scholarly journals CLINICAL AND LABORATORY DIAGNOSES OF NEWCASTLE AND INFECTIOUS BURSAL DISEASES OF CHICKENS

2012 ◽  
Vol 8 (2) ◽  
pp. 131-140 ◽  
Author(s):  
AKM Rakibul Hasan ◽  
MH Ali ◽  
MP Siddique ◽  
MM Rahman ◽  
MA Islam
Keyword(s):  
Newcastle Disease ◽  
Serological Test ◽  
Clinical Signs ◽  
Virus Detection ◽  
Clinical History ◽  
Rapid Identification ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Serological Tests ◽  
Field Samples

A comparative study was conducted to compare the disease diagnostic parameters (clinical signs & postmortem findings, organism isolation, serological test and molecular method) used to diagnose the Newcastle disease (ND) and infectious bursal disease (IBD) during the period from March 2009 to February 2010 in the laboratory of the Department of Microbiology and Hygiene, Bangladesh Agricultural University (BAU), Mymensingh. A total of 187 sick and dead chickens (63 broilers and 124 layers) of different ages (1 week to >15 weeks) were collected from 12 selective poultry farms (4 broilers and 8 layers) of Mymensingh and Gazipur districts. Clinically, 7 (14.89%) of 63 affected broiler and 27 (30.68%) of 124 affected layer chickens were diagnosed as Newcastle disease (ND) whereas, 11 (23.4%) of 63 affected broiler and 6 (4.82%) of the 124 affected layer birds were diagnosed as IBD on the basis of clinical history, clinical signs and postmortem findings. Virus isolation from field samples was performed by inoculating each suspected sample into 10-day-old chicken embryos. Out of 34 ND suspected field samples, 26 (5 broilers and 21 layers) were positive for NDV isolation and 11 (8 broilers and 3 layers) of 17 IBD suspected field samples, were positive for IBDV isolation. For confirmatory diagnosis, virus detection was confirmed by serological tests (HI and AGID) and RT-PCR assay. Out of 34 clinically diagnosed ND field samples, 20 (5 broiler & 15 layer) were positive by RT-PCR assay and 15 (10 broiler & 5 layer) of 17 IBD suspected field samples, were positive by both AGIDT and RT-PCR assay. Of the 26 HA positive NDV suspected AF, 19 (4 broilers and 15 layers) were positive by both HI & RT-PCR assay whereas, 10 (7 broilers and 3 layers) of 11 IBDV isolation positive tissue suspension were positive by both AGIDT & RT-PCR assay in the laboratory. Therefore, it may be concluded that serological (HI & AGIDT) and molecular (RT-PCR) techniques which allow rapid identification of most of samples are the reliable, sensitive, specific and more accurate methods to detect the viruses for the confirmatory diagnosis of diseases.DOI = http://dx.doi.org/10.3329/bjvm.v8i2.11196 Bangl. J. Vet. Med. (2010). 8 (2) : 131-140 

scholarly journals Diagnosis of COVID-19 by Serology in Admitted Patients with Negative RT-PCR Assay

2021 ◽  
Author(s):  
Mitra Rezaei ◽  
Parvaneh Baghaei ◽  
Makan Sadr ◽  
Afshin Moniri ◽  
Abdolreza Babamahmoodi ◽  
...  
Keyword(s):  
Diagnostic Yield ◽  
Serological Test ◽  
False Negative ◽  
Diagnostic Methods ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Serological Tests ◽  
Negative Results ◽  
False Negative Results ◽  
Polymerase Chain

Considering the increasing prevalence and burden of coronavirus disease 2019 (COVID-19) disease and false-negative results in routine reverse transcription-polymerase chain reaction (RT-PCR) tests, additional diagnostic methods are needed to diagnose active cases of this disease. This prospective study was conducted on patients, in whom clinical and radiological symptoms/signs were in favor of COVID-19 while their first PCR test was negative. Later on, a second RT-PCR was performed and serological evaluation was carried out and results were compared with each other. Out of 707 patients who had been referred to the hospital and were clinically and radiologically suspicious of disease, 137 patients with negative RT-PCR tests entered the study. RT-PCR assay became positive for the second time in 45 (32.8%). Anti-COVID-19 IgM and IgG antibodies were positive in 83 (60.6%) and 86 (62.8%) patients, respectively. Finally, it was determined that serological test was diagnostic in 73% of patients and the diagnostic yield of serology was significantly higher after the first week of illness (54.8% in the first week and 88% after that). Taking advantage of both serological tests and RT-PCR helps in diagnosing 83.9% of cases. Based on the present study, the serology may be useful as a complementary test and in parallel to RT-PCR assay for diagnosis of COVID-19 among admitted symptomatic cases.

scholarly journals Importance of serological testing in the convalescence phase in patients with pulmonary impairment due to COVID 19 - a health care workers analysis

2021 ◽  
Author(s):  
José Rodrigues Pereira ◽  
Ilka Lopes Santoro ◽  
Maria Silvia Biagioni Santos ◽  
Andreia Padilha de Toledo ◽  
Greice Elen Copelli ◽  
...  
Keyword(s):  
Serological Test ◽  
Rt Pcr ◽  
Serological Tests ◽  
Care Workers ◽  
Pulmonary Impairment ◽  
Increased Sensitivity ◽  
Pulmonary Changes ◽  
The Subject ◽  
Convalescence Phase ◽  
The Ideal

1AbstractSince its discovery, more than 37 million people have been infected by SARS-CoV-2 with deaths around 1 million worldwide. The prevalence is not known because infected individuals may be asymptomatic. In addition, the use of specific diagnostic tests is not always conclusive, raising doubts about the etiology of the disease.The best diagnostic method and the ideal time of collection remains the subject of study. The gold standard for diagnosing COVID 19 is the RT PCR molecular test, usually using an oropharynx and nasopharynx swab. Its sensitivity is 70% and drops significantly after the second week of symptoms. Serological tests, in turn, have increased sensitivity after 14 days, and can contribute to the diagnosis when SARS-CoV-2 infection is suspected, even with negative RT PCR.Our study showed sensitivity and specificity of 100% of the serological test (ELISA method) for cases of viral pneumonia caused by the new coronavirus, suggesting that this test could assist in the diagnosis of pulmonary interstitial changes that have not yet been etiologically clarified. We found a greater immune response in men, regardless of the severity of symptoms. The greater the severity, the higher the levels of IgA and IgG, mainly found in patients with multilobar impairment and in need for oxygen. We concluded that the serological test collected around 30 days after the onset of symptoms is the best diagnostic tool in the convalescence phase, not only for epidemiological purposes, but also for the etiological clarification of pulmonary changes that have not yet been diagnosed.

scholarly journals Best Molecular Tools to Investigate Coronavirus Diversity in Mammals: A Comparison

Viruses ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1975
Author(s):  
Petra Drzewnioková ◽  
Francesca Festa ◽  
Valentina Panzarin ◽  
Davide Lelli ◽  
Ana Moreno ◽  
...  
Keyword(s):  
Literature Review ◽  
In Silico ◽  
Host Shift ◽  
Molecular Tools ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Field Samples ◽  
Low Sensitivity

Coronaviruses (CoVs) are widespread and highly diversified in wildlife and domestic mammals and can emerge as zoonotic or epizootic pathogens and consequently host shift from these reservoirs, highlighting the importance of veterinary surveillance. All genera can be found in mammals, with α and β showing the highest frequency and diversification. The aims of this study were to review the literature for features of CoV surveillance in animals, to test widely used molecular protocols, and to identify the most effective one in terms of spectrum and sensitivity. We combined a literature review with analyses in silico and in vitro using viral strains and archive field samples. We found that most protocols defined as pan-coronavirus are strongly biased towards α- and β-CoVs and show medium-low sensitivity. The best results were observed using our new protocol, showing LoD 100 PFU/mL for SARS-CoV-2, 50 TCID50/mL for CaCoV, 0.39 TCID50/mL for BoCoV, and 9 ± 1 log2 ×10−5 HA for IBV. The protocol successfully confirmed the positivity for a broad range of CoVs in 30/30 field samples. Our study points out that pan-CoV surveillance in mammals could be strongly improved in sensitivity and spectrum and propose the application of a new RT-PCR assay, which is able to detect CoVs from all four genera, with an optimal sensitivity for α-, β-, and γ-.

Establishment and evaluation of real-time PCR for West Nile virus detection

2009 ◽  
Vol 6 (1) ◽  
pp. 55-59 ◽  
Author(s):  
Shi Li-Jun ◽  
Lu Mao-Min ◽  
Li Gang ◽  
Li Cheng-Yao ◽  
Zhang Jin-Gang
Keyword(s):  
West Nile Virus ◽  
Real Time ◽  
Virus Detection ◽  
Rt Pcr ◽  
Pcr Assay ◽  
West Nile ◽  
Capsid Protein Gene ◽  
Specific Test ◽  
Intercalating Dye ◽  
Polymerase Chain

AbstractA rapid real-time polymerase chain reaction (RT-PCR) for detecting West Nile virus (WNV) was established. Primers were designed according to the sequence of the capsid protein gene of WNV by Primer Premier 5.0. In this way, an inexpensive assay using the intercalating dye SYBR Green I was developed and validated. The amplifying curve showed that this method could successfully amplify 102 copies/μl of the WNV gene, while reference to Japanese encephalitis virus (JEV) and blank control were all negative. Tenfold successive dilutions of positive WNV DNA were used to measure the sensitivity of RT-PCR. The assay system showed high reproducibility with coefficient of variation (CV) <2%. Thus the newly established RT-PCR assay was shown to be a rapid, sensitive and specific test for detecting WNV.

scholarly journals Real-Time Reverse Transcription-Polymerase Chain Reaction Detection of Newcastle Disease Virus Using Light upon Extension Fluorogenic Primers

2007 ◽  
Vol 19 (4) ◽  
pp. 400-404 ◽  
Author(s):  
Márta Antal ◽  
Tibor Farkas ◽  
Péter Germán ◽  
Sándor Belák ◽  
István Kiss
Keyword(s):  
Newcastle Disease Virus ◽  
Real Time ◽  
Disease Virus ◽  
Newcastle Disease ◽  
Plasmid Copy Number ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Plasmid Copy ◽  
Infectious Dose ◽  
Efficient Detection

A real-time reverse transcriptase (RT)-PCR assay, applying light upon extension (LUX) fluorogenic primers, was developed for rapid and efficient detection of Newcastle disease virus (NDV). The method, which targets the fusion (F) protein gene of the viral genome, gave positive signal with all NDV isolates tested (32/32), while negative results were obtained with heterologous pathogens (35/35), including 13 avian influenza virus isolates. The detection limit of the assay was approximately 10+1.2 egg infectious dose (EID)50/0.2 ml and 10+2.2 EID50/0.2 ml for virus suspensions and spiked chicken fecal samples, respectively. As expressed in plasmid copy number, the procedure has a sensitivity of approximately 20 copies of the plasmid harboring the target gene. Due to its high specificity, sensitivity, and relative simplicity, the LUX RT-PCR assay provides a novel, rapid, and practical tool for the detection of NDV.

Quantification of viable eggs of the potato cyst nematodes (Globodera spp.) using either trehalose or RNA-specific Real-Time PCR

Nematology ◽  
2014 ◽  
Vol 16 (10) ◽  
pp. 1219-1232 ◽  
Author(s):  
Johanna E. Beniers ◽  
Thomas H. Been ◽  
Odette Mendes ◽  
Marga P.E. van Gent-Pelzer ◽  
Theo A.J. van der Lee
Keyword(s):  
Real Time ◽  
Visual Inspection ◽  
Membrane Integrity ◽  
Globodera Pallida ◽  
Potato Cyst Nematodes ◽  
Original Sample ◽  
Rt Pcr ◽  
Cyst Nematodes ◽  
Pcr Assay ◽  
Field Samples

Two novel methods for the quantitative estimation of the number of viable eggs of the potato cyst nematodes (Globodera pallida and G. rostochiensis) were tested and compared with visual inspection. One is based on the loss of membrane integrity upon death and uses trehalose (a disaccharide) as a marker, the second test exploits the rapid degeneration of mRNA upon decease with a RNA-specific Real-Time Polymerase Chain Reaction (RT-PCR) assay. The viability of eggs in suspensions with different numbers of eggs was determined morphologically and was compared with both trehalose and elongation-factor-1-alpha (EF1α) mRNA measurements. The trehalose assay provided results that were close to those of the visual assessment using a microscope but only when samples contained low numbers of eggs. The lowest detectable value is 1.1 egg in the original sample and small differences in the number of viable eggs can be detected. Unfortunately, trehalose measurements reached a saturation limit at 1 cyst 10 μl−1; therefore, samples with nematode numbers above 262 eggs have to be diluted. The presence of dead cysts did not have a negative effect on the trehalose measurements. However, the use of egg suspensions instead of encysted eggs improved both the trehalose absorbance and the reliability of the measurements. When cysts were exposed to a treatment with allylisothiocyanate, the trehalose measurement detected the presence of more viable eggs than a hatching assay. The RT-PCR assay required a minimum of 30 eggs before detection occurred but can detect up to 8000 eggs in a 25 μl sample, which is an advantage when samples with high PCN infestations have to be processed. However, the confidence intervals (CI) of the RT-PCR assay are larger than those of the trehalose assay, which results in a high variation of single measurements. For example, at a density of 210 eggs in the original sample the 95% CI for the trehalose assay covers 191-228 eggs, and the 95% CI for the RT-PCR assay for G. pallida lies between 73 and 602 eggs and for G. rostochiensis between 59 and 745 eggs. Trials with field samples using both methods supported the laboratory tests. 95% of the field samples tested with the trehalose assay lie within the CI of the standard curve compared to 58% of the RT-PCR tested samples for G. pallida. The measurements of the field samples of G. pallida and G. rostochiensis populations using both methods resulted in larger numbers of viable eggs being detected compared to a hatching test. Neither of the investigated methods in their current state of development is optimal for use as a substitute for the visual inspection used in monitoring labs. The variance of the RT-PCR assay is too high if used for quantitative monitoring; the density range of eggs that can be detected using the trehalose assay is too small.

scholarly journals Molecular characterisation of Newcastle disease virus exotic isolate in East Java, Indonesia

2021 ◽  
Vol 24 (2) ◽  
pp. 191-199
Author(s):  
N. P. Kusumarahayu ◽  
N. Putri ◽  
R. Ernawati ◽  
J. Rahmahani ◽  
S. Suwarno ◽  
...  
Keyword(s):  
Newcastle Disease Virus ◽  
Disease Virus ◽  
Newcastle Disease ◽  
Clinical Signs ◽  
Rt Pcr ◽  
Genetic Characteristics ◽  
Basic Work ◽  
Specific Pathogen ◽  
Baseline Information ◽  
Native Chickens

Newcastle disease virus (NDV) is ssRNA paramyxovirus causing clinical signs, varying from subclinical infections to 100% mortality in infected chickens. Haemagglutinin-neuraminidase (HN) protein has an important role related to infection and pathogenesis, therefore, the protein was characterised in this study. Samples were collected from 45 cloacal swabs of native chickens. They were isolated by inoculating in specific pathogen-free embryonated eggs. Molecular detection of NDV was done by reverse transcriptase polymerase chain reaction (RT-PCR) encoding HN protein. RT-PCR for HN gene of NDV generated DNA fragments sized 503 bp, which were then sequenced using ABI Prism. The results have shown that virus isolates were mostly lentogenic and might contribute to outbreak in East Java, Indonesia. Based on this fact, NDV infected native chickens can act as reservoir and contribute to outbreak in the poultry. Our study provides baseline information on genetic characteristics of NDV circulating in East Java and serves as a basic work for further research.

scholarly journals Sero-prevalence of anti-SARS-CoV-2 Antibodies in Addis Ababa, Ethiopia

2020 ◽  
Author(s):  
Berhanu Nega Alemu ◽  
Adamu Addissie ◽  
Gemechis Mamo ◽  
Negussie Deyessa ◽  
Tamrat Abebe ◽  
...  
Keyword(s):  
Serological Test ◽  
Addis Ababa ◽  
Rapid Test ◽  
Cross Sectional Study ◽  
Rt Pcr ◽  
Serological Tests ◽  
Cross Sectional ◽  
History Of ◽  
Community Transmission ◽  
Pcr Test

AbstractBackgroundAnti-SARS-CoV-2 antibody tests are being increasingly used for sero-epidemiological purposes to provide better understanding of the extent of the infection in the community, and monitoring the progression of the COVID-19 epidemic. We conducted sero-prevalence study to estimate prior infection with with SARS-CoV-2 in Addis Ababa.MethodsA cross-sectional study was done from April 23 to 28, 2020 among 301 randomly selected residents of Addis Ababa; with no known history of contact with confirmed COVID-19 person. Interviews on socio demographic and behavioural risk factor followed by serological tests were performed for SARS-CoV-2 IgM, and IgG antibodies, using COVID-19 IgG/IgM Rapid Test Cassette. The test has sensitivity of 87·9% and specificity of 100% for lgM; and a sensitivity of 97·2% and specificity of 100% for IgG. RT-PCR test was also done on combined nasopharyngeal and oropharengeal swabs as an important public health consideration.FindingsThe unadjusted antibody-based crude SARS-CoV-2 prevalence was 7·6% and the adjusted true SARS-CoV-2 prevalence was estimated at 8·8% (95% CI 5·5%-11·6%) for the study population. Higher sero-prevalence were observed for males (9.0%), age below 50 years (8.2%), students and unemployed (15.6%), those with primary education (12.1%), smokers (7.8%), alcohol consumers (8.6%), chatt-chewers (13.6%) and shish smokers (18.8%). Seroprevalence was not significantly associated neither with socio-demographic not behavioral characteristics. According to the findings, possibly more individuals had been infected in Addis Ababa than what was being detected and reported by RT-PCR test suggestive of community transmission. The use of serological test for epidemiological estimation of the extent of SARS-CoV-2 epidemic gives a more precise estimate of magnitude which would be used for further monitoring and surveillance of the magnitude of the SARS CoV-2 infection.

scholarly journals RAPID SEROLOGICAL TESTS HAVE A ROLE IN ASYMPTOMATIC HEALTH WORKERS COVID-19 SCREENING

2020 ◽  
Author(s):  
Angelo Virgilio Paradiso ◽  
SimonaDe Summa ◽  
Nicola Silvestris ◽  
Stefania Tommasi ◽  
Antonio Tufaro ◽  
...  
Keyword(s):  
High Risk ◽  
Cancer Patients ◽  
Health Workers ◽  
Serological Test ◽  
Analytical Sensitivity ◽  
Rt Pcr ◽  
Serological Tests ◽  
Clinical Meaning ◽  
Asymptomatic Subjects

AbstractHealth workers are at high risk for SARS-CoV-2 infection and, if asymptomatic, for transmitting the virus on to fragile cancer patients. We screened 525 health workers of our Cancer Institute with rapid serological test Viva-Diag analyzingCOVID-19 associated-IgG/IgM. Six subjects (1,1%) resulted with Viva-Diag test not-negative for IgM. All 6 cases had RT-PCR SARS-CoV-2 test negative; repeating analysis ofIgG/IgM expression by CLIA assay also, 2 cases resulted IgM positive and 1 case IgG/IgM positive. This latter subject reported a contact with an infected SARS-CoV-2 person, a month earlier.In conclusion our study seems to suggest: a) a different analytical sensitivity inIgG/IgM evaluation for Viva-Diag and CLIA assays needing to be further determined; b) the ability of Viva-Diagrapid COVID-19 test to evidence health workers positive for Immunoglobulins expression. Discordant results of rapid serological tests with respect to RT-PCR stress the different clinical meaning the two assays can have, question clearly referring to further studies to optimize the utilization of rapid serological test in asymptomatic subjects at high risk for infection.

Sign in / Sign up

Export Citation Format

Share Document