scholarly journals Testing out of quarantine

2021 ◽  
Author(s):  
Lucy D’Agostino McGowan ◽  
Elizabeth C. Lee ◽  
Kyra H. Grantz ◽  
Lauren M. Kucirka ◽  
Emily S. Gurley ◽  
...  
Keyword(s):  
Incubation Period ◽  
Post Infection ◽  
Infected Individual ◽  
Sensitive Test ◽  
Antigen Test ◽  
Rt Pcr ◽  
Increasing Risk

AbstractSince SARS-CoV-2 emerged, a 14-day quarantine has been recommended based on COVID-19”s incubation period. Using an RT-PCR or rapid antigen test to “test out” of quarantine is a frequently proposed strategy to shorten duration without increasing risk. We calculated the probability that infected individuals test negative for SARS-CoV-2 on a particular day post-infection and remain symptom free for some period of time. We estimate that an infected individual has a 20.1% chance (95% CI 9.8-32.6) of testing RT-PCR negative on day five post-infection and remaining asymptomatic until day seven. We also show that the added information a test provides decreases as we move further from the test date, hence a less sensitive test that returns rapid results is often preferable to a more sensitive test with a delay.

scholarly journals Avian influenza and Newcastle disease virusindead chickens in markets in Dhaka, Bangladesh in 2011-2012

2017 ◽  
Vol 33 (1) ◽  
pp. 8-15
Author(s):  
LR Barman ◽  
RD Sarker ◽  
BC Das ◽  
EH Chowdhury ◽  
PM Das ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Avian Influenza ◽  
Newcastle Disease ◽  
Rapid Test ◽  
Type A ◽  
Antigen Test ◽  
Rt Pcr ◽  
Test Kit ◽  
Live Bird

A virological survey for avian influenza (AI) and Newcastle disease (ND) was conducted in two selected live bird markets (LBMs), namely Kaptan Bazar and Karwan Bazar in Dhaka city, Bangladesh from August 2011 to July 2012. A total of 513 dead chickens were collected. An immune-chromatographic rapid antigen test for Type A influenza virus and both conventional and real time RT-PCR were used for the detection and characterization of AI and ND viruses. All carcasses were first screened by the rapid antigen test kit and 93 were positive for Type A influenza virus. RT-PCR on a representative number of rapid antigen test positive samples (n = 24) confirmed the presence of Type A influenza virus and mostly H5 influenza virus (22 out of 24 tested samples). Influenza rapid test negative samples (n = 420) were subjected to routine necropsy. Heat stress, suffocation and physical injury were the most common cause of mortality (163 cases), followed by ND, suspected to be the cause of 85 deaths. On molecular investigation of these 85 samples, the presence of ND virus was confirmed in 59 and AI virus in 6; 15 were negative for both ND and AI viruses and 5 were unsuitable for investigation. Among the 59 ND confirmed cases 18 also contained AI virus. In summary, out of 513 carcasses 117 (22.81%) contained AI virus and 59 (11.50%) contained ND virus. Eighteen (3.51%) carcasses contained both AI and ND viruses. The findings suggest that both AI and ND should be considered as major threats to the poultry industry.Bangl. vet. 2016. Vol. 33, No. 1, 8-15

scholarly journals Field evaluation of a rapid antigen test (Panbio™ COVID-19 Ag Rapid Test Device) for the diagnosis of COVID-19 in primary healthcare centers

2020 ◽  
Author(s):  
Eliseo Albert ◽  
Ignacio Torres ◽  
Felipe Bueno ◽  
Dixie Huntley ◽  
Estefanía Molla ◽  
...  
Keyword(s):  
Primary Healthcare ◽  
Rapid Test ◽  
Field Evaluation ◽  
Antigen Test ◽  
Rt Pcr ◽  
Test Device ◽  
Specificity And Sensitivity ◽  
Primary Healthcare Centers

AbstractWe evaluated the Panbio™ COVID-19 AG Rapid Test Device (RAD) for the diagnosis of COVID-19 in symptomatic patients attended in primary healthcare centers (n=412). Overall specificity and sensitivity of RAD was 100% and 79.6%, respectively, taking RT-PCR as the reference. SARS-CoV-2 could not be cultured from specimens yielding RT-PCR+/RAD- results.

Role of Covid Antigen in the Diagnosis of Covid Positive in Obstetric Patients

2021 ◽  
Vol 15 (10) ◽  
pp. 3356-3358
Author(s):  
Ambreen Fatima ◽  
Nidda Yaseen ◽  
Amna Fareed ◽  
Kashif Ali Samin ◽  
Shumaela Kanwal ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Early Detection ◽  
Negative Predictive Value ◽  
Predictive Value ◽  
False Negative ◽  
Nucleic Acid Amplification ◽  
Antigen Test ◽  
Rt Pcr ◽  
Cross Sectional ◽  
Specificity And Sensitivity

Background and Aim: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapid emergence postured significant challenges on the health system in recent years. The early detection of cases is thought to be critical in preventing this pandemic by coronavirus disease (COVID-19), especially important in the obstetrical population due to theirs numerous interactions with another parturient when hospitalized for delivery. Therefore, the present study aimed to assess the COVID antigen test performance in COVID-positive obstetrics patients. Materials and Methods: This cross-sectional study was conducted on 1296 Covid-19 asymptomatic women admitted to the Obstetrics and Gynaecology Department of Muhammad Teaching Hospital & Medical College, Peshawar and Fauji Foundation Hospital, Rawalpindi for the duration of six months from February 2021 to July 2021. Antigen-based test rapid diagnostic test (RDT) was used for screening out COVID-19 positive obstetrics patients or women through nasopharyngeal swabs. Women with negative rapid antigen test results were confirmed with RT-polymers chain reaction test of nucleic acid amplification tests (NAAT). Ethical approval and informed consent were taken from the hospital ethical committee and each individual respectively. All the known positive COVID-19 patients during admission were excluded. SPSS version 24 was used for data analysis. Results: The overall prevalence of rapid antigen-positive tested patients was 13.2% (171/1296). The prevalence of positive tested women through rapid antigen test, Nucleic Acid Amplification Test (NAAT), and RT-PCR were 27 (2.1%), 51 (3.9%), and 93 (7.2%) respectively. Of the total 1296 rapid antigen tests, 27 were positive, and the false-negative confirmed positive by NAAT was 144.Thus the sensitivity of the rapid antigen test was 15.8% and the negative predictive value was 93.7%. Of the total 298 Nucleic Acid Amplification Tested had sensitivity and negative predictive value of 89.6% and 99.06% respectively. RT-PCR was carried out on 972 patients, positive diagnosed cases were 36 while 15 were initially negative and were positive with the test was repeated. The sensitivity and negative predictive value was 71.45% and 95.8% respectively. Conclusion: Our study found that Ag-RDT plays a significant role in SARS-CoV-2 early detection in infected individuals, with high specificity and sensitivity to disease infectious stage, whether symptomatic or asymptomatic, and can be used as a decision supported tool. Early detection of COVID-19 status in women admitted for delivery could benefit neonatal protection care. Keywords: Covid-19; Rapid antigen test; RT-PCR test

Development and validation of an integrated cell culture-qRTPCR assay for simultaneous quantification of coxsackieviruses, echoviruses, and polioviruses in disinfection studies

2010 ◽  
Vol 61 (2) ◽  
pp. 375-387 ◽  
Author(s):  
B. K. Mayer ◽  
H. Ryu ◽  
D. Gerrity ◽  
M. Abbaszadegan
Keyword(s):  
Cell Culture ◽  
Viral Replication ◽  
Incubation Period ◽  
Post Infection ◽  
Microbial Inactivation ◽  
Ultraviolet Disinfection ◽  
Simultaneous Quantification ◽  
Green Monkey ◽  
Development And Validation ◽  
Assay Conditions

This study demonstrated the applicability of integrated cell culture-quantitative RTPCR (ICC-qRTPCR) for the simultaneous quantification of coxsackievirus, echovirus, and poliovirus in disinfection studies. Buffalo green monkey cells were inoculated with a 10-fold dilution series of mixed enteroviruses and incubated prior to qRTPCR quantification. Optimal assay conditions included three post infection washes and a 24-hour post infection incubation period based on successful differentiation between infectious and noninfectious viruses and significant and consistent viral replication rates. Ultraviolet disinfection studies were performed to validate the ICC-qRTPCR assay. Using the optimized assay, three-log microbial inactivation was achieved at UV doses of 30–44, 28–42, and 28–29 mJ/cm2 for coxsackievirus B6, echovirus 12, and poliovirus 1, respectively. These results compare favorably to side-by-side assessments using conventional cultural techniques and values previously reported in the literature. This indicates that ICC-qRTPCR is a practical alternative for the simultaneous quantification of enteroviruses in disinfection studies.

scholarly journals Open reading frame 132 of Heliocoverpa armigera nucleopolyhedrovirus encodes a functional per os infectivity factor (PIF-2)

2006 ◽  
Vol 87 (9) ◽  
pp. 2563-2569 ◽  
Author(s):  
Minggang Fang ◽  
Yingchao Nie ◽  
Qian Wang ◽  
Fei Deng ◽  
Ranran Wang ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Western Blot ◽  
Blot Analysis ◽  
Post Infection ◽  
Spodoptera Exigua ◽  
Open Reading Frame ◽  
Rt Pcr ◽  
Western Blots ◽  
Reading Frame ◽  
Budded Virus

Open reading frame 132 (Ha132) of Helicoverpa armigera nucleopolyhedrovirus (HearNPV) is a homologue of per os infectivity factor 2 (pif-2) of Spodoptera exigua multiple nucleopolyhedrovirus. Sequence analysis indicated that Ha132 encoded a protein of 383 aa with a predicted molecular mass of 44.5 kDa. Alignment of HA132 and its baculovirus homologues revealed that HA132 was highly conserved among baculoviruses, with 14 absolutely conserved cysteine residues. RT-PCR indicated that Ha132 was first transcribed at 24 h post-infection. Western blot analysis showed that a 43 kDa band was detectable in HearNPV-infected HzAM1 cells from 36 h post-infection. Western blots also indicated that HA132 was a component of the occlusion-derived virus, but not of budded virus. Deletion of Ha132 from HearNPV abolished per os infectivity, but had no effect on the infectivity of the budded virus phenotype.

scholarly journals Comparison of SARS-CoV-2 antigen electrochemiluminescence immunoassay to RT-PCR assay for laboratory diagnosis of COVID-19 in Peshawar

Diagnosis ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bilal Iqbal ◽  
Maria Khan ◽  
Noman Shah ◽  
Mirza Muhammad Dawood ◽  
Valeed Jehanzeb ◽  
...  
Keyword(s):  
Laboratory Diagnosis ◽  
Cross Sectional Study ◽  
Antigen Test ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Cross Sectional ◽  
Viral Loads ◽  
Testing Algorithms ◽  
Frequent Testing ◽  
Antigen Testing

Abstract Objectives Antigen based rapid diagnostic tests possesses a potential to be utilized along with Gold standard methods to detect Covid-19 infection to cope with the demand of testing. The aim of this study was to determine diagnostic accuracy of electrochemiluminescence based automated antigen detection immunoassay comparing with molecular based test RT-PCR (Covid-19). Methods It was a cross-sectional study conducted in RMI Peshawar, from 1st April 2021 till 30th April 2021. The study comprised 170 individuals who were suspected of having Covid-19. Nasopharyngeal samples taken from suspected individuals were analyzed by RT-PCR and automated antigen test (Elecsys SARS-CoV-2 Antigen) simultaneously. The correlation of SARS-CoV-2 antigen with PCR positive and negative cases was analyzed for specificity, sensitivity respectively. Results The ECLIA based Elecsys antigen test (Roche) revealed overall sensitivity 72%, specificity 95% and accuracy of 94.9%. Sensitivity of antigen test progressively declined from 94.3% in Ct <25 to 70.8% in Ct 26–29 and then to 47.2% in Ct 30–35. Conclusions Based on the findings of our study we conclude that automated antigen testing (Elecsys SARS-CoV-2 Antigen) cannot replace molecular based testing like RT PCR. Elecsys SARS-CoV-2 Ag test should be used complementary to RT-PCR in testing algorithms. Frequent testing strategy should be adopted while using automated antigen testing to overcome its limitation in individuals with low viral loads.

scholarly journals Effect of Sinefungin on the attachment of the parasite Leishmania to the macrophages cell line J774G8

2018 ◽  
Vol 49 (1) ◽  
pp. 59
Author(s):  
A. TZORA (Α. ΤΖΩΡΑ) ◽  
F. LAWRENCE ◽  
M. ROBERT-GERO
Keyword(s):  
Cell Line ◽  
Incubation Period ◽  
Post Infection ◽  
Common Finding ◽  
Macrophage Cell Line ◽  
Macrophage Cell ◽  
Major Strain ◽  
Parasite Leishmania

The effect of Sinefungin on the attachment of the Leishmania strains L. infantum, L. tropica and L. major to the macrophages cell line J774G8 was studied. Inhibition ofthe attachment to the surface of macrophages was observed to the Sinefungin sensitive strains L. tropica and L. major. This inhibition was obtained only for Sinefungin pretreated promastigotes (72 hours with 2.6 and 26 Μμ Sinefungin) when incubated with macrophages for 2 and 24 hours. After 2 h incubation period of the promastigote forms of the sensitive L. tropica with macrophages, the inhibition of the attachment was 100%, whereas for the sensitive L. major strain the inhibition was 17 and 36% at a concentration of Sinefungin 2.6 and 26 μΜ respectively. The percentage of the inhibition 24 h post infection was in the range of 52 to 77% for the L. tropica strain and from 73 to 86% for the L. major strain for promastigote pretreated with 2.6 and 26 μΜ Sinefungin respectively. Controls showed that Sinefungin was not toxic for the macrophages when used for 3 days at the above mentioned concentrations. Inhibition of the protozoa - macrophage cell line J774G8 adherence was a common finding leading us to the conclusion that Sinefungin is involved actively into that process.

scholarly journals Longitudinal serology in SARS-CoV-2 infected individuals in India – a prospective cohort study

2021 ◽  
Author(s):  
Ramachandran Thiruvengadam ◽  
Souvick Chattopadhyay ◽  
Farha Mehdi ◽  
Bapu Koundinya Desiraju ◽  
Susmita Chaudhuri ◽  
...  
Keyword(s):  
Post Infection ◽  
Prospective Cohort ◽  
Seroconversion Rate ◽  
Severe Disease ◽  
P Value ◽  
Serological Response ◽  
National Capital Region ◽  
Rt Pcr ◽  
Clinical Predictors ◽  
Epidemiological Characteristics

AbstractClinical and epidemiological characteristics of SARS-CoV-2 infection are now widely available, but there are few data on longitudinal serology in large cohorts, particularly from low-and middle-income countries. We established an ongoing prospective cohort of 3840 SARS-CoV-2 RT-PCR positive individuals in the Delhi-National Capital Region of India, to document clinical and immunological characteristics during illness and convalescence. The IgG responses to the receptor binding domain (RBD) and nucleocapsid were assessed at 0-7, 10-28 days and 6-10 weeks after infection. The clinical predictors of seroconversion were identified by multivariable regression analysis. The seroconversion rates in the post-infection windows of 0–7 days, 10–28 days and 6–10 weeks were 46%, 84.7% and 85.3% respectively (n=782). The proportion with a serological response increased with severity of COVID-19 disease. All participants with severe disease, 89.6% with mild to moderate infection and 77.3% of asymptomatic participants had IgG antibodies to the RBD antigen. The threshold values in the nasopharyngeal viral RNA RT-PCR in a subset of asymptomatic and symptomatic seroconverters were comparable (p value: 0.48), with similar results among non-seroconverters (p value: 0.16) (n=169). This is the first report of longitudinal humoral immune responses to SARS-CoV-2 infection over a period of ten weeks from South Asia. The low seropositivity in asymptomatic participants and differences between assays highlight the importance of contextualizing the understanding of population serosurveys.SummaryWe measured anti-SARS-CoV-2 RBD and NC protein IgG in a multi-hospital-based prospective cohort from northern India up to ten weeks post-infection. The lower seroconversion rate among asymptomatic RT-PCR positive participants has public health significance particularly for interpreting community seroprevalence estimates.

scholarly journals Clinico-epidemiological profile of COVID-19 among health care workers from a tertiary care hospital

2021 ◽  
Author(s):  
Anuradha Tolpadi ◽  
Abhijeet Mane ◽  
Jitendra Oswal ◽  
Sujata Rege ◽  
Meera Modak ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Tertiary Care ◽  
Management Strategies ◽  
Care Hospital ◽  
Antigen Test ◽  
Rt Pcr ◽  
Tertiary Care Centre ◽  
Care Workers ◽  
Global Health Issue ◽  
Epidemiological Profile

Background: Coronavirus disease 2019 (COVID-19) is a global health issue. Healthcare workers (HCWs) are especially vulnerable to infection by SARS-CoV-2. The present study was conducted to determine the proportion of HCWs infected with COVID 19 in a tertiary care centre with emphasis on the epidemiological and clinical aspectMethods: HCWs (symptomatic and asymptomatic contacts) who tested positive for COVID-19 by SARS-CoV-RTPCR or COVID-19 rapid antigen test were included in the study. Demographic and clinical data of the infected HCWs was obtained through a detailed telephonic interview with structured questionnaire.Results: Out of total 921 HCWs tested for COVID-19 (SARS-CoV-2 RT-PCR and Rapid antigen test), 323 (35%) HCWs were positive. Proportion of COVID-19 positive HCWs among all HCWs was 13.67% (323/2362). Most COVID-19 positive HCWs (88%) were symptomatic. Majority of infected HCWs (62.23%) were between the age group of 21-30 years. Nurses were the most predominantly affected among various categories of HCWs (42.41%). Fever was the most common presenting symptom, seen in 160 (49.50%) HCWs. Comorbidities were found in 28 (8.66%) of infected HCWs. Majority of HCWs (86%) suffered from mild infection.Conclusions: HCWs, especially nurses, face a high risk of COVID-19 infection while providing care for suspected or confirmed COVID-19 patients. It is important to characterize the epidemiological and clinical profile of HCWs regarding COVID-19 for formulation of prevention and management strategies.

scholarly journals Performance of SARS-CoV-2 rapid antigen test compared with real-time RT-PCR in asymptomatic individuals

2021 ◽  
Author(s):  
Mónica Peña ◽  
Manuel Ampuero ◽  
Carlos Garcés ◽  
Aldo Gaggero ◽  
Patricia García ◽  
...  
Keyword(s):  
Real Time ◽  
False Negative ◽  
Pivotal Role ◽  
Contact Tracing ◽  
Antigen Test ◽  
Rt Pcr ◽  
Asymptomatic Carriers ◽  
Asymptomatic Individuals ◽  
Pcr Diagnostics

AbstractScreening, testing and contact tracing plays a pivotal role in the control of COVID-19 pandemic. To carry out this strategy it is necessary to increase the testing capacity. Here, we compared a SARS CoV-2 rapid antigen test (RAT) and RT-PCR in 842 asymptomatic individuals from Tarapacá, Chile. We report a sensibility of 69.86%, a specificity of 99.61%, PPV of 94.44% and NPP of 97.22% with Ct values (Ct > 27) that were significantly higher among individuals with false-negative RAT. These results support the fact that RAT might have a significant impact in the identification of asymptomatic carriers in areas that lack well-equipped laboratories to perform SARS-CoV-2 real -time RT-PCR diagnostics or the results take more than 24-48 hours, as well as zones with high traffic of individuals, such as border/customs, airports, interregional bus, train stations or in any mass testing campaign requiring rapid results.

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