scholarly journals Detection of SARS-CoV-2 on Surfaces in Households of Persons with COVID-19

2021 ◽  
Vol 18 (15) ◽  
pp. 8184
Author(s):  
Perrine Marcenac ◽  
Geun Woo Park ◽  
Lindsey M. Duca ◽  
Nathaniel M. Lewis ◽  
Elizabeth A. Dietrich ◽  
...  
Keyword(s):  
Surface Contamination ◽  
Environmental Sampling ◽  
Limited Information ◽  
Rt Pcr ◽  
Environmental Detection ◽  
Prolonged Contact ◽  
Nasal Swabs ◽  
Potential Risks

SARS-CoV-2 transmission from contaminated surfaces, or fomites, has been a concern during the COVID-19 pandemic. Households have been important sites of transmission throughout the COVID-19 pandemic, but there is limited information on SARS-CoV-2 contamination of surfaces in these settings. We describe environmental detection of SARS-CoV-2 in households of persons with COVID-19 to better characterize the potential risks of fomite transmission. Ten households with ≥1 person with laboratory-confirmed COVID-19 and with ≥2 members total were enrolled in Utah, U.S.A. Nasopharyngeal and anterior nasal swabs were collected from members and tested for the presence of SARS-CoV-2 by RT-PCR. Fifteen surfaces were sampled in each household and tested for presence and viability of SARS-CoV-2. SARS-CoV-2 RNA was detected in 23 (15%) of 150 environmental swab samples, most frequently on nightstands (4/6; 67%), pillows (4/23; 17%), and light switches (3/21; 14%). Viable SARS-CoV-2 was cultured from one sample. All households with SARS-CoV-2-positive surfaces had ≥1 person who first tested positive for SARS-CoV-2 ≤ 6 days prior to environmental sampling. SARS-CoV-2 surface contamination occurred early in the course of infection when respiratory transmission is most likely, notably on surfaces in close, prolonged contact with persons with COVID-19. While fomite transmission might be possible, risk is low.

scholarly journals Performance of Unobserved Self-Collected Nasal Swabs for Detection of SARS-CoV-2 by RT-PCR Utilizing a Remote Specimen Collection Strategy

2021 ◽  
Author(s):  
Ron M Kagan ◽  
Amy A Rogers ◽  
Gwynngelle A Borillo ◽  
Nigel J Clarke ◽  
Elizabeth M Marlowe
Keyword(s):  
Return To Work ◽  
Screening Program ◽  
False Negative ◽  
N Gene ◽  
Rt Pcr ◽  
Pooled Testing ◽  
Specimen Collection ◽  
Asymptomatic Patients ◽  
Nasal Swabs ◽  
The Impact

Abstract Background The use of a remote specimen collection strategy employing a kit designed for unobserved self-collection for SARS-CoV-2 RT-PCR can decrease the use of PPE and exposure risk. To assess the impact of unobserved specimen self-collection on test performance, we examined results from a SARS-CoV-2 qualitative RT-PCR test for self-collected specimens from participants in a return-to-work screening program and assessed the impact of a pooled testing strategy in this cohort. Methods Self-collected anterior nasal swabs from employee return to work programs were tested using the Quest Diagnostics SARS-CoV-2 RT-PCR EUA. The Ct values for the N1 and N3 N-gene targets and a human RNase P (RP) gene control target were tabulated. For comparison, we utilized Ct values from a cohort of HCP-collected specimens from patients with and without COVID-19 symptoms. Results Among 47,923 participants, 1.8% were positive. RP failed to amplify for 13/115,435 (0.011%) specimens. The median (IQR) Cts were 32.7 (25.0-35.7) for N1 and 31.3 (23.8-34.2) for N3. Median Ct values in the self-collected cohort were significantly higher than those of symptomatic, but not asymptomatic patients. Based on Ct values, pooled testing with 4 specimens would have yielded inconclusive results in 67/1,268 (5.2%) specimens but only a single false-negative result. Conclusions Unobserved self-collection of nasal swabs provides adequate sampling for SARS-CoV-2 RT-PCR testing. These findings alleviate concerns of increased false negatives in this context. Specimen pooling could be used for this population as the likelihood of false negative results is very low due when using a sensitive, dual-target methodology.

Effect of pooling udder skin wipes on the detection of influenza A virus in preweaning pigs

2021 ◽  
pp. 104063872110394
Author(s):  
Anne C. de Lara ◽  
Jorge Garrido-Mantilla ◽  
Gustavo Lopez-Moreno ◽  
My Yang ◽  
David E.S.N. Barcellos ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Active Surveillance ◽  
Influenza A ◽  
Sampling Method ◽  
Threshold Value ◽  
Limited Information ◽  
Nasal Swabs ◽  
Lactating Sows ◽  
Suckling Piglets ◽  
Positive Cycle

Influenza A virus (IAV) active surveillance in pigs prior to weaning is commonly conducted by collecting individual samples, mostly nasal swabs. Recently, the use of udder skin wipes collected from lactating sows was identified as an effective sampling method to indicate IAV status of suckling piglets prior to weaning. However, there is limited information on the effect of pooling multiple udder wipes on the ability to detect IAV. We evaluated the effect of pooling 3, 5, or 10 udder wipes on the sensitivity of detecting IAV and compared the results with testing the wipes individually. The likelihood of detecting positive udder wipes decreased with pooling when the initial positive cycle threshold value was ≥31.5; pooling of up to 3 samples could be performed without affecting sensitivity significantly. Our results support pooling of udder skin wipes to conduct surveillance of IAV in pigs prior to weaning.

scholarly journals PSI-7 Prevalence and distribution of Senecavirus A in United States swine feed mills

2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 243-244
Author(s):  
Shannon P Ney ◽  
Vlad Petrovan ◽  
Savannah C Stewart ◽  
Shania Davis ◽  
Megan C Niederwerder ◽  
...  
Keyword(s):  
United States ◽  
Environmental Samples ◽  
Limited Information ◽  
Rt Pcr ◽  
Chi Square ◽  
Late Fall ◽  
Chi Square Test ◽  
Swine Feed ◽  
Ct Data ◽  
Feed Mill

Abstract There is limited information about Senecavirus A (SVA) transmission in the feed supply chain. The objective of this experiment was to determine the prevalence and distribution of SVA in U.S. swine feed mills. A total of 375 samples were collected from 11 surfaces + one feed sample collected from 11 different feed mills in 8 different states. Due to the seasonality associated with pathogenic hazards, the same locations in feed mills were swabbed in Late Fall 2016, Winter 2016/17, and Summer 2017. Surfaces were swabbed according to the Centers for Disease Control protocols for collecting environmental samples using pre-moistened environmental swabs in 5 mL of neutralizing broth. Detection of SVA was performed via RT-PCR and reported in Cycle threshold (Ct). Data were analyzed using the freq procedure of SAS, with chi-square test to determine the prevalence of SVA within season or distribution among feed mill locations. Notably, no mills were manufacturing feed for SVA-positive herds at the time of analysis. Five of 375 samples analyzed positive for SVA, with Ct ranging from 37.4 to 39.9. There was a tendency (P = 0.069) for SVA prevalence to be greater in winter than late fall or summer. There was no detected impact (P = 0.409) of SVA distribution varying across location within feed mill. A sow farm being fed by the mill with SVA on worker shoes was subsequently diagnosed with SVA after the sample as collected. These results indicate that SVA was not widespread throughout the swine feed mills analyzed in this experiment. However, we are unaware of any other studies evaluating presence in feed mills. Little is known about SVV transmission, but the clinically affected farm fed out of the mill with SVV presence suggest further investigation, as feed or feed delivery may be a route of entry into farms.

scholarly journals Serologic SARS-CoV-2 testing in healthcare workers with positive RT-PCR test or Covid-19 related symptoms

2020 ◽  
Author(s):  
Giovanni Visci ◽  
Vittorio Lodi ◽  
Roberta Bonfiglioli ◽  
Tiziana Lazzarotto ◽  
Francesco S. Violante ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Lateral Flow ◽  
Public Hospitals ◽  
Lateral Flow Immunoassay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Limited Information ◽  
Rt Pcr ◽  
Positive Serology ◽  
Serologic Response ◽  
Pcr Test

AbstractBackgroundLimited information is available on prevalence and determinants of serologic response to SARS-CoV-2 infection among healthcare workers (HCWs).MethodsWe analyzed the results of serologic testing with chemiluminescence immunoassay analyzer (CLIA), lateral flow immunoassay (LFIA) and enzyme-linked immunosorbent assay (ELISA) test among 544 HCWs with at least one positive RT-PCR test and 157 HCWs with Covid-19 related symptoms without a positive RT-PCR test from public hospitals in Bologna, Northern Italy. Tests were performed between March and August 2020. We fitted multivariate logistic regression models to identify determinants of positive serology.ResultsThe sensitivity of SARS-CoV-2 was 75.2% (LFIA) and 90.6% (CLIA). No differences in seropositivity were observed by sex, while older HCWs had higher positivity than other groups, and nurses had higher positivity compared to physicians, but not other HCWs. An estimated 73.4% of HCWs with Covid-19 symptoms without RT-PCR test were not infected with SARS-CoV-2.ConclusionsOur study provides the best available data on sensitivity of serologic tests and on determinants of serologic response among HCWs positive for SARS-CoV-2, and provide evidence on the low specificity of Covid-19 related symptoms to identify infected HCWs.SummaryThe sensitivity of SARS-CoV-2 lateral flow immunoassay serology in healthcare workers (HCWs) was 75.2%. Older HCWs and nurses had higher positivity than other groups. An estimated 73.4% of HCWs with Covid-19 symptoms without RT-PCR test were not infected with SARS-CoV-2.

scholarly journals Shedding and transmission of a live attenuated influenza A virus vaccine in pre-weaned pigs under field conditions

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246690
Author(s):  
Gustavo Lopez Moreno ◽  
Jayaveeramuthu Nirmala ◽  
Christa Goodell ◽  
Marie Culhane ◽  
Montserrat Torremorell
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Post Vaccination ◽  
Nasal Swabs ◽  
Common Strategy ◽  
Low Levels ◽  
Live Attenuated Influenza Virus ◽  
Pig Health

Influenza A virus (IAV) is one of the most important respiratory viruses affecting pig health and vaccination is the most common strategy to control influenza infections. In this field study we assessed the onset and duration of shedding of a live attenuated influenza virus (LAIV) vaccine, its ability to transmit to non-vaccinated pigs and whether the LAIV could be aerosolized and detected in the environment. Thirty-three litters (n = 33) of a farm using the LAIV vaccine were selected for the study, a subset of them (n = 12) were left unvaccinated and a subset of piglets (n = 3) in vaccinated litters were also left unvaccinated to serve as sentinels. Selected piglets from the litters were sampled multiple days post vaccination (DPV) by collecting nasal swabs and blood, and were tested using a LAIV vaccine specific RT-PCR assay and hemagglutination inhibition assay against the LAIV strains respectively. Environmental specimens consisting of air and surface wipes were also collected. One hundred percent (21/21) of the vaccinated litters tested LAIV positive 1 DPV and until 6 DPV. In contrast, only five (5/33) of the thirty-three non-vaccinated pigs tested positive during the course of the study. Viable LAIV was confirmed in vaccinated pigs by cell culture and whole genome sequencing. In addition, low levels of LAIV RNA (RT-PCR Ct values ranging between 33 and 38) were detected in all air specimens collected on the day of vaccination and until 6 DPV (3/10). Pigs had maternally derived antibodies reactive against the LAIV strains which may have influenced the degree of shedding observed. Under the conditions of this study, shedding of the LAIV from vaccinated pigs was limited in time, resulted in minimal transmission to non-vaccinated pigs and was detected in low levels in aerosols collected in the vaccinated rooms likely influenced by the presence of maternally derived antibodies against the LAIV strains.

scholarly journals Evaluation of sample collection and transport strategies to enhance yield, accessibility, and biosafety of COVID-19 RT-PCR testing

2021 ◽  
Author(s):  
Padmapriya Banada ◽  
David Elson ◽  
Naranjargal Daivaa ◽  
Claire Park ◽  
Samuel Desind ◽  
...  
Keyword(s):  
Sampling Methods ◽  
Diagnostic Yield ◽  
Sampling Strategy ◽  
Sample Collection ◽  
Rt Pcr ◽  
Viral Inactivation ◽  
Viral Transport ◽  
Nasal Swabs ◽  
Polymerase Chain ◽  
Transport Buffer

ABSTRACTSensitive, accessible, and biosafe sampling methods for COVID-19 reverse-transcriptase polymerase chain reaction (RT-PCR) assays are needed for frequent and widespread testing. We systematically evaluated diagnostic yield across different sample collection and transport workflows, including the incorporation of a viral inactivation buffer. We prospectively collected nasal swabs, oral swabs, and saliva, from 52 COVID-19 RT-PCR-confirmed patients, and nasopharyngeal (NP) swabs from 37 patients. Nasal and oral swabs were placed in both viral transport media (VTM) and eNAT™, a sterilizing transport buffer, prior to testing with the Xpert Xpress SARS-CoV-2 (Xpert) test. The sensitivity of each sampling strategy was compared using a composite positive standard. Overall, swab specimens collected in eNAT showed superior sensitivity compared to swabs in VTM (70% vs 57%, P=0.0022). Direct saliva 90.5%, (95% CI: 82%, 95%), followed by NP swabs in VTM and saliva in eNAT, was significantly more sensitive than nasal swabs in VTM (50%, P<0.001) or eNAT (67.8%, P=0.0012) and oral swabs in VTM (50%, P<0.0001) or eNAT (56%, P<0.0001). Saliva and use of eNAT buffer each increased detection of SARS-CoV-2 with the Xpert test; however, no single sample matrix identified all positive cases.

scholarly journals Real-life evaluation of a rapid antigen test (Panbio™ COVID-19 Ag Rapid Test Device) for SARS-CoV-2 detection in asymptomatic close contacts of COVID-19 patients

2020 ◽  
Author(s):  
Ignacio Torres ◽  
Sandrine Poujois ◽  
Eliseo Albert ◽  
Javier Colomina ◽  
David Navarro
Keyword(s):  
Point Of Care ◽  
Real Life ◽  
Rapid Test ◽  
Optimal Timing ◽  
Upper Respiratory Tract ◽  
Limited Information ◽  
Rt Pcr ◽  
Test Device ◽  
Household Contacts ◽  
Close Contacts

ABSTRACTObjectivesThere is limited information on the performance of rapid antigen detection (RAD) tests to identify SARS-CoV-2-infected asymptomatic individuals. In this field study, we evaluated the Panbio™ COVID-19 Ag Rapid Test Device (Abbott Diagnostics, Jena, Germany) for the purpose.MethodsA total of 634 individuals (355 female; median age, 37 years; range, 9-87) were enrolled. Household (n=338) contacts were tested at a median of 2 days (range, 1-7) after diagnosis of the index case and non-household contacts (n=296) at a median of 6 days (range, 1-7) after exposure. RAD testing was carried out at the point of care. The RT-PCR test used was the TaqPath COVID-19 Combo Kit (Thermo Fisher Scientific, Massachusetts, USA).ResultsIn total, 79 individuals (12.4%) tested positive by RT-PCR, of whom 38 (48.1%) yielded positive RAD results. The overall sensitivity and specificity of the RAD test was 48.1% (95% CI: 37.4-58.9) and 100% (95% CI: 99.3-100), respectively. Sensitivity was higher in household (50.8%; 95% CI: 38.9-62.5) than in non-household (35.7%; 95% CI:16.3-61.2%) contacts. Individuals testing positive by RAD test were more likely (P<0.001) to become symptomatic than their negative counterparts.ConclusionThe Panbio test displays low sensitivity in asymptomatic close contacts of COVID-19 patients, particularly in non-household contacts. Nonetheless, establishing the optimal timing for upper respiratory tract collection in this group seems imperative to pinpoint test sensitivity.

scholarly journals Quantitative Detection and Viral Load Analysis of SARS-CoV-2 in Infected Patients

2020 ◽  
Vol 71 (15) ◽  
pp. 793-798 ◽  
Author(s):  
Fengting Yu ◽  
Liting Yan ◽  
Nan Wang ◽  
Siyuan Yang ◽  
Linghang Wang ◽  
...  
Keyword(s):  
Viral Load ◽  
Target Genes ◽  
Single Gene ◽  
Clinical Staging ◽  
N Gene ◽  
Quantitative Detection ◽  
Imaging Data ◽  
Rt Pcr ◽  
Viral Loads ◽  
Nasal Swabs

Abstract Background Coronavirus disease 2019 (COVID-19) has become a public health emergency. The widely used reverse transcription–polymerase chain reaction (RT-PCR) method has limitations for clinical diagnosis and treatment. Methods A total of 323 samples from 76 COVID-19–confirmed patients were analyzed by droplet digital PCR (ddPCR) and RT-PCR based 2 target genes (ORF1ab and N). Nasal swabs, throat swabs, sputum, blood, and urine were collected. Clinical and imaging data were obtained for clinical staging. Results In 95 samples that tested positive by both methods, the cycle threshold (Ct) of RT-PCR was highly correlated with the copy number of ddPCR (ORF1ab gene, R2 = 0.83; N gene, R2 = 0.87). Four (4/161) negative and 41 (41/67) single-gene positive samples tested by RT-PCR were positive according to ddPCR with viral loads ranging from 11.1 to 123.2 copies/test. The viral load of respiratory samples was then compared and the average viral load in sputum (17 429 ± 6920 copies/test) was found to be significantly higher than in throat swabs (2552 ± 1965 copies/test, P &lt; .001) and nasal swabs (651 ± 501 copies/test, P &lt; .001). Furthermore, the viral loads in the early and progressive stages were significantly higher than that in the recovery stage (46 800 ± 17 272 vs 1252 ± 1027, P &lt; .001) analyzed by sputum samples. Conclusions Quantitative monitoring of viral load in lower respiratory tract samples helps to evaluate disease progression, especially in cases of low viral load.

Field study on swine influenza virus (SIV) infection in weaner pigs and sows

2014 ◽  
Vol 42 (06) ◽  
pp. 351-359 ◽  
Author(s):  
C. Meiners ◽  
S. Loesken ◽  
S. Doehring ◽  
E. Starick ◽  
S. Pesch ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Field Study ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Reproductive Disorders ◽  
Rt Pcr ◽  
Nasal Swabs ◽  
History Of ◽  
Siv Infection ◽  
Weaner Pigs

SummaryObjective: The aim of this field study was to explore the occurrence of and factors associated with the detection of swine influenza virus (SIV) by RTqPCR in weaner pigs and sows from herds with a history of respiratory or reproductive disorders. Material and methods: The sample set was based on nasal swabs from 823 sows (123 submissions) and 562 weaner pigs (80 submissions). Nasal swab samples were taken and submitted by 51 veterinary practices from all over Germany. Corresponding to the pig density most of the submissions ori ginated from the north-western part of Germany. The nasal swabs were used to detect SIV RNA by real-time RT-PCR (RTqPCR). Subtyping of SIV RNA by conventional RT-PCR and sequencing was attempted directly from clinical samples or from isolates when available. The herd characteristics, management and housing conditions of the pig herd as well as the course of the disease were collected by a telephone questionnaire with the herd attending veterinarian. Results: SIV was detected by RTqPCR in 53.8% of the submissions from weaner pigs with a history of respiratory disease. Moreover SIV was detected in 10.6% of the submissions from sows. The predominant endemic subtype found in nasal swabs from sows and weaner pigs was H1N1 (60.5%) whereas subtypes H1N2 (14.0%) and H3N2 (14.0%) were detected less frequently. In addition, human pandemic H1N1 virus or reassortants thereof were found in 11.5%. Conclusion and clinical relevance: The results underline the significance of a SIV infection in young pigs. A significant lower detection of SIV in weaner pigs was associated with the vaccination of piglets against porcine circovirus type 2 (PCV2), possibly indicating an interaction of SIV and PCV2. Most of the positive samples from sows originated from gilts, whereas only two originated from sows. An association between reproductive disorders and the detection of SIV could not be confirmed.

Sign in / Sign up

Export Citation Format

Share Document