scholarly journals Viral load and infectivity of SARS-CoV-2 in paired respiratory and oral specimens from symptomatic, asymptomatic or post-symptomatic individuals

2021 ◽  
Author(s):  
Rebecca L. Tallmadge ◽  
Melissa A Laverack ◽  
Brittany Cronk ◽  
Roopa Venugopalana ◽  
Mathias Martins ◽  
...  
Keyword(s):  
Viral Load ◽  
Healthcare Provider ◽  
Diagnostic Testing ◽  
Sampling Frequency ◽  
Diagnostic Sensitivity ◽  
Specimen Type ◽  
Asymptomatic Patients ◽  
Asymptomatic Individuals ◽  
Time Point

In the present study, we assessed the diagnostic sensitivity and determined the viral load and infectivity of SARS-CoV-2 in paired respiratory (nasopharyngeal and anterior nares) and oral samples (saliva and sublingual swab). Samples were collected from 77 individuals of which 75 were diagnosed with COVID-19 and classified as symptomatic (n=29), asymptomatic (n=31), or post-symptomatic (n=15). Specimens were collected at one time point from each individual, between day 1 to 23 after the initial COVID-19 diagnosis, and included self-collected saliva (S), or sublingual (SL) swab, and bilateral anterior nares (AN) swab, followed by healthcare provider collected nasopharyngeal (NP) swab. Sixty-three specimen sets were tested using five assay/platforms. The diagnostic sensitivity of each assay/platform and specimen type was determined. Of the 63 specimen sets, SARS-CoV-2 was detected in 62 NP specimens, 52 AN specimens, 59 saliva specimens, and 31 SL specimens by at least one platform. Infectious SARS-CoV-2 was isolated from 21 NP, 13 AN, 12 saliva, and one SL specimen out of 50 specimen sets. SARS-CoV-2 isolation was most successful up to 5 days after initial COVID-19 diagnosis using NP specimens from symptomatic patients (16 of 24 positives, 66.67%), followed by specimens from asymptomatic patients (5 of 17 positives, 29.41%), while it was not very successful with specimens from post-symptomatic patients. Benefits of self-collected saliva and AN specimens balance the loss of sensitivity relative to NP specimens. Therefore, saliva and AN specimens are acceptable alternatives for symptomatic SARS-CoV-2 diagnostic testing or surveillance with increased sampling frequency of asymptomatic individuals.

scholarly journals Differential Kinetics of Cycle Threshold Values during Admission by Symptoms among Patients with Mild COVID-19: A Prospective Cohort Study

2021 ◽  
Vol 18 (15) ◽  
pp. 8181
Author(s):  
Teppei Sakano ◽  
Mitsuyoshi Urashima ◽  
Hiroyuki Takao ◽  
Kohei Takeshita ◽  
Hiroe Kobashi ◽  
...  
Keyword(s):  
Cohort Study ◽  
Viral Load ◽  
Prospective Cohort Study ◽  
Prospective Cohort ◽  
Polymerase Chain Reaction Test ◽  
Cycle Threshold ◽  
Viral Loads ◽  
Asymptomatic Patients ◽  
Asymptomatic Individuals ◽  
Chain Reaction Test

In the coronavirus disease 2019 (COVID-19) pandemic, more than half of the cases of transmission may occur via asymptomatic individuals, which makes it difficult to contain. However, whether viral load in the throat during admission is different between asymptomatic and symptomatic patients is not well known. By conducting a prospective cohort study of patients with asymptomatic or mild COVID-19, cycle threshold (Ct) values of the polymerase chain reaction test for COVID-19 were examined every other day during admission. The Ct values during admission increased more steadily in symptomatic patients and febrile patients than in asymptomatic patients, with significance (p = 0.01 and p = 0.004, respectively), although the Ct values as a whole were not significantly different between the two groups. Moreover, the Ct values as a whole were higher in patients with dysosmia/dysgeusia than in those without it (p = 0.02), whereas they were lower in patients with a headache than those without (p = 0.01). Patients who were IgG-positive at discharge maintained higher Ct values, e.g., more than 35, during admission than those with IgG-negative (p = 0.03). Assuming that viral load and Ct values are negatively associated, the viral loads as a whole and their changes by time may be different by symptoms and immune reaction, i.e., IgG-positive at discharge.

scholarly journals 496. Higher SARS-CoV-2 RT-PCR Cycle Threshold (Ct) Values Associated with Longer Symptom Duration Among Patients Hospitalized with COVID-19

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S314-S314
Author(s):  
Lillian B Brown ◽  
Lisa Gail Winston ◽  
Barbara Haller ◽  
Phong Pham ◽  
Beatrice Marcelo ◽  
...  
Keyword(s):  
Viral Load ◽  
San Francisco ◽  
Symptom Onset ◽  
Diagnostic Testing ◽  
Symptom Duration ◽  
Rt Pcr ◽  
Duration Of Symptoms ◽  
Cycle Threshold ◽  
Asymptomatic Patients

Abstract Background Most diagnostic tests for SARS-CoV-2, the causative agent of COVID-19, are RT-PCR based. This method is sensitive but cannot distinguish replicating from non-replicating virus. RT-PCR cycle threshold (Ct) values are inversely correlated with viral load, and higher Ct values have been correlated with lower in vitro viral infectivity. However, relatively few data exist on the association between Ct values and patients’ duration of symptoms remains unclear. We thus evaluated Ct values and symptom duration in a cohort of patients hospitalized with COVID-19. Methods We assessed all patients admitted to San Francisco General Hospital between April 1 and May 18, 2020 with confirmed COVID-19 infection based on RT-PCR testing (Abbott m2000 platform). We included patients having diagnostic testing for suspected COVID-19 and patients having asymptomatic testing per hospital policy. For symptomatic patients, date of symptom onset was abstracted from hospital records, and time from symptom onset to test date was calculated. RT-PCR Ct values were manually extracted. Median Ct and IQR were calculated for patients with < 10 days of symptoms, ≥10 days of symptoms, and asymptomatic disease. Between-group comparisons were performed using the Kruskal-Wallis test. Results Among 61 patients with positive RT-PCR tests, 40 patients reported < 10 days of symptoms at the time of testing, 15 reported ≥10 days of symptoms, and 6 were asymptomatic. The median Ct value was 14.2 cycles (IQR, 10.2, 18.3) among patients reporting < 10 days of symptoms, 19.7 cycles (IQR, 15.3, 23.9) among patients reporting ≥10 days of symptoms, and 26.3 (IQR, 25.0, 29.1) among asymptomatic patients. Ct values were significantly lower among patients with < 10 days of symptoms compared to patients with >=10 days of symptoms (p=0.01) and when compared to asymptomatic patients (p=0.0002) [Figure]. Cycle threshold (Ct) by days of symptoms at time of testing Conclusion SARS-CoV-2 RT-PCR cycle threshold values were higher (indicating lower viral load) in patients with longer symptom duration and were highest in asymptomatic patients. These results add to emerging data suggesting that strategies for optimal isolation of patients in both community and hospital settings could be informed by a combination of symptom duration and RT-PCR Ct values. Disclosures All Authors: No reported disclosures

scholarly journals 458. Molecular SARS-CoV-2 Testing During the COVID-19 Outbreak: Experiences of a Hospital in Southeast Michigan, USA

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S296-S297
Author(s):  
Trini A Mathew ◽  
Jonathan Hopkins ◽  
Diane Kamerer ◽  
Shagufta N Ali ◽  
Daniel Ortiz ◽  
...  
Keyword(s):  
Clinical Features ◽  
Diagnostic Testing ◽  
Beaumont Hospital ◽  
High Capacity ◽  
Turnaround Time ◽  
Molecular Diagnostic ◽  
The Novel ◽  
Repeat Testing ◽  
Asymptomatic Patients ◽  
Novel Coronavirus

Abstract Background The novel Coronavirus SARS CoV-2 (COVID-19) outbreak was complicated by the lack of diagnostic testing kits. In early March 2020, leadership at Beaumont Hospital, Royal Oak Michigan (Beaumont) identified the need to develop high capacity testing modalities with appropriate sensitivity and specificity and rapid turnaround time. We describe the molecular diagnostic testing experience since initial rollout on March 16, 2020 at Beaumont, and results of repeat testing during the peak of the COVID-19 pandemic in MI. Methods Beaumont is an 1100 bed hospital in Southeast MI. In March, testing was initially performed with the EUA Luminex NxTAG CoV Extended Panel until March 28, 2020 when testing was converted to the EUA Cepheid Xpert Xpress SARS-CoV-2 for quicker turnaround times. Each assay was validated with a combination of patient samples and contrived specimens. Results During the initial week of testing there was > 20 % specimen positivity. As the prevalence grew the positivity rate reached 68% by the end of March (Figure 1). Many state and hospital initiatives were implemented during the outbreak, including social distancing and screening of asymptomatic patients to increase case-finding and prevent transmission. We also adopted a process for clinical review of symptomatic patients who initially tested negative for SARS-CoV-2 by a group of infectious disease physicians (Figure 2). This process was expanded to include other trained clinicians who were redeployed from other departments in the hospital. Repeat testing was performed to allow consideration of discontinuation of isolation precautions. During the surge of community cases from March 16 to April 30, 2020, we identified patients with negative PCR tests who subsequently had repeat testing based on clinical evaluation, with 7.1% (39/551) returning positive for SARS- CoV2. Of the patients who expired due to COVID-19 during this period, 4.3% (9/206) initially tested negative before ultimately testing positive. Figure 1 BH RO testing Epicurve Figure 2: Screening tool for repeat COVID19 testing and precautions Conclusion Many state and hospital initiatives helped us flatten the curve for COVID-19. Our hospital testing experience indicate that repeat testing may be warranted for those patients with clinical features suggestive of COVID-19. We will further analyze these cases and clinical features that prompted repeat testing. Disclosures All Authors: No reported disclosures

scholarly journals Histopathological Features of Symptomatic and Asymptomatic Honeybees Naturally Infected by Deformed Wing Virus

Pathogens ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 874
Author(s):  
Karen Power ◽  
Manuela Martano ◽  
Gennaro Altamura ◽  
Nadia Piscopo ◽  
Paola Maiolino
Keyword(s):  
Viral Load ◽  
Asymptomatic Group ◽  
Deformed Wing Virus ◽  
Stage Of Development ◽  
Pathogenic Action ◽  
Degenerative Alterations ◽  
Flight Muscles ◽  
Asymptomatic Individuals ◽  
Histopathological Results

Deformed wing virus (DWV) is capable of infecting honeybees at every stage of development causing symptomatic and asymptomatic infections. To date, very little is known about the histopathological lesions caused by the virus. Therefore, 40 honeybee samples were randomly collected from a naturally DWV infected hive and subjected to anatomopathological examination to discriminate between symptomatic (29) and asymptomatic (11) honeybees. Subsequently, 15 honeybee samples were frozen at −80° and analyzed by PCR and RTqPCR to determinate the presence/absence of the virus and the relative viral load, while 25 honeybee samples were analyzed by histopathological techniques. Biomolecular results showed a fragment of the expected size (69bp) of DWV in all samples and the viral load was higher in symptomatic honeybees compared to the asymptomatic group. Histopathological results showed degenerative alterations of the hypopharyngeal glands (19/25) and flight muscles (6/25) in symptomatic samples while 4/25 asymptomatic samples showed an inflammatory response in the midgut and the hemocele. Results suggest a possible pathogenic action of DWV in both symptomatic and asymptomatic honeybees, and a role of the immune response in keeping under control the virus in asymptomatic individuals.

scholarly journals The First Harmonic of Radial Pulse as an Early Predictor of Silent Coronary Artery Disease and Adverse Cardiac Events in Type 2 Diabetic Patients

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Chi-Wei Chang ◽  
Kuo-meng Liao ◽  
Yi-Ting Chang ◽  
Sheng-Hung Wang ◽  
Ying-chun Chen ◽  
...  
Keyword(s):  
Coronary Artery Disease ◽  
Coronary Artery ◽  
Hazard Ratio ◽  
Radial Pulse ◽  
Cardiac Events ◽  
Asymptomatic Patients ◽  
Adverse Cardiac Events ◽  
Silent Coronary Artery Disease ◽  
Artery Disease ◽  
Asymptomatic Individuals

Background. It has been reported that harmonics of radial pulse is related to coronary artery disease (CAD) in patients with type 2 diabetes mellitus (T2DM). It is still unclear whether or not the first harmonics of the radial pulse spectrum is an early independent predictor of silent coronary artery disease (SCAD) and adverse cardiac events (ACE). Objectives. To measure the risk of SCAD in patients with T2DM and also to survey whether or not an increment of the first harmonic (C1) of the radial pulse increases ACE. Methods. 1968 asymptomatic individuals with T2DM underwent radial pulse wave measurement. First harmonic of the radial pressure wave, C1, was calculated. Next, the new occurrence of ACE and the new symptoms and signs of coronary artery disease were recorded. The follow-up period lasted for 14.7 ± 3.5 months. Results. Out of 1968 asymptomatic individuals with T2DM, ACE was detected in 239 (12%) of them during the follow-up period. The logrank test demonstrated that the cumulative incidence of ACE in patients with C1 above 0.96 was greater than that in those patients with C1 below 0.89 (P<0.01). By comparing the data of patients with C1 smaller than the first quartile and the patients with C1 greater than the third quartile, the hazard ratios were listed as follows: ACE (hazard ratio, 2.29; 95% CI, 1.55–3.37), heart failure (hazard ratio, 2.22; 95% CI, 1.21–4.09), myocardial infarction (hazard ratio, 2.44; 95% CI, 1.51–3.93), left ventricular dysfunction (Hazard ratio, 2.01; 95% CI, 0.86–4.70), and new symptoms and signs for coronary artery disease (hazard ratio, 2.03; 95% CI, 1.45–2.84). As C1 increased, the risk for composite ACE (P<0.001 for trend) and for coronary disease (P<0.001 for trend) also increased. The hazard ratio and trend for cardiovascular-cause mortality were not significant. Conclusions. This study showed that C1 of the radial pulse wave is correlated with cardiovascular events. Survival analysis showed that C1 value is an independent predictor of ACE and SCAD in asymptomatic patients with T2DM. Thus, screening for the first harmonic of the radial pulse may improve the risk stratification of cardiac events and SCAD in asymptomatic patients although they had no history of coronary artery disease or angina-related symptom.

scholarly journals Simulations of the spread of COVID-19 and control policies in Tunisia

2020 ◽  
Author(s):  
Slimane BenMiled ◽  
Amira Kebir
Keyword(s):  
Epidemiological Model ◽  
Tunisian Population ◽  
Control Policies ◽  
Asymptomatic Patients ◽  
Asymptomatic Individuals ◽  
And Control

AbstractWe develop and analyze in this work an epidemiological model for COVID-19 using Tunisian data. Our aims are first to evaluate Tunisian control policies for COVID-19 and secondly to understand the effect of different screening, quarantine and containment strategies and the rule of the asymptomatic patients on the spread of the virus in the Tunisian population. With this work, we show that Tunisian control policies are efficient in screening infected and asymptomatic individuals and that if containment and curfew are maintained the epidemic will be quickly contained.

Changes in hepatitis C viral load during first 14 days can predict the undetectable time point of serum viral load by pegylated interferon and ribavirin therapy

2011 ◽  
Vol 41 (3) ◽  
pp. 217-224 ◽  
Author(s):  
Jun Itakura ◽  
Yasuhiro Asahina ◽  
Nobuharu Tamaki ◽  
Itsuko Hirayama ◽  
Yutaka Yasui ◽  
...  
Keyword(s):  
Viral Load ◽  
Hepatitis C ◽  
Pegylated Interferon ◽  
Serum Viral Load ◽  
Time Point

scholarly journals Healthcare provider diagnostic testing practices for identification of Clostridioides (Clostridium) difficile in children: an Emerging Infections Network survey

2019 ◽  
Vol 40 (3) ◽  
pp. 276-280 ◽  
Author(s):  
Larry K. Kociolek ◽  
Preeta K. Kutty ◽  
Philip M. Polgreen ◽  
Susan E. Beekmann
Keyword(s):  
Clostridium Difficile ◽  
Infectious Diseases ◽  
Healthcare Provider ◽  
Neonatal Intensive Care ◽  
Diagnostic Testing ◽  
Emerging Infections ◽  
Electronic Survey ◽  
Testing Practices ◽  
E Mail ◽  
Infants And Young Children

AbstractObjective:To characterize healthcare provider diagnostic testing practices for identifying Clostridioides (Clostridium) difficile infection (CDI) and asymptomatic carriage in children.Design:Electronic survey.Methods:An 11-question survey was sent by e-mail or facsimile to all pediatric infectious diseases (PID) members of the Infectious Diseases Society of America’s Emerging Infections Network (EIN).Results:Among 345 eligible respondents who had ever responded to an EIN survey, 196 (57%) responded; 162 of these (83%) were aware of their institutional policies for CDI testing and management. Also, 159 (98%) respondents knew their institution’s C. difficile testing method: 99 (62%) utilize NAAT without toxin testing and 60 (38%) utilize toxin testing, either as a single test or a multistep algorithm. Of 153 respondents, 10 (7%) reported that formed stools were tested for C. difficile at their institution, and 76 of 151 (50%) reported that their institution does not restrict C. difficile testing in infants and young children. The frequency of symptom- and age-based testing restrictions did not vary between institutions utilizing NAAT alone compared to those utilizing toxin testing for C. difficile diagnosis. Of 143 respondents, 26 (16%) permit testing of neonatal intensive care unit patients and 12 of 26 (46%) treat CDI with antibiotics in this patient population.Conclusions:These data suggest that there are opportunities to improve CDI diagnostic stewardship practices in children, including among hospitals using NAATs alone for CDI diagnosis in children.

Molecular diagnostic testing as an adjunct to morphologic evaluation of pancreatic ductal system brushings: Potential augmentation for diagnostic sensitivity

2007 ◽  
Vol 35 (4) ◽  
pp. 218-224 ◽  
Author(s):  
Carlynn Willmore-Payne ◽  
Keith E. Volmar ◽  
Michael A. Huening ◽  
Joseph A. Holden ◽  
Lester J. Layfield
Keyword(s):  
Diagnostic Testing ◽  
Diagnostic Sensitivity ◽  
Molecular Diagnostic ◽  
Ductal System ◽  
Molecular Diagnostic Testing

Prevention and Management of Stroke in Sickle Cell Anemia

Hematology ◽  
2006 ◽  
Vol 2006 (1) ◽  
pp. 54-57 ◽  
Author(s):  
Orah S. Platt
Keyword(s):  
Brain Injury ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Preventive Treatment ◽  
Diagnostic Techniques ◽  
Magnetic Resonance Images ◽  
Transfusion Therapy ◽  
Asymptomatic Patients ◽  
Wide Range ◽  
Asymptomatic Individuals

Abstract As the overall health of patients with sickle cell anemia (SS) improves and diagnostic techniques become more sensitive, physicians are seeing patients with an increasingly wide range of subtle and not-so-subtle brain injury. The major breakthrough in the field of sickle-related brain injury has been the unprecedented success of transcranial Doppler ultrasonography (TCD) to identify asymptomatic patients at high risk of stroke, coupled with chronic transfusion therapy to prevent it. The evidence for TCD screening and preventive treatment is strong and compelling, but there are still important unanswered questions regarding the implications of “silent infarcts” found in the magnetic resonance images (MRIs) of asymptomatic individuals, and the growing awareness of the burden of neuropsychiatric dysfunction in otherwise apparently healthy individuals.

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