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African swine fever (ASF) is one of the deadliest swine diseases, causing significant economic losses, threatening food security, and limiting pig production in affected countries. In the absence of an effective ASF vaccine, prevention and control of ASF depend mainly on effective biosecurity measures. In this study, the efficacy of SAFER®, a powdered disinfectant containing clay, an acid complex, and the active ingredient thyme essential oil, was tested against the ASF virus. The results showed that ASFV isolate (VNUA/HY/ASF1/Vietnam/2019) was inactivated by 3.5 and 5 Log10HAD50/ml after 20 and 120 min of treatment with SAFER®, respectively. When body fluids contaminated with ASFV, such as blood, saliva, urine, and feces, were treated with SAFER® for 20 min, the ASFV titer was reduced by 1.6, 2.2, 2.0, and 2.2 Log10HAD50/ml, respectively.
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Porcine transmissible gastroenteritis virus (TGEV) is a major pathogen that causes viral enteritis and severe diarrhea in newborn piglets. TGEV strains have been isolated in the USA, Europe, and China, and their molecular characteristics are well known. However, there have been few reports of molecular analysis of TGEV strains isolated in Southeast Asia. In 2016, we isolated TGEV strain VET-16 from fecal samples collected from piglets in Vietnam and determined its complete genome sequence by Sanger sequencing. We found that, while the full genome of the VET-16 strain was 92.4-99.9% identical to those of other TGEV strains, the ORF3 gene showed very little sequence similarity. Phylogenetic analysis suggested that the VET-16 strain belongs to the Purdue subgroup. Comparison of the predicted amino acid (aa) sequence of the spike protein of strain VET-16 with those of other TGEV strains revealed three aa substitutions (V378L, S379T, and D380N) and a 3-aa insertion (F383_F387insWEK) in antigenic site D of the VET-16 strain. Also, a single aa deletion (∆F1413) was found in the transmembrane domain of the spike gene of VET-16. Like the ORF3 gene from the TGEV Miller M60 vaccine strain, the VET-16 strain has a large deletion (∆725 nt) in the ORF3 gene. Previous studies have suggested that these mutations in the spike and ORF3 genes might be associated with a reduction in pathogenicity. The data from this study will facilitate further genetic analysis and research into the evolution of TGEV in pigs in Vietnam.
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Gastroenteritis Porcina Transmisible , Genoma Viral , Filogenia , Virus de la Gastroenteritis Transmisible , Animales , Porcinos , Vietnam , Virus de la Gastroenteritis Transmisible/genética , Virus de la Gastroenteritis Transmisible/aislamiento & purificación , Virus de la Gastroenteritis Transmisible/clasificación , Gastroenteritis Porcina Transmisible/virología , Genoma Viral/genética , Heces/virología , Secuenciación Completa del Genoma , Enfermedades de los Porcinos/virología , Secuencia de AminoácidosRESUMEN
Parrot bornavirus (PaBV) is an infectious disease linked with proventricular dilatation disease (PDD) with severe digestive and neurological symptoms affecting psittacine birds. Despite its detection in 2008, PaBV prevalence in Taiwan remains unexplored. Taiwan is one of the leading psittacine bird breeders; hence, understanding the distribution of PaBV aids preventive measures in controlling spread, early disease recognition, epidemiology, and transmission dynamics. Here, we aimed to detect the prevalence rate of PaBV and assess its genetic variation in Taiwan. Among 124 psittacine birds tested, fifty-seven were PaBV-positive, a prevalence rate of 45.97%. Most of the PaBV infections were adult psittacine birds, with five birds surviving the infection, resulting in a low survival rate (8.77%). A year of parrot bornavirus surveillance presented a seasonal pattern, with peak PaBV infection rates occurring in the spring season (68%) and the least in the summer season (25%), indicating the occurrence of PaBV infections linked to seasonal factors. Histopathology reveals severe meningoencephalitis in the cerebellum and dilated cardiomyopathy of the heart in psittacine birds who suffered from PDD. Three brain samples underwent X/P gene sequencing, revealing PaBV-2 and PaBV-4 viral genotypes through phylogenetic analyses. This underscores the necessity for ongoing PaBV surveillance and further investigation into its pathophysiology and transmission routes.
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Enfermedades de las Aves , Bornaviridae , Infecciones por Mononegavirales , Filogenia , Psittaciformes , Animales , Taiwán/epidemiología , Bornaviridae/genética , Bornaviridae/clasificación , Bornaviridae/aislamiento & purificación , Infecciones por Mononegavirales/veterinaria , Infecciones por Mononegavirales/virología , Infecciones por Mononegavirales/epidemiología , Enfermedades de las Aves/virología , Enfermedades de las Aves/epidemiología , Prevalencia , Psittaciformes/virología , Estaciones del Año , Variación Genética , Loros/virología , Monitoreo Epidemiológico/veterinariaRESUMEN
African swine fever virus (ASFV) genotype II is endemic to Vietnam. We detected recombinant ASFV genotypes I and II (rASFV I/II) strains in domestic pigs from 6 northern provinces in Vietnam. The introduction of rASFV I/II strains could complicate ongoing ASFV control measures in the region.
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Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Genotipo , Filogenia , Animales , Virus de la Fiebre Porcina Africana/genética , Virus de la Fiebre Porcina Africana/clasificación , Vietnam/epidemiología , Fiebre Porcina Africana/epidemiología , Fiebre Porcina Africana/virología , Porcinos , Sus scrofa/virología , Recombinación GenéticaRESUMEN
In this paper, we report the characterization of a genetically modified live-attenuated African swine fever virus (ASFV) field strain isolated from Vietnam. The isolate, ASFV-GUS-Vietnam, belongs to p72 genotype II, has six multi-gene family (MGF) genes deleted, and an Escherichia coli GusA gene (GUS) inserted. When six 6-8-week-old pigs were inoculated with ASFV-GUS-Vietnam oro-nasally (2 × 105 TCID50/pig), they developed viremia, mild fever, lethargy, and inappetence, and shed the virus in their oral and nasal secretions and feces. One of the pigs developed severe clinical signs and was euthanized 12 days post-infection, while the remaining five pigs recovered. When ASFV-GUS-Vietnam was inoculated intramuscularly (2 × 103 TCID50/pig) into four 6-8 weeks old pigs, they also developed viremia, mild fever, lethargy, inappetence, and shed the virus in their oral and nasal secretions and feces. Two contact pigs housed together with the four intramuscularly inoculated pigs, started to develop fever, viremia, loss of appetite, and lethargy 12 days post-contact, confirming horizontal transmission of ASFV-GUS-Vietnam. One of the contact pigs died of ASF on day 23 post-contact, while the other one recovered. The pigs that survived the exposure to ASFV-GUS-Vietnam via the mucosal or parenteral route were fully protected against the highly virulent ASFV Georgia 2007/1 challenge. This study showed that ASFV-GUS-Vietnam field isolate is able to induce complete protection in the majority of the pigs against highly virulent homologous ASFV challenge, but has the potential for horizontal transmission, and can be fatal in some animals. This study highlights the need for proper monitoring and surveillance when ASFV live-attenuated virus-based vaccines are used in the field for ASF control in endemic countries.
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Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Animales , Virus de la Fiebre Porcina Africana/genética , Virus de la Fiebre Porcina Africana/aislamiento & purificación , Virus de la Fiebre Porcina Africana/patogenicidad , Virus de la Fiebre Porcina Africana/clasificación , Fiebre Porcina Africana/virología , Porcinos , Vietnam , Viremia , Genoma Viral , Genotipo , Eliminación de Secuencia , Esparcimiento de Virus , FilogeniaRESUMEN
Porcine epidemic diarrhea (PED) is one of the diseases that causes great losses for livestock farmers. Because vaccines against the disease are not very effective, there is a great demand for biological products with effective resistance to PED virus (PEDV). One of the most important trends today is the use of active ingredients from nature in animal husbandry. This study aimed to create an effective agent against PEDV from the extract of Stixis scandens, which has been shown to inhibit PEDV. The aqueous (denoted as TCN) and ethanolic extracts (denoted as TCC) of Stixis scandens leaves were first prepared and then qualitatively analyzed for their chemical compositions. The TCN was used to synthesize ZnO nanoparticles (NPs) at various sizes from 20 to 120 nm. Subsequently, TCC was loaded on ZnO NPs to form ZnO-extract nanoformulations with an extract loading content of 5.8-7.6%. Total polyphenols (TP) and total alkaloids (TA) in TCC were 38.51 ± 0.25 µg GAE per mg and 22.37 ± 0.41 µg AtrE per mg, respectively. TP was less loaded but more released from the nanoformulations than TA. The A1T nanoformulation, containing only 7.6% extract, had a minimum PEDV inhibitory concentration of 3.9 µg mL-1, which was comparable to that of TCC. The experiments confirmed that the nanoformulations are promising for PEDV inhibition applications.
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Porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus (PDCoV), and swine acute diarrhea syndrome coronavirus (SADS-CoV) cause intestinal diseases with similar manifestations in suckling piglets. In this study, we developed a multiplex real-time PCR for differential diagnosis of PEDV, PDCoV, and SADS-CoV. The assay demonstrated high specificity with a detection limit of 5 copies/µl for each virus. The assay specifically detected PEDV, PDCoV, and SADS-CoV and excluded all other swine pathogens circulating in pigs. Furthermore, the assay exhibited satisfactory performance in analyzing clinical samples. The data indicate that the newly developed multiplex real-time PCR method can be applied for differential diagnosis of porcine enteric coronaviruses.
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Alphacoronavirus , Infecciones por Coronavirus , Deltacoronavirus , Virus de la Diarrea Epidémica Porcina , Enfermedades de los Porcinos , Animales , Porcinos , Virus de la Diarrea Epidémica Porcina/genética , Diarrea/diagnóstico , Diarrea/veterinaria , Sensibilidad y Especificidad , Infecciones por Coronavirus/diagnóstico , Infecciones por Coronavirus/veterinaria , Infecciones por Coronavirus/epidemiologíaRESUMEN
African swine fever (ASF) emerged in domestic pigs and wild boars in China in 2018 and rapidly spread to neighboring Asian countries. Currently, no effective vaccine or diagnostic tests are available to prevent its spread. We developed a robust quadruple recombinant-protein-based indirect enzyme-linked immunosorbent assay (QrP-iELISA) using four antigenic proteins (CD2v, CAP80, p54, and p22) to detect ASF virus (ASFV) antibodies and compared it with a commercial kit (IDvet) using ASFV-positive and -negative serum samples. The maximum positive/negative value was 24.033 at a single antigen concentration of 0.25 µg/mL and quadruple ASFV antigen combination of 1 µg/mL at a 1:100 serum dilution. Among 70 ASFV-positive samples, 65, 67, 65, 70, 70, and 14 were positive above the cut-offs of 0.121, 0.121, 0.183, 0.065, 0.201, and 0.122, for CD2v, CAP80, p54, p22-iELISA, QrP-iELISA, and IDvet, respectively, with sensitivities of 92.9%, 95.7%, 92.9%, 100%, 100%, and 20%, respectively, all with 100% specificity. The antibody responses in QrP-iELISA and IDvet were similar in pigs infected with ASFV I. QrP-iELISA was more sensitive than IDvet for early antibody detection in pigs infected with ASFV II. These data provide a foundation for developing advanced ASF antibody detection kits critical for ASF surveillance and control.
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African swine fever (ASF) is one of the most lethal infectious diseases affecting domestic pigs and wild boars of all ages. Over a span of 100 years, ASF has continued to spread over continents and adversely affects the global pig industry. To date, no vaccine or treatment has been approved. The complex genome structure and diverse variants facilitate the immune evasion of the ASF virus (ASFV). Recently, advanced technologies have been used to design various potential vaccine candidates and effective diagnostic tools. This review updates vaccine platforms that are currently being used worldwide, with a focus on genetically modified live attenuated vaccines, including an understanding of their potential efficacy and limitations of safety and stability. Furthermore, advanced ASFV detection technologies are presented that discuss and incorporate the challenges that remain to be addressed for conventional detection methods. We also highlight a nano-bio-based system that enhances sensitivity and specificity. A combination of prophylactic vaccines and point-of-care diagnostics can help effectively control the spread of ASFV.
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Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Vacunas Virales , Porcinos , Animales , Fiebre Porcina Africana/diagnóstico , Fiebre Porcina Africana/prevención & control , Virus de la Fiebre Porcina Africana/genética , Sus scrofa , Vacunas AtenuadasRESUMEN
Since its initial report in Vietnam in early 2019, the African swine fever (ASF), a highly lethal and severe viral swine disease worldwide, continues to cause outbreaks in other Southeast Asian countries. This study analyzed and compared the genomic sequences of ASF viruses (ASFVs) during the first outbreak in Hung Yen (VN/HY/2019-ASFV1) and Quynh Phu provinces (VN/QP/2019-ASFV1) in Vietnam in 2019, and the subsequent outbreak in Hung Yen (VN/HY/2022-ASFV2) in 2022, to those of other ASFV strains. VN/HY/2019-ASFV1, VN/QP/2019-ASFV1, and VN/HY/2022-ASFV2 genomes were 189,113, 189,081, and 189,607 bp in length, encoding 196, 196, and 203 open reading frames (ORFs), respectively. VN/HY/2019-ASFV1 and VN/QP/2019-ASFV1 shared a 99.91-99.99% average nucleotide identity with genotype II strains. Variations were identified in 28 ORFs in VN/HY/2019-ASFV1 and VN/QP/2019-ASFV1 compared to 20 ASFV strains, and 16 ORFs in VN/HY/2022-ASFV2 compared to VN/HY/2019-ASFV1 and VN/QP/2019-ASFV1. Vietnamese ASFV genomes were classified as IGR II variants between the I73R and I329L genes, with two copy tandem repeats between the A179L and A137R genes. A phylogenetic analysis based on the whole genomes of 27 ASFV strains indicated that the Vietnamese ASFV strains are genetically related to Estonia 2014, ASFV-SY18, and Russia/Odintsovo_02/14. These results reveal the complete genome sequences of ASFV circulating during the first outbreak in 2019, providing important insights into understanding the evolution, transmission, and genetic variation of ASFV in Vietnam.
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Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Animales , Porcinos , Virus de la Fiebre Porcina Africana/genética , Vietnam/epidemiología , Fiebre Porcina Africana/epidemiología , Filogenia , Brotes de EnfermedadesRESUMEN
African swine fever virus (ASFV) has continuously devastated the global pig industry. Viral persistence causes problems in large pig farms and kills small farms. Timely diagnostic tools play an important role in controlling outbreaks and minimizing losses. In this study, we developed a lateral flow assay to detect ASFV on-site. The VDRG® ASFV Ag Rapid Kit was established using two monoclonal antibodies (mAbs) against the p30 protein. The conjunction pad of the kit was coated with a mixture of the mAb and colloidal gold. This rapid kit was capable of detecting 11.5 ng of antigen and 0.16 HAD50 of virus from samples, in 20 min for the entire procedure. It passed cross-specific tests using common viruses that cause infectious diseases in pigs. ASFV was detected after 4 days in experimental infection in pigs by the kit. The specificity and sensitivity of the kit for clinical samples were 99.88% and 84.52% (93.8% for samples with a Ct value below 30), respectively. Finally, the kit can detect 100% positive herd outbreaks. The VDRG® ASFV Ag Rapid Kit presents a useful point-of-care tool for ASFV detection.
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Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Porcinos , Animales , Antígenos ViralesRESUMEN
Porcine reproductive and respiratory syndrome (PRRS) caused by PRRS virus (PRRSV) is one of the most complicated and dangerous diseases in pigs with high mortality since it modulates the immune system of the lungs and has been closely associated with secondary infection of other lethal bacteria and viruses. The gold standard of molecular diagnosis for PRRSV, reverse transcription (RT)-PCR, is time-consuming, expensive and requires transportation of samples to a specialized laboratory. In this study, a direct colorimetric RT-loop-mediated isothermal amplification (RT-LAMP) method was developed to specifically and rapidly detect PRRSV. The RT-LAMP outcomes can be visualized by the naked eye after 45 min of incubation at 65ËC without any cross-reactivity recorded with the bacteria and other viruses tested. In particular, the mobile, non-instrumented, commercial pocket hand warmers were demonstrated to su-ccessfully provide constant temperature for consistent nucleic acid amplification throughout the RT-LAMP reactions. The limit of detection of the assay was defined as the genomic RNA concentration extracted from a known viral titer of 10-2.5 TCID50/ml. The direct use of clinical serum samples required a simple dilution to maintain the performance of the colorimetric RT-LAMP assay. Therefore, the direct colorimetric RT-LAMP assay developed is well-qualified for producing a ready-to-use kit for PRRSV diagnosis in the field. Keywords: porcine reproductive and respiratory syndrome; rapid testing; RT-LAMP; colorimetric; direct detection; instrument-free.
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Síndrome Respiratorio y de la Reproducción Porcina , Virus del Síndrome Respiratorio y Reproductivo Porcino , Animales , Porcinos , Virus del Síndrome Respiratorio y Reproductivo Porcino/genética , Síndrome Respiratorio y de la Reproducción Porcina/diagnóstico , Configuración de Recursos Limitados , Sensibilidad y Especificidad , Pulmón , Técnicas de Amplificación de Ácido Nucleico/métodos , ARN ViralRESUMEN
African swine fever (ASF) is currently Vietnam's most economically significant swine disease. The first ASF outbreak in Vietnam was reported in February 2019. In this study, VNUA/HY/ASF1 strain isolated from the first ASF outbreak was used to infect 10 eight-week-old pigs orally with 103 HAD50 per animal. The pigs were observed daily for clinical signs, and whole blood samples were collected from each animal for viremia detection. Dead pigs were subjected to full post-mortem analyses. All 10 pigs displayed acute or subacute clinical signs and succumbed to the infection between 10 to 27 (19.8 ± 4.66) days post-inoculation (dpi). The onset of clinical signs started around 4-14 dpi. Viremia was observed in pigs from 6-16 dpi (11.2 ± 3.55). Enlarged, hyperemic, and hemorrhagic lymph nodes, enlarged spleen, pneumonia, and hydropericardium were observed at post-mortem examinations.
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We describe results from a panel study in which pigs from a 17-sow African swine fever (ASF) positive herd in Thái Bình province, Vietnam, were followed over time to record the date of onset of ASF signs and the date of death from ASF. Our objectives were to (1) fit a susceptible-exposed-infectious-removed disease model to the data with transmission coefficients estimated using approximate Bayesian computation; (2) provide commentary on how a model of this type might be used to provide decision support for disease control authorities. For the outbreak in this herd, the median of the average latent period was 10 days (95% HPD (highest posterior density interval): 2 to 19 days), and the median of the average duration of infectiousness was 3 days (95% HPD: 2 to 4 days). The estimated median for the transmission coefficient was 3.3 (95% HPD: 0.4 to 8.9) infectious contacts per ASF-infectious pig per day. The estimated median for the basic reproductive number, R0, was 10 (95% HPD: 1.1 to 30). Our estimates of the basic reproductive number R0 were greater than estimates of R0 for ASF reported previously. The results presented in this study may be used to estimate the number of pigs expected to be showing clinical signs at a given number of days following an estimated incursion date. This will allow sample size calculations, with or without adjustment to account for less than perfect sensitivity of clinical examination, to be used to determine the appropriate number of pigs to examine to detect at least one with the disease. A second use of the results of this study would be to inform the equation-based within-herd spread components of stochastic agent-based and hybrid simulation models of ASF.
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African swine fever virus (ASFV) causes African swine fever (ASF), a deadly disease affecting both domestic pigs and wild boars. ASF has become endemic in Vietnam since its first appearance in early 2019. Our previous molecular surveillance studies revealed that all the ASFV strains circulating in Vietnam belong to p72 genotype II, p54 genotype II, CD2v serogroup 8, and CVR of B602L gene variant type I. However, the genetic analysis based on the tandem repeat sequences located between I73R and I329L genes revealed three different intergenic region (IGR) variants; I, II, and III. In this study, using ASFV field isolates collected from September 24th to December 27th, 2021, we report, for the first time, novel IGR IV variants circulating in the Vietnamese pig population.
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Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Enfermedades de los Porcinos , Porcinos , Animales , Sus scrofa , Virus de la Fiebre Porcina Africana/genética , Fiebre Porcina Africana/epidemiología , Fiebre Porcina Africana/genética , ADN Intergénico/genética , Vietnam/epidemiología , Brotes de Enfermedades , Filogenia , Genotipo , Enfermedades de los Porcinos/epidemiologíaRESUMEN
African swine fever (ASF) is a deadly disease in swine caused by African swine fever virus (ASFV). The global spread of ASFV has resulted in significant economic losses worldwide. Improved early detection has been the most important first line of defense for preventing ASF outbreaks and for activating control measures. Despite the availability of rapid amplification methods, nucleic acid extraction from specimens still needs to be performed in a laboratory. To facilitate this step, we exploited the strong affinity of biotin-streptavidin binding by functionalizing streptavidin-coated magnetic beads with biotinylated oligonucleotide capture probes to efficiently capture genotype II ASFV DNA directly from crude clinical samples. The captured DNA is suitable for detection using real-time quantitative PCR (qPCR) and recombinase polymerase amplification (RPA). In this study, ASFV DNA was efficiently captured from swine feces, serum, and tissue samples. Both DNA-capture-assisted qPCR and RPA-based detection methods have a limit of detection (LOD) of 102 copies/µl, which is comparable to those of commercially available kits. In addition, an RPA-SYBR Green I method was developed for the immediate visual detection of ASFV DNA, which is time-saving and efficient for resource-limited field settings. In summary, a rapid, versatile, sequence-specific DNA capture method was developed to efficiently capture ASFV DNA from swine clinical samples and subsequent detection by qPCR and RPA, which has the potential to be used for robust screening and surveillance of ASFV and in point-of-care (POC) diagnostics.
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Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Porcinos , Animales , Virus de la Fiebre Porcina Africana/genética , Fiebre Porcina Africana/diagnóstico , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Recombinasas , Estreptavidina/genética , ADN Viral/genética , Fenómenos Magnéticos , Sensibilidad y EspecificidadRESUMEN
Canine distemper (CD), caused by the canine distemper virus (CDV), is a lethal systemic disease to a wide range of wild and domestic carnivorous hosts, including civets. In this study, a possible CD outbreak in a backyard farm with 32 diseased civets (Viverricula indica) in Hanoi, Vietnam, was investigated. The sick civets showed CD-like clinical signs such as anorexia, sedentary behavior, diarrhea, dermatitis, nasal, and footpad hyperkeratosis. Various tissue samples collected from the dead civets were utilized for molecular screening of CDV and histopathological examination. The genetic detection and characterization confirmed that samples collected from dead civets tested positive for CDV. The phylogenetic analysis based on the full-length H gene sequences indicated that all CDV strains isolated from civets belonged to the Asia-1 lineage and were closely related to the CDV strains previously reported from dogs in Thailand, China, and Vietnam. Histopathological examination showed severe interstitial pneumonia, hemorrhagic alveolar septa, necrotic alveolar epithelial cells, necrotic, degenerated, or lost Purkinje cells, eosinophilic intracytoplasmic inclusion bodies, edema, and perivascular cuff. This study confirmed the detection of CDV in civets for the first time in Vietnam.
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Virus del Moquillo Canino , Moquillo , Enfermedades de los Perros , Animales , Perros , Viverridae , Filogenia , Virus del Moquillo Canino/genética , Vietnam/epidemiología , Moquillo/epidemiologíaRESUMEN
African swine fever virus (ASFV) causes a highly contagious and fatal disease affecting both domesticated and wild pigs. Substandard therapies and inadequate vaccinations cause severe economic damages from pig culling and removal of infected carcasses. Therefore, there is an urgent need to develop a rapid point-of-use approach that assists in avoiding the spread of ASFV and reducing economic loss. In this study, we developed a colorimetric sensing platform based on dual enzymatic amplification that combined the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 12a (Cas12a) system and the enzyme urease for accurate and sensitive detection of ASFV. The mechanism of the sensing platform involves a magnetic bead-anchored urease-conjugated single-stranded oligodeoxynucleotide (MB@urODN), which in the presence of ASFV dsDNA is cleaved by activated CRISPR/Cas12a. After magnetically separating the free urease, the presence of virus can be confirmed by measuring the colorimetric change in the solution. The advantage of this method is that it can detect the presence of virus without undergoing a complex target gene duplication process. The established method detected ASFV from three clinical specimens collected from porcine clinical tissue samples. The proposed platform is designed to provide an adequate, simple, robust, highly sensitive and selective analytical technique for rapid zoonotic disease diagnosis while eliminating the need for vast or specialized tools.
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Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Técnicas Biosensibles , Porcinos , Animales , Virus de la Fiebre Porcina Africana/genética , Fiebre Porcina Africana/diagnóstico , Fiebre Porcina Africana/genética , Sistemas CRISPR-Cas/genética , Colorimetría , UreasaRESUMEN
African swine fever (ASF) is a devastating disease affecting the global swine industry. Recently, it has spread to many countries in Africa, Europe, Asia, and the Caribbean, leaving severe damage to local, regional, national, and global economies. Due to its highly complex molecular characteristics and pathogenesis, the development of a successful vaccine has been an unmet challenge. Therefore, ASF control relies solely on biosecurity, rapid detection, and elimination. Epidemiological information obtained from natural ASF outbreaks is critical for designing and implementing ASF control measures. Basic reproduction number (R0), an epidemiological metric used to describe the contagiousness or transmissibility of infectious agents, is an important epidemiological tool. In this study, we have calculated R0 for the in-farm spread of ASF among fattening pigs and sows in two midsize commercial pig farms, HY1 and HY2, that practice the spot removal approach in controlling ASF outbreaks in Vietnam. The R0 values for the sows and fattening pigs were 1.78 (1.35-2.35) and 4.76 (4.18-5.38) for HY1 and 1.55 (1.08-2.18) and 3.8 (3.33-4.28) for HY2. This is the first study to evaluate the transmission potential of ASF in midsize commercial pig farms in Vietnam. Based on the R0 values, we predict that the spot removal approach could be used to successfully control ASF outbreaks in midsize commercial sow barns but not in fattening pens.
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In total, 130 tissue-pooled samples collected from ducks in some provinces/cities in north Vietnam were examined for waterfowl parvovirus genome identification. Twenty-six (20%) samples were positive for the parvovirus infection, based on polymerase chain reaction analysis. Of the 38 farms tested, 14 (36.84%) were positive for the waterfowl parvovirus genome. The rate of the parvovirus genome detection in ducks aged 2−4 weeks (37.04%) was significantly (p < 0.05) higher than that at ages <2 weeks (9.09%) and >4 weeks (16.30%). The positive rate on medium-scale farms (9.36%) was significantly (p < 0.05) lower than for small-scale (31.03%) and large-scale (29.73%) farms. The lengths of the four Vietnamese waterfowl parvovirus genomes identified were 4750 nucleotides. Among the four Vietnamese parvovirus genomes, nucleotide identities were from 99.29% to 99.87%. Phylogenetic analysis of the near-complete genomes indicated that the waterfowl circulating in northern Vietnam belonged to the novel goose parvovirus (NGPV) group. The Vietnamese NGPV group was closely related to the Chinese group. Recombination analysis suggested that the Vietnam/VNUA-26/2021 strain was generated by a recombination event. One positive selection site of the capsid protein was detected.