RESUMO
African swine fever virus (ASFV) is the etiological agent causing African swine fever (ASF), affecting domestic pigs and wild boar, which is currently the biggest animal epidemic in the world and a major threat to the swine sector. At present, some safety concerns about using LAVs against ASFV still exist despite a commercial vaccine licensed in Vietnam. Therefore, the efforts to identify virulence factors and their mechanisms, as well as to generate new vaccine prototypes, are of major interest. In this work, we have identified the MGF505-2R gene product as an inhibitor of the cGAS/STING pathway, specifically through its interaction with STING protein, controlling IFN-ß production. In addition, immunization of a recombinant virus lacking this gene, Arm/07-ΔMGF505-2R, resulted in complete attenuation, demonstrating its involvement in ASFV virulence. Finally, immunization with Arm/07-ΔMGF505-2R induced the generation of antibodies and proved to be partially protective against virulent ASFV strains. These results identify MGF505-2R, as well as its mechanism of action, as a gene contributing to understanding the molecular mechanisms of ASFV virulence, which will be of great value in the design of future vaccine prototypes.
RESUMO
Introduction: The molecular contamination of an animal facility was investigated during and after an infection with highly pathogenic African swine fever virus (ASFV) among domestic pigs. The investigation evaluated the risk of indirect transmission of the disease and indicated points that may facilitate cleaning and disinfection processes. Material and Methods: Six domestic pigs were infected oronasally with the highly pathogenic Georgia 2007 strain. Environmental samples from the floors, walls, rubber floor mats, feeders, drinkers, high-efficiency particulate-absorbing filter covers and doors were collected 7 days post infection (dpi), 7 days later and 24 h after disinfection of the facility. The samples were investigated by real-time PCR and in vitro assays to find genetic traces of ASFV and infectious virus. Results: Typical clinical outcomes for ASF (i.e. fever, apathy, recumbency and bloody diarrhoea) were observed, and all animals died or required euthanasia before or at 9 dpi. No infectious virus was found in environmental samples at the sampling time points. Genetic traces of ASFV were found in all locations except the doors. The initial virus load was calculated using real-time PCR threshold cycle values and was the highest at the drain. A statistically significant decrease of virus load over time was found on non-porous surfaces mechanically cleaned by water (the floor and drain). Conclusion: The gathered data confirmed different routes of virus excretion (oral and nasal, faeces and urine, and aerosol) and showed virus locations and different initial concentrations in the animal facility. Maintaining the facility with mechanical cleaning and using personal protection (gloves) and hand disinfection may efficiently minimise the risk of further virus spread. Together with the results of previously published studies, the present investigations' failure to isolate infectious virus may suggest that if stable environmental conditions are assured, the time needed before the introduction of new herds into previously ASF-affected farm facilities could be shortened and in this way the economic losses caused by the disease outbreak mitigated.
RESUMO
African swine fever is a contagious disease, affecting pigs and wild boars, which poses a major threat to the pig industry worldwide and, therefore, to the agricultural economies of many countries. Despite intensive studies, an effective vaccine against the disease has not yet been developed. Since 2007, ASFV has been circulating in Eastern and Central Europe, covering an increasingly large area. As of 2018, the disease is additionally spreading at an unprecedented scale in Southeast Asia, nearly ruining China's pig-producing sector and generating economic losses of approximately USD 111.2 billion in 2019. ASFV's high resistance to environmental conditions, together with the lack of an approved vaccine, plays a key role in the spread of the disease. Therefore, the biosecurity and disinfection of pig farms are the only effective tools through which to prevent ASFV from entering the farms. The selection of a disinfectant, with research-proven efficacy and proper use, taking into account environmental conditions, exposure time, pH range, and temperature, plays a crucial role in the disinfection process. Despite the significant importance of ASF epizootics, little information is available on the effectiveness of different disinfectants against ASFV. In this review, we have compiled the current knowledge on the transmission, spread, and control of ASF using the principles of biosecurity, with particular attention to disinfection, including a perspective based on Polish experience with ASF control.
Assuntos
Vírus da Febre Suína Africana , Febre Suína Africana , Desinfetantes , Vacinas , Suínos , Animais , Febre Suína Africana/epidemiologia , Febre Suína Africana/prevenção & controle , Polônia/epidemiologia , Desinfecção , Biosseguridade , Desinfetantes/farmacologia , Sus scrofaRESUMO
African swine fever remains one of the most economically important and dangerous diseases of the Suidae family. Until now, neither a safe vaccine nor a treatment against ASF has been available, which is why prevention of the disease involves biosecurity measures and early recognition based on accurate diagnosis. Nowadays, different strategies for ASF detection are discussed to reduce both animal suffering and the costs of ASF surveillance. This article aims to indicate the risk, with regard to non-invasive sampling, for the detection of ASFV. In this study, we analyzed data from three independent animal trials, in the framework of the detection of positive samples in different matrices (blood, sera, oral and rectal swabs) collected from nineteen domestic pigs infected with similar doses but under different scenarios, including different ASFV strains or routes of infection. Genetic material of ASFV was found in all matrices, but detection occurred earlier in the blood samples than in the oral and the rectal swabs. Furthermore, analyses revealed that at relevant sampling timepoints, PCR-positive blood samples were detected more frequently and reached higher percentages (up to 100% during fever) than oral and rectal swabs. Moreover, mean Ct values in blood samples collected from animals infected with virulent strains were significantly lower than in oral and rectal swabs, ensuring a higher probability of ASFV detection. High Ct values and occasional shedding in all tested matrices, in the cases of animals infected by an attenuated ASFV-strain, showed that blood sampling may be necessary to confirm the presence of anti-ASFV antibodies in sera. This study showed that during veterinary surveillance, blood sampling (for both PCR and serological analyses) is essential for the accurate diagnosis of ASF and provides the highest probability of detection of the disease.
Assuntos
Vírus da Febre Suína Africana , Febre Suína Africana , Febre Suína Africana/epidemiologia , Vírus da Febre Suína Africana/genética , Animais , Técnicas de Amplificação de Ácido Nucleico , Manejo de Espécimes , Sus scrofa , SuínosRESUMO
African swine fever (ASF) is one of the most dangerous hemorrhagic infectious diseases that affect domestic and wild pigs. Currently, neither a vaccine nor effective treatments are available for this disease. As regards the degree of virulence, ASFV strains can be divided into high, moderate, or low virulence. The main detection methods are based on the use of the polymerase chain reaction (PCR). In order to prevent an uncontrolled spread of ASF, new on-site techniques that can enable the identification of an early-stage disease are needed. We have developed a specific immunological SPR-based assay for ASFV antigen detection directly in liquid samples. The developed assay allows us to detect the presence of ASFV at the dose of 103 HAD50/mL.
Assuntos
Vírus da Febre Suína Africana , Febre Suína Africana , Febre Suína Africana/diagnóstico , Animais , Ressonância de Plasmônio de Superfície , Sus scrofa , Suínos , VirulênciaRESUMO
Introduction: African swine fever virus (ASFV) causes one of the most dangerous diseases of pigs and wild boar - African swine fever (ASF). Since its second introduction into Europe (in 2007), the disease has been spreading consistently, and now ASF-free European countries are at risk. Complex interactions between the host's immune system and the virus have long prevented the development of a safe vaccine against ASF. This study analysed the possibility of neutralisation of the ASFV in vitro by sera collected from ASF-survivor animals. Material and Methods: Two pig and three wild boar serum samples were collected from previously selected potential ASF survivors. All sera presented high antibody titres (>5 log10/mL). Primary alveolar macrophages were cultured in growth medium containing 10% and 20% concentrations of selected sera and infected with a haemadsorbing ASFV strain (Pol18_28298_O111, genotype II). The progress of infection was investigated under a light microscope by observing the cytopathic effect (CPE) and the haemadsorption phenomenon. Growth kinetics were investigated using a real-time PCR assay. Results: Haemadsorption inhibition was detected in the presence of almost all selected sera; however, the inhibition of virus replication in vitro was excluded. In all samples, a CPE and decreasing quantification cycle values of the viral DNA were found. Conclusion: Anti-ASFV antibodies alone are not able to inhibit virus replication. Interactions between the humoral and cellular immune response which effectively combat the disease are implicated in an ASF-survivor's organism.
RESUMO
African swine fever is one of the most dangerous and fatal swine diseases, described for the first time roughly a hundred years ago. Even now, there is neither a commercially approved vaccine nor treatment available. The only way to hinder further spread of the disease is by culling the affected herds and applying prevention based mainly on proper biosecurity. Due to growing awareness of the potential ASF threat among pig producers, disinfection processes are considered as one of the most important preventive measures. Currently, a variety of chemical compounds are applied for the disinfection of pig farms. Meanwhile, these chemicals may pose a potential risk, due to their toxic, irritant or corrosive effect. The aim of this study was to determine whether any plant-based natural compounds may show a virucidal effect against ASFV, and simultaneously be depleted of some of the side-effects typical for chemical compounds. Ideally, natural virucidal compounds should be safe for both humans and animals, biodegradable, easily available and inexpensive. Fourteen plant extracts were selected and screened for their virucidal effect against ASFV, using the suspension test inspired by the PN-EN 14675:2015 European Standard procedure. The results of our study showed that most of the tested plant extracts were ineffective against ASFV. Some extracts suspended in a hydroglycolic medium exhibited high virus titre reduction, but it was confirmed that the effect resulted from medium composition. However, a 1.05% peppermint extract showed high effectiveness against ASFV, reducing the virus titre by ≥4 log10, thus demonstrating that natural compounds used as virucidal agents could potentially be used in disinfection procedures, being both effective and harmless to humans and animals.
RESUMO
This study aimed to indicate the influence of infection caused by genotype II African swine fever virus (ASFV)-isolate Pol18_28298_O111, currently circulating in Poland, on blood counts, biochemical parameters, as well as inflammatory and immune responses. Blood and sera collected from 21 domestic pigs infected intranasally with different doses of virulent ASFV were analysed. The infection led to variable changes in blood counts depending on the stage of the disease with a tendency towards leukopenia and thrombocytopenia. The elevated C-reactive protein (CRP) concentrations and microscopic lesions in organs confirmed the development of the inflammation process, which also resulted in an increased level of biochemical markers such as: Aspartate transaminase (AST), creatine kinase (CK), creatinine, and urea. Antibodies could be detected from 9 to 18 days post infection (dpi). Two survivors presented the highest titer of antibodies (>5 log10/mL) with a simultaneous increase in the lymphocyte T (CD3+) percentage-revealed by flow cytometry. Results confirmed a progressive inflammatory process occurring during the ASFV infection, which may lead to multiple organs failure and death of the majority of affected animals.
Assuntos
Vírus da Febre Suína Africana/patogenicidade , Febre Suína Africana , Imunidade , Proteínas Virais/metabolismo , Febre Suína Africana/epidemiologia , Febre Suína Africana/imunologia , Febre Suína Africana/virologia , Animais , Polônia/epidemiologia , Sus scrofa , Suínos , VirulênciaRESUMO
African swine fever (ASF) causes huge economic losses and is one of most dangerous diseases of pigs. The disease is known for almost 100 years, an effective vaccine or treatment is still unavailable, only proper biosecurity measures, including disinfection, are being applied, in order to prevent disease outbreaks. Eight active substances, i.e., formaldehyde, sodium hypochlorite, caustic soda, glutaraldehyde, phenol, benzalkonium chloride, potassium peroxymonosulfate and acetic acid, were tested, in order to confirm their effectiveness against African swine fever virus (ASFV). This specific selection was done based on the World Organisation for Animal Health (OIE)'s recommendation and previous disinfectant studies on surfaces. The result of our study shows that most of them inactivate the virus, in recommended concentrations. In order to reduce the cytotoxicity of the four substances, Microspin S-400 HR columns were applied, therefore making it possible to demonstrate four logarithms virus titer reduction. Sodium hypochlorite, glutaraldehyde, caustic soda and potassium peroxymonosulfate showed the best ASFV inactivation rates, achieving titer reductions over 5 logs. Despite microfiltration, the virucidal activity of formaldehyde was not assessable, due to its high cytotoxicity. Our results showed that cleaning is particularly important, because removal of the soiling provides improved effectiveness of the tested chemical compounds.
RESUMO
The African swine fever epidemic occurred in Poland at the beginning of 2014 and, up to date, the disease has been spreading mainly in the eastern part of the country. Unexpectedly, in November 2019 an infected wild boar case was confirmed in Lubuskie voivodship in western Poland. During the following weeks, several dozen African swine fever virus (ASFV)-positive animals were notified in the neighboring area, causing severe concern regarding further spread of the disease to the mostly pig-dense region in Poland, namely, Wielkopolskie voivodship. Moreover, almost a year after, several infected wild boar cases were confirmed for the first time in Germany, just beyond the Polish border, sending out a shock wave through the global pig market. The whole genome sequence of ASFV, isolated from the first case of ASF in western Poland, and three selected viruses from other affected areas, revealed the tandem repeat and single nucleotide polymorphism (SNP) variations in reference to the Georgia 2007/1 strain. These data, supported by the conventional sequencing of selected genomic regions from a total of 154 virus samples isolated between 2017 and 2020 in Poland, shed a new light on pathogen epidemiology. The sequence variations within the O174L gene detected in this study showed that cases identified in western Poland might be originating from the so-called southern Warsaw cluster. Moreover, the viruses originating from the northern Warsaw cluster do not possess single nucleotide polymorphism (SNP) mutations within the K145R and MGF 505-5R genes, which are specific to all of the other Polish ASFV strains. These results led to a conclusion of their distinct origin. Supporting these results, the nucleotide sequencing of I73R/I329L intergenic region revealed its new, previously undescribed variant, called IGR IV, with an additional three tandem repeats of 10 nucleotides in comparison to the reference sequence of the Georgia 2007/1 strain.
Assuntos
Vírus da Febre Suína Africana/genética , Febre Suína Africana/epidemiologia , Proteínas Virais/genética , Febre Suína Africana/virologia , Vírus da Febre Suína Africana/isolamento & purificação , Animais , Mapeamento Cromossômico , Surtos de Doenças , Genoma Viral/genética , Epidemiologia Molecular , Polônia/epidemiologia , Polimorfismo de Nucleotídeo Único/genética , Análise de Sequência de DNA , Sus scrofa/virologia , Suínos/virologia , Sequenciamento Completo do GenomaRESUMO
INTRODUCTION: African swine fever (ASF) is a pressing economic problem in a number of Eastern European countries. It has also depleted the Chinese sow population by 50%. Managing the disease relies on culling infected pigs or hunting wild boars as sanitary zone creation. The constraints on the development of an efficient vaccine are mainly the virus' mechanisms of host immune response evasion. The study aimed to adapt a field ASFV strain to established cell lines and to construct recombinant African swine fever virus (ASFV) strain. MATERIAL AND METHODS: The host immune response modulation genes A238L, EP402R, and 9GL were deleted using the clustered regularly interspaced short palindromic repeats/caspase 9 (CRISPR/Cas9) mutagenesis system. A representative virus isolate (Pol18/28298/Out111) from Poland was isolated in porcine primary pulmonary alveolar macrophage (PPAM) cells. Adaptation of the virus to a few established cell lines was attempted. The plasmids encoding CRISPR/Cas9 genes along with gRNA complementary to the target sequences were designed, synthesised, and transfected into ASFV-infected PPAM cells. RESULTS: The reconstituted virus showed similar kinetics of replication in comparison to the parent virus isolate. CONCLUSION: Taking into account the usefulness of the developed CRISPR/Cas9 system it has been shown that modification of the A238L, EP402R, and 9GL genes might occur with low frequency, resulting in difficulties in separation of various virus populations.
RESUMO
This paper was aimed to characterize clinical signs and pathomorphological lesions in twenty-two pigs, infected intranasally by different doses of African swine fever virus (Pol18_28298_O111), isolated during the outbreak in a pig farm that occurred in Eastern Poland throughout 2018. This article also attempts to indicate risk, related to virus load and shedding, and present possible difficulties with proper disease recognition at the farm level. The results revealed that even a very low dose (5 HAU) may initiate the infection. Various forms of the disease (acute, subacute, and chronic), mainly with prodromal clinical signs like fever, apathy, and reduced feed intake were observed. The most frequently observed lesions (82%) were: hyperemia and enlargement of lymph nodes and splenomegaly. The minimal incubation period was estimated at five days post-infection (dpi). Mortality ranged from 80-100%. Two pigs survived the infection. Some viremic animals presented delayed fever. In some cases, the fever was not detectable. Shortly after viremia, the virus was secreted ion the urine, feces, and saliva. The highest levels of virus were found in the internal organs and blood; however in the case of one pig (chronic form), viral DNA was not detected in the spleen, liver, bone marrow, and brain. Veterinary diagnosis may be difficult, and the final results should always be based on laboratory investigations.
RESUMO
African swine fever (ASF), caused by African swine fever virus (ASFV), is currently one of the most important and serious diseases of pigs, mainly due to the enormous sanitary and socio-economic consequences. It leads to serious economic losses, not only because of the near 100% mortality rate, but also through the prohibitions of pork exports it triggers. Currently neither vaccines nor safe and effective chemotherapeutic agents are available against ASFV. The disease is controlled by culling infected pigs and maintaining high biosecurity standards, which principally relies on disinfection. Some countries have approved and/or authorised a list of biocides effective against this virus. This article is focused on the characteristics of chemical substances present in the most popular disinfectants of potential use against ASFV. Despite some of them being approved and tested, it seems necessary to perform tests directly on ASFV to ensure maximum effectiveness of the disinfectants in preventing the spread of ASF in the future.
RESUMO
Diffuse large B-cell lymphoma is the most common type of non-Hodgkin's lymphoma. More than 50% of patients have some site of extra-nodal involvement at diagnosis, including the gastrointestinal tract and bone marrow. However, a diffuse large B-cell lymphoma presenting as acute pancreatitis is rare. A 57-year-old female presented with abdominal pain and matted lymph nodes in her axilla. She was admitted with a diagnosis of acute pancreatitis. Abdominal computed tomography (CT) scan showed diffusely enlarged pancreas due to infiltrative neoplasm and peripancreatic lymphadenopathy. Biopsy of the axillary mass revealed a large B-cell lymphoma. The patient was classified as stage IV, based on the Ann Arbor Classification, and as having a high-risk lymphoma, based on the International Prognostic Index. She was started on chemotherapy with CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone). Within a week after chemotherapy, the patient's abdominal pain resolved. Follow-up CT scan of the abdomen revealed a marked decrease in the size of the pancreas and peripancreatic lymphadenopathy. A literature search revealed only seven cases of primary involvement of the pancreas in B-cell lymphoma presenting as acute pancreatitis. However, only one case of secondary pancreatic involvement by B-cell lymphoma presenting as acute pancreatitis has been published. Our case appears to be the second report of such a manifestation. Both cases responded well to chemotherapy.