmacodynamic effects of drugs reported from experiments in outbred rat strains, e.g. Sprague-Dawleys, do not necessarily translate to the SH rat. When the findings are compared with the clinical efficacy of drugs used in treating ADHD, they indicate that the most efficacious drugs powerfully increase both norepinephrinergic and dopaminergic neurotransmission.
Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/tratamento farmacológico , Dopamina/metabolismo , Microdiálise/métodos , Norepinefrina/metabolismo , Anfetamina/farmacologia , Animais , Cloridrato de Atomoxetina , Modelos Animais de Doenças , Humanos , Metilfenidato/farmacologia , Propilaminas/farmacologia , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKYRESUMO
BACKGROUND AND PURPOSE: Intrinsic T1-hyperintense signal has recently been reported in the deep gray nuclei on brain MR imaging after multiple doses of gadolinium-based contrast agents. Most reports have included adult patients and excluded those undergoing radiation or chemotherapy. We investigated whether T1 shortening is also observed in children and tried to determine whether radiochemotherapy is a risk factor for this phenomenon. MATERIALS AND METHODS: In this single-center retrospective study, we reviewed clinical charts and images of all patients 18 years of age or younger with ≥4 gadobenate dimeglumine-enhanced MRIs for 6 years. Seventy-six children (mean age, 9.3 years; 60 unconfounded by treatment, 16 with radiochemotherapy) met the selection criteria (>4 MR imaging examinations; mean, 8). T1 signal intensity ratios for the dentate to pons and globus pallidus to thalamus were calculated and correlated with number of injections, time interval, and therapy. RESULTS: Among the 60 children without radiochemotherapy, only 2 had elevated T1 signal intensity ratios (n = 20 and 16 injections). Twelve of the 16 children with radiochemotherapy showed elevated signal intensity ratios. Statistical analysis demonstrated a significant signal intensity ratio change for the number of injections (P < .001) and amount of gadolinium (P = .008), but not for the interscan time interval (P = .35). There was a significant difference in the average signal intensity ratio change between those with and without radiochemotherapy (P < .001). Chart review revealed no new neurologic deficits in any patients, related to their underlying conditions and prior surgeries. CONCLUSIONS: Compared with published adult series, children show a similar pattern of T1 hyperintense signal changes of the dentate and globus pallidus after multiple gadobenate dimeglumine injections. The T1 signal changes in children may have a later onset but are accelerated by radiochemotherapy.
Assuntos
Encéfalo/efeitos dos fármacos , Meios de Contraste/efeitos adversos , Imageamento por Ressonância Magnética/métodos , Meglumina/análogos & derivados , Compostos Organometálicos/efeitos adversos , Adolescente , Encéfalo/diagnóstico por imagem , Encéfalo/efeitos da radiação , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/radioterapia , Quimiorradioterapia , Criança , Feminino , Humanos , Masculino , Meglumina/efeitos adversos , Estudos RetrospectivosRESUMO
HYPR TRICKS is an acquisition method that combines radial k-space trajectories, sampling k-space at different rates (TRICKS), and a new strategy for image reconstruction that uses highly constrained backprojection reconstruction (HYPR). This approach provides 3D time-resolved contrast-enhanced MR angiograms of the cerebral vessels with subsecond frame update times and submillimeter in-plane spatial resolution. Artifacts are suppressed, and signal-to-noise ratio is well maintained, by using HYPR reconstruction.
Assuntos
Artérias Cerebrais/anatomia & histologia , Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional , Angiografia por Ressonância Magnética/métodos , Artérias Cerebrais/patologia , Circulação Cerebrovascular , Meios de Contraste , Gadolínio DTPA , Humanos , Aumento da Imagem , Malformações Arteriovenosas Intracranianas/diagnósticoRESUMO
Four patients underwent angioplasty and stenting of medically refractory symptomatic intracranial atherosclerosis with the new Wingspan stent system. In all 4 patients, CT angiography (CTA) showed an abnormality within the stented segment that was suggestive of nonocclusive in-stent thrombus. However, subsequent conventional angiography findings were typical for in-stent restenosis. The CTA imaging features of in-stent restenosis are important to recognize, and the misinterpretation of in-stent restenosis as in-stent thrombus may result in inappropriate management.
Assuntos
Prótese Vascular/efeitos adversos , Angiografia Cerebral , Oclusão de Enxerto Vascular/diagnóstico por imagem , Doenças Arteriais Intracranianas/diagnóstico por imagem , Doenças Arteriais Intracranianas/etiologia , Stents/efeitos adversos , Tomografia Computadorizada por Raios X , Adulto , Feminino , Oclusão de Enxerto Vascular/etiologia , Humanos , Masculino , Resultado do TratamentoRESUMO
A prospective longitudinal survey for sleeping disease (SD) was carried out over a 20 wk period on a caged freshwater population of farmed rainbow trout Oncorhynchus mkyiss. Pancreas, heart and red and white skeletal muscle were examined histologically and the presence and severity of lesions recorded. Sera were tested for viraemia with Salmonid Alphavirus (SAV) and for virus neutralizing (VN) antibodies. Viraemia was detected for 4 wk, beginning at Week 6 and with a peak prevalence of 57.9% at Week 7. Clinical signs and mortalities appeared at Week 8. Total mortality in the study cage from Week 6 onward was 6.3 %, but other cages at the site had mortality levels of up to 47.2%. VN antibodies were first detected at Week 9, with seroprevalence increasing to 80% by the end of the study (Week 20). Geometric mean antibody titres peaked at 1/89.4 at Week 17. Histological lesions were first detected at Week 7 (pancreas only), before increasing in prevalence and severity to peak at Weeks 9 and 10. The majority of lesions were resolved by Week 15.
Assuntos
Infecções por Alphavirus/veterinária , Alphavirus/patogenicidade , Doenças dos Peixes/patologia , Doenças dos Peixes/virologia , Oncorhynchus mykiss/virologia , Alphavirus/imunologia , Infecções por Alphavirus/epidemiologia , Infecções por Alphavirus/imunologia , Infecções por Alphavirus/patologia , Animais , Anticorpos Antivirais/sangue , Surtos de Doenças/veterinária , Doenças dos Peixes/epidemiologia , Pesqueiros , Estudos Longitudinais , Músculo Esquelético/patologia , Miocárdio/patologia , Pâncreas/patologia , Estudos Prospectivos , Estudos Soroepidemiológicos , Fatores de TempoRESUMO
We report a case of a large oral teratoma in a foetus diagnosed on antenatal ultrasound. Due to the anticipated difficulty in securing the airway at birth an ex-utero intrapartum treatment (EXIT) procedure was planned. In this case simultaneous excision of the tumour mass was carried out while on placental support this allowed safe procurement of the airway and successful delivery of an otherwise healthy infant. This case highlights the challenge presented by such unusual cases and illustrates the successful treatment of this condition.
Assuntos
Cesárea , Feto/cirurgia , Neoplasias Bucais/cirurgia , Teratoma/cirurgia , Adulto , Feminino , Humanos , Recém-Nascido , Neoplasias Bucais/diagnóstico , Gravidez , Teratoma/diagnóstico , Ultrassonografia Pré-NatalRESUMO
BACKGROUND: The incidence of thyroid cancer is increasing. There is conflicting evidence as to why. However, studies suggest that it is not an apparent increase resulting from enhanced diagnostic practices, but a true increase with more affected patients. This study aimed to assess racial variation in thyroid cancer. METHOD: A narrative systematic review of the literature was conducted. RESULTS: Eight retrospective cohort studies were identified, comprising 611 777 adult patients. Variations exist between racial groups, which are also dependent on gender; white patients have a slightly higher male population when compared to their counterparts. Black and white patients have a higher proportion of follicular cancer. Hispanics were younger at the age of diagnosis. Outcomes are greatly affected by socioeconomic status. CONCLUSION: This study identified many gaps in the way that these types of data are presented. A more concise manner of reporting, with individual-level risk factors, is recommended.
Assuntos
População Negra/estatística & dados numéricos , Disparidades nos Níveis de Saúde , Hispânico ou Latino/estatística & dados numéricos , Neoplasias da Glândula Tireoide/etnologia , População Branca/estatística & dados numéricos , Adulto , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Fatores Sexuais , Fatores Socioeconômicos , Neoplasias da Glândula Tireoide/epidemiologiaRESUMO
BACKGROUND AND OBJECTIVE: Patients with a clinical diagnosis of neurodegeneration with brain iron accumulation (NBIA, formerly called Hallervorden-Spatz syndrome) often have mutations in PANK2, the gene encoding pantothenate kinase 2. We investigated correlations between brain MR imaging changes, mutation status, and clinical disease features. METHODS: Brain MRIs from patients with NBIA were reviewed by 2 neuroradiologists for technical factors, including signal intensity abnormalities in specific brain regions, presence and location of atrophy, presence of white matter abnormality, contrast enhancement, and other comments. PANK2 genotyping was performed by polymerase chain reaction amplification of patient genomic DNA followed by automated nucleotide sequencing. RESULTS: Sixty-six MR imaging examinations from 49 NBIA patients were analyzed, including those from 29 patients with mutations in PANK2. All patients with mutations had the specific pattern of globus pallidus central hyperintensity with surrounding hypointensity on T2-weighted images, known as the eye-of-the-tiger sign. This sign was not seen in any studies from patients without mutations. Even before the globus pallidus hypointensity developed, patients with mutations could be distinguished by the presence of isolated globus pallidus hyperintensity on T2-weighted images. Radiographic evidence for iron deposition in the substantia nigra was absent early in disease associated with PANK2 mutations. MR imaging abnormalities outside the globus pallidus, including cerebral or cerebellar atrophy, were more common and more severe in mutation-negative patients. No specific MR imaging changes could be distinguished among the mutation-negative patients. CONCLUSION: MR imaging signal intensity abnormalities in the globus pallidus can distinguish patients with mutations in PANK2 from those lacking a mutation, even in the early stages of disease.
Assuntos
Encéfalo/patologia , Ferro/metabolismo , Imageamento por Ressonância Magnética , Mutação , Neurodegeneração Associada a Pantotenato-Quinase/diagnóstico , Neurodegeneração Associada a Pantotenato-Quinase/genética , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Adolescente , Adulto , Encéfalo/metabolismo , Globo Pálido/patologia , Humanos , Degeneração Neural/patologia , Neurodegeneração Associada a Pantotenato-Quinase/patologiaRESUMO
In clinical MR spectroscopy at higher field strengths, lactate may show reduced or absent signal intensity at an echo time of 144 ms. Although this false-negative result may be predicted from theory, experimental verification and clinical impact have not been fully established. Using scanners from 3 major vendors, spectra from phantoms and patients demonstrate the lactate signal loss and potential error in interpretation. Strategies are discussed to overcome, or at least alleviate, this problem.
Assuntos
Encefalopatias/diagnóstico , Encefalopatias/metabolismo , Ácido Láctico/metabolismo , Espectroscopia de Ressonância Magnética , Reações Falso-Negativas , Humanos , Imagens de FantasmasRESUMO
A prospective longitudinal study of salmonid alphavirus infection in farmed Atlantic salmon Salmo salar L. was initiated in post-transfer smolts on a UK farm in July 2004 and continued for 320 d. Sampling was concentrated on a single caged population (C4) with serum and tissue samples collected and tested for viraemia, virus neutralising (VN) antibodies and viral nucleic acid by real time RT-PCR and by histopathology; 380 sera collected between Days 0 (DO) and 139 (D139) were consistently negative for both viraemia and VN antibodies. The first evidence of infection was detected on D146, when 4 out of 20 fish were found to be viraemic and 1 of 20 to be antibody-positive. On D153 only 2 of 20 fish was viraemic and 1 antibody positive. At the next sampling (D158) no viraemic or antibody positive fish were detected. Thereafter, one or two viraemic fish were detected on 6 occasions, including on D320. The prevalence of antibody-positive fish remained low (0 to 5%) until D192 after which time it rose irregularly to a peak of 57.9% on D320. Real time RT-PCR testing of sera was more sensitive than screening for viraemia, detecting a peak of 35 % positive on D153 before declining. Histological lesions diagnostic for pancreas disease (PD) were observed at D146 and D153 only. In addition, mild cardiac and to a lesser extent brain lesions were frequently found after virus was detected, but not in earlier samples. No clinical signs or mortalities attributable to PD occurred throughout the study. This is the first detailed report of sub-clinical infection and highlights the usefulness of longitudinal surveys and the detection of virus and antibodies as diagnostic and epidemiological tools.
Assuntos
Infecções por Alphavirus/veterinária , Alphavirus/patogenicidade , Doenças dos Peixes/epidemiologia , Salmo salar , Alphavirus/imunologia , Alphavirus/isolamento & purificação , Infecções por Alphavirus/epidemiologia , Infecções por Alphavirus/patologia , Animais , Anticorpos Antivirais/sangue , Células Cultivadas , Surtos de Doenças/veterinária , Doenças dos Peixes/patologia , Doenças dos Peixes/virologia , Pesqueiros , Estudos Longitudinais , Miocárdio/patologia , Testes de Neutralização/veterinária , Estudos Prospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Estudos Soroepidemiológicos , Fatores de Tempo , Viremia/sangueRESUMO
Pancreas disease (PD) of farmed Atlantic salmon Salmo salar L., which is caused by an alphavirus known as salmon pancreas disease virus (SPDV), can have serious economic consequences. An epidemiological survey carried out in Ireland in 2003 indicated that within individual farms there were significant differences in the susceptibility of different strains of farmed Atlantic salmon to infection with SPDV, as measured by levels of clinical disease and mortality. The aim of this preliminary study was to investigate this field observation by comparing lesion development, viraemia and serological responses of 3 commercial strains of Atlantic salmon (A, B and C) experimentally infected with SPDV. Highly significant differences in the severity of lesions in the pancreas at Day 21 post-infection (pi) were detected (p < 0.01), with Group B being more severely affected. There were also significant differences in the prevalence and severity of lesions in heart and skeletal muscle at Day 21 and 35 pi respectively, with Group B results again significantly higher than those from both Groups A and C (p < 0.05). There was no overlap between viraemia and the presence of specific SPDV antibody. Some fish in all groups had no viraemia, lesions or evidence of seroconversion. There were no significant differences seen between the challenged groups in relation to the percentage of viraemic fish at each time point. Viral loads were not determined. Differences between the number of antibody-positive fish in each challenge group were found at Days 28 and 35 pi (p < 0.1). Highly significant differences (p < 0.01) in the geometric mean titres of seropositive fish were detected at Day 28. These results, obtained using a challenge model, confirm that there are strain differences in the susceptibility to experimental SPDV infection in commercial farmed Atlantic salmon.