Analysis of the recombination and evolution of the new type mutant pseudorabies virus XJ5 in China.

Pseudorabies have caused enormous economic losses in China's pig industry and have recurred on many large pig farms since late 2011. The disease is caused by highly pathogenic, antigenic variant pseudorabies virus (vPRV) strains. Our laboratory isolated a pseudorabies virus in 2015 and named it XJ5. The pathogenic ability of this mutant strain was much stronger than that of the original isolate. After we sequenced its whole genome (GenBank accession number: OP512542), we found that its overall structure was not greatly changed compared with that of the previous strain Ea (KX423960.1). The whole genome alignment showed that XJ5 had a strong genetic relationship with the strains isolated in China after 2012 reported in GenBank. Based on the isolation time of XJ5 and the mutation and recombination analysis of programs, we found that the whole genome homology of XJ5 and other strains with Chinese isolates was greater than 95%, while the homology with strains outside Asia was less than 94%, which indicated that there may be some recombination and mutation patterns. We found that virulent PRV isolates emerged successively in China in 2011 and formed two different evolutionary clades from foreign isolates. At the same time, this may be due to improper immunization and the presence of wild strains in the field, and recent reports have confirmed that Bartha vaccine strains recombine with wild strains to obtain new pathogenic strains. We performed genetic evolution analysis of XJ5 isolated and sequenced in our laboratory to trace its possible mutations and recombination. We found that XJ5 may be the result of natural mutation of a virus in a branch of mutant strains widely existing in China.

Rapid, sensitive, and visual detection of pseudorabies virus with an RPA-CRISPR/EsCas13d-based dual-readout portable platform.

Pseudorabies viruses (PRV) pose a major threat to the global pig industry and public health. Rapid, intuitive, affordable, and accurate diagnostic testing is critical for controlling and eradicating infectious diseases. In this study, a portable detection platform based on RPA-CRISPR/EsCas13d was developed. The platform exhibits high sensitivity (1 copy/µL), good specificity, and no cross-reactivity with common pathogens. The platform uses rapid preamplification technology to provide visualization results (lateral flow assays or visual fluorescence) within 1 h. Fifty pig samples (including tissues, oral fluids, and serum) were tested using this platform and real-time quantitative polymerase chain reaction (qPCR), showing 34.0 % (17 of 50) PRV positivity with the portable CRISPR/EsCas13d dual-readout platform, consistent with the qPCR results. These results highlight the stability, sensitivity, efficiency, and low equipment requirements of the portable platform. Additionally, a novel point-of-care test is being developed for clinical use in remote rural and resource-limited areas, which could be a prospective measure for monitoring the progression of pseudorabies and other infectious diseases worldwide.

Six underreported viral diseases of domesticated and wild swine in Africa: Implications and perspectives.

Pig production is increasing annually in Africa as it is recognized as a significant source of income, livelihood and food security, particularly in rural communities. Understanding the circulating swine pathogens is crucial for the success of this emerging industry. Although there is extensive data available on the African swine fever virus due to its devastating impact on pig production, knowledge about the presence of other viral swine pathogens on the continent is still extremely limited. This review discusses what is currently known about six swine pathogens in Africa: classical swine fever virus, porcine reproductive and respiratory syndrome virus, porcine circovirus-2, porcine circovirus-3, porcine parvovirus-1, and pseudorabies virus. Gaps in our knowledge are identified and topics of future focus discussed.

Use of FTA card for the detection of two RNA (CSFV and SV-A) and two DNA viruses (ASFVand SuHV-1) of importance in veterinary medicine.

The FTA card has emerged as a promising alternative for nucleic acid extraction. The FTA card is a filter paper impregnated with chemicals that preserve and stabilize the genetic material present in the sample, allowing for its storage and transport at room temperature. The aim of this study was to test the card for the detection of RNA and DNA nucleic acids. Two RNA viruses (Senecavirus A and classical swine fever virus) and two DNA viruses (African swine fever virus and suid alphaherpesvirus 1) were tested, and in all cases, there was a decrease in sensitivity. The methods exhibited good repeatability and demonstrated a rapid and practical use for sample transport and nucleic acid extraction.

Detección serológica de Brucella suis, virus de influenza y virus de la enfermedad de Aujeszky en criaderos porcinos familiares de menos de 100 madres en Argentina / Serological detection of Brucella suis, influenza virus and Aujeszky's disease virus in backyard and small swine holders in Argentina

Los criaderos porcinos de menos de 100 madres representan más del 99% de los de todo el país; sin embargo, existen escasos reportes sobre su situación sanitaria y productiva. Se recabó información productiva y se tomaron muestras para detectar anticuerpos contra Brucella suis (Bs), virus de la enfermedad de Aujeszky (VA) y virus de influenza (VI) en 68 establecimientos de menos de 100 madres ubicados en la región norte, centro y sur del país. El 80% de los establecimientos fueron positivos al VI H1 pandémico 2009, el 11% al H3 clúster 2, mientras que el 11,7% presentó anticuerpos contra el VA y el 6% contra Bs. Ninguno de los productores conocía los factores de riesgo para la transmisión de enfermedades del cerdo al humano. El 47% compra sus reproductores a pares o en ferias. En lo que respecta a normas de bioseguridad, solo el 16% de los establecimientos tenía cerco perimetral y el 37% de las granjas contaba con asesoramiento veterinario. Los resultados de este estudio demuestran que la caracterización productiva y el relevamiento sanitario son de suma importancia para mejorar la productividad y reducir el riesgo de transmisión de enfermedades. El conocimiento de la situación sanitaria y de los factores de riesgo es necesario para conseguir un mejor control y la erradicación de enfermedades en sistemas de baja tecnificación. Se deberían llevar a cabo estudios más representativos a nivel país para detectar los agentes circulantes y, sobre la base de esta información, implementar medidas de prevención y control.

Farmers raising less than 100 sows represent more than 99% of swine producers in Argentina, although little is known about their sanitary status and productive characteristics in the country. Sanitary and productive information was obtained. Furthermore, samples for serological studies were taken to detect antibodies against Brucella suis (Bs), Aujeszky's disease virus (AV) and influenza virus (IV) in 68 backyard and small producers with less than 100 sows located in the north, central and south regions of Argentina. Antibodies against H1 pandemic were detected in 80% of the farms while 11%, 11.7% and 6.0% of the producers were positive to influenza H3 cluster 2, AV and Bs, respectively. None of the producers was aware of the risk factors concerning the transmission of diseases from pigs to humans. A percentage of 47% of them buy pigs for breeding from other farmers and markets. With regard to biosecurity measures, only 16% of the farms had perimeter fences. The results of this study demonstrate that productive characterization and disease surveys are important to improve productivity and to reduce the risk of disease transmission among animals and humans. The study of sanitary status and risk factors is necessary for better control and eradication of diseases in backyard or small producers. More representative studies at country level should be carried out to detect the pathogensthat circulate and, with this knowledge, to implement prevention and control measures.

Atividade antiviral de extratos de plantas medicinais disponíveis comercialmente frente aos herpesvírus suíno e bovino / Antiviral activity of commercially available medicinal plants on suid and bovine herpesviruses

O presente trabalho teve como objetivo pesquisar a atividade antiviral in vitro de plantas medicinais disponíveis comercialmente sobre herpesvírus suíno (SuHV-1) e bovino (BoHV-1). As espécies adquiridas foram Mikania glomerata, Cymbopogon citratus, Equisetum arvense, Peumus boldus, Solanum paniculatum, Malva sylvestris, Piper umbellatun e Solidago microglossa. A citotoxicidade dos extratos foi avaliada na linhagem celular MDBK pelas alterações morfológicas das células e obtenção da concentração máxima não citotóxica (CMNC) de cada planta. A atividade antiviral foi realizada com os extratos em suas respectivas CMNC e avaliada com base na redução do título viral e expressos em porcentagem de inibição. Os extratos aquosos de Peumus boldus e Solanum paniculatum apresentaram atividade antiviral sobre o SuHV-1 com 98% de inibição viral enquanto o de Peumus boldus inibiu apenas o BoHV-1 em 99%.

This paper aims to find commercially available medicinal plants showing antiviral activity in vitro on suid and bovine herpesviruses. The following species were tested: Mikania glomerata, Cymbopogon citratus, Equisetum arvense, Peumus boldus, Solanum paniculatum, Malva sylvestris, Piper umbellatun and Solidago microglossa. The cytotoxicity was evaluated by morphological changes in cells determining the maximum not cytotoxic concentration (MNCC). The antiviral activity was evaluated by viral title reduction. The extracts from Peumus boldus and Solanum paniculatum showed antiviral activity against SuHV-1 with 98% of inhibition. The extract of Peumus boldus also showed activity against BoHV-1 with 99% of inhibition.

PCR duplex para diferenciação de amostras vacinais e selvagens do vírus da doença de Aujeszky / A duplex PCR for differentiation of wild and vaccine virus of Aujeszkyïs disease

A duplex PCR was developed to differentiate the wild-type virus from the attenuated virus used in vaccinations. The PCR was able to amplify fragments of 493bp for glycoprotein E (gE) gene and 207bp for glycoprotein B (gB) gene. The analytical sensitivity was determined by addition of a virus field sample titled in the brain samples of pigs. The standard virus strain Shope, the vaccine strain Bartha, and ten other field isolates were subjected to PCR. The PCR was able to amplify fragments of gE and gB in all field samples and only fragments of gB were amplified in the attenuated virus, as expected. The technique was able to detect up to 100.5 TCID50/50mL virus in samples of brain. Duplex PCR proved to be an important tool for differentiation of naturally-infected animals and animals vaccinated with the virus deleted for gE.

Caracterizaçäo parcial de uma amostra brasileira do vírus da doença de Aujeszky isolada / Partial characterization of a Brazilian strain of Aujeszky's disease virus recovered from a pig with subclinical infection

Uma amostra brasileira do vírus da doença de Aujeszky, isolada de um leitäo, foi estudada quanto à virulência para suínos e seu genoma analisado no que se refere ao padräo de fragmentaçäo pela enzima de restriçäo Bam HI. Leitöes com 50 dias de idade, sorologicamente negativos, expostos a essa amostra, näo mostraram sinais de doença e o vírus foi detectado na regiäo orofaríngeana durante pelo menos três dias após exposiçäo. Com base no padräo de migraçäo dos fragmentos de restriçäo, o isolamento foi classificado como pertencente ao grupo I da classificaçäo proposta por Herrmann. Infecçäo latente foi detectada por PCR em todos os suínos. Algumas variaçöes foram identificadas no mapa físico de Bam HI da amostra ASB Piau quando se comparou com o mapa obtido da amostra virulenta brasileira LA03l

Non-pathogenic strains of Aujeszky's disease virus are not reactivated in swine after corticosteroid treatment

The Bartha-K and NIA-4 strain of Aujeszky's disease virus (ADV) were readily isolated from oropharyngeal swabs up to 7 days after intranasal vaccination of young piglets. Neither strain could be reisolated 14 days after starting treatment with 10 mg of the corticosteroid isoflupredone acetate per kg of body weight, administered intramuscularly for 4 consecutive days when pigs were 7-9 months of age. Similar treatment with corticosteroid pigs infected with two virulent ADV strains resulted in the reactivation of infection and recovery of ADV from oropharyngeal swabs. Serum neutralizing antibodies were present in all pigles vaccinated twice (2 week interval) intranasally with the attenuated ADV strains, 4 weeks after primary vaccination. However, these antibodies were no longer detectable in some pigs at 12(NIA-4) and 20(Bartha-K) weeks of age even in undilluted sera. Neutralizing antibodies resulting from infection virulent ADV were always detectable, were higher in titer than those produced by the vaccine strains and did not vary in a clear pattern after corticosteroid treatment. These results indicated that the Bartha-K and NIA-4 strains undergo little or no latency in swine and confirm the latency of virulent strains of ADV