RESUMEN
Knowledge of Mycobacterium avium subsp. paratuberculosis (MAP) herd infection status is important to plan appropriate control and prevention strategies for Paratuberculosis (PTB); however, in Uganda MAP infection status of most herds is unknown. This study aimed at determining the MAP infection status of cattle herds and the associated risk factors for MAP infection in six western districts of Uganda. The survey covered a total of 93 herds where faecal and blood samples were collected from 1814 cattle. A Recombinase Polymerase Amplification (RPA) and an antibody-based (ELISA) assays were used to test for the presence of MAP DNA in faeces and MAP antibodies in serum, respectively. The apparent cow-level prevalence of MAP infection was 3.2 and 2.7% using ELISA and RPA respectively and the true cow-level prevalence using ELISA and RPA was 4.9 and 3% respectively. A herd-level prevalence of 43% (ELISA) and 40.8% (RPA) and a within-herd prevalence of 3.8 ± 2.1% based on ELISA were obtained. Among the risk factors investigated, long dry spells were significantly associated with high MAP infection (p < 0.05). These results indicate that MAP is actively present in most areas where surveillance was carried out. This poses a serious threat to the livestock industry and potentially to public health as MAP is highly suspected to play a role in the pathogenesis of several diseases in humans. Other areas of the country are to be surveyed as well in order to establish full data on MAP infection status to enable interventions for the control and prevention of the disease.
Asunto(s)
Enfermedades de los Bovinos , Mycobacterium avium subsp. paratuberculosis , Paratuberculosis , Femenino , Humanos , Bovinos , Animales , Paratuberculosis/epidemiología , Paratuberculosis/microbiología , Uganda/epidemiología , Enfermedades de los Bovinos/epidemiología , Enfermedades de los Bovinos/microbiología , Ensayo de Inmunoadsorción Enzimática/veterinaria , Heces/microbiología , Prevalencia , Industria LecheraRESUMEN
Vaccinia virus (VACV) belongs to the genus Orthopoxvirus of the family Poxviridae. There are four different forms of infectious virus particles: intracellular mature virus (IMV), intracellular en-veloped virus (IEV), cell-associated enveloped virus (CEV) and extracellular enveloped virus (EEV). The F13 protein occupies the inner side of the CEV- and EEV-membranes and the outer side of the IEV-membranes. It plays an important role in wrapping progress and EEV production. We constructed a human single-chain fragment variable (scFv) library with a diversity of ≥4 × 108 independent colonies using peripheral blood from four vaccinated donors. One anti-F13 scFv was isolated and characterised after three rounds of panning. In Western blotting assays, the scFv 3E2 reacted with the recombinant F13VACV protein with a reduction of binding under denatured and reduced conditions. Two antigenic binding sites (139-GSIHTIKTLGVYSDY-153 and 169-AFNSAKNSWLNL-188) of scFv 3E2 were mapped using a cellulose membrane encompassing 372 15-mere peptides with 12 overlaps covering the whole F13 protein. No neutralisation capa-bilities were observed either in the presence or absence of complement. In conclusion, the con-struction of recombinant immunoglobulin libraries is a promising strategy to isolate specific scFvs to enable the study of the host-pathogen interaction.
Asunto(s)
Anticuerpos Antivirales/inmunología , Anticuerpos de Cadena Única/inmunología , Virus Vaccinia/inmunología , Secuencia de Aminoácidos , Anticuerpos Antivirales/química , Anticuerpos Antivirales/genética , Mapeo Epitopo , Biblioteca de Genes , Humanos , Pruebas de Neutralización , Anticuerpos de Cadena Única/química , Anticuerpos de Cadena Única/genética , Virus Vaccinia/química , Virus Vaccinia/genéticaRESUMEN
A panel of potent neutralizing antibodies are protective against orthopoxvirus (OPXV) infections. For the development of OPXV-specific recombinant human single-chain antibodies (scFvs), the IgG repertoire of four vaccinated donors was amplified from peripheral B-lymphocytes. The resulting library consisted of ≥4 × 108 independent colonies. The immuno-screening against vaccinia virus (VACV) Elstree revealed a predominant selection of scFv clones specifically binding to the D8 protein. The scFv-1.2.2.H9 was engineered into larger human scFv-Fc-1.2.2.H9 and IgG1-1.2.2.H9 formats to improve the binding affinity and to add effector functions within the human immune response. Similar binding kinetics were calculated for scFv-1.2.2.H9 and scFv-Fc-1.2.2.H9 (1.61 nM and 7.685 nM, respectively), whereas, for IgG1-1.2.2.H9, the Michaelis-Menten kinetics revealed an increased affinity of 43.8 pM. None of the purified recombinant 1.2.2.H9 formats were able to neutralize VACV Elstree in vitro. After addition of 1% human complement, the neutralization of ≥50% of VACV Elstree was achieved with 0.0776 µM scFv-Fc-1.2.2.H9 and 0.01324 µM IgG1-1.2.2.H9, respectively. In an in vivo passive immunization NMRI mouse model, 100 µg purified scFv-1.2.2.H9 and the IgG1-1.2.2.H9 partially protected against the challenge with 4 LD50 VACV Munich 1, as 3/6 mice survived. In contrast, in the scFv-Fc-1.2.2.H9 group, only one mouse survived the challenge.
RESUMEN
The stability of canine urine samples is essential when the samples cannot be analyzed immediately. The objective of this study was to investigate the stability of canine urine samples at room temperature and under refrigerated conditions. Samples from 20 dogs were collected, divided, and stored at 4°C and 20°C. The samples were examined up to 48 h after collection for specific gravity, pH, protein, bilirubin, glucose, ketones, and sediment and at 4 h and 24 h for bacterial growth. Specific gravity and all chemistry parameters were stable for a minimum of 48 h in 90% of samples. The sediment was stable, apart from crystals. The bacterial growth of 3 bacterial species tested in vitro, as well as the clinical samples, was mostly constant over 24 h at the refrigerated temperature. In urine samples stored at room temperature, the total number of aerobic growing bacteria was increasing. The results of our study showed that routinely measured parameters were stable in unpreserved urine for a minimum of 4 h and up to 48 h in most cases. If it is not possible to culture urine immediately, it is recommended that urine samples be stored at 4°C for a period of up to 24 h.
La stabilité des échantillons d'urine canins est essentielle lorsque les échantillons ne peuvent être analysés immédiatement. L'objectif de la présente étude était d'examiner la stabilité d'échantillons d'urine canins à température ambiante et réfrigérés. Des échantillons provenant de 20 chiens furent prélevés, divisés et entreposés à 4 °C et 20 °C. Les échantillons furent examinés jusqu'à 48 h après le prélèvement pour la gravité spécifique, le pH, les protéines, la bilirubine, le glucose, les cétones et le sédiment, et à 4 h et 24 h pour la croissance bactérienne. La gravité spécifique et tous les paramètres chimiques étaient stables pour un minimum de 48 h dans 90 % des échantillons. Le sédiment était stable, sauf pour les cristaux. La croissance bactérienne de trois espèces bactériennes testée in vitro, ainsi que dans les échantillons cliniques, était généralement constante sur une période de 24 h à la température de réfrigération. Dans les échantillons d'urine entreposés à la température ambiante, le nombre total de bactérie aérobie augmentait. Les résultats de notre étude démontrent que les paramètres mesurés de routine sont stables dans de l'urine sans agent de préservation pour un minimum de 4 h et jusqu'à 48 h dans la majorité des cas. S'il n'est pas possible de mettre l'urine en culture immédiatement, il est recommandé que les échantillons d'urine soient entreposés à 4 °C pour une période allant jusqu'à 24 h.(Traduit par Docteur Serge Messier).
Asunto(s)
Perros/orina , Manejo de Especímenes , Animales , Femenino , Masculino , Temperatura , Urinálisis , Orina/microbiologíaRESUMEN
Buffalopox virus (BPXV) is the cause of buffalopox, which was recognized by the FAO/WHO Joint Expert Committee on Zoonosis as an important zoonotic disease. Buffalopox was first described in India, later in other countries, and has become an emerging contagious viral zoonotic disease infecting milkers with high morbidity among affected domestic buffalo and cattle. BPXV is a member of the genus Orthopoxvirus and a close variant of the vaccinia virus (VACV). Recent genome data show that BPXV shares a most recent common ancestor of VACV Lister strain, which had been used for inoculating buffalo calves to produce a Smallpox vaccine. Over time, VACV evolved into BPXV by establishing itself in buffaloes to be increasingly pathogenic to this host and to make infections in cattle and humans. Together with the current pandemic of SARS-COV2/COVID 19, BPXV infections illustrate how vulnerable the human population is to the emergence and re-emergence of viral pathogens from unsuspected sources. In view that majority of the world population are not vaccinated against smallpox and are most vulnerable in the event of its re-emergence, reviewing and understanding the biology of vaccinia-like viruses are necessary for developing a new generation of safer smallpox vaccines in the smallpox-free world.
RESUMEN
BACKGROUND: Mycobacteria of the Mycobacterium avium complex (MAC) pose a significant risk to zoological collections. Mycobacterium avium subspecies paratuberculosis (MAP) is a member of MAC and the causative agent of Johne's disease. Despite many reports in animals kept in zoological gardens, systemic surveillance has rarely been reported. METHODS: In this study, archived serum samples collected from animal species at the Wilhelma Zoological and Botanical Gardens in Stuttgart, Germany, were screened for the presence of antibodies against MAC and MAP. In addition, molecular investigations were performed on necropsy, fecal, and environmental samples. RESULTS: In total, 30/381 serum samples of various mammalian species were positive for MAC antibodies in ELISA, while one sample of a reticulated giraffe (Giraffa camelopardalis reticulata) was positive in MAP-specific ELISA. Samples from many species were positive in pan-Mycobacterium real-time PCR (40/43 fecal samples, 27/43 environmental samples, and 31/90 necropsy samples). Surprisingly, no sample was positive in the MAP-specific molecular assays. However, two environmental samples from primate enclosures were positive in Mycobacterium avium subspecies hominissuis (MAH)-specific real-time PCR. CONCLUSIONS: The results reveal serological indications of MAC infections in the zoological collection. However, the presence of a MAP-contaminated environment by a high-shedding individual animal or MAP-infected population is unlikely.
RESUMEN
The Mycobacterium avium subspecies paratuberculosis (MAP) is the causative agent of paratuberculosis, which is an economically important disease of ruminants. The zoonotic role of MAP in Crohn's disease and, to a lesser extent, in ulcerative colitis, the two major forms of idiopathic inflammatory bowel disease (IIBD), has been debated for decades and evidence continues to mount in support of that hypothesis. The aim of this paper is to present a review of the current information on paratuberculosis in animals and the two major forms of IIBD in Africa. The occurrence, epidemiology, economic significance and "control of MAP and its involvement IIBD in Africa" are discussed. Although the occurrence of MAP is worldwide and has been documented in several African countries, the epidemiology and socioeconomic impacts remain undetermined and limited research information is available from the continent. At present, there are still significant knowledge gaps in all these areas as far as Africa is concerned. Due to the limited research on paratuberculosis in Africa, in spite of growing global concerns, it may rightfully be considered a neglected tropical disease with a potentially zoonotic role.
RESUMEN
Development of novel point of care diagnostic methods in order to help in implementing disease control program and identifying the causative agent of an outbreak is crucial. Classical diagnostic techniques, e.g., real-time polymerase chain reaction (PCR), rely on the presence of the nucleic acid sequence of the target in GenBank. In the case of an emerging new strain of a known or novel pathogen, false-negative results will be recorded by PCR. On the other hand, next-generation sequencing technologies allow rapid whole genome sequencing without previous knowledge of the target. One of these methods is the Oxford Nanopore sequencing technique, which utilizes a portable device named MinION and has a short run time. In this protocol, we describe the development of a novel nanopore sequencing protocol by combining random isothermal amplification technology and nanopore sequencing. The established protocol is rapid (<7 h) and sensitive as less than 4% of the sequenced RNA belonged to the target virus, Zika. Interestingly, we have established an offline BLAST search for the data analysis that facilitates the use of the whole protocol at remote settings without the need of an Internet connection.
Asunto(s)
Secuenciación de Nanoporos/métodos , Reacción en Cadena de la Polimerasa/métodos , Infección por el Virus Zika/diagnóstico , Virus Zika/genética , ADN Complementario/análisis , ADN Complementario/biosíntesis , ADN Complementario/aislamiento & purificación , Brotes de Enfermedades , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Unidades Móviles de Salud , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificación de Ácido Nucleico/métodos , Pruebas en el Punto de Atención , ARN Viral/genética , ARN Viral/aislamiento & purificación , Juego de Reactivos para Diagnóstico , Análisis de Secuencia de ADN/métodos , Flujo de Trabajo , Virus Zika/aislamiento & purificación , Infección por el Virus Zika/virologíaRESUMEN
Detection of animal species in meat product is crucial to prevent adulterated and unnecessary contamination during processing. Gold standard is the real-time PCR assays, which can be conducted at highly equipped laboratories. Toward the development of point-of-need test, two rapid molecular assays based on recombinase polymerase amplification (RPA) for the detection of pork and horse DNA were established. Target genes are the porcine mitochondrial ND2 and equine ATP 6-8 genes. The pork and horse_RPA assays detected 16 and one DNA molecules/µl in eleven to six minutes, respectively. The myoglobin in the meat did not influence the assays performances, while the presence of high background-DNA induced a one log decrease in the sensitivity. Both assays are highly specific and identify down to 0.1% of their target DNA in meat mixtures. Both RPA assays could be used on-site as a rapid and mobile detection system to determine contamination of meat products.
Asunto(s)
ADN/análisis , Caballos/genética , Carne/análisis , Técnicas de Amplificación de Ácido Nucleico/métodos , Porcinos/genética , Animales , ADN/metabolismo , Mitocondrias/metabolismo , ATPasas de Translocación de Protón Mitocondriales/genética , NADH Deshidrogenasa/genética , Sistemas de Atención de Punto , Recombinasas/metabolismoRESUMEN
Mycobacterium avium subspecies paratuberculosis (MAP) is the causative agent of paratuberculosis (ParaTB or Johne's disease), a contagious, chronic and typically fatal enteric disease of domestic and non-domestic ruminants. Clinically affected animals present wasting and emaciation. However, MAP can also infect non-ruminant animal species with less specific signs. Zoological gardens harbor various populations of diverse animal species, which are managed on limited space at higher than natural densities. Hence, they are predisposed to endemic trans-species pathogen distribution. Information about the incidence and prevalence of MAP infections in zoological gardens and the resulting potential threat to exotic and endangered species are rare. Due to unclear pathogenesis, chronicity of disease as well as the unknown cross-species accuracy of diagnostic tests, diagnosis and surveillance of MAP and ParaTB is challenging. Differentiation between uninfected shedders of ingested bacteria; subclinically infected individuals; and preclinically diseased animals, which may subsequently develop clinical signs after long incubation periods, is crucial for the interpretation of positive test results in animals and the resulting consequences in their management. This review summarizes published data from the current literature on occurrence of MAP infection and disease in susceptible and affected zoo animal species as well as the applied diagnostic methods and measures. Clinical signs indicative for ParaTB, pathological findings and reports on detection, transmission and epidemiology in zoo animals are included. Furthermore, case reports were re-evaluated for incorporation into accepted consistent terminologies and case definitions.
RESUMEN
Feeding pasteurized milk to suckling calves is a popular practice used increasingly on dairy farms. Waste milk is frequently fed to calves because of its high nutritional value and economic benefits compared to milk replacement products. However, one of the disadvantages of feeding waste milk is the potential for exposure to a high number of bacterial contaminants, which may lead to serious illnesses or infections in calves. One of these contaminants is Mycobacterium avium ssp. paratuberculosis (MAP), the causative agent of Johne's disease (paratuberculosis). The transmission and distribution of paratuberculosis in dairy herds occurs mostly through the feeding newborn calves with contaminated colostrum or milk, because this age group is believed to be most susceptible to infection. To reduce the risk of transmission of pathogens, on-farm pasteurization of milk has become increasingly popular. In this study, we analyzed the efficacy of a new commercial high-temperature, short-time pasteurizer (73.5°C for 20 to 25 s) in terms of MAP inactivation under experimental on-farm conditions. The pasteurizer uses a newly developed steam-heating technique, allowing for the pasteurization of the transition milk without clumping. In 3 independent trials, we spiked fresh raw milk samples to a level of 107 or 104 viable MAP cells/mL before pasteurization. We examined the thermal inactivation and viability of MAP using culture and a D29 bacteriophage-based assay. To verify the identity and number of MAP cells, we also performed PCR assays. Pasteurization of the inoculated milk (107 and 104 MAP cells/mL) resulted in a remarkable reduction in viable MAP cells. The mean inactivation rate of MAP ranged from 0.82 to 2.65 log10 plaque-forming units/mL, depending on the initial MAP amount inoculated and the addition of conservative agents to the pasteurized milk. Nevertheless, approximately 103 MAP cells/mL remained viable and could be transferred to calves after high-temperature, short-time pasteurization of milk.
Asunto(s)
Alimentación Animal , Enfermedades de los Bovinos/prevención & control , Leche , Mycobacterium avium subsp. paratuberculosis , Paratuberculosis/prevención & control , Pasteurización , Animales , Bovinos , Enfermedades de los Bovinos/microbiología , Calostro/microbiología , Industria Lechera , Femenino , Calor , Leche/microbiología , Mycobacterium avium subsp. paratuberculosis/fisiología , Pasteurización/métodos , Reacción en Cadena de la Polimerasa , EmbarazoRESUMEN
The vaccinia virus (VACV) A27 protein and its homologs, which are found in a large number of members of the genus Orthopoxvirus (OPXV), are targets of viral neutralization by host antibodies. We have mapped six binding sites (epitopes #1A: aa 32-39, #1B: aa 28-33, #1C: aa 26-31, #1D: 28-34, #4: aa 9-14, and #5: aa 68-71) of A27 specific monoclonal antibodies (mAbs) using peptide arrays. MAbs recognizing epitopes #1A-D and #4 neutralized VACV Elstree in a complement dependent way (50% plaque-reduction: 12.5-200 µg/mL). Fusion of VACV at low pH was blocked through inhibition of epitope #1A. To determine the sequence variability of the six antigenic sites, 391 sequences of A27 protein homologs available were compared. Epitopes #4 and #5 were conserved among most of the OPXVs, while the sequential epitope complex #1A-D was more variable and, therefore, responsible for species-specific epitope characteristics. The accurate and reliable mapping of defined epitopes on immuno-protective proteins such as the A27 of VACV enables phylogenetic studies and insights into OPXV evolution as well as to pave the way to the development of safer vaccines and chemical or biological antivirals.
Asunto(s)
Antígenos Virales/genética , Epítopos/inmunología , Proteínas de la Membrana/genética , Virus Vaccinia/genética , Vaccinia/virología , Proteínas Virales de Fusión/genética , Animales , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Antígenos Virales/inmunología , Sitios de Unión de Anticuerpos , Reacciones Cruzadas , Mapeo Epitopo , Epítopos/genética , Concentración de Iones de Hidrógeno , Proteínas de la Membrana/inmunología , Mutación , Pruebas de Neutralización , Filogenia , Especificidad de la Especie , Virus Vaccinia/inmunología , Proteínas Virales de Fusión/inmunologíaRESUMEN
In this study, a rapid method for the detection of Central and West Africa clades of Monkeypox virus (MPXV) using recombinase polymerase amplification (RPA) assay targeting the G2R gene was developed. MPXV, an Orthopoxvirus, is a zoonotic dsDNA virus, which is listed as a biothreat agent. RPA was operated at a single constant temperature of 42°C and produced results within 3 to 10 minutes. The MPXV-RPA-assay was highly sensitive with a limit of detection of 16 DNA molecules/µl. The clinical performance of the MPXV-RPA-assay was tested using 47 sera and whole blood samples from humans collected during the recent MPXV outbreak in Nigeria as well as 48 plasma samples from monkeys some of which were experimentally infected with MPXV. The specificity of the MPXV-RPA-assay was 100% (50/50), while the sensitivity was 95% (43/45). This new MPXV-RPA-assay is fast and can be easily utilised at low resource settings using a solar powered mobile suitcase laboratory.
Asunto(s)
Monkeypox virus/aislamiento & purificación , Mpox/diagnóstico , Técnicas de Amplificación de Ácido Nucleico/métodos , Recombinasas , Animales , ADN Viral/genética , Humanos , Unidades Móviles de Salud , Mpox/virología , Monkeypox virus/genética , Técnicas de Amplificación de Ácido Nucleico/normas , Sensibilidad y Especificidad , Factores de Tiempo , Proteínas Virales/genéticaRESUMEN
The rapid identification of Mycobacterium avium subspecies paratuberculosis (MAP) infected animals within the herd is essential for preventing the spread of the disease as well as avoiding human exposure. Although culture is seen as the gold standard, there are various molecular assays available i.e., polymerase chain reaction (PCR) or isothermal amplification technique (recombinase polymerase amplification (RPA)) for the detection of MAP. The accuracy of the molecular assays is highly dependent on the DNA extraction method. In order to establish a rapid point of need system for the detection of MAP DNA from stool samples, we developed a rapid DNA extraction protocol (MAP DNA SpeedXtract) specified for use in combination with the RPA. The whole procedure from "sample in" to "result out" was conducted in a mobile suitcase laboratory. The DNA extraction is based on reverse purification by magnetic beads, which reduces the required technical demand. The MAP DNA SpeedXtract was performed within 25 min and only three pipetting steps were needed. The amplification and detection time were 20 min in RPA. The sensitivity and specificity of the developed protocol in comparison with the lab-based silica membrane column extraction and real-time PCR were 90.9% (n = 22) and 100% (n = 23), respectively. In conclusion, we established a rapid and reliable protocol for the extraction and detection of MAP DNA. All reagents are cold chain independent. The entire setup is ideal for point of need identification of MAP infected cases.
RESUMEN
Zika virus (ZIKV) is a mosquito-borne flavivirus. Homologous proteins of different flaviviruses display high degrees of sequence identity, especially within subgroups. This leads to extensive immunological cross-reactivity and corresponding problems for developing a ZIKV-specific serological assay. In this study, peptide microarrays were employed to identify individual ZIKV antibody targets with promise in differential diagnosis. A total of 1643 overlapping oligopeptides were synthesized and printed onto glass slides. Together, they encompass the full amino acid sequences of ZIKV proteomes of African, Brazilian, USA, and French Polynesian origins. The resulting ZIKV scanning microarray chips were used to screen three pools of sera from recent Zika outbreaks in Senegal and Cape Verde, in Brazil, and from overseas travelers returning to the EU. Together with a mixed pool of well characterized, archived sera of patients suffering from infections by dengue, yellow fever, tick-borne encephalitis, and West Nile viruses, a total of 42 sera went into the study. Sixty-eight antibody target regions were identified. Most of which were hitherto unknown. Alignments and sequence comparisons revealed 13 of which could be classified as bona fide ZIKV-specific. These identified antibody target regions constitute a founding set of analytical tools for serological discrimination of ZIKV from other flaviviruses.
Asunto(s)
Anticuerpos Antivirales/química , Antígenos Virales/metabolismo , Péptidos/inmunología , Infección por el Virus Zika/diagnóstico , Virus Zika/clasificación , Brasil , Cabo Verde , Reacciones Cruzadas , Diagnóstico Diferencial , Brotes de Enfermedades , Flavivirus/clasificación , Flavivirus/inmunología , Flavivirus/aislamiento & purificación , Humanos , Análisis por Matrices de Proteínas , Senegal , Especificidad de la Especie , Virus Zika/inmunología , Virus Zika/aislamiento & purificación , Infección por el Virus Zika/inmunologíaRESUMEN
Foot-and-mouth disease virus (FMDV), belonging to the family of Picornaviridae, infects mostly cloven-hoofed animals and leads to huge economic losses. Since there is no cross-protection between the seven serotypes of FMDV, effective vaccination relies on the knowledge of the serotype causing the outbreak. The most common methods of serotyping are antigen ELISAs and amplification-based sequencing. Serotype-specific PCR methods exist but have limitations due to emerging mutants within serotypes. Sequencing is a promising technology, but currently suffers from cumbersome procedures and long turnaround times. In this study, we have established a novel sequencing protocol relying on nanopore sequencing and offline BLAST search. The procedure was completed in 5 h including RNA extraction, reverse transcription, second-strand synthesis, barcoding, sequencing and data analysis, which did not require a bioinformatician. In total, 12,193 sequence files were obtained. The offline BLAST search to the P1 region revealed the most successful categorization of the seven FMDV serotypes (specificity: 98.3%) over whole genome (24.8%), P2 (23.6%) and P3 (21.4%). In conclusion, our protocol enables rapid and reliable FMDV serotyping. The whole procedure can be conducted with a mobile suitcase laboratory, which is easy to use at the point of need in endemic countries.
Asunto(s)
Pruebas Diagnósticas de Rutina/veterinaria , Virus de la Fiebre Aftosa/aislamiento & purificación , Fiebre Aftosa/virología , Técnicas de Diagnóstico Molecular/veterinaria , Nanoporos , Serotipificación/métodos , Animales , Línea Celular , Virus de la Fiebre Aftosa/clasificación , Virus de la Fiebre Aftosa/genética , ARN Viral/genética , Sensibilidad y Especificidad , Serogrupo , Factores de TiempoRESUMEN
BACKGROUND: Outbreaks of fever of unknown origin start with nonspecific symptoms and case definition is only slowly developed and adapted, therefore, identifying the causative agent is crucial to ensure suitable treatment and control measures. As an alternative method for Polymerase Chain Reaction in molecular diagnostics diagnostic, metagenomics can be applied to identify the pathogen responsible for the outbreak through sequencing all nucleic acids present in a sample extract. Sequencing data obtained can identify new or variants of known agents. OBJECTIVES: To develop a rapid and field applicable protocol to allow the identification of the causative agent of an outbreak. STUDY DESIGN: We explored a sequencing protocol relying on multiple displacement isothermal amplification and nanopore sequencing in order to allow the identification of the causative agent in a sample. To develop the procedure, a mock sample consisting of supernatant from Zika virus tissue culture was used. RESULTS: The procedure took under seven hours including sample preparation and data analysis using an offline BLAST search. In total, 63,678 sequence files covering around 10,000 bases were extracted. BLAST search revealed the presence of Zika virus. CONCLUSION: In conclusion, the protocol has potential for point of need sequencing to identify RNA viruses. The whole procedure was operated in a suitcase laboratory. However, the procedure is cooling chain dependent and the cost per sequencing run is still high.
Asunto(s)
Brotes de Enfermedades , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Nanoporos , Técnicas de Amplificación de Ácido Nucleico/métodos , Temperatura , Infección por el Virus Zika/diagnóstico , Biblioteca de Genes , Humanos , Metagenómica/métodos , Virus ARN/genética , Virus ARN/aislamiento & purificación , Manejo de Especímenes , Virus Zika/genética , Virus Zika/aislamiento & purificaciónAsunto(s)
Transmisión de Enfermedad Infecciosa , Ectima/diagnóstico , Ectima/veterinaria , Exposición Profesional , Virus del Orf/aislamiento & purificación , Enfermedades de las Ovejas/diagnóstico , Enfermedades de las Ovejas/patología , Anciano , Animales , Biopsia , Ectima/patología , Antebrazo/patología , Humanos , Masculino , Ovinos , Enfermedades de las Ovejas/transmisión , Piel/patología , Zoonosis/diagnóstico , Zoonosis/patología , Zoonosis/transmisiónRESUMEN
Rickettsioses are zoonotic vector-transmitted bacterial infections leading to flu-like symptoms and can progress to severe illness in humans. The gold standard for diagnosis of rickettsial infections is the indirect immunofluorescence assay, a serological method which is not suitable for pathogen identification during the acute phase of the disease. Therefore, several real-time PCR assays were developed. These assays are very sensitive, but require high-equipped laboratories and well-trained personnel. Hence, in this study, a rapid point-of-need detection method was developed to detect all Rickettsia species. The 23S and 16S rRNA genes were targeted to develop a recombinase polymerase amplification (RPA) assay. Both 23S and 16S_RPA assays required between seven to ten minutes to amplify and detect one or ten DNA molecules/reaction, respectively. The 16S_RPA assay detected all tested species, whereas the 23S_RPA assay identified only species of the spotted fever and transitional rickettsial groups. All results were compared with real-time PCR assays directed against the same rickettsial genes. The RPA assays are easy to handle and produced quicker results in comparison to real-time PCRs. Both RPA assays were implemented in a mobile suitcase laboratory to ease the use in rural areas. This method can help to provide rapid management of rickettsial infections.
Asunto(s)
Técnicas de Amplificación de Ácido Nucleico , ARN Ribosómico 16S/genética , ARN Ribosómico 23S/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Rickettsia/genética , Humanos , Rickettsia/aislamiento & purificaciónRESUMEN
BACKGROUND: Due to a sporadic occurrence of Mycobacterium avium subsp. paratuberculosis (MAP) in non-human primates (NHP), the susceptibility of different NHP to MAP should be investigated. METHODS: Fecal and tissue samples (ileum, ileocecal lymph node, bone marrow) of 20 animals (seven species) were analyzed by IS900-based PCRs and sequenced. Samples of MAP PCR positive NHP were further cultivated. RESULTS: MAP DNA was detectable in two animals; the ileum of a cottontop tamarin and the bone marrow of a common marmoset. Cultivation of MAP failed. Sequence analysis revealed 100% homology to the MAP-K10 sequence. Pathohistological examinations offered no direct correlation to a MAP infection. CONCLUSIONS: MAP was detected for the first time in a common marmoset. But as both NHP suffered from other diseases, an asymptomatic infection with MAP was assumed. The detection of MAP in the bone marrow might play a role in establishing latent paratuberculosis, as known from tuberculosis.