ABSTRACT
OBJECTIVE@#To establish a sensitive, simple and rapid detection method for African swine fever virus (ASFV) B646L gene.@*METHODS@#A recombinase-aided amplification-lateral flow dipstick (RAA-LFD) assay was developed in this study. Recombinase-aided amplification (RAA) is used to amplify template DNA, and lateral flow dipstick (LFD) is used to interpret the results after the amplification is completed. The lower limits of detection and specificity of the RAA assay were verified using recombinant plasmid and pathogenic nucleic acid. In addition, 30 clinical samples were tested to evaluate the performance of the RAA assay.@*RESULTS@#The RAA-LFD assay was completed within 15 min at 37 °C, including 10 min for nucleic acid amplification and 5 minutes for LFD reading results. The detection limit of this assay was found to be 200 copies per reaction. And there was no cross-reactivity with other swine viruses.@*CONCLUSION@#A highly sensitive, specific, and simple RAA-LFD method was developed for the rapid detection of the ASFV.
Subject(s)
Animals , African Swine Fever/virology , African Swine Fever Virus/isolation & purification , Nucleic Acid Amplification Techniques/methods , Recombinases/chemistry , Sensitivity and Specificity , Swine , Viral Proteins/geneticsABSTRACT
In order to screen African swine fever virus (ASFV) diagnostic antigen with the best enzyme linked immunosorbent assay (ELISA) reactivity. By establishing the ELISA method, the diagnostic antigen of ASFV p30 protein expressed by baculovirus-insect cell expression system as reference, we explored the antigenic properties and diagnostic potential of ASFV p35 protein expressed by prokaryotic expression system as a diagnostic antigen. The results of Western blotting and immunofluorescence show that the molecular weight of the recombinant p35 protein and p30 protein obtained was 40 kDa and 30 kDa, respectively, and these two proteins had good immuno-reactivity with ASFV positive serum. Recombinant p30 and p35 proteins were used as diagnostic antigens to establish ELISA, and the sensitivity and repeatability of these methods were tested. The results show that although the detection sensitivity of the p30-ELISA established in this study was higher than that of the p35-ELISA, the sensitivity of p35-ELISA was 95.8%, and variations in intra- and inter-assay repeatability of the two methods were less than 10%. The coincidence rate between the p35-ELISA and the imported kit was 97.2%. Results show that p35-ELISA was sensitive and stable, and could detect specific antibodies against ASFV.
Subject(s)
Animals , African Swine Fever/diagnosis , African Swine Fever Virus/genetics , Antibodies, Viral , Enzyme-Linked Immunosorbent Assay , Recombinant Proteins/genetics , SwineABSTRACT
African Swine Fever (ASF) is a highly contagious and deadly viral disease affecting both domestic pig and wild boar populations. Once introduced, it is a terrible disease that can devastate the swine industry in many countries. ASF has spread most recently beyond China to Southeast Asia, and parts of the Korean Peninsula. The majority of Asian countries consume pork as the primary source of meat compared to all other meat products. Particular emphasis is on the spread of ASF within North Korea and on future perspectives including protective guidelines. Thus far, the Korean peninsula has endured an extensive history of diseases, most notably from foot and mouth disease. For this reason, the Korean swine industries are familiar with the detrimental impacts of such a disease. On the other hand, exposure to a disease like ASF will decimate the swine industry even further. Therefore, it is crucial to bring urgent awareness to the spread of ASF.
Subject(s)
Animals , Humans , African Swine Fever , Asia, Southeastern , Asian People , China , Democratic People's Republic of Korea , Epidemiology , Foot-and-Mouth Disease , Hand , Meat , Meat Products , Red Meat , Sus scrofa , Swine , Virus DiseasesABSTRACT
African swine fever (ASF) is a hemorrhagic and devastating infectious disease of pigs caused by African swine fever virus (ASFV), with mortality up to 100%. The first ASF outbreak occurred in China in August 2018, followed by 69 cases of ASF in 18 provinces in more than three months, causing a heavy burden to the pig industry. Based on the global epidemic situation of ASF and the experience of prevention and control in other countries, the ASF control and eradication situation in China is extremely complex and serious. The availability of effective and safe ASF vaccines is an urgent requirement to reinforce control and eradication strategies. Therefore, this article starts with the latest findings of ASFV, summarizes the progress in prevention and control strategies and vaccine approaches for ASFV. We also discuss the challenges of preventing and controlling ASF, focusing on current vaccine strategies, the gaps, future research directions, and key scientific issues in commercial applications. We hope to provide basic information for the development of vaccines and prevention control strategies against this disease in China.
Subject(s)
Animals , African Swine Fever , African Swine Fever Virus , Biomedical Research , China , Disease Outbreaks , Swine , VaccinesABSTRACT
African swine fever (ASF) is a devastating viral infirmity that affects domestic and wild swine caused by the ASF virus (ASFV) that belongs to the family Asfaviridae in the Asfavirus genus. Studies for genotypic and antigenic determination of ASFV including samples from Brazilian outbreaks were carried out outside Brazil. Here, we have reviewed studies on the molecular aspects of Brazilian isolates from 1978 and 1979. Results obtained from restriction fragment analysis, cloning and gene sequencing display the genotypic variation of viral samples. Viral genotyping based on sequences of the 3' region of the p72 gene included in genotype I Brazilian samples, reinforcing the suggestion of the European origin for the virus that infected Brazilian herds and having low virulence potential. Corroborating those findings, at the American station PIADC, the infection of healthy pigs with the Brazilian strain induced ASF sub acute disease with low mortality and a low-virulence. Those results were similar with epidemiological vigilance forms of Brazilian swineherd in good health conditions having at least one ASFV isolation, and the ASF pioneer's studies on the low mortality in the Brazilian herds affected by ASF. The ASFV spreading in Eastern Europe and Russia triggered a greater concern with intensifying the risk of viral dissemination from country to country. The low virulence ASF strains can increase the problem because of hidden viral reservoirs - which further reinforces the need for safety and preventive measures in virus-free countries. Finally, the problem is further compounded by the lack of vaccines and other immunological resources.(AU)
A peste suína africana é uma enfermidade viral devastadora que afeta suínos domésticos e selvagens causada pelo vírus pertencente à família Asfaviridae no gênero Asfavirus. Estudos para determinação genotípica e antigênica do vírus da peste suína africana, incluindo as amostras de surtos brasileiros, foram realizados em laboratórios fora do Brasil. Aqui, revisamos os estudos sobre o aspecto molecular de isolados brasileiros de 1978 e 1979. Os resultados obtidos pela análise de fragmentos de restrição, clonagem e sequenciamento mostram variação genotípica das amostras virais. A genotipagem viral baseada nas sequências da região 3' do gene p72 incluíram amostras brasileiras no genótipo I, reforçando a sugestão da origem europeia do vírus que infectou rebanhos brasileiros e potencialmente de baixa virulência. Corroborando, na estação americana Plum Island Animal Disease Center, a inoculação do vírus da peste suína africana do surtos brasileiros em suínos saudáveis evoluiu para peste suína africana subaguda com baixa mortalidade sugerindo a baixa virulência. Similarmente aos formulários de vigilância epidemiológica de rebanhos em boas condições sanitárias que tiveram pelo menos um isolamento de vírus da peste suína africana e com os estudos pioneiros sobre a baixa mortalidade nos rebanhos afetados pela peste suína africana. A dispersão do vírus da peste suína africana na Europa Oriental e Rússia desencadearam uma preocupação com o risco de disseminação do vírus entre países. O vírus da peste suína africana de baixa virulência pode aumentar o problema porque esconde reservatórios virais e reforça a necessidade de medidas preventivas e de segurança em países livres de vírus. Finalmente, o problema é ainda mais agravado pela falta de vacinas e outros recursos imunológicos.(AU)
Subject(s)
Swine , African Swine Fever/virology , Genotyping Techniques/methods , Epidemiological Monitoring/veterinaryABSTRACT
Este trabalho teve como objetivo determinar a soroprevalência de pseudorraiva, peste suína clássica (PSC) e brucelose suína em suínos do estado do Piauí, Brasil. Foram coletadas amostras sanguíneas de 384 suínos de criações intensivas e extensivas do estado. Anticorpos anti-Brucella spp. foram detectados pelo teste do antígeno acidificado tamponado e confirmados pelo teste 2-mercaptoetanol, enquanto a detecção de anticorpos contra os vírus da PSC e pseudorraiva foi realizada por ensaio imunoenzimático (ELISA), utilizando-se kits comerciais específicos. Anticorpos anti-Brucella spp. foram detectados em 1,04% (2/192) dos suínos de criações intensivas. Dos rebanhos avaliados, 0,78% (3/384) dos animais exibiram anticorpos contra o vírus da PSC, sendo 1,04% (2/192) de criações intensivas e 0,52% (1/192) de criações extensivas. Anticorpos contra o vírus da pseudorraiva foram detectados apenas em suínos de criação extensiva, com prevalência de 5,2% (10/192). Esses são os primeiros dados sobre a soroprevalência da brucelose suína, pseudorraiva e PSC em rebanhos do Piauí. A detecção de 10 amostras positivas para pseudorraiva causa preocupação sobre a possibilidade da circulação viral na população suídea desse estado e revela uma necessidade premente de realização de estudos mais extensos para melhor compreender a importância dessas enfermidades de notificação obrigatória em estados da região Nordeste brasileira.
This study aimed to determine the prevalence of Pseudorabies, Classical Swine Fever (CSF) and Swine Brucellosis in swine in the state of Piauí, Brazil. Blood samples were collected from 384 pigs from intensive and small outdoor systems in the state. Anti-Brucella spp. antibodies were detected by Buffered Acidified Antigen Test and positive results confirmed by 2-Mercaptoethanol Test. Detection of antibodies against CSF and Pseudorabies virus were performed by Enzyme-Linked Immunosorbent Assay (ELISA) using specific commercial kits. Only two samples (1.04% - 2/192) from the intensive system were seropositive to Brucella spp. In the evaluated herds, 0.78% (3/384) of animals had antibodies against CSF virus, two from outdoor pigs (1.04% - 2/192) and one from intensive systems (0.52% - 1/192). Antibodies against the Pseudorabies virus were detected only in outdoor pigs, with seroprevalence of 5.2% (10/192). This is the first report on seroprevalence of Pseudorabies, CSF and Brucellosis in hog farms in Piauí, Brazil. The detection of 10 positive cases raises a concern regarding Pseudorabies virus circulation in the swine population in the state and reveals a need for further studies to better understand the real situation and status of obligatory notified diseases in the swine herds in the Northestern states of Brazil.
Subject(s)
Animals , African Swine Fever/diagnosis , African Swine Fever/parasitology , African Swine Fever/virology , Pseudorabies/diagnosis , Pseudorabies/virology , Seroepidemiologic Studies , Brucellosis/diagnosis , Brucellosis/veterinaryABSTRACT
Em função das dúvidas que ainda perduram 25 anos após a ocorrência do surto de peste suína africana (PSA), em Paracambi, Estado do Rio de Janeiro, Brasil, em 1978, são apresentados os resultados, relativos a este foco, obtidos pelos estudos epidemiológico, clínico-patológico, virológico, bacteriológico e ultra-estrutural dos casos naturais, bem como os relativos à reprodução experimental da doença no Brasil e sua confirmação por isolamento e determinação de patogenicidade realizada no Plum Island Animal Disease Center, New York, EUA. Os animais se infectaram pela ingestão de restos de comida de aviões procedentes de Portugal e da Espanha, países nos quais a doença existia. De acordo com publicação do Ministério da Agricultura, após o diagnóstico do surto de PSA descrito neste trabalho, 223 novos focos foram relatados, entre 1978 e 1979, em todas Regiões do país (Norte, Nordeste, Centro-Oeste, Sudeste e Sul) e focos adicionais em 1981, sem informações exatas referentes ao seu número. O último caso foi relatado em 15 de novembro de 1981, e em 5 de dezembro 1984 o Brasil foi declarado livre da PSA. Para o diagnóstico da PSA foram processadas 54.002 amostras no Departamento de Virologia do Instituto de Microbiologia da Universidade Federal do Rio de Janeiro, no período de 1978 a 1981. No processamento das amostras foram usadas as técnicas de hemadsorção em cultura de leucócitos (HAd), imunoflorescência em cortes de tecido (FATS), imunoflorescência em cultivo celular (FATCC), imuno-eletrosmoforese (IEOP) e imunoflorescência...
Subject(s)
Animals , African Swine Fever/epidemiology , Swine , Hemadsorption/immunology , Fluorescent Antibody Technique/methodsABSTRACT
El área de control de la fiebre porcina clásica se encuentra localizada en la parte central y sur de México. Se continúa con la vacunación de los animales y se han seguido presentando casos de la enfermedad. El número de brotes se incrementó durante 1997, siendo 87 por ciento en explotaciones de traspatio. Con el propósito de determinar algunos de los factores que contribuyeron al incremento de los brotes en 1997, se hicieron encuestas en 424 explotaciones de traspatio de cuatro municipios, cuatro mercados o tianguis de animales, cuatro rastros municipales y 16 granjas de ciclo completo de la zona poniente del Estado de México, México, que se encuentra dentro del área de control. En las explotaciones de traspatio, en promedio, 25 por ciento de los cerdos fueron vacunados y en el muestreo serológico 43 por ciento tenían anticuerpos. En promedio 37 por ciento de los cerdos eran vendidos y remplazados cada tres meses. De las granjas de ciclo completo, en 12 por ciento no vacunaban a los animales. En los tianguis, un promedio de 40 por ciento de los cerdos comercializados provenían de la zona en erradicación y 60 por ciento de la zona en control. En los cuatro rastros encuestados, los veterinarios oficiales informaron el decomiso de animales con lesiones sugerentes de fiebre porcina clásica. Se concluyó que los factores que contribuyeron al incremento del número de brotes en 1997 en la población de traspatio, fueron el elevado número de animales susceptibles que estaban entrando al área de control y eran mezclados con otros cerdos en los tianguis, su gran movilidad y bajo nivel de inmunidad, y cerdos enfermos y virémicos eran mandados al rastro por lo que los vehículos y choferes se pudieron contaminar en los rastros y acarrear el virus a las explotaciones porcinas.
Subject(s)
Animals , African Swine Fever , Vaccination/veterinary , SwineABSTRACT
La Peste Porcine Africaine (PPA) a récemment fait son apparition à Madagascar.Officiellement diagnostiquée fin 1998, la PPA a vraisemblablement été introduite à Madagascar en 1997 dans le sud du pays à partir de virus provenant du continent africain. La PPA s'estensuite propagée dans la quasi-totalité du pays à l'exception de la région d'Antsiranana (Nord) et de Morondava (Ouest). La maladie a eu des conséquences économiques désastreuses et aentraîné la désorganisation de la filière porcine malgache.Nous rapportons ici l'histoire de cette émergence et l'existence de particularités locales comme la présence de vecteurs, les tiques du genre Ornithodoros - O. moubata porcinus - et de réservoirs sauvages potentiels comme le potamochère - Potamochoerus larvatus - qui compromettentl'éradication de la maladie.Ces faits renforcent la nécessité pour Madagascar de disposer d'un système d'alerte et de riposte rapide
Subject(s)
African Swine Fever/diagnosis , African Swine Fever/epidemiology , Disease Eradication , MadagascarABSTRACT
Se han elaborado equipos con nuevo diseno y procedimientos que permiten detectar con mayor rapidez las precipitinas contra el virus de la fiebre porcina africana. La metodologia se puede aplicar tambien en el diagnostico de la hepatitis y en otros procedimientos electroforeticos. La gran reduccion de los costos hace estos metodos accesibles a los laboratorios pequenos