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1.
Vet Microbiol ; 293: 110073, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38579481

RESUMO

African swine fever virus (ASFV) is a large double stranded DNA arbovirus that is highly contagious and seriously endangers domestic and wild pigs. In the past decade, African swine fever (ASF) has spread in many countries in the Caucasus, Russian Federation, Eastern Europe and Asia, causing significant losses to the pig industry. At present, there is a lack of effective vaccine and treatment for ASF. Therefore, the rapid and accurate detection is crucial for ASF prevention and control. In this study, we have developed a portable lateral flow strip (LFS) detection mediated by recombinase polymerase amplification (RPA) and CRISPR/LwCas13a, which is performed at 37 ℃ and visualized by eyes without the need for complex instruments. This RPA-LwCas13a-LFS is based on the ASFV structural protein p17 gene (D117L), with a detection sensitivity up to 2 gene copies. This method is highly specific and has no cross reactivity to 7 other pig viruses. In the detection of two batches of 100 clinical samples, the p17 (D117L) RPA-LwCas13a-LFS had 100% coincidence with conventional quantitative PCR (qPCR). These findings demonstrate the potential of this simple, rapid, sensitive, and specific ASFV detection method for on-site ASFV detection.


Assuntos
Vírus da Febre Suína Africana , Febre Suína Africana , Sistemas CRISPR-Cas , Vírus da Febre Suína Africana/genética , Vírus da Febre Suína Africana/isolamento & purificação , Animais , Suínos , Febre Suína Africana/virologia , Febre Suína Africana/diagnóstico , Sensibilidade e Especificidade , Técnicas de Amplificação de Ácido Nucleico/métodos , Técnicas de Amplificação de Ácido Nucleico/veterinária , Proteínas Estruturais Virais/genética
2.
J Vet Diagn Invest ; 35(3): 307-310, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37029660

RESUMO

The lack of quick, accurate, and low-cost detection methods has hindered the active control strategies for bovine tuberculosis (bTB) in resource-limited countries with a high burden of disease. We developed a dry loop-mediated isothermal amplification (LAMP) assay for rapid and specific detection of Mycobacterium bovis, the principal causative agent of bTB, and evaluated the efficacy of the assay using suspected bTB samples collected during routine meat inspection at major regional abattoirs in Malawi. Template genomic DNA was extracted directly from the granulomatous bTB-like lesion (crude extracted DNA), as well as growth from the incubated mycobacterial growth indicator tubes (MGIT). Field results were visualized by the naked eye within 40 min following a color change of the amplified products. The sensitivity and specificity of the dry LAMP assay while using 152 DNA samples extracted from MGIT with confirmed M. bovis results were 98% and 88%, respectively. When 43 randomly selected crude DNA samples from lesions were used, the sensitivity and specificity of the dry LAMP assay were 100% and 75%, respectively. Our LAMP assay offers the potential to meet the demands for a low-cost and rapid field detection tool for bTB in resource-limited countries in which bTB is endemic.


Assuntos
Doenças dos Bovinos , Mycobacterium bovis , Tuberculose Bovina , Bovinos , Animais , Mycobacterium bovis/genética , Matadouros , Malaui , Técnicas de Amplificação de Ácido Nucleico/veterinária , Técnicas de Amplificação de Ácido Nucleico/métodos , Tuberculose Bovina/diagnóstico , Tuberculose Bovina/epidemiologia , DNA , Sensibilidade e Especificidade
3.
Transbound Emerg Dis ; 69(6): 3850-3857, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36335589

RESUMO

Ovine papillomavirus (OaPV) comprises four genotypes; OaPV1, OaPV2 and OaPV4 are fibropapillomaviruses within the genus Deltapapillomavirus, whereas OaPV3 is an epitheliotropic virus that belongs to the genus Dyokappapapillomavirus. To date, all of them have been known to infect sheep only. OaPV1, OaPV2 and OaPV4 have been associated with ovine cutaneous and mucosal fibropapillomas, whereas OaPV3 is a key factor in the squamous cell carcinoma pathway of the sheep skin. Whole blood samples obtained from 128 cattle at public slaughterhouses were investigated using droplet digital polymerase chain reaction (ddPCR). ddPCR is a new-generation PCR technique that enables an accurate and absolute quantification of target molecules with high sensitivity and specificity. All OaPVs were detected by identification and quantification of nucleic acids using specific fluorescent probes. Of 128 blood samples, 100 (∼78%) showed OaPV infections. Further, 42, 35 and 23 blood samples showed single, double and triple OaPV infections, respectively. OaPV1 was responsible for 22 single infections, OaPV2 caused 16 single infections and OaPV3 and OaPV4 caused two single infections each. OaPV1 and OaPV2 were the most frequent ovine viruses in dual and triple infections. In many blood samples, both ovine deltapapillomavirus and dyokappapapillomavirus were found to be transcriptionally active, as shown by the detection and quantification of E5 oncogene transcripts for OaPV1, L1 transcripts for OaPV2, E6 and E7 transcripts for OaPV3 and E6 for OaPV4. OaPVs were found in the blood samples from cattle that shared grasslands rich in bracken ferns known to contain immunosuppressant substances. Furthermore, OaPVs were also found in cattle from intensive livestock farming without any contact with sheep. Because OaPV DNA was detected in both grass hay and corn silage, it is conceivable that these feed may be the viral sources.


Assuntos
Doenças dos Bovinos , Deltapapillomavirus , Infecções por Papillomavirus , Doenças dos Ovinos , Ovinos , Animais , Bovinos , Deltapapillomavirus/genética , Papillomaviridae/genética , Pele/patologia , Reação em Cadeia da Polimerase/veterinária , Reação em Cadeia da Polimerase/métodos , Técnicas de Amplificação de Ácido Nucleico/veterinária , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/veterinária , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/diagnóstico
4.
Transbound Emerg Dis ; 69(4): 2390-2397, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33991179

RESUMO

Taenia hydatigena is a widespread tapeworm of canids (primarily dogs) that causes cysticercosis in ruminants (domestic and wild) and manifests as depression and weakness secondary to various hepatic damages and sometimes mortality in young animals, although, commonly encountered cases are asymptomatic. In most taeniids, genetic polymorphism has been found to impact host preferences, distribution, disease epidemiology and management. Recently, we identified two main mitochondrial lineages of T. hydatigena in China, and here, we examined the mitochondrial nad4-nad5 genes of T. hydatigena from China, Nigeria, Pakistan and Sudan to assess the intraspecies variation of isolates from these countries and also the distribution of the distinct mitochondrial groups. In addition to China, haplogroup B variant was found in Pakistan, while haplogroup A demonstrated a widespread distribution. We then designed a PCR-restriction fragment length polymorphism (PCR-RFLP) assay using XmiI (AccI) and RsaI (AfaI) restriction enzymes to differentiate members of both haplogroups. This result provides more molecular evidence supporting the existence of distinct mitochondrial variants of T. hydatigena. The epidemiological significance of these different mitochondrial groups remains to be explored further. The current PCR-RFLP assay offers a useful molecular approach for investigating the genetic population structure of T. hydatigena in enzootic regions and in identifying/discriminating the different mitochondrial groups (haplogroups A and B).


Assuntos
Cisticercose , Doenças do Cão , Taenia , Animais , Cisticercose/epidemiologia , Cisticercose/veterinária , Cães , Técnicas de Amplificação de Ácido Nucleico/veterinária , Reação em Cadeia da Polimerase/veterinária , Polimorfismo de Fragmento de Restrição , Taenia/genética
5.
J Fish Dis ; 45(1): 107-120, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34613623

RESUMO

Scale drop disease virus (SDDV) is a major pathogen of Asian sea bass that has emerged in many countries across the Asia Pacific since 1992 and carries the potential to cause drastic economic losses to the aquaculture sector. The lack of an approved vaccine for SDDV necessitates timely prevention as the first line of defence against the disease, but current diagnostic platforms still face challenges that render them incompatible with field applications, particularly in resource-limited settings. Here, we developed a novel detection platform for SDDV based on a CRISPR-Cas12a-based nucleic acid detection technology combined with recombinase polymerase amplification (RPA-Cas12a). Using the viral adenosine triphosphatase (SDDV-ATPase) gene as a target, we achieved the detection limit of 40 copies per reaction and high specificity for SDDV. The coupling with fluorescence and lateral flow readouts enables naked-eye visualization and straightforward data interpretation requiring minimal scientific background. Compared with semi-nested PCR in field sample evaluation, our RPA-Cas12a assay is more sensitive and capable of detecting SDDV in asymptomatic fish. Importantly, the entire workflow can be carried out at a constant temperature of 37°C within an hour from start to finish, thus removing the need for an expensive thermal cycling apparatus and long turnaround times associated with PCR-based methods. Therefore, owing to its high accuracy, rapidity and user-friendliness, the developed RPA-Cas12a platform shows the potential for diagnosis of SDDV at point of need and could be a valuable tool to help protect fish farming communities from large-scale epidemics.


Assuntos
Bass , Doenças dos Peixes , Iridoviridae , Perciformes , Animais , Doenças dos Peixes/diagnóstico , Iridoviridae/genética , Técnicas de Amplificação de Ácido Nucleico/veterinária , Sensibilidade e Especificidade
6.
Vet Parasitol ; 299: 109573, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34521042

RESUMO

Alveolar echinococcosis, which is caused by a larval-stage infection of Echinococcus multilocularis, is a zoonosis with public health importance. Recently, alveolar echinococcosis in slaughtered horses has been reported in Japan and Poland. In terms of public health, a highly sensitive and specific diagnostic method is essential for early detection during meat inspection. In this study, the loop-mediated isothermal amplification (LAMP) assay was developed and validated to target the mitochondrial cytochrome b (cob) gene of E. multilocularis. Forty-one hepatic solid nodules obtained from each horse were evaluated based on histopathological examination and cob-targeted PCR and then submitted to the LAMP assay. The optimal condition of the developed LAMP assay was 64℃ for 30 min. The results of the developed LAMP assay were completely consistent with those of cob PCR. In addition, the detection limit for the number of copies of the cob gene was 135 copies/µL in the LAMP assay. These findings suggest that the ability of the LAMP assay developed in this study is equivalent to that of the conventional PCR testing. The LAMP assay developed in this study can be used as an alternative to PCR testing for the routine genetic diagnosis of alveolar echinococcosis in horses.


Assuntos
Equinococose , Doenças dos Cavalos , Animais , Citocromos b/genética , Equinococose/veterinária , Doenças dos Cavalos/diagnóstico , Cavalos , Técnicas de Diagnóstico Molecular , Técnicas de Amplificação de Ácido Nucleico/veterinária , Sensibilidade e Especificidade
7.
J Fish Dis ; 44(4): 401-413, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33340375

RESUMO

Rapid and user-friendly diagnostic tests are necessary for early diagnosis and immediate detection of diseases, particularly for on-site screening of pathogenic microorganisms in aquaculture. In this study, we developed a dual-sample microfluidic chip integrated with a real-time fluorogenic loop-mediated isothermal amplification assay (dual-sample on-chip LAMP) to simultaneously detect 10 pathogenic microorganisms, that is Aeromonas hydrophila, Edwardsiella tarda, Vibrio harveyi, V. alginolyticus, V. anguillarum, V. parahaemolyticus, V. vulnificus, infectious hypodermal and haematopoietic necrosis virus, infectious spleen and kidney necrosis virus, and white spot syndrome virus. This on-chip LAMP provided a nearly automated protocol that can analyse two samples simultaneously, and the tests achieved limits of detection (LOD) ranging from 100 to 10-1  pg/µl for genomic DNA of tested bacteria and 10-4 to 10-5  pg/µl for recombinant plasmid DNA of tested viruses, with run times averaging less than 30 min. The coefficient of variation for the time-to-positive value was less than 10%, reflecting a robust reproducibility. The clinical sensitivity and specificity were 93.52% and 85.53%, respectively, compared to conventional microbiological or clinical methods. The on-chip LAMP assay provides an effective dual-sample and multiple pathogen analysis, and thus would be applicable to on-site detection and routine monitoring of multiple pathogens in aquaculture.


Assuntos
Aeromonas hydrophila/isolamento & purificação , Densovirinae/isolamento & purificação , Edwardsiella tarda/isolamento & purificação , Iridoviridae/isolamento & purificação , Microfluídica/métodos , Técnicas de Diagnóstico Molecular/veterinária , Técnicas de Amplificação de Ácido Nucleico/veterinária , Vibrio/isolamento & purificação , Vírus da Síndrome da Mancha Branca 1/isolamento & purificação , Animais , Crustáceos/microbiologia , Crustáceos/virologia , Infecções por Vírus de DNA/diagnóstico , Infecções por Vírus de DNA/veterinária , Infecções por Vírus de DNA/virologia , Doenças dos Peixes/diagnóstico , Doenças dos Peixes/microbiologia , Doenças dos Peixes/virologia , Peixes/microbiologia , Peixes/virologia , Infecções por Bactérias Gram-Negativas/diagnóstico , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/veterinária , Limite de Detecção , Técnicas de Diagnóstico Molecular/métodos , Moluscos/microbiologia , Moluscos/virologia , Técnicas de Amplificação de Ácido Nucleico/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
8.
Mol Cell Probes ; 54: 101669, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33203619

RESUMO

Feline coronavirus (FCoV) is classified into two pathotypes: the avirulent feline enteric coronavirus (FECV), and the virulent feline infectious peritonitis virus (FIPV). Rapid pathogen detection, which is efficient and convenient, is the best approach for early confirmatory diagnosis. In this study, we first developed and evaluated a rapid recombinase polymerase amplification (RPA) detection method for FCoV that can detect FCoV within 15 min at 39 °C. The detection limit of that assay was 233 copies/µL DNA molecules per reaction. The specificity was high: it did not cross-react with canine distemper virus (CDV), canine coronavirus (CCoV), canine adenovirus (CAV), feline calicivirus (FCV), feline herpesvirus (FHV), or feline parvovirus (FPV). This assay was evaluated using 42 clinical samples (30 diarrhea samples and 12 ascites samples). The coincidence rate between FCoV-RPA and RT-qPCR for detection in clinical samples was 95.2%. In summary, FCoV-RPA analysis provides an efficient, rapid, and sensitive detection method for FCoV.


Assuntos
Infecções por Coronavirus/diagnóstico , Coronavirus Felino/genética , Peritonite Infecciosa Felina/diagnóstico , Técnicas de Diagnóstico Molecular/veterinária , Técnicas de Amplificação de Ácido Nucleico/métodos , RNA Viral/genética , Animais , Doenças do Gato/diagnóstico , Doenças do Gato/virologia , Gatos , Coronavirus Felino/isolamento & purificação , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/veterinária , Reação em Cadeia da Polimerase em Tempo Real/métodos , Sensibilidade e Especificidade
9.
Poult Sci ; 99(12): 6446-6453, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33248559

RESUMO

Fowl adenovirus (FAdV) has posed a grave threat to the health of poultry, and the sudden outbreak highlights the importance of the new rapid diagnostic method for the control and prevention of transmission. Hence, in the present study, a novel recombinase polymerase amplification (RPA) assay, which was suitable for all 12 serotypes (FAdV-1 to 8a and 8b to 11) had been successfully launched to detect FAdV. Also, the entire amplification process could be completed in the isothermal condition when temperature ranged from 26 to 42°C within no more than 14 min, which was remarkably superior to endpoint polymerase chain reaction (98 min) with the same detecting sensitivity (as low as 0.1 fg viral DNA), avoiding sophisticated thermal cyclers with simple operation. Additionally, the same primers did not produce positive reactions with other viruses tested, demonstrating that the specificity of the RPA assay was acceptable. Moreover, this developed method could be efficiently used in the diagnosis of FAdV references and epidemic strains from different avian origins, thus making it a rapid, reliable, and point-of-care FAdV diagnostics tool, as well as an alternative to endpoint PCR.


Assuntos
Aviadenovirus , Epidemias , Doenças das Aves Domésticas , Animais , Aviadenovirus/genética , Técnicas de Amplificação de Ácido Nucleico/veterinária , Aves Domésticas , Doenças das Aves Domésticas/diagnóstico , Doenças das Aves Domésticas/epidemiologia , Recombinases , Sensibilidade e Especificidade
10.
J Vet Diagn Invest ; 32(6): 961-963, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32964810

RESUMO

African swine fever (ASF) is a devastating viral disease of pigs and wild boar, and it threatens global food security. We aimed to identify suitable sample matrices for use in ASF surveillance programs. Six pigs inoculated with ASFV were sampled at postmortem. Blood, bone marrow, ear biopsies, and oral, nasal, and rectal swabs were taken from all pigs. All samples were analyzed using 3 real-time PCR (rtPCR) assays and a LAMP assay. ASFV was detected at > 107 genome copies/mL in blood; bone marrow was found to provide the highest viral load. Ct values provided by the rtPCR assays were correlated, and ASFV was detected in all oral, nasal, and rectal swabs and in all ear biopsy samples irrespective of the location from which they were taken. The LAMP assay had lower sensitivity, and detected ASFV in 54 of 66 positive samples, but delivered positive results within 17 min. We identified additional sample matrices that can be considered depending on the sampling situation: bone marrow had a high probability of detection, which could be useful for decomposed carcasses. However, ear biopsies provide an appropriate, high-throughput sample matrix to detect ASFV and may be useful during surveillance programs.


Assuntos
Febre Suína Africana/diagnóstico , Vigilância da População/métodos , Vírus da Febre Suína Africana/genética , Animais , DNA Viral/genética , Técnicas de Diagnóstico Molecular/normas , Técnicas de Diagnóstico Molecular/veterinária , Técnicas de Amplificação de Ácido Nucleico/normas , Técnicas de Amplificação de Ácido Nucleico/veterinária , Reação em Cadeia da Polimerase em Tempo Real/normas , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Sensibilidade e Especificidade , Suínos
11.
Lett Appl Microbiol ; 71(6): 560-566, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32852051

RESUMO

Along with progress in globalization of society, the spread of infectious diseases has accelerated worldwide. The deployment of highly sensitive genetic tests is essential for early diagnosis and early containment of potential outbreaks and epidemics, as well as routine surveillance, although tedious and expensive nucleic acid extraction steps represent a major drawback. Here we developed a simple and rapid DNA extraction method, named as an EZ-Fast kit, applicable to the field setting. The kit does not require advanced laboratory equipment or expensive DNA extraction kits and achieves crude DNA extraction within 10 min at extremely low cost and can easily be performed in field settings. When combined with real-time PCR and LAMP analyses, the performance of the POCT, using 183 bovine blood samples, was similar to that of the existing DNA extraction method: 92·5% (135/146) (real-time PCR) and 93·7% (133/142) (LAMP) diagnostic sensitivities, and 100% diagnostic specificities. The developed POCT provides a powerful tool to facilitate on-site diagnosis in a field setting.


Assuntos
DNA/genética , Testes Diagnósticos de Rotina/métodos , Leucose Enzoótica Bovina/diagnóstico , Técnicas de Amplificação de Ácido Nucleico/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Animais , Bovinos , DNA/sangue , Leucose Enzoótica Bovina/sangue , Leucose Enzoótica Bovina/genética , Técnicas de Amplificação de Ácido Nucleico/veterinária , Testes Imediatos , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Sensibilidade e Especificidade
12.
Arch Virol ; 165(3): 743-747, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31980939

RESUMO

A cross-priming isothermal amplification (CPA) assay was developed for detection of feline herpesvirus type 1 (FHV-1). In this assay, the target fragment of the FHV-1 glycoprotein B gene is amplified rapidly by Bst DNA polymerase at a constant temperature (63 °C, 45 min), using a simple thermostat. The assay had no cross-reactions with four types of feline viruses, and the detection limit was 100 copies/µl. The positive rate of clinical samples from CPA was 100% consistent with qPCR but higher than ordinary PCR, indicating its superiority to ordinary PCR. Visualization was achieved using SYBR Green I dye.


Assuntos
Doenças do Gato/virologia , Apresentação Cruzada , Técnicas de Amplificação de Ácido Nucleico/veterinária , Varicellovirus/isolamento & purificação , Proteínas do Envelope Viral/isolamento & purificação , Animais , Doenças do Gato/diagnóstico , Gatos , Primers do DNA/genética , Técnicas de Amplificação de Ácido Nucleico/economia , Técnicas de Amplificação de Ácido Nucleico/métodos , Sensibilidade e Especificidade
13.
J Vet Diagn Invest ; 31(5): 756-760, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31378162

RESUMO

DNA amplification by PCR detects KIT exon 11 internal tandem duplications in canine mast cell tumors (MCTs). Tissue-specific inhibitors often contaminate DNA extracted from formalin-fixed, paraffin-embedded (FFPE) canine MCTs, blocking PCR amplification and, consequently, preventing mutation detection. We used a commercial kit to extract DNA from FFPE canine MCTs. Two independent PCR assays, each with one primer set, were used to amplify target genes (HPRT and KIT) directly after FFPE DNA extraction. PCR amplification failed with at least one primer set in 153 of 280 samples (54.6%, 95% CI: 48.8-60.5%). One or 2 DNA washing steps were required to remove PCR inhibitors in 130 of 280 (46.4%) and 23 of 280 (8.2%) of these cases, respectively. DNA concentration and quality (A260/A280 and A260/A230) either pre- or post-washing were not associated with ability of the samples to be amplified by PCR using both HPRT and KIT primer sets. Low-grade and subcutaneous MCTs were less likely to amplify directly after DNA extraction and without any washing steps compared to high-grade MCTs using KIT gene primers.


Assuntos
DNA Tumoral Circulante/análise , Doenças do Cão/diagnóstico , Mastocitoma/veterinária , Técnicas de Amplificação de Ácido Nucleico/veterinária , Reação em Cadeia da Polimerase/veterinária , Animais , Cães , Formaldeído , Mastócitos/citologia , Mastocitoma/diagnóstico , Mutação , Técnicas de Amplificação de Ácido Nucleico/métodos , Inclusão em Parafina/veterinária , Reação em Cadeia da Polimerase/métodos , Proteínas Proto-Oncogênicas c-kit/análise , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/veterinária
14.
BMC Vet Res ; 15(1): 256, 2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31337397

RESUMO

BACKGROUND: Fowl adenovirus (FAdV) is an infectious agent that can cause jaundice, severe anaemia, dyspnoea and reproductive disorders in fowls. Since 2015, FAdV disease has been rapidly spreading among broiler chickens in China, where it has caused significant economic losses. In this study, a loop-mediated isothermal amplification (LAMP) real-time turbidity method with strong specificity to FAdV was established. RESULTS: The established assay was specific to FAdV-4, and the lower limit of detection was 75 copies/µL of extracted DNA. The positive detection rate for the suspected tissue samples was 33.3% (14/42), which was consistent with that of the real-time PCR. CONCLUSION: The proposed LAMP method can quickly and accurately detect prevalent FAdV via real-time turbidity assay, thereby providing a diagnostic platform for the prevention and control of the FAdV disease.


Assuntos
Infecções por Adenoviridae/veterinária , Adenoviridae/isolamento & purificação , Técnicas de Amplificação de Ácido Nucleico/veterinária , Doenças das Aves Domésticas/virologia , Adenoviridae/genética , Infecções por Adenoviridae/diagnóstico , Infecções por Adenoviridae/virologia , Animais , Galinhas , DNA Viral , Técnicas de Amplificação de Ácido Nucleico/métodos , Doenças das Aves Domésticas/diagnóstico , Sensibilidade e Especificidade
15.
J Virol Methods ; 270: 79-86, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31054280

RESUMO

Fowl adenovirus serotype-4 (FAdV-4) has been recognized as a predominant threat to the broilers aged from three to five weeks. Hydropericardium syndrome (HPS) is one of its major clinical diseases by FAdV-4 resulting in heavy economic losses. In this study, a loop-mediated isothermal amplification coupling with a lateral flow dipstick (LAMP-LFD) was developed for rapid and specific detection of fowl adenovirus serotype-4. The optimized LAMP-LFD can be completed in 60 min at 65 °C. The minimum detection limits of PCR, real-time PCR, nested PCR and LAMP-LFD are 1 × 104 copies/µl, 1 × 102 copies/µl, 10 copies/µl and 10 copies/µl respectively. Moreover, the specificity of the LAMP-LFD assay is satisfactory and does not produce cross reactions with other species. In field samples, 150 samples were assayed by PCR and LAMP-LFD. They agreed on the diagnosis "positive" in 13% of clinical samples, and they agreed on the diagnosis "negative" in 85% of clinical samples. Their probability of agreement is p0 = 147/150 = 13% + 85% = 98%. LAMP-LFD can potentially be modified and applied as a diagnostic tool for FAdV-4 infection especially in resource-limited areas, such as small breeding farms and basic veterinary labs to offer an affordable diagnostic.


Assuntos
Adenoviridae/isolamento & purificação , Galinhas/virologia , Cromatografia/veterinária , Técnicas de Amplificação de Ácido Nucleico/veterinária , Adenoviridae/genética , Animais , Primers do DNA/genética , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Sensibilidade e Especificidade , Sorogrupo
16.
J Vet Med Sci ; 81(5): 787-792, 2019 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-30918136

RESUMO

Bovine leukemia virus (BLV) causes enzootic bovine leukosis (EBL), a condition that threatens the sustainability of the livestock industry. A fluorescent loop-mediated isothermal amplification (fLAMP) assay targeting BLV env sequences was developed and used to evaluate 100 bovine blood samples. Compared with a conventional real-time PCR (rPCR) assay, the fLAMP assay achieved 87.3% (62/71) sensitivity and 100% (29/29) specificity. The rPCR assay took 65 min, while the fLAMP assay took 8 min to 30 min from the beginning of DNA amplification to final judgement with a comparable limit of detection. The fLAMP is a potential tool for the rapid and simple diagnosis of BLV infection to supplement ELISA testing and can be used by local laboratories and slaughterhouses without special equipment.


Assuntos
Leucose Enzoótica Bovina/diagnóstico , Vírus da Leucemia Bovina/isolamento & purificação , Técnicas de Amplificação de Ácido Nucleico/veterinária , Animais , Bovinos , Leucose Enzoótica Bovina/genética , Vírus da Leucemia Bovina/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Sensibilidade e Especificidade
17.
BMC Vet Res ; 14(1): 49, 2018 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-29439721

RESUMO

BACKGROUND: Egg drop syndrome (EDS), caused by the adenovirus "egg drop syndrome virus" (EDSV) causes severe economic losses through reduced egg production in breeder and layer flocks. The diagnosis of EDSV has been done by molecular tools since its complete genome sequence was identified. In order to enhance the capabilities of the real-time fluorescence loop-mediated isothermal amplification (RealAmp) assay, we aimed to apply the method for direct detection of the EDSV without viral DNA extraction. In order to detect the presence of the EDSV DNA, three pairs of primers were designed, from the conserved region of fiber gene of the EDSV. RESULTS: For our assay, test and control samples were directly used in the reaction mixture in 10-fold serial dilution. The target DNA was amplified at 65 °C, which yield positive results in a relatively short period of 40-45 min. The method reported in this study is highly sensitive as compared to polymerase chain reaction (PCR) and showed no sign of cross-reactivity or false positive results. The RealAmp accomplished specific identification of EDSV among a variety of poultry disease viruses. CONCLUSIONS: The direct RealAmp can be used to detect the presence of EDSV. As our result showed, the RealAmp method could be suitable for the direct detection of other DNA viruses.


Assuntos
Infecções por Adenoviridae/veterinária , Atadenovirus/genética , Técnicas de Amplificação de Ácido Nucleico/veterinária , Doenças das Aves Domésticas/diagnóstico , Infecções por Adenoviridae/diagnóstico , Infecções por Adenoviridae/virologia , Animais , Células Cultivadas , DNA Viral/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Reação em Cadeia da Polimerase/veterinária , Doenças das Aves Domésticas/virologia , Sensibilidade e Especificidade
18.
J Vet Med Sci ; 79(12): 1986-1993, 2017 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-29057765

RESUMO

For field-identification of taeniid cestodes in canine animals in Tibetan area, loop-mediated isothermal amplification (LAMP) assays for Echinococcus multilocularis, E. shiquicus, Taenia hydatigena, T. multiceps, T. pisiformis and T. crassiceps were developed and evaluated along with the reported assay for E. granulosus. The LAMP assays showed specific reaction with their corresponding target species DNA with the detection limit of 1 to 10 pg. Moreover, the assays for E. granulosus, E. multilocularis, T. hydatigena and T. multiceps could detect DNA extracted from 3 or more eggs of their corresponding target species. Then, the LAMP assays were applied on samples containing 3 to 35 taeniid eggs obtained from 61 field-collected canine feces in Qinghai, and the result was compared with a reported multiplex PCR and sequence analysis. The LAMP assays and the PCR detected single species DNA of E. granulosus, E. shiquicus, T. hydatigena and T. multiceps in 5, 2, 44 and 2 samples, respectively. In the rest 8 samples, DNA of both E. granulosus and T. hydatigena were detected by the PCR but the LAMP assays detected those DNAs in 2 samples and only T. hydatigena DNA in 6 samples. It was assumed that less than 3 E. granulosus eggs were mixed in the samples although the samples contained 21 to 27 eggs in total. In conclusion, the LAMP assays were less sensitive than the multiplex PCR, but would have adequate sensitivity for field use in Tibetan area.


Assuntos
Doenças do Cão/parasitologia , Técnicas de Amplificação de Ácido Nucleico/veterinária , Teníase/veterinária , Animais , DNA de Helmintos/genética , Doenças do Cão/diagnóstico , Doenças do Cão/epidemiologia , Cães , Equinococose/diagnóstico , Equinococose/epidemiologia , Equinococose/veterinária , Echinococcus/genética , Echinococcus multilocularis/genética , Reação em Cadeia da Polimerase Multiplex/veterinária , Técnicas de Amplificação de Ácido Nucleico/métodos , Sensibilidade e Especificidade , Taenia/genética , Teníase/diagnóstico , Teníase/epidemiologia , Tibet/epidemiologia
19.
PLoS One ; 12(5): e0178349, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28542573

RESUMO

Bovine digital dermatitis (DD) is a severe infectious cause of lameness in cattle worldwide, with important economic and welfare consequences. There are three treponeme phylogroups (T. pedis, T. phagedenis, and T. medium) that are implicated in playing an important causative role in DD. This study was conducted to develop real-time PCR and loop-mediated isothermal amplification (LAMP) assays for the detection and differentiation of the three treponeme phylogroups associated with DD. The real-time PCR treponeme phylogroup assays targeted the 16S-23S rDNA intergenic space (ITS) for T. pedis and T. phagedenis, and the flagellin gene (flaB2) for T. medium. The 3 treponeme phylogroup LAMP assays targeted the flagellin gene (flaB2) and the 16S rRNA was targeted for the Treponeme ssp. LAMP assay. The real-time PCR and LAMP assays correctly detected the target sequence of all control strains examined, and no cross-reactions were observed, representing 100% specificity. The limit of detection for each of the three treponeme phylogroup real-time PCR and LAMP assays was ≤ 70 fg/µl. The detection limit for the Treponema spp. LAMP assay ranged from 7-690 fg/µl depending on phylogroup. Treponemes were isolated from 40 DD lesion biopsies using an immunomagnetic separation culture method. The treponeme isolation samples were then subjected to the real-time PCR and LAMP assays for analysis. The treponeme phylogroup real-time PCR and LAMP assay results had 100% agreement, matching on all isolation samples. These results indicate that the developed assays are a sensitive and specific test for the detection and differentiation of the three main treponeme phylogroups implicated in DD.


Assuntos
Doenças dos Bovinos/diagnóstico , Dermatite Digital/diagnóstico , Técnicas de Amplificação de Ácido Nucleico/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Treponema/genética , Infecções por Treponema/veterinária , Animais , Bovinos , Doenças dos Bovinos/microbiologia , Dermatite Digital/microbiologia , Humanos , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico/veterinária , Filogenia , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Sensibilidade e Especificidade , Infecções por Treponema/diagnóstico , Infecções por Treponema/microbiologia
20.
J Vet Diagn Invest ; 29(2): 176-180, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28061549

RESUMO

Dogs with a 4-bp deletion in the MDR1 (or ABCB1) gene show intolerance to certain drugs routinely used in veterinary medicine, such as ivermectin, vincristine, and doxorubicin. The mutation leads to a dysfunctional P-glycoprotein drug transporter, which results in drug accumulation in the brain and severe neurotoxicity. A rapid and accurate in-house test to determine the genotype of patients in cases of acute neurotoxic signs or in tumor patients is desirable. We describe a cost-effective detection method with simple technical equipment for veterinary practice. Two allele-specific methods are presented, which allow discrimination of all genotypes, require little hands-on time, and show the results within ~1 h after DNA sampling. DNA from buccal swabs of 115 dogs with known genotype (no mutation, n = 54; heterozygous for the mutation, n = 37; homozygous for the mutation, n = 24) was extracted either by using a column-based extraction kit or by heating swabs in a simple NaOH-Tris buffer. Amplification was performed either by allele-specific fast polymerase chain reaction or by allele-specific loop-mediated isothermal amplification (LAMP). Analysis was done either on agarose gels, by simple endpoint visualization using ultraviolet light, or by measuring the increase of fluorescence and time to threshold crossing. Commercial master mixes reduced the preparation time and minimized sources of error in both methods. Both methods allowed the discrimination of all 3 genotypes, and the results of the new methods matched the results of the previous genotyping. The presented methods could be used for fast individual MDR1/ ABCB1 genotyping with less equipment than existing methods.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Genes MDR/genética , Animais , Análise Mutacional de DNA/veterinária , Primers do DNA , Cães , Técnicas de Amplificação de Ácido Nucleico/veterinária , Reação em Cadeia da Polimerase/veterinária , Deleção de Sequência
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