Microelisa test for detecting antibodies to rinderpest virus antigens

Summary A microplate enzyme-linked immunosorbent assay (ELISA) was developed which detected antibodies to a soluble antigen prepared from sonicated rinderpest virus-infected cells. The ELISA detected titres of antibody to the virus in the sera of cattle 3 weeks after immunisation with tissue culture rinderpest virus vaccine which were similar to those detected by the virus neutralisation test. The ELISA test shows potential as a rapid and economic technique for screening large numbers of sera for antibody to rinderpest virus.

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La Prueba Micro-Elisa Para Detectar Anticuerpos Producidos Por Antigenos Del Virus De Rinderpest

Resumen Se utilizó la prueba micro-ELISA para detectar anticuerpos producidos por un antígeno soluble preparado con células sonicadasinfectadas con el virus de rinderpest. La prueba ELISA detectó anticuerpos en el suero de bovinos, 3 semanas después de que éstos fueron inmunizados con la vacuna de rinderpest, preparada ésta en cultivos celulares. Los anticuerpos detectados fueron similares a los estudiados mediante la prueba de neutralización viral. La prueba ELISA se perfila como una técnica rápida y económica para trabajar un número apreciable de muestras de suero con el fin de detectar anticuerpos del virus de rinderpest.

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Un Micro-Test Elisa Pour Deceler Les Anticorps Specifiques Du Vir Us Bovipestique

Résumé Un test immuno-enzymatique (ELISA) a été mis au point déceler les anticorps correspondant à un antigène préparé par traitement aux ultra-sons de cellules infectées. Les titres sériques obtenus par cette méthode dans les sérums de bovins immunisés trois semaines auparavant avec du vaccin de culture cellulaire se sont révélés comparables à ceux obtenus par la méthode classique de séroneutralisation. Le test ELISA apparait comme un moyen rapide et économique pour rechercher les anticorps spécifiques du virus bovipestique dans des sérums en grand nombre.

     

Detection of rinderpest virus antigens in vitro and in vivo by direct immunofluorescence

Cell-culture attenuated and virulent strains of rinderpest virus (RV) were inoculated on to bovine kidney cell cultures. A direct immunofluorescent antibody test detected RV antigens in cell cultures within one to three days after inoculation whereas RV cytopathic effects usually took three to nine days to develop. Cells containing RV antigens were also detected in impression smears and frozen sections of tissues collected from RV infected animals at post mortem examination, and in smears of lymph node biopsies taken from cattle with clinical rinderpest. These techniques may offer additional methods for rapid diagnosis of rinderpest.     

Rapid detection of bovid herpes virus 1 antigens by counter immunoelectrophoresis and agar-gel immunodiffusion

Summary Using hyperimmune rabbit sera to BHV1, ID and CIEP tests detected one antigen in BHV1 infected cell culture harvests. In nasal and ocular secretions collected from experimentally infected cattle during the early course of clinical disease two and one BHV1 antigens were detected by the ID and CIEP tests respectively. In specimens collected from eight cattle for 10 days after the onset of pyrexia the ID test demonstrated precipitating antigens in 22/35 ocular secretions and 43/60 nasal secretions, whereas the CIEP detected antigens in 40/64 ocular secretions and 44/69 nasal secretions. The antigens were thermostable, being detectable by CIEP 14 days and seven days after storage at 4°C and room temperature respectively.

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Deteccion Rapida De Antigenos De Virus 1 Herpes Bovido Mediante Contra Inmunoelectroforesis E Inmunodifusion En Agar Gelatina

Resumen Las pruebas CIEP e ID, detectaron un antígeno en cultivos celulares infectados con BHVI. Se utilizó suero hiperinmune de conejo para correr las pruebas diagnósticas. Se detectaron dos y un antígeno BHVI, en secreciones nasales y oculares colectadas de ganado infectado durante el estadío temprano de la enfermedad, mediante ID y CIEP respectivamente. La prueba ID detectó antígenos precipitadoes en especímenes colectados de ocho bovinos por 10 días después del inicio de pirexia, en 22/35 secreciones oculares y 40/64 secreciones nasales, mientras que la prueba CIEP detectó antígenos en 43/60 secreciones oculares y 44/69 secreciones nasales. Los antígenos fueron termoestables, pudiendo detectarse mediante CIEP 14 días y 7 días después del almacenamiento a 4°C y temperatura ambiente respectivamente.

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Detection Rapide Des Antigenes De l'herpesvirus I Bovin Par Contre-Immunoelectrophorese Et Immunodiffusion En Gelose

Résumé A l'aide d'un antisérum de lapin contre le BHV1, un antigène est détecté par les tests ID et CIEP dans les récoltes de cultures cellulaires infectées par le BHV1. Dans les secrétions nasales et oculaires recueillies lors du début de la maladie clinique chez des bovins expérimentalement infectés, on détecte 2 et 1 antigènes BHV1 par l'ID et le CIEP respectivement. Dans les échantillons recueillis chez huit animaux pendant les 10 jours suivant le début de la fièvre, le test ID démontre des antigènes prècipitants dans 22/35 secrétions oculaires et 43/60 secrétions nasales, alors que le CIEP détecte des antigènes dans 40/64 secrétions oculaires et 44/69 secrétions nasales. Les antigènes sont thermostables; on les détecte par le CIEP pendant 14 jours et 7 jours après conservation à 4°C et à température ambiante respectivement.

     

Development and stability of rinderpest virus antigens in cattle tears and lymph nodes

Summary Diffusible rinderpest virus antigens were demonstrated in increasing quantities in ocular and lymph node biopsies from rinderpest-infected cattle using agar gel immunodiffusion (AGID) and counterimmunoelectrophoresis (CIEP) tests. Positive samples were detected from the second day of pyrexia to two days after death. The antigens in ocular secretions and lymph nodes were thermolabile being destroyed within five minutes at 56°C and within two weeks at 4°C.

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Resumen Se demostró un incremento de antígenos difusibles del virus de rinderpest, en biopsias oculares y linfáticas tomadas de ganado inoculado experimentalmente. Las pruebas utilizadas fueron la inmunodifusión en agar gelatina y la contrainmunoelectroforesis. Se detectaron muestras positivas desde el segundo día de pirexia, hasta dos días antes de la muerte. Los antígenos en las secreciones oculares y nódulos linfáticos fueron termolábiles, siendo destruidos a los cinco minutos a 56°C y en dos semanas a 4°C.

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Résumé Les tests d’immuno-diffusion en gélose (IDG) et de contre-immunoélectrophorèse (CIE) ont permis de mettre en évidence des quantités croissantes d’antigènes diffusibles du virus de la peste bovine dans les prélèvements de larmes et de ganglions lymphatiques. Des résultats positifs ont été enregistrés à partir du deuxième jour de la fièvre jusqu’au 2e jour après la mort. Les antigènes des secrétions oculaires et des ganglions lymphatiques sont thermolabiles: destruction en cinq minutes à 56°C et en deux semaines à 4°C.

     

Monoclonal antibody-based competitive ELISA for simultaneous detection of rinderpest virus and peste des petits ruminants virus antibodies

An experimental competitive enzyme-linked immunosorbent assay (morbillivirus cELISA) using a recombinant N antigen (rRPV N) expressed in a baculovirus and a ruminant morbillivirus (RPV and PPRV)-specific monoclonal antibody (P-13A9) was developed for simultaneous detection of rinderpest virus (RPV) and peste des petits ruminants virus (PPRV) antibodies and its diagnostic performance was evaluated. A set of known reference antisera against RPV and PPRV belonging to different lineages, experimental sera from cattle vaccinated for a RPV of Asian lineage, and field sera from cattle and sheep/goat populations known to be positive (West Africa) and negative (Korea) for RPV and PPRV were used for the evaluation. Morbillivirus cELISA results on the panel of experimental RPV and PPRV antisera showed high correlation (r=0.97) between the whole virus and the rRPV N antigens, suggesting that the rRPV N contains a ruminant morbillivirus-specific antigenic determinant recognized by the P-13A9 and it may be suitable as an ELISA antigen in place of the whole virus. Morbillivirus cELISA detected anti-RPV and anti-PPRV antibodies in all reference RPV and PPRV antisera containing VN titers >/=1:8, suggesting that the assay can simultaneously detect antibodies against RPV and PPRV. Anti-RPV antibody was detected by morbillivirus cELISA in vaccinated cattle as early as the VNT and continued to be detectable by both the cELISA and the VNT until termination of the study. When applied to field samples from Africa, morbillivirus cELISA showed good agreement with a RP cELISA kit (kappa value of 0.86) in bovine sera and with a peste des petits ruminant cELISA kit (kappa value of 0.81) in caprine/ovine sera. Usefulness of morbillivirus cELISA using the rRPV N protein was discussed.     

鸡传染性法氏囊病病毒的快速检测

随着 IBDV变异株的出现 ,发病鸡常不产生法氏囊的肉眼病变 ,由于传染性和非传染性因素亦可引起淋巴细胞减少和法氏囊坏死 ,所以 ,采取组织病理学方法诊断 IBDV感染并不完全可靠。由于主动性抗体应答需要一定的时间及大多数雏鸡都带有母源抗体 ,因此血清学早期诊断也不完全可靠。该试验采用本所研究的 IBD快速试纸与经典的琼扩试验 ,在对 IBDV的检测效果上进行了详细的比较 ,介绍如下。1　材料与方法1 .1　 IBD快速检测试纸　由河南省农业科学院生物技术研究所制备提供。1 .2　试验鸡　 1日龄试验鸡 30 0只由河南农业大学试验鸡场提…     

Rapid and sensitive detection of African horse sickness virus by real-time PCR

A highly sensitive and specific TaqMan-MGB real-time RT-PCR assay has been developed and standardised for the detection of African horse sickness virus (AHSV). Primers and MGB probe specific for AHSV were selected within a highly conserved region of genome segment 7. The robustness and general application of the diagnostic method were verified by the detection of 12 AHSV isolates from all of the nine serotypes. The analytical sensitivity ranged from 0.001 to 0.15 TCID₅₀ per reaction, depending on the viral serotype. Real-time PCR performance was preliminarily assessed by analysing a panel of field equine samples. The same primer pair was used to standardise a conventional RT-PCR as an affordable, useful and simple alternative method in laboratories without access to real-time PCR instruments. The two techniques present novel tools to improve the molecular diagnosis of African horse sickness (AHS).     

Rapid detection of Marek's disease virus in feather follicles by loop-mediated amplification

Marek's disease (MD) remains a serious problem in the production of poultry. The disease is caused by Marek's disease virus (MDV), and despite the ubiquitous use of vaccination to control losses, MD still affects poultry farming worldwide. The aim of this study was to develop a loop-mediated isothermal amplification (LAMP) method for the simple and inexpensive detection of MDV in feather tips of chickens. Two pairs of specific primers complementary to the meq oncogene of MDV were designed, targeting the sequence of the very virulent MDV strain, RB1B. Bst polymerase was used for the isothermal amplification of viral DNA at 65 C for 90 min in a water bath. The fluorescence signal was identified in MDV-positive samples after the addition of SYBR Green and ultraviolet (UV) illumination. The sensitivity of LAMP was 2 log 10 plaque-forming units (PFU)/ml of HPRS16 and 10(3) copies/il of plasmid containing the target gene (meq) and was equal in sensitivity to PCR amplification. Due to the use of three sets of primers, LAMP was highly specific for MDV-1 DNA. The developed LAMP technique is a rapid and simple tool for the specific detection of MDV in samples of feathers taken from live chickens. Since the use of thermocyclers is not necessary for LAMP assay, it can be conducted by small laboratories and even field veterinarians.     

The shedding of a virulent Kabete O strain of rinderpest virus by cattle

A Muguga substrain of the virulent Kabete O strain of rinderpest virus was demonstrated in the ocular, nasal, oral and rectal swabs collected from infected cattle. Ocular shedding was detected at the onset of viraemia and before the onset of clinical signs whilst virus shedding in nasal, oral and rectal discharges appeared at the same time as lesions. It is suggested that virus isolation from ocular and nasal swabs should be considered in the diagnosis of rinderpest in addition to the other methods currently employed, as virus was isolated from swabs collected from dead animals.     

Quantitative counter-immunoelectrophoresis for estimation of antibodies to infectious bursal disease virus

Quantitative counter-immunoelectrophoresis was standardized to detect antibodies to the avian infectious bursal disease virus. This technique correlated well with the conventional quantitative agar gel precipitation test in estimating antibodies to IBDV. The use of blood dried on filter paper as an alternative to serum is discussed. QCIE is simple, easy to perform and faster than QAGP.Abbreviations AGP agar gel precipitation - CID₅₀ half-minimal chick infective dose - CIE counter-immunoelectrophoresis - EEO electroendosmosis - IBD infectious bursal disease - IBDV infectious bursal disease virus - QAGP quantitative agar gel precipitation - QCIE quantitative counter-immunoelectrophoresis     

An epidemiological model of rinderpest. II. Simulations of the behaviour of rinderpest virus in populations

Fixed parameters for different hypothetical strains of rinderpest virus (RV) and different susceptible populations are described together with details of their derivation. Simulations were then carried out in a computer model to determine the effects that varying these parameters would have on the behaviour of RV in the different populations. The results indicated that virulent strains of RV are more likely to behave in epidemic fashion whereas milder strains tend towards persistence and the establishment of endemicity. High herd immunity levels prevent virus transmission and low herd immunity levels encourage epidemic transmission. Intermediate levels of immunity assist the establishment of endemicity. The virus is able to persist in large populations for longer than in small populations. Different vaccination strategies were also investigated. In areas where vaccination is inefficient annual vaccination of all stock may be the best policy for inducing high levels of herd immunity. In endemic areas and in herds recovering from epidemics the prevalence of clinically affected animals may be very low. In these situations veterinary officers are more likely to find clinical cases by examining cattle for mouth lesions rather than by checking for diarrhoea or high mortalities.     

Use of the caprinised strain of rinderpest virus for potency testing an attenuated cell culture rinderpest vaccine

The caprinised strain of rinderpest virus was inoculated into goats to produce a challenge stock. These goats were kept with control animals (goats, sheep, calves). In this trial the caprinised strain was shown to have a mild pathogenicity for goats and it spread to one of two contact goats but not from goats to other species. The caprinised strain was then tested on cattle where a febrile reaction was observed. The caprinised strain also did not spread between cattle. The cattle vaccinated with a freeze-dried vaccine produced from the attenuated Kabete RBKO strain on bovine kidney cells were then challenged with the caprinised strain with good results.