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1.
Transbound Emerg Dis ; 57(5): 305-14, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20626708

RESUMEN

The aim of this study was to characterize foot-and-mouth disease (FMD) viruses collected between 2004 and 2008 from Sudan, a country where FMD is endemic. Using virus isolation and antigen ELISA, three FMD virus serotypes (O, A and SAT2) were detected in 24 samples that were submitted to the FAO World Reference Laboratory for FMD. Pan-serotypic real-time RT-PCR assays targeting the 5' untranslated region (5'UTR) and 3D genes of FMD virus were also used to contribute to the laboratory diagnosis of these cases. The lack of concordant results between the real-time RT-PCR assays for three serotype O viruses was attributed to four nucleotide mismatches in the 5'UTR PCR primer and probe sites (three substitutions for the sense-primer and one in the TaqMan(®) probe region). Taken together, the laboratory results showed that recent FMD outbreaks that occurred during 2008 in northern and central Sudan were caused by serotypes O and SAT2, while serotype A was last detected in 2006. Phylogenetic analyses of VP1 sequences from these viruses were used to determine the relationships with 23 older viruses from Sudan and other viruses from West and East Africa. For serotype O, closest genetic identities were between concurrent and historical Sudanese isolates, indicating that within-country circulation is an important mechanism by which FMD is maintained year-on-year in Sudan. A similar pattern was also evident for serotype A and SAT2 viruses; however, these lineages also contained recent representative FMD viral isolates from other countries in the region suggesting that long-distance animal movement can also contribute to FMD dispersal across sub-Saharan Africa. These findings provide the first molecular description of FMD viruses that are circulating in Sudan, and highlight that further sampling of representative viruses from the region is required before the complex epidemiology of FMD in sub-Saharan Africa can be fully understood.


Asunto(s)
Virus de la Fiebre Aftosa/genética , Fiebre Aftosa/virología , Animales , Bovinos , Brotes de Enfermedades/veterinaria , Fiebre Aftosa/epidemiología , Regulación Viral de la Expresión Génica , Filogenia , Sudán/epidemiología , Factores de Tiempo
2.
Transbound Emerg Dis ; 57(4): 237-43, 2010 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-20545909

RESUMEN

This article reviews the options for use of virus detection techniques for decentralized testing of samples from suspected secondary outbreaks of foot-and-mouth disease (FMD). These options have been expanded by the advent of new tests including disposable lateral flow devices (LFDs) that detect viral proteins and portable RT-PCR equipment that detects viral RNA. LFDs have been developed with similar sensitivity to antigen detection ELISA but with the ability to provide a result 1-30 min after the addition of epithelium or vesicular fluid. Portable RT-PCR platforms are being developed that can detect FMD viral RNA in blood, epithelium or other materials with minimal sample processing and with high sensitivity, in as little as 60 min in some cases. These devices may be used on infected farms as pen-side tests, in regional, local or mobile laboratories, or in National Reference Laboratories (NRL). Advantages and disadvantages of different testing options are considered to inform decisions on the optimal strategies for different national circumstances. Issues include validation and quality control, containment needs, availability of test devices and reagents, the decision tree for declaring an outbreak, training issues and provision of samples for subsequent viral characterization. Tests to confirm the diagnosis of the index case of an outbreak of FMD should continue to be carried out in the NRL.


Asunto(s)
Brotes de Enfermedades/veterinaria , Fiebre Aftosa/diagnóstico , Fiebre Aftosa/epidemiología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Animales , Sistemas de Atención de Punto , Reproducibilidad de los Resultados
3.
Transbound Emerg Dis ; 56(8): 321-8, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19744234

RESUMEN

In 2007, serological evidence for foot-and-mouth disease (FMD) infection was found as a result of differential diagnostic testing of Cypriot sheep suspected to be infected with bluetongue or contagious ecthyma. Seropositive sheep and goats were subsequently uncovered on ten geographically clustered flocks, while cattle and pigs in neighbouring herds were all seronegative. These antibodies were specific for serotype-O FMD virus, reacting with both structural and non-structural (NS) FMD viral proteins. However, no FMD virus could be recovered from the seropositive flocks. FMD had not been recorded in Cyprus since 1964 and there has been no vaccination programme since 1984. Since all the seropositive animals were at least 3 years old and home-bred, it was concluded that infection had occurred approximately 3 years previously had passed un-noticed and died out spontaneously. It therefore appears that antibodies to FMD virus NS proteins can still be detected around 3 years after infection of small ruminants, but that virus carriers cannot be detected at this time. This unusual situation of finding evidence of historical infection in a FMD-free country caused considerable disruption and alarm and posed questions about the definition of what constitutes a FMD outbreak.


Asunto(s)
Anticuerpos Antivirales/sangre , Virus de la Fiebre Aftosa/inmunología , Fiebre Aftosa/epidemiología , Enfermedades de las Cabras/epidemiología , Enfermedades de las Ovejas/epidemiología , Animales , Portador Sano/veterinaria , Portador Sano/virología , Chipre/epidemiología , Fiebre Aftosa/virología , Virus de la Fiebre Aftosa/aislamiento & purificación , Enfermedades de las Cabras/virología , Cabras , Estudios Seroepidemiológicos , Serotipificación/veterinaria , Ovinos , Enfermedades de las Ovejas/virología , Factores de Tiempo
4.
J Clin Microbiol ; 47(10): 3156-60, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19656987

RESUMEN

A fetal goat cell line (ZZ-R 127) supplied by the Collection of Cell Lines in Veterinary Medicine of the Friedrich Loeffler Institute was examined for susceptibility to infection by foot-and-mouth disease (FMD) virus (FMDV) and by two other viruses causing clinically indistinguishable vesicular conditions, namely, the viruses of swine vesicular disease and vesicular stomatitis. Primary bovine thyroid (BTY) cells are generally the most sensitive cell culture system for FMDV detection but are problematic to produce, particularly for laboratories that infrequently perform FMD diagnostic tests and for those in countries where FMD is endemic that face problems in sourcing thyroid glands from FMD-negative calves. Strains representing all seven serotypes of FMDV could be isolated in ZZ-R 127 cells with a sensitivity that was considerably higher than that of established cell lines and within 0.5 log of that for BTY cells. The ZZ-R 127 cell line was found to be a sensitive, rapid, and convenient tool for the isolation of FMDV and a useful alternative to BTY cells for FMD diagnosis.


Asunto(s)
Técnicas de Cultivo de Célula/métodos , Células Epiteliales/virología , Virus de la Fiebre Aftosa/crecimiento & desarrollo , Virus de la Fiebre Aftosa/aislamiento & purificación , Animales , Línea Celular , Cabras , Sensibilidad y Especificidad , Vesiculovirus/crecimiento & desarrollo
5.
Transbound Emerg Dis ; 56(5): 157-69, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19432637

RESUMEN

This report describes the characterization of a new genotype of foot-and-mouth disease virus (FMDV) type A responsible for recent FMD outbreaks in the Middle East. Initially identified in samples collected in 2003 from Iran, during 2005 and 2006 this FMDV lineage (proposed to be named A-Iran-05) spread into Saudi Arabia and Jordan and then further west into Turkey reaching European Thrace in January 2007. Most recently A-Iran-05 has been found in Bahrain. To the east of Iran, it has been recognized in Afghanistan (2004-07) and Pakistan (2006-07). Throughout the region, this lineage is now the predominant genotype of FMDV serotype A sampled, and has appeared to have replaced the A-Iran-96 and A-Iran-99 strains which were previously encountered. In August 2007, a new A-Iran-05 sub-lineage (which we have called A-Iran-05(ARD-07)) was identified in Ardahan, Turkey, close to the border with Georgia. This new sub-lineage appeared to predominate in Turkey in 2008, but has, so far, not been identified in any other country. Vaccine matching tests revealed that the A-Iran-05 viruses are antigenically different to A-Iran-96 and more like A(22). These findings emphasize the importance of undertaking continued surveillance in the Middle East and Central Asia in order to detect and monitor the emergence and spread of new FMDV strains.


Asunto(s)
Enfermedades Transmisibles Emergentes/veterinaria , Virus de la Fiebre Aftosa/clasificación , Virus de la Fiebre Aftosa/genética , Fiebre Aftosa/epidemiología , Animales , Secuencia de Bases , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/virología , Brotes de Enfermedades/veterinaria , Fiebre Aftosa/virología , Virus de la Fiebre Aftosa/aislamiento & purificación , Genotipo , Geografía , Medio Oriente/epidemiología , Filogenia , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
6.
Vet Rec ; 163(5): 139-47, 2008 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-18676997

RESUMEN

A case of foot-and-mouth disease (fmd) on a cattle farm in Normandy, Surrey, was confirmed on Friday August 3, 2007, the first case in the uk since 2001. The infection was detected nearby on a second farm on August 6. On September 12, fmd was confirmed on a farm approximately 20 km from Normandy in Egham, and this was followed by cases on five more farms in that area in the next three weeks. The majority of the infected farms consisted of multiple beef cattle holdings in semi-urban areas. In total, 1578 animals were culled on the infected farms, and fmd virus infection was confirmed in 278 of them by the detection of viral antigen, genome or antibodies to the virus, or by clinical signs. This paper describes the findings from animal inspections on the infected farms, including the estimated ages of the fmd lesions and the numbers of animals infected. It also summarises the test results from samples taken for investigation, including the detection of preclinically viraemic animals by using real-time reverse transcriptase-pcr.


Asunto(s)
Enfermedades de los Bovinos/epidemiología , Brotes de Enfermedades/veterinaria , Fiebre Aftosa/epidemiología , Enfermedades de las Ovejas/epidemiología , Enfermedades de los Porcinos/epidemiología , Animales , Anticuerpos Antivirales/sangre , Antígenos Virales/sangre , Bovinos , Enfermedades de los Bovinos/sangre , Enfermedades de los Bovinos/virología , Inglaterra/epidemiología , Femenino , Fiebre Aftosa/sangre , Fiebre Aftosa/virología , Virus de la Fiebre Aftosa/inmunología , Virus de la Fiebre Aftosa/aislamiento & purificación , Masculino , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Ovinos , Enfermedades de las Ovejas/sangre , Enfermedades de las Ovejas/virología , Porcinos , Enfermedades de los Porcinos/sangre , Enfermedades de los Porcinos/virología
7.
Transbound Emerg Dis ; 55(5-6): 215-25, 2008 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-18666965

RESUMEN

Nine viral diseases included in the World Organization for Animal Health list of notifiable diseases (former list A) were chosen for their contagiousness and high capacity of spreading to improve their diagnosis using new and emerging technologies. All the selected diseases--foot-and-mouth disease, swine vesicular disease, vesicular stomatitis, classical swine fever, African swine fever, bluetongue, African horse sickness, Newcastle disease and highly pathogenic avian influenza--are considered as transboundary diseases, which detection causes the prohibition of livestock exportation, and, thus, it leads to high economical losses. The applied diagnostic techniques can fall into two categories: (i) nucleic-acid detection, including padlock probes, real-time PCR with TaqMan, minor groove binding probes and fluorescence energy transfer reaction probes, isothermal amplification like the Cleavase/Invader assay or the loop-mediated amplification technology and the development of rapid kits for 'mobile' PCR and (ii) antigen-antibody detection systems like simplified and more sensitive ELISA tests. Besides, internal controls have been improved for nucleic acid-detecting methods by using an RNA plant virus--Cowpea Mosaic Virus--to ensure the stability of the RNA used as a positive control in diagnostic real-time RT-PCR assays. The development of these diagnosis techniques has required the joint efforts of a European consortium in which nine diagnostic laboratories and an SME who have collaborated since 2004 within the European Union-funded Lab-on-site project. The results obtained are shown in this paper.


Asunto(s)
Técnicas de Laboratorio Clínico/veterinaria , Enfermedades Transmisibles/veterinaria , Notificación de Enfermedades , Virosis/veterinaria , Animales , Técnicas de Laboratorio Clínico/normas , Enfermedades Transmisibles/diagnóstico , Ensayo de Inmunoadsorción Enzimática/métodos , Ensayo de Inmunoadsorción Enzimática/normas , Ensayo de Inmunoadsorción Enzimática/veterinaria , Reacción en Cadena de la Polimerasa/métodos , Reacción en Cadena de la Polimerasa/normas , Reacción en Cadena de la Polimerasa/veterinaria , Sensibilidad y Especificidad , Virosis/diagnóstico
9.
Rev Sci Tech ; 27(3): 839-49, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19284051

RESUMEN

Foot and mouth disease (FMD) causes sporadic disease outbreaks in the Lao People's Democratic Republic (Lao PDR). As the Lao PDR is a major thoroughfare for transboundary animal movements, regular FMD outbreaks occur, causing economic hardship for farmers and their families. In this review of the recent history of FMD in the Lao PDR between 1997 and 2006, the authors examine the virological and epidemiological aspects of the disease and appropriate control measures, including the distribution of outbreaks, causative serotypes and the molecular epidemiology of the viruses, as well as large-scale vaccination programmes. The dominant serotype, type O, was reported every year from 1998 to 2005. The majority of outbreaks occurred in Vientiane Capital (n = 42; 28%) and the highest number of outbreaks were reported in cattle (n = 94; 61%); followed by buffalo (n = 41; 27%) and pigs (n = 18; 12%). All type A outbreaks occurred in cattle. Type Asia 1 outbreaks were reported in the central provinces around Vientiane Capital between 1996 and 1998.


Asunto(s)
Brotes de Enfermedades/veterinaria , Fiebre Aftosa/epidemiología , Fiebre Aftosa/prevención & control , Vacunación/veterinaria , Vacunas Virales/administración & dosificación , Animales , Búfalos , Bovinos , Enfermedades de los Bovinos/epidemiología , Enfermedades de los Bovinos/prevención & control , Brotes de Enfermedades/prevención & control , Laos/epidemiología , Serotipificación/veterinaria , Porcinos , Enfermedades de los Porcinos/epidemiología , Enfermedades de los Porcinos/prevención & control , Vacunación/métodos
11.
Vet Rec ; 160(19): 647-54, 2007 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-17496271

RESUMEN

During a field study in Zimbabwe, clinical specimens were collected from 403 cattle in six herds, in which the history of foot-and-mouth disease (FMD) vaccination and infection appeared to be known with some certainty. Five herds had reported outbreaks of disease one to five months previously but clinical FMD had not been observed in the sixth herd. A trivalent vaccine (South African Territories [SAT] types 1, 2 and 3) had been used in some of the herds at various times either before and/or after the recent outbreaks of FMD. The primary aim of this study was to evaluate the performance of serological tests for the detection of SAT-type FMD virus infection, particularly elisas for antibodies to non-structural proteins (NSPs) of FMD virus and solid phase competition ELISAS (SPCEs) for serotypes SAT1 and SAT2. Secondary aims were to examine NSP seroconversion rates in cattle that had been exposed to infection and to compare virus detection rates by virus isolation and real-time reverse transcriptase-PCR (rtRT-PCR) tests on both oesophagopharyngeal fluids and nasopharyngeal brush swabbings. In addition, the hooves of sampled animals were examined for growth arrest lines as clinical evidence of FMD convalescence. Laboratory tests provided evidence of FMD virus infection in all six herds; SAT2 viruses were isolated from oesophagopharyngeal fluids collected from two herds in northern Zimbabwe, and SAT1 viruses were isolated from three herds in southern Zimbabwe. Optimised rtRT-PCR was more sensitive than virus isolation at detecting FMD virus persistence and when the results of the two methods were combined for oesophagopharyngeal fluids, between 12 and 35 per cent of the cattle sampled in the convalescent herds were deemed to be carriers. In contrast, nasopharyngeal swabs yielded only two virus-positive specimens. The overall seroprevalence in the five affected herds varied with the different NSPS from 56 per cent to 75 per cent, compared with 81 per cent and 91 per cent by homologous SPCE and virus neutralisation tests respectively. However, if serological test results were considered only for the cattle in which persistent infection with FMD virus had been demonstrated, 70 to 90 per cent scored seropositive in the different NSPs.


Asunto(s)
Anticuerpos Antivirales/sangre , Enfermedades de los Bovinos/epidemiología , Virus de la Fiebre Aftosa/inmunología , Fiebre Aftosa/epidemiología , Animales , Bovinos , Enfermedades de los Bovinos/sangre , Enfermedades de los Bovinos/diagnóstico , Brotes de Enfermedades/veterinaria , Ensayo de Inmunoadsorción Enzimática/métodos , Ensayo de Inmunoadsorción Enzimática/veterinaria , Fiebre Aftosa/sangre , Fiebre Aftosa/diagnóstico , Virus de la Fiebre Aftosa/clasificación , Virus de la Fiebre Aftosa/aislamiento & purificación , Pezuñas y Garras/patología , Pruebas de Neutralización/veterinaria , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Sensibilidad y Especificidad , Estudios Seroepidemiológicos , Serotipificación/veterinaria , Zimbabwe/epidemiología
12.
Vet Rec ; 159(12): 373-8, 2006 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-16980522

RESUMEN

There were 2030 designated cases of foot-and-mouth disease (FMD) during the course of the epidemic in the UK in 2001 (including four from Northern Ireland). Samples from 1720 of the infected premises (IPs) were received in the laboratory and examined for either the presence of FMD virus (virological samples from 1421 IPs) or both FMD virus and antibody (virological and serological samples from 255 IPs) or antibody alone (from 44 IPs). The time taken to issue final diagnostic results ranged from a few hours in cases in which positive results were obtained by ELISA on epithelia containing sufficient virus to be detected, to several days for samples containing small amounts of virus requiring amplification through cell culture, negative samples or samples tested for antibody. Two subsets of samples were analysed retrospectively by real-time reverse transcriptase-PCR (RT-PCR); first, epithelia that were negative by both ELISA and virus isolation (VI) in cell culture, and secondly, samples that were negative by ELISA on epithelial suspension but positive by VI. There was broad agreement between the RT-PCR and VI/ELISA combined, except that the RT-PCR procedure did not detect a group of related virus isolates from Wales. These viruses had evidently evolved during the epidemic and had a nucleotide substitution in the RT-PCR probe site, which prevented them from being detected by the routine diagnostic probe. No evidence of FMD virus, antibody or nucleic acid was found in approximately 23 per cent (390 of 1730) of IPs from which samples were received, suggesting that the incidence of FMD during the outbreak may have been over-reported.


Asunto(s)
Brotes de Enfermedades/veterinaria , Virus de la Fiebre Aftosa/genética , Fiebre Aftosa/epidemiología , Fiebre Aftosa/virología , Animales , Anticuerpos Antivirales/análisis , Bovinos , Técnicas de Laboratorio Clínico/estadística & datos numéricos , Técnicas de Laboratorio Clínico/veterinaria , ADN Viral/análisis , Ensayo de Inmunoadsorción Enzimática/veterinaria , Fiebre Aftosa/etiología , Fiebre Aftosa/prevención & control , Virus de la Fiebre Aftosa/inmunología , Cabras , Incidencia , Registros/veterinaria , Estudios Retrospectivos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Ovinos , Porcinos , Reino Unido/epidemiología
13.
Vet Microbiol ; 117(2-4): 130-40, 2006 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-16846700

RESUMEN

Five European reference laboratories participated in an exercise to evaluate the sensitivity and specificity of their routinely employed RT-PCR tests and cell cultures for the detection and isolation of foot-and-mouth disease (FMD) virus. Five identical sets of 20 coded samples were prepared from 10 vesicular epithelia, which were derived from submissions from suspect cases of FMD or swine vesicular disease (SVD). Sixteen samples were derived from six FMD virus positive epithelia representing four different serotypes (two each of types O and A and one each of types Asia 1 and SAT 2), two from samples which had been found to be negative by antigen ELISA and virus isolation (VI) in cell culture and two from SVD virus positive epithelia. Some of the FMD virus positive samples were prepared from 10-fold serial dilutions of three of the initial suspensions. Each laboratory tested the samples by one or more of its available RT-PCR procedures and inoculated cell cultures that it routinely uses for FMD diagnosis in attempts to isolate virus, the specificity of which was confirmed by antigen ELISA. The best of the RT-PCR assays used in each laboratory gave comparable results while the sensitivity of cell cultures was variable from high in one laboratory, moderate in two and low in two others. This prototype panel of samples would appear suitable for external quality assurance of these tests but would benefit from the inclusion of more negative samples and an extension in the serial dilution range of one or more of the FMD positive sample titration series.


Asunto(s)
Técnicas de Laboratorio Clínico/normas , Virus de la Fiebre Aftosa/aislamiento & purificación , Fiebre Aftosa/diagnóstico , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Animales , Células Cultivadas , Ensayo de Inmunoadsorción Enzimática/métodos , Ensayo de Inmunoadsorción Enzimática/normas , Ensayo de Inmunoadsorción Enzimática/veterinaria , Fiebre Aftosa/virología , Virus de la Fiebre Aftosa/genética , Virus de la Fiebre Aftosa/inmunología , Reproducibilidad de los Resultados , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/normas , Sensibilidad y Especificidad , Porcinos , Factores de Tiempo , Cultivo de Virus
15.
J Comp Pathol ; 131(4): 308-17, 2004 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-15511539

RESUMEN

Automated real-time RT-PCR was evaluated as a diagnostic tool for swine vesicular disease virus (SVDV) infection on a range of samples (vesicular epithelium, serum, nasal swabs, faeces) from four inoculated and three in-contact pigs over a period of 28 days. Traditional diagnostic procedures (virus isolation, and ELISAs for antigen and antibody) were used in parallel. Each inoculated pig developed a significant viraemia and clinical disease, and excreted virus, which was transmitted to the in-contact animals. The latter, however, developed only a short-lived, low-level viraemia and no clinical disease. The RT-PCR and virus isolation were generally comparable in detecting SVDV in the serum and nasal swabs from inoculated and in-contact pigs up to day 6 after infection; it was possible, however, to isolate virus for a longer period from the faeces of a few pigs. This suggested that further optimization of the template extraction method was required to counteract the effects of RT-PCR inhibitors in faeces. It was concluded that the automated real-time RT-PCR is a useful diagnostic method for SVD in clinically or subclinically affected pigs and contributed to the study of the pathogenesis of SVD in the pigs.


Asunto(s)
Transmisión de Enfermedad Infecciosa , Enterovirus Humano B/patogenicidad , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Enfermedades de los Porcinos/diagnóstico , Enfermedad Vesicular Porcina , Animales , Enterovirus Humano B/genética , Enterovirus Humano B/inmunología , Ensayo de Inmunoadsorción Enzimática/veterinaria , ARN Viral/análisis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Porcinos , Enfermedades de los Porcinos/virología , Enfermedad Vesicular Porcina/patología , Enfermedad Vesicular Porcina/transmisión , Enfermedad Vesicular Porcina/virología
16.
Rev Sci Tech ; 23(3): 783-90, 2004 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-15861873

RESUMEN

African buffalo were introduced into a wildlife conservancy in the southeast of Zimbabwe in an effortto increase the conservancy's economic viability, which is primarily based on eco-tourism. The buffalo were infected with SAT serotypes (SAT-1, SAT-2 and SAT-3) of foot and mouth disease (FMD) virus, and in order to isolate the conservancy and prevent the transmission of FMD to adjacent populations of domestic livestock, the conservancy was surrounded by a double-fence system, 1.8 m in height. The intention was to prevent the movement of both wildlife and domestic animals across the perimeter. However, two years after the buffalo were introduced, FMD occurred in cattle farmed just outside of the conservancy. Using serological and molecular diagnostic tests, epidemiological investigations showed that it was most likely that antelope (impala or kudu), infected through contact with the buffalo herd within the conservancy, had jumped over the fence and transmitted the virus to the cattle.


Asunto(s)
Antílopes/virología , Búfalos/virología , Enfermedades de los Bovinos/transmisión , Brotes de Enfermedades/veterinaria , Fiebre Aftosa/transmisión , Animales , Animales Domésticos/virología , Animales Salvajes/virología , Anticuerpos Antivirales/sangre , Bovinos , Enfermedades de los Bovinos/epidemiología , Enfermedades de los Bovinos/prevención & control , Conservación de los Recursos Naturales , Brotes de Enfermedades/prevención & control , Fiebre Aftosa/epidemiología , Fiebre Aftosa/prevención & control , Virus de la Fiebre Aftosa/clasificación , Virus de la Fiebre Aftosa/inmunología , Zimbabwe/epidemiología
17.
Rev Sci Tech ; 23(3): 1003-9, 2004 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-15861896

RESUMEN

The performance of an automated real-time reverse transcription polymerase chain reaction (RT-PCR) was compared to virus isolation (VI) in cell culture and antigen detection enzyme-linked immunosorbent assay (ELISA) for the laboratory diagnosis of foot and mouth disease (FMD). The World Reference Laboratory for FMD in Woking, the United Kingdom, examined a collection of 334 epithelia received from eighteen countries between August 2002 and January 2004. The results showed that all VI positive (n = 195) and VI and ELISA positive samples combined (n = 204) were also positive by RT-PCR. Depending on the cut-off used, FMD virus genome was detected in a minimum of an additional 60 samples (18% of all samples tested). Furthermore, the RT-PCR generated results in less than one day from test commencement in contrast to up to 4 days to define some positive and all negative samples by VI. The study demonstrates that real-time RT-PCR provides an extremely sensitive and rapid procedure for improved laboratory diagnosis of FMD.


Asunto(s)
Técnicas de Laboratorio Clínico/veterinaria , Virus de la Fiebre Aftosa/aislamiento & purificación , Fiebre Aftosa/diagnóstico , Reacción en Cadena de la Polimerasa/veterinaria , Animales , Bovinos , Técnicas de Laboratorio Clínico/normas , Ensayo de Inmunoadsorción Enzimática/métodos , Ensayo de Inmunoadsorción Enzimática/veterinaria , Virus de la Fiebre Aftosa/inmunología , Reacción en Cadena de la Polimerasa/métodos , Valores de Referencia , Sensibilidad y Especificidad , Factores de Tiempo
18.
J Virol Methods ; 97(1-2): 33-48, 2001 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11483215

RESUMEN

A solid-phase competition ELISA has been developed to measure antibodies to foot-and-mouth disease (FMD) virus and has been validated using an extensive range of sera from cattle. The assay uses polyclonal antisera and inactivated purified 146S antigens of FMD virus and was compared with the liquid-phase blocking ELISA and the virus neutralisation test on a range of serum sets. When examining test sera at a 1:5 dilution with a cut-off point of 30% inhibition of reaction, the solid-phase competition ELISA was as sensitive as the liquid-phase blocking ELISA for sera from infected or vaccinated animals. The limit of detection of the solid-phase ELISA was similar to that of the liquid-phase assay and both tests had lower limit of detection (i.e. were able to detect lower amounts of antibody) than the virus neutralisation test. The specificity of the solid-phase ELISA was considerably higher than that of the liquid-phase blocking ELISA and almost equivalent to that of the virus neutralisation test. The assay thus retains the sensitivity of the liquid-phase blocking ELISA whilst being easier to use, more robust and specific, and therefore offers an improvement for FMD virus antibody detection.


Asunto(s)
Enfermedades de los Bovinos/diagnóstico , Enfermedades de los Bovinos/inmunología , Ensayo de Inmunoadsorción Enzimática/métodos , Virus de la Fiebre Aftosa/inmunología , Fiebre Aftosa/diagnóstico , Fiebre Aftosa/inmunología , Animales , Anticuerpos Antivirales/inmunología , Antígenos Virales/inmunología , Bovinos , Enfermedades de los Bovinos/virología , Fiebre Aftosa/virología , Virus de la Fiebre Aftosa/clasificación , Sueros Inmunes/inmunología , Sensibilidad y Especificidad , Vacunación
19.
J Virol Methods ; 96(2): 189-202, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11445149

RESUMEN

Foot-and-mouth disease (FMD) is the most contagious animal virus disease of cloven-hoofed livestock and requires reliable and accurate diagnosis for the implementation of measures to control effectively its spread. Routine diagnosis of FMD is carried out at the OIE/FAO World Reference Laboratory for Foot-and-Mouth Disease (WRL for FMD), Pirbright by the combined use of ELISA and virus isolation in cell culture supplemented by reverse transcription polymerase chain reaction (RT-PCR) methods. These techniques require skilled personnel and dedicated laboratory facilities which are expensive. The development of a rapid and simple test for the detection of FMD virus antigen using Clearview chromatographic strip test technology for field application is described. This device detected FMD viral antigen in nasal swabs, epithelial suspensions and probangs from clinical samples submitted from the field, from animals infected experimentally and in supernatant fluids resulting from their passage in cell culture. The test system was more sensitive than ELISA for the diagnosis of all seven serotypes of FMD virus in the epithelial suspensions and nasal swabs and had equivalent sensitivity to the ELISA for the detection of contemporary virus strains in cell culture supernatant fluids. The study demonstrated the potential for this device to confirm a clinical diagnosis at the site of a suspected FMD outbreak, thereby offering the possibility of implementing control procedures more rapidly. Such pen-side diagnosis would have particular benefits in FMD emergencies, relevance to FMD control programmes which operate in endemic regions of the world such as South East Asia and for increasing disease awareness in other areas where efforts to control disease may be difficult. In each circumstance the availability of a pen-side device for diagnosis would reduce the necessity for sending routine diagnostic samples to an FMD laboratory and thereby reduce the delay in diagnosis, which can in some areas be considerable.


Asunto(s)
Antígenos Virales/análisis , Aphthovirus/aislamiento & purificación , Fiebre Aftosa/diagnóstico , Fiebre Aftosa/virología , Juego de Reactivos para Diagnóstico/veterinaria , Animales , Anticuerpos Monoclonales/inmunología , Anticuerpos Antivirales/inmunología , Aphthovirus/inmunología , Búfalos , Bovinos , Enfermedades de los Bovinos/diagnóstico , Enfermedades de los Bovinos/virología , Células Cultivadas , Cromatografía/métodos , Cromatografía/veterinaria , Ensayo de Inmunoadsorción Enzimática , Serotipificación , Porcinos , Enfermedades de los Porcinos/diagnóstico , Enfermedades de los Porcinos/virología , Factores de Tiempo
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