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1.
Dis Aquat Organ ; 150: 169-182, 2022 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-35979991

RESUMEN

This study aimed to generate data on performance characteristics for 2 real-time TaqMan PCR assays (CSIRO and WOAH WSSV qPCRs) for the purposes of (1) detection of white spot syndrome virus (WSSV) in clinically diseased prawns and (2) detection of WSSV in apparently healthy prawns. Analytical sensitivity of both assays was 2 to 20 genome copies per reaction, and analytical specificity was 100% after testing nucleic acid from 9 heterologous prawn pathogens and 4 prawn species. Results obtained after testing more than 20 000 samples in up to 559 runs with the CSIRO WSSV qPCR and up to 293 runs with the WOAH WSSV qPCR demonstrated satisfactory repeatability for both assays. Both assays demonstrated median diagnostic sensitivity (DSe) 100% (95% CI: 94.9-100%) when testing clinically diseased prawns. When 1591 test results from apparently healthy prawns were analysed by Bayesian latent class analysis, median DSe and diagnostic specificity (DSp) were 82.9% (95% probability interval [PI]: 75.0-90.2%) and 99.7% (95% PI: 98.6-99.99%) for the CSIRO WSSV qPCR and 76.8% (95% PI: 68.9-84.9%) and 99.7% (95% PI: 98.7-99.99%) for the WOAH WSSV qPCR. When both assays were interpreted in parallel, median DSe increased to 98.3 (95% PI: 91.6-99.99%), and median DSp decreased slightly to 99.4% (95% PI: 97.9-99.99%). Routine testing of quantified positive controls by laboratories in the Australian laboratory network demonstrated satisfactory reproducibility of the CSIRO WSSV qPCR assay. Both assays demonstrated comparable performance characteristics, and the results contribute to the validation data required in the WOAH validation pathway for the purposes of detection of WSSV in clinically diseased and apparently healthy prawns.


Asunto(s)
Decápodos , Virus del Síndrome de la Mancha Blanca 1 , Animales , Australia , Teorema de Bayes , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Virus del Síndrome de la Mancha Blanca 1/genética
2.
J Fish Dis ; 42(11): 1471-1491, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31637760

RESUMEN

Samples from multiple animals may be pooled and tested to reduce costs of surveillance for infectious agents in aquatic animal populations. The primary advantage of pooling is increased population-level coverage when prevalence is low (<10%) and the number of tests is fixed, because of increased likelihood of including target analyte from at least one infected animal in a tested pool. Important questions and a priori design considerations need to be addressed. Unfortunately, pooling recommendations in disease-specific chapters of the 2018 OIE Aquatic Manual are incomplete and, except for amphibian chytrid fungus, are not supported by peer-reviewed research. A systematic review identified only 12 peer-reviewed aquatic diagnostic accuracy and surveillance studies using pooled samples. No clear patterns for pooling methods and characteristics were evident across reviewed studies, although most authors agreed there is a negative effect on detection. Therefore, our purpose was to review pooling procedures used in published aquatic infectious disease research, present evidence-based guidelines, and provide simulated data examples for white spot syndrome virus in shrimp. A decision tree of pooling guidelines was developed for use by peer-reviewed journals and research institutions for the design, statistical analysis and reporting of comparative accuracy studies of individual and pooled tests for surveillance purposes.


Asunto(s)
Crustáceos/virología , Pruebas Diagnósticas de Rutina/normas , Monitoreo Epidemiológico/veterinaria , Enfermedades de los Peces/epidemiología , Guías como Asunto , Virus del Síndrome de la Mancha Blanca 1/fisiología , Animales , Enfermedades Transmisibles/epidemiología , Enfermedades Transmisibles/veterinaria , Vigilancia de la Población/métodos , Prevalencia
3.
Microorganisms ; 10(6)2022 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-35744614

RESUMEN

Since the identification of Hendra virus (HeV) infections in horses in Australia in 1994, more than 80 outbreaks in horses have been reported, and four out of seven spillover infections in humans had a fatal outcome. With the availability of a subunit vaccine based on the HeV-Glycoprotein (HeV-G), there is a need to serologically Differentiate the Infected from the Vaccinated Animals (DIVA). We developed an indirect ELISA using HeV-G expressed in Leishmania tarentolae and HeV-Nucleoprotein (HeV-N) expressed in recombinant baculovirus-infected insect cells as antigens. During evaluation, we tested panels of sera from naïve, vaccinated and infected horses that either originated from a Hendra-virus free region, or had been pre-tested in validated diagnostic tests. Our data confirm the reliability of this approach, as HeV-N-specific antibodies were only detected in sera from infected horses, while HeV-G-specific antibodies were detected in infected and vaccinated horses with a high level of specificity and sensitivity. Given the excellent correlation of data obtained for German and Australian HeV-negative horses, we assume that this test can be applied for the testing of horse serum samples from a variety of geographical regions.

4.
Transbound Emerg Dis ; 68(4): 1835-1849, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33058533

RESUMEN

Remote and rural communities in low- and middle-income countries (LMICs) are disproportionately affected by infectious animal diseases due to their close contact with livestock and limited access to animal health personnel). However, animal disease surveillance and diagnosis in LMICs is often challenging, and turnaround times between sample submission and diagnosis can take days to weeks. This diagnostic gap and subsequent disease under-reporting can allow emerging and transboundary animal pathogens to spread, with potentially serious and far-reaching consequences. Point-of-care tests (POCTs), which allow for rapid diagnosis of infectious diseases in non-laboratory settings, have the potential to significantly disrupt traditional animal health surveillance paradigms in LMICs. This literature review sought to identify POCTs currently available for diagnosing infectious animal diseases and to determine facilitators and barriers to their use and uptake in LMICs. Results indicated that some veterinary POCTs have been used for field-based animal disease diagnosis in LMICs with good results. However, many POCTs target a small number of key agricultural and zoonotic animal diseases, while few exist for other important animal diseases. POCT evaluation is rarely taken beyond the laboratory and into the field where they are predicted to have the greatest impact, and where conditions can greatly affect test performance. A lack of mandated test validation regulations for veterinary POCTs has allowed tests of varying quality to enter the market, presenting challenges for potential customers. The use of substandard, improperly validated or unsuitable POCTs in LMICs can greatly undermine their true potential and can have far-reaching negative impacts on disease control. To successfully implement novel rapid diagnostic pathways for animal disease in LMICs, technical, regulatory, socio-political and economic challenges must be overcome, and further research is urgently needed before the potential of animal disease POCTs can be fully realized.


Asunto(s)
Enfermedades de los Animales , Enfermedades Transmisibles , Enfermedades de los Animales/diagnóstico , Enfermedades de los Animales/epidemiología , Animales , Enfermedades Transmisibles/diagnóstico , Enfermedades Transmisibles/epidemiología , Enfermedades Transmisibles/veterinaria , Países en Desarrollo , Sistemas de Atención de Punto , Pruebas en el Punto de Atención , Zoonosis/diagnóstico
5.
Dis Aquat Organ ; 92(1): 1-10, 2010 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-21166309

RESUMEN

The recent emergence of a herpes-like virus in both farmed and wild populations of abalone in Victoria, Australia, has been associated with high mortality rates in animals of all ages. Based on viral genome sequence information, a virus-specific real-time TaqMan assay was developed for detection and identification of the abalone herpes-like virus (AbHV). The assay was shown to be specific as it did not detect other viruses from either the Herpesvirales or the Iridovirales orders which have genome sequence similarities. However, the TaqMan assay was able to detect DNA from the Taiwanese abalone herpes-like virus, suggesting a relationship between the Taiwanese and Australian viruses. In addition, the assay detected < 300 copies of recombinant plasmid DNA per reaction. Performance characteristics for the AbHV TaqMan assay were established using 1673 samples from different abalone populations in Victoria and Tasmania. The highest diagnostic sensitivity and specificity were 96.7 (95% CI: 82.7 to 99.4) and 99.7 (95% CI: 99.3 to 99.9), respectively, at a threshold cycle (C(T)) value of 35.8. The results from 2 separate laboratories indicated good repeatability and reproducibility. This molecular assay has already proven useful in confirming presumptive diagnosis (based on the presence of ganglioneuritis) of diseased abalone in Victorian waters as well as being a tool for surveillance of wild abalone stocks in other parts of Australia.


Asunto(s)
Herpesviridae/aislamiento & purificación , Moluscos/virología , Reacción en Cadena de la Polimerasa/métodos , Animales , Australia , ADN Viral/genética , ADN Viral/aislamiento & purificación , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
6.
J Vet Diagn Invest ; 32(6): 776-792, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32468923

RESUMEN

Evaluation of the diagnostic sensitivity (DSe) and specificity (DSp) of tests for infectious diseases in wild animals is challenging, and some of the limitations may affect compliance with the OIE-recommended test validation pathway. We conducted a methodologic review of test validation studies for OIE-listed diseases in wild mammals published between 2008 and 2017 and focused on study design, statistical analysis, and reporting of results. Most published papers addressed Mycobacterium bovis infection in one or more wildlife species. Our review revealed limitations or missing information about sampled animals, identification criteria for positive and negative samples (case definition), representativeness of source and target populations, and species in the study, as well as information identifying animals sampled for calculations of DSe and DSp as naturally infected captive, free-ranging, or experimentally challenged animals. The deficiencies may have reflected omissions in reporting rather than design flaws, although lack of random sampling might have induced bias in estimates of DSe and DSp. We used case studies of validation of tests for hemorrhagic diseases in deer and white-nose syndrome in hibernating bats to demonstrate approaches for validation when new pathogen serotypes or genotypes are detected and diagnostic algorithms are changed, and how purposes of tests evolve together with the evolution of the pathogen after identification. We describe potential benefits of experimental challenge studies for obtaining DSe and DSp estimates, methods to maintain sample integrity, and Bayesian latent class models for statistical analysis. We make recommendations for improvements in future studies of detection test accuracy in wild mammals.


Asunto(s)
Animales Salvajes , Enfermedades Transmisibles/veterinaria , Ciervos , Animales , Teorema de Bayes , Enfermedades Transmisibles/diagnóstico , Sensibilidad y Especificidad
7.
Transbound Emerg Dis ; 67(6): 2494-2506, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32311239

RESUMEN

Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hooved animals. Global outbreaks have highlighted the significant economic, trade, psychosocial and animal welfare impacts that can arise from the detection of disease in previously 'FMD-free' countries. Rapid and early diagnosis provides significant advantages in disease control and minimization of deleterious consequences. We describe the process of further development and validation of a reverse-transcription loop-mediated isothermal amplification foot-and-mouth disease virus (RT-LAMP-FMDV) test, using a published LAMP primer set, for use in the field. An internal positive control (IPC) was designed and introduced for use with the assay to mitigate any intrinsic interference from the unextracted field samples and avoid false negatives. Further modifications were included to improve the speed and operability of the test, for use by non-laboratory trained staff operating under field conditions, with shelf-stable reaction kits which require a minimum of liquid handling skills. Comparison of the assay performance with an established laboratory-based real-time reverse transcriptase PCR (rRT-PCR) test targeting the 3D region of FMD virus (Tetracore Inc) was investigated. LAMP has the potential to complement current laboratory diagnostics, such as rRT-PCR, as a preliminary tool in the investigation of FMD. We describe a strategic approach to validation of the test for use in the field using extracted RNA samples of various serotypes from Thailand and then finally unextracted field samples collected from FMD-suspected animals (primarily oral lesion swabs) from Bhutan and Australia. The statistical approach to validation was performed by Frequentist and Bayesian latent class methods, which both confirmed this new RT-LAMP-FMDV test as fit-for-purpose as a herd diagnostic tool with diagnostic specificity >99% and sensitivity 79% (95% Bayesian credible interval: 65, 90%) on unextracted field samples (oral swabs).


Asunto(s)
Virus de la Fiebre Aftosa/aislamiento & purificación , Fiebre Aftosa/diagnóstico , Técnicas de Diagnóstico Molecular/veterinaria , Técnicas de Amplificación de Ácido Nucleico/veterinaria , Animales , Australia , Teorema de Bayes , Bután , Fiebre Aftosa/virología , Virus de la Fiebre Aftosa/genética , Sensibilidad y Especificidad , Tailandia
8.
Vet Microbiol ; 137(1-2): 1-9, 2009 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-19153018

RESUMEN

Equine influenza (EI) virus (H3N8) was identified in the Australian horse population for the first time in August 2007. The principal molecular diagnostic tool used for detection was a TaqMan real-time reverse transcription-polymerase chain reactions (RT-PCR) assay specific for the matrix (MA) gene of influenza virus type A (IVA). As this assay is not specific for EI, we developed a new EI H3-specific TaqMan assay targeting the haemagglutinin (HA) gene of all recent EI H3 strains. The IVA and the EI H3 TaqMan assays were assessed using in vitro transcribed RNA template, virus culture, diagnostic samples from the outbreak and samples from experimentally infected horses. The EI H3 TaqMan assay had a higher diagnostic sensitivity (DSe) when compared to the IVA TaqMan assay and also when using a conventional PCR for EI H3 as a standard of comparison. The performance of both TaqMan assays was compared with an antigen detection ELISA and virus isolation using nasal swabs collected daily from horses experimentally infected with the outbreak strain A/equine/Sydney/2888-8/2007. The EI H3 TaqMan assay was the most sensitive of the assays, able to detect EI from day 1 or 2 post-challenge, as early as virus isolation, and before clinical signs of disease were observed.


Asunto(s)
Enfermedades de los Caballos/virología , Subtipo H3N8 del Virus de la Influenza A/aislamiento & purificación , Infecciones por Orthomyxoviridae/veterinaria , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Animales , Secuencia de Bases , Genes Virales , Enfermedades de los Caballos/diagnóstico , Caballos , Subtipo H3N8 del Virus de la Influenza A/genética , Infecciones por Orthomyxoviridae/diagnóstico , Infecciones por Orthomyxoviridae/virología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Sensibilidad y Especificidad , Proteínas Reguladoras y Accesorias Virales
9.
Vet Microbiol ; 137(1-2): 178-83, 2009 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-19181459

RESUMEN

Foot-and-mouth disease (FMD) causes sporadic disease outbreaks in the Lao People's Democratic Republic (Lao PDR) and appears to be endemic within a livestock population largely susceptible to infection. As Lao PDR is a major thoroughfare for transboundary animal movement, regular FMD outbreaks occur causing economic hardship for farmers and their families. The dominant serotype causing outbreaks between 1998 and 2006 was type O. Using phylogenetic analysis, type O isolated viruses were divided into two topotypes: South East Asia (SEA) and the Middle East-South Asia (ME-SA). Type A virus was reported only in 2003 and 2006 and type Asia 1 only in 1996 and 1998.


Asunto(s)
Enfermedades de los Bovinos/virología , Virus de la Fiebre Aftosa/genética , Fiebre Aftosa/epidemiología , Epidemiología Molecular , Enfermedades de los Porcinos/virología , Animales , Asia Sudoriental/epidemiología , Proteínas de la Cápside/genética , Bovinos , Enfermedades de los Bovinos/epidemiología , Fiebre Aftosa/virología , Filogenia , Porcinos , Enfermedades de los Porcinos/epidemiología
10.
Prev Vet Med ; 162: 46-55, 2019 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-30621898

RESUMEN

The quality of diagnostic accuracy studies (DAS) for infectious diseases of animals has improved over the last 20 years because of international educational efforts, use of design and reporting standards to guide researchers and test developers, and acceptance of the use of latent class models to account for imperfect reference tests. In this review, we focus on measurement of diagnostic sensitivity and specificity as a measure of clinical validity, describe the leadership role of the World Organisation of Animal Health (OIE) in setting standards for test validation in the context of fitness-for-purpose, and describe how design and reporting quality have facilitated the increased use of systematic reviews and meta-analysis of DAS. Ongoing challenges for design, conduct, analysis and reporting of DAS are identified; and we make recommendations for improvements in these areas for OIE-listed and non-listed infectious diseases.


Asunto(s)
Enfermedades Transmisibles/veterinaria , Enfermedades Transmisibles/diagnóstico , Reproducibilidad de los Resultados , Proyectos de Investigación , Sensibilidad y Especificidad , Estadística como Asunto , Medicina Veterinaria/normas
11.
Trop Med Infect Dis ; 3(4)2018 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-30287778

RESUMEN

Australian bat lyssavirus (ABLV) is closely related to the classical rabies virus and has been associated with three human fatalities and two equine fatalities in Australia. ABLV infection in humans causes encephalomyelitis, resulting in fatal disease, but has no effective therapy. The virus is maintained in enzootic circulation within fruit bats (Pteropid spp.) and at least one insectivorous bat variety (Saccolaimus flaviventris). Most frequently, laboratory testing is conducted on pteropodid bat brains, either following a potential human exposure through bites, scratches and other direct contacts with bats, or as opportunistic assessment of sick or dead bats. The level of medical intervention and post-exposure prophylaxis is largely determined on laboratory testing for antigen/virus as the demonstrable infection status of the in-contact bat. This study evaluates the comparative diagnostic performance of a lateral flow test, Anigen Rabies Ag detection rapid test (RDT), in pteropodid variant of ABLV-infected bat brain tissues. The RDT demonstrated 100% agreement with the reference standard fluorescent antibody test on 43 clinical samples suggesting a potential application in rapid diagnosis of pteropodid variant of ABLV infection. A weighted Kappa value of 0.95 confirmed a high level of agreement between both tests.

12.
J Vet Diagn Invest ; 30(3): 362-369, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29463198

RESUMEN

Obtaining statistically sound numbers of sera from Hendra virus (HeV)-infected horses is problematic because affected individuals usually die or are euthanized before developing a serum antibody response. As a consequence, test validation becomes a challenge. Our approach is an extension of OIE principles for provisional recognition and included 7 validation panels tested across multiple laboratories that provided estimates for test performance characteristics. At a 0.4 S/P cutoff, 16 of 19 sera from HeV-infected horses gave positive results in the HeV soluble G, indirect ELISA (HeVsG iELISA; DSe 84.2% [95% CI: 60.4-96.6%]); 463 of 477 non-infected horse sera tested negative (DSp 97.1% [95% CI: 95.1-98.4%]). The HeVsG iELISA eliminated almost all false-positive results from the previously used HeV iELISA, with marginally decreased relative sensitivity. Assay robustness was evaluated in inter-laboratory and proficiency testing panels. The HeVsG iELISA is considered to be fit for purpose for serosurveillance and international movement of horses when virus neutralization is used for follow-up testing of positive or inconclusive serum samples.


Asunto(s)
Anticuerpos Antivirales/sangre , Ensayo de Inmunoadsorción Enzimática/veterinaria , Virus Hendra/inmunología , Enfermedades de los Caballos/virología , Animales , Caballos , Sensibilidad y Especificidad
13.
PLoS Negl Trop Dis ; 11(11): e0006079, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-29131859

RESUMEN

Rabies continues to pose a significant threat to human and animal health in regions of Indonesia. Indonesia has an extensive network of veterinary diagnostic laboratories and the 8 National laboratories are equipped to undertake diagnostic testing for rabies using the commercially-procured direct fluorescent antibody test (FAT), which is considered the reference (gold standard) test. However, many of the Indonesian Provincial diagnostic laboratories do not have a fluorescence microscope required to undertake the FAT. Instead, certain Provincial laboratories continue to screen samples using a chemical stain-based test (Seller's stain test, SST). This test has low diagnostic sensitivity, with negative SST-tested samples being forwarded to the nearest National laboratory resulting in significant delays for completion of testing and considerable additional costs. This study sought to develop a cost-effective and diagnostically-accurate immunoperoxidase antigen detection (RIAD) test for rabies that can be readily and quickly performed by the resource-constrained Provincial laboratories. This would reduce the burden on the National laboratories and allow more rapid diagnoses and implementation of post-exposure prophylaxis. The RIAD test was evaluated using brain smears fixed with acetone or formalin and its performance was validated by comparison with established rabies diagnostic tests used in Indonesia, including the SST and FAT. A proficiency testing panel was distributed between Provincial laboratories to assess the reproducibility of the test. The performance of the RIAD test was improved by using acetone fixation of brain smears rather than formalin fixation such that it was of equivalent accuracy to that of the World Organisation for Animal Health (OIE)-recommended FAT, with both tests returning median diagnostic sensitivity and specificity values of 0.989 and 0.993, respectively. The RIAD test and FAT had higher diagnostic sensitivity than the SST (median = 0.562). Proficiency testing using a panel of 6 coded samples distributed to 16 laboratories showed that the RIAD test had good reproducibility with an overall agreement of 97%. This study describes the successful development, characterisation and use of a novel RIAD test and its fitness for purpose as a screening test for use in provincial Indonesian veterinary laboratories.


Asunto(s)
Antígenos Virales , Técnicas para Inmunoenzimas/métodos , Virus de la Rabia/aislamiento & purificación , Rabia/diagnóstico , Animales , Encéfalo/virología , Regulación Viral de la Expresión Génica , Humanos , Inmunización , Técnicas para Inmunoenzimas/economía , Indonesia/epidemiología , Nucleoproteínas/inmunología , Nucleoproteínas/aislamiento & purificación , Conejos , Rabia/epidemiología , Juego de Reactivos para Diagnóstico , Reproducibilidad de los Resultados , Proteínas Virales/inmunología , Proteínas Virales/aislamiento & purificación
14.
J Vet Diagn Invest ; 27(6): 704-15, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26462759

RESUMEN

Oropharyngeal and cloacal swabs have been widely used for the detection of H5N1 highly pathogenic avian Influenza A virus (HPAI virus) in birds. Previous studies have shown that the feather calamus is a site of H5N1 virus replication and therefore has potential for diagnosis of avian influenza. However, studies characterizing the value of feathers for this purpose are not available, to our knowledge; herein we present a study investigating feathers for detection of H5N1 virus. Ducks and chickens were experimentally infected with H5N1 HPAI virus belonging to 1 of 3 clades (Indonesian clades 2.1.1 and 2.1.3, Vietnamese clade 1). Different types of feathers and oropharyngeal and cloacal swab samples were compared by virus isolation. In chickens, virus was detected from all sample types: oral and cloacal swabs, and immature pectorosternal, flight, and tail feathers. During clinical disease, the viral titers were higher in feathers than swabs. In ducks, the proportion of virus-positive samples was variable depending on viral strain and time from challenge; cloacal swabs and mature pectorosternal feathers were clearly inferior to oral swabs and immature pectorosternal, tail, and flight feathers. In ducks infected with Indonesian strains, in which most birds did not develop clinical signs, all sampling methods gave intermittent positive results; 3-23% of immature pectorosternal feathers were positive during the acute infection period; oropharyngeal swabs had slightly higher positivity during early infection, while feathers performed better during late infection. Our results indicate that immature feathers are an alternative sample for the diagnosis of HPAI in chickens and ducks.


Asunto(s)
Pollos , Técnicas y Procedimientos Diagnósticos/veterinaria , Patos , Subtipo H5N1 del Virus de la Influenza A/aislamiento & purificación , Gripe Aviar/diagnóstico , Enfermedades de las Aves de Corral/diagnóstico , Animales , Cloaca/virología , Técnicas y Procedimientos Diagnósticos/instrumentación , Plumas/virología , Gripe Aviar/virología , Orofaringe/virología , Enfermedades de las Aves de Corral/virología , Carga Viral/veterinaria
15.
Mol Biochem Parasitol ; 200(1-2): 19-24, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25936954

RESUMEN

Mikrocytos mackini is an internationally regulated pathogen and causative agent of Denman Island disease in Pacific oysters Crassostrea gigas. Recent phylogenetic breakthroughs have placed this parasite within a highly divergent and globally distributed eukaryotic lineage that has been designated a new taxonomic order, Mikrocytida. The discovery of this new radiation of parasites is accompanied by a heightened awareness of the many knowledge gaps that exist with respect to the general biology, epizootiology, and potential impact of mikrocytid parasites on hosts, ecosystems, and commercial fisheries. It has also highlighted current shortcomings regarding our ability to detect these organisms. In this study, we developed a species-specific, sensitive, and quantitative method for detecting M. mackini DNA from host tissues using probe-based real-time qPCR technology. A limit of sensitivity between 2 and 5 genome copy equivalents was achieved in a reaction matrix containing ≥ 40 ng/µL host gDNA without inhibition. This detection proved superior to existing methods based on conventional PCR, histology or gross pathology and is the first species-specific diagnostic test for M. mackini. Quantitative assessment of parasite DNA using this assay remained accurate to between 10 and 50 copies identifying that during infection, M. mackini DNA was significantly more prevalent in hemolymph, labial palp, and mid-body cross-sections compared to mantle or adductor muscle. DNA extracted from a mid-body cross-section also provided the highest likelihood for detection during diagnostic screening of infected oysters. Taken together, these findings provide strong analytical evidence for the adoption of qPCR as the new reference standard for detecting M. mackini and give preliminary insight into the distribution of the parasite within host tissues. Standardised operating methodologies for sample collection and qPCR testing are provided to aid in the international regulatory diagnosis of M. mackini and serve as a useful platform for the future development of multiplexed or alternate mikrocytid species detection.


Asunto(s)
Eucariontes/genética , Eucariontes/aislamiento & purificación , Ostreidae/parasitología , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Animales , Eucariontes/clasificación , Especificidad de la Especie
16.
J Virol Methods ; 203: 65-72, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24690622

RESUMEN

Flaviviruses of the Japanese encephalitis virus (JEV) serocomplex include major human and animal pathogens that have a propensity to spread and emerge in new geographic areas. Different genotypes or genetic lineages have been defined for many of these viruses, and they are distributed worldwide. Tools enabling rapid detection of new or emerging flaviviruses and differentiation of important subgroups have widespread application for arbovirus diagnosis and surveillance, and are crucial for detecting virus incursions, tracking virus emergence and for disease control. A microsphere suspension array assay was developed to identify JEV serocomplex flaviviruses of medical and veterinary importance. Assay performance was evaluated using representative virus strains as well as clinical and surveillance samples. The assay detected all JEV serocomplex viruses tested in this study with an apparent analytical sensitivity equal or better than the reference real-time or conventional RT-PCR assays and was able to identify mixed virus populations. The ability to identify mixed virus populations at a high analytical sensitivity would be pertinent in the Australian context when attempting to detect exotic JEV or West Nile virus (WNV), and differentiate from endemic Murray Valley encephalitis virus and WNV-Kunjin virus. The relatively low cost, the ability to identify mixed virus populations and the multiplex nature makes this assay valuable for a wide range of applications including diagnostic investigations, virus exclusions, and surveillance programs.


Asunto(s)
Virus de la Encefalitis Japonesa (Subgrupo)/clasificación , Virus de la Encefalitis Japonesa (Subgrupo)/aislamiento & purificación , Encefalitis por Arbovirus/diagnóstico , Encefalitis por Arbovirus/veterinaria , Infecciones por Flavivirus/diagnóstico , Infecciones por Flavivirus/veterinaria , Técnicas de Diagnóstico Molecular/métodos , Animales , Virus de la Encefalitis Japonesa (Subgrupo)/genética , Humanos , Microesferas , Sensibilidad y Especificidad , Medicina Veterinaria/métodos
17.
Pesqui. vet. bras ; 39(1): 1-11, Jan. 2019. ilus
Artículo en Inglés, Portugués | LILACS, VETINDEX | ID: biblio-990238

RESUMEN

Dr. Jürgen Döbereiner was born in Germany, on the 1st of November 1923, and lived in Brazil for 68 years during which time he developed a range of scientific projects in veterinary pathology and related disciplines. His main interests were the identification of new poisonous plants and mineral deficiencies and the causes of "cara inchada" ("swollen face" a periodontal disease) and botulism in livestock. This research has resulted in the improved health and saving of hundreds of thousands of animals, mainly cattle, annually, and is consequently of enormous economic value to the country. This contribution remains largely under appreciated. He was also involved in organizing diagnostic methods for identifying infectious diseases such as African swine fever and glanders in horses. One of his other major achievements has been the foundation and editing of specialized scientific journals for the documentation of veterinary science research results. At the beginning of his career in the 1950s, he and colleagues from the Institute for Animal Biology (IBA) were struggling to find a national scientific journal where research results from veterinary medicine could be published with practical application to the Brazilian reality. In consequence, the team founded "Arquivos do Instituto de Biologia Animal" and published three volumes (1959-1961). He then founded and edited "Pesquisa Agropecuária Brasileira" (The Brazilian Journal of Agricultural Research") that included a veterinary section. A series of veterinary volumes were published (1966-1976). Finally, in 1978 he helped create the Brazilian College of Veterinary Pathology (CBPA) that published "Pesquisa Veterinária Brasileira" (The Brazilian Journal of Veterinary Research) from 1981. The main goal was to communicate the most relevant disease problems of Brazilian livestock, in particular pathology and related subjects such as epidemiology, clinical study series and laboratory diagnosis to field veterinarians and academics. Dr. Jürgen Döbereiner was president of CBPA (1978-2018) and chief editor of "Pesquisa Veterinária Brasileira" (1981-2018). He passed away on the 16th of October, 2018, at the age of 94 at his home in Seropédica/RJ, Brazil.(AU)


Dr. Jürgen Döbereiner nasceu na Alemanha em 1 de novembro de 1923, durante 68 anos viveu no Brasil e desenvolveu trabalhos científicos no campo da patologia veterinária latu sensu. Sua contribuição científica de destaque foi em temas como plantas tóxicas de interesse pecuário, deficiências minerais em animais de produção, cara inchada (doença periodontal) dos ruminantes, botulismo e diagnóstico de doenças infecciosas. Estas pesquisas resultaram na melhoria da saúde e de centenas de milhares de animais, principalmente bovinos e, consequentemente, foram de enorme valor econômico para o país. Esta contribuição ainda permanece em grande parte subestimada. De grande destaque para a ciência brasileira foi ainda a sua atuação profissional na documentação científica de resultados de pesquisa. No início de sua carreira na década de 1950, Dr. Döbereiner e outros pesquisadores do Instituto de Biologia Animal (IBA) detectaram a necessidade de um periódico científico nacional para publicar resultados de pesquisas com aplicação pratica à realidade brasileira. Dessa iniciativa surgiram os Arquivos do Instituto de Biologia Animal, que publicou três fascículos (1959-1961), em seguida o Dr. Jürgen Döbereiner participou na fundação da revista Pesquisa Agropecuária Brasileira que publicou a Série Veterinária (1966-1976) e finalmente em 1978, houve a fundação do Colégio Brasileiro de Patologia Animal (CBPA) que publica desde 1981 a revista Pesquisa Veterinária Brasileira. Este periódico científico foi criado para apresentar à comunidade, principalmente veterinários de campo e professores, os principais problemas de saúde em animais de produção no Brasil, ou seja, patologia em seu sentido amplo, envolvendo as áreas de epidemiologia, clínica e diagnóstico laboratorial. Dr. Jürgen Döbereiner, que foi presidente do CBPA (1978-2018) e Editor-Chefe da revista Pesquisa Veterinária Brasileira (1981-2018), faleceu em casa, em 16 de outubro de 2018, aos 94 anos, no município de Seropédica/RJ.(AU)


Asunto(s)
Animales , Bovinos , Patología Veterinaria/historia , Periodontitis/veterinaria , Intoxicación por Plantas/veterinaria , Botulismo/veterinaria , Enfermedades de los Bovinos , Dieta/veterinaria , Deficiencia de Minerales
18.
Biomed Res Int ; 2013: 289295, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23509705

RESUMEN

Microsphere suspension array systems enable the simultaneous fluorescent identification of multiple separate nucleotide targets in a single reaction. We have utilized commercially available oligo-tagged microspheres (Luminex MagPlex-TAG) to construct and evaluate multiplexed assays for the detection and differentiation of Hendra virus (HeV) and Nipah virus (NiV). Both these agents are bat-borne zoonotic paramyxoviruses of increasing concern for veterinary and human health. Assays were developed targeting multiple sites within the nucleoprotein (N) and phosphoprotein (P) encoding genes. The relative specificities and sensitivities of the assays were determined using reference isolates of each virus type, samples from experimentally infected horses, and archival veterinary diagnostic submissions. Results were assessed in direct comparison with an established qPCR. The microsphere array assays achieved unequivocal differentiation of HeV and NiV and the sensitivity of HeV detection was comparable to qPCR, indicating high analytical and diagnostic specificity and sensitivity.


Asunto(s)
Virus Hendra/aislamiento & purificación , Infecciones por Henipavirus/diagnóstico , Infecciones por Henipavirus/veterinaria , Microesferas , Virus Nipah/aislamiento & purificación , Animales , ADN Viral/análisis , Brotes de Enfermedades , Infecciones por Henipavirus/virología , Caballos , Nucleoproteínas/análisis , Fosfoproteínas/análisis , Reacción en Cadena de la Polimerasa , ARN Viral/análisis , Curva ROC , Proteínas del Envoltorio Viral/análisis
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