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1.
Int J Environ Res Public Health ; 19(1)2021 12 21.
Article in English | MEDLINE | ID: covidwho-1580859

ABSTRACT

High ferritin serum levels can be found in patients with macrophage activation syndrome, and increased serum ferritin due to cytokine storm have been reported in severe COVID-19 patients. Saliva is being increasingly used in COVID-19 tests as a diagnostic sample for virus detection and quantification. This study aimed to evaluate the possible changes in ferritin in saliva in COVID-19 patients. In addition, the effects of different inactivation SARS-CoV-2 treatments in ferritin measurements in saliva, the correlation between ferritin in saliva and serum, and the possible effects of correction of ferritin values by total protein were assessed. Ferritin was measured in saliva from healthy (n = 30) and COVID-19 (n = 65) patients with severe, (n = 18) or mild (n = 47) disease, depending on the need for nasal flow oxygen or assisted respiration. Ferritin was also measured in paired serum and saliva samples (n = 32) from healthy and COVID-19 patients. The evaluated inactivation protocols did not affect the assay's results except the addition of 0.5% SDS. Significantly higher ferritin was found in the saliva of COVID-19 patients (median; 25-75th percentile) (27.75; 9.77-52.2 µg/L), compared with healthy controls (4.21; 2.6-8.08 µg/L). Individuals with severe COVID-19 showed higher ferritin values in saliva (48.7; 18.7-53.9) than mild ones (15.5; 5.28-41.3 µg/L). Significant correlation (r = 0.425; p < 0.001) was found between serum and saliva in ferritin. Ferritin levels were higher in COVID-19 patients in serum and saliva, and the highest values were found in those patients presenting severe symptomatology. In conclusion, ferritin in saliva has the potential to be a biomarker to evaluate severity in patients with COVID-19.


Subject(s)
COVID-19 , Ferritins/analysis , Saliva/chemistry , Biomarkers , COVID-19/diagnosis , Humans
2.
PLoS One ; 16(10): e0259094, 2021.
Article in English | MEDLINE | ID: covidwho-1496528

ABSTRACT

INTRODUCTION: We read, see and hear news from various media sources every day. A large majority of the news is negative. A previous study from our laboratory showed that reading negative news is associated with both increased stress reactivity (measured via the stress hormone cortisol) and recall of the negative news segments in women. OBJECTIVES: The present study investigated the effects of positive news on cortisol stress reactivity, memory and affect using a methodology highly similar to the study on negative news that was previously used by our team. METHODS: Sixty-two healthy participants aged between 18 and 35 years (81% women) were randomly exposed to either positive or neutral news segments, followed by a laboratory stressor. We assessed participants' affect three times during the procedure and measured cortisol in saliva eight times (at 10-minute intervals). Twenty-four hours later, participants were contacted by phone to assess their recall of the news segments. RESULTS: Results showed that exposure to positive news, relative to neutral news, did not modulate participants' cortisol levels in response to the laboratory stressor. Positive news had no impact on memory recall of the news and did not change participants' positive or negative affect. Bayes factors suggested that these nonsignificant results are not attributable to low statistical power. CONCLUSION: Contrary to negative news, positive and neutral news do not modulate stress reactivity, memory and affect. These results suggest that people can stay informed without physiological and psychological costs when the news to which they are exposed adopt a positive or neutral approach.


Subject(s)
Cognition/physiology , Emotions/physiology , Hydrocortisone/analysis , Mass Media , Memory/physiology , Stress, Psychological/physiopathology , Adolescent , Adult , Female , Humans , Male , Saliva/chemistry , Young Adult
3.
Molecules ; 26(21)2021 Oct 31.
Article in English | MEDLINE | ID: covidwho-1488680

ABSTRACT

Early diagnosis with rapid detection of the virus plays a key role in preventing the spread of infection and in treating patients effectively. In order to address the need for a straightforward detection of SARS-CoV-2 infection and assessment of viral spread, we developed rapid, sensitive, extraction-free one-step reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and reverse transcription loop-mediated isothermal amplification (RT-LAMP) tests for detecting SARS-CoV-2 in saliva. We analyzed over 700 matched pairs of saliva and nasopharyngeal swab (NSB) specimens from asymptomatic and symptomatic individuals. Saliva, as either an oral cavity swab or passive drool, was collected in an RNA stabilization buffer. The stabilized saliva specimens were heat-treated and directly analyzed without RNA extraction. The diagnostic sensitivity of saliva-based RT-qPCR was at least 95% in individuals with subclinical infection and outperformed RT-LAMP, which had at least 70% sensitivity when compared to NSBs analyzed with a clinical RT-qPCR test. The diagnostic sensitivity for passive drool saliva was higher than that of oral cavity swab specimens (95% and 87%, respectively). A rapid, sensitive one-step extraction-free RT-qPCR test for detecting SARS-CoV-2 in passive drool saliva is operationally simple and can be easily implemented using existing testing sites, thus allowing high-throughput, rapid, and repeated testing of large populations. Furthermore, saliva testing is adequate to detect individuals in an asymptomatic screening program and can help improve voluntary screening compliance for those individuals averse to various forms of nasal collections.


Subject(s)
COVID-19/diagnosis , COVID-19/genetics , Reverse Transcriptase Polymerase Chain Reaction/methods , COVID-19 Testing/methods , Humans , Mass Screening/methods , Nucleic Acid Amplification Techniques/methods , RNA/isolation & purification , RNA, Viral/genetics , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Saliva/chemistry , Sensitivity and Specificity , Specimen Handling/methods
4.
Sci Rep ; 11(1): 19980, 2021 10 07.
Article in English | MEDLINE | ID: covidwho-1462034

ABSTRACT

The coronavirus disease 2019 (COVID-19) is the latest biological hazard for the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Even though numerous diagnostic tests for SARS-CoV-2 have been proposed, new diagnosis strategies are being developed, looking for less expensive methods to be used as screening. This study aimed to establish salivary vibrational modes analyzed by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy to detect COVID-19 biological fingerprints that allow the discrimination between COVID-19 and healthy patients. Clinical dates, laboratories, and saliva samples of COVID-19 patients (N = 255) and healthy persons (N = 1209) were obtained and analyzed through ATR-FTIR spectroscopy. Then, a multivariate linear regression model (MLRM) was developed. The COVID-19 patients showed low SaO2, cough, dyspnea, headache, and fever principally. C-reactive protein, lactate dehydrogenase, fibrinogen, D-dimer, and ferritin were the most important altered laboratory blood tests, which were increased. In addition, changes in amide I and immunoglobulin regions were evidenced in the FTIR spectra analysis, and the MLRM showed clear discrimination between both groups. Specific salivary vibrational modes employing ATR-FTIR spectroscopy were established; moreover, the COVID-19 biological fingerprint in saliva was characterized, allowing the COVID-19 detection using an MLRM, which could be helpful for the development of new diagnostic devices.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , Saliva/chemistry , Spectroscopy, Fourier Transform Infrared/methods , Adult , Aged , Female , Humans , Immunoglobulins/analysis , Male , Middle Aged , Oxygen/analysis , SARS-CoV-2/isolation & purification
5.
PLoS One ; 16(9): e0257727, 2021.
Article in English | MEDLINE | ID: covidwho-1448574

ABSTRACT

Translators face hectic daily schedules with deadlines they must duly meet. As trainees they receive tuition on how to work swiftly to meet them efficiently. But despite the prominent role of time pressure, its effects on the translation process are still scarcely researched. Studies point to the higher occurrence of errors under stringent time constraints. Most of these studies use key-logging or eye-tracking techniques to identify the problems encountered. But no attempt has yet been made to measure the physiological effects of time pressure in English-to-Spanish translation and their interplay with trainees' psychological state. The present study researches the influence of time pressure on translation by exploring trainees' physiological response (i.e., salivary cortisol) and psychological traits (i.e., self-esteem and anxiety). 33 Spanish translation trainees translated 3 English literary texts under different time pressure conditions: Text 1 (no time limit), Text 2 (10 minutes), Text 3 (5 minutes). Regression analysis results showed that higher cortisol levels during preparation predicted higher number of meaning errors in Text 1 and lower number of translated words in Text 2 and 3. Besides, higher trait anxiety emerged as predictor of lower number of translated words, but higher accuracy under extreme time constraints and in the absence of time pressure. Higher self-esteem correlated with lower levels of anxiety and lower levels of cortisol during preparation and recovery, suggesting that it may act as a protective factor against stress. And yet, the regression analysis showed that higher self-esteem predicted lower meaning and total accuracy under extreme time pressure. Besides, in our correlation analysis self-esteem was positively related to the number of translated words in Text 2 and 3. Results suggest that even if self-esteem could be a protective factor against stress, it may also have a negative effect on task performance mediated by overconfidence.


Subject(s)
Anxiety/metabolism , Hydrocortisone/analysis , Occupational Stress/psychology , Saliva/chemistry , Female , Humans , Male , Regression Analysis , Self Concept , Self Report , Time Factors , Young Adult
6.
Mol Oral Microbiol ; 36(6): 291-294, 2021 12.
Article in English | MEDLINE | ID: covidwho-1398524

ABSTRACT

COVID-19, caused by the SARS-CoV-2 virus, has become a significant global public health problem, with a wide variety of clinical manifestations and disease progression outcomes. LncRNAs are key regulators of the immune response and have been associated with COVID-19 risk infection. Previous studies focused mainly on in-silico analysis of lncRNA expression in the lungs or peripheral blood cells. We evaluated the expression of lncRNAs NEAT1, MALAT1, and MIR3142 in saliva and nasopharyngeal swab from SARS-CoV-2 positive (n = 34) and negative patients (n = 46). A higher expression of the lncRNAs NEAT1 and MALAT1 (p < 0.05) were found in positive samples. NEAT1 had a higher expression mainly in saliva samples (p < 0.001), and MALAT1 was upregulated in nasopharyngeal samples (p < 0.05). Area under the ROC curve for NEAT1 in saliva was 0.8067. This study was the first to investigate the expression of lncRNAs in saliva and nasopharyngeal samples of COVID-19 patients, which gives new insights into the initial response to infection and infectivity and may provide new biomarkers for severity and targets for therapy.


Subject(s)
COVID-19 , RNA, Long Noncoding/genetics , Saliva , Humans , Nasopharynx/chemistry , RNA, Long Noncoding/analysis , SARS-CoV-2 , Saliva/chemistry
7.
Sci Rep ; 11(1): 16430, 2021 08 12.
Article in English | MEDLINE | ID: covidwho-1356582

ABSTRACT

Until there is an effective implementation of COVID-19 vaccination program, a robust testing strategy, along with prevention measures, will continue to be the most viable way to control disease spread. Such a strategy should rely on disparate diagnostic tests to prevent a slowdown in testing due to lack of materials and reagents imposed by supply chain problems, which happened at the beginning of the pandemic. In this study, we have established a single-tube test based on RT-LAMP that enables the visual detection of less than 100 viral genome copies of SARS-CoV-2 within 30 min. We benchmarked the assay against the gold standard test for COVID-19 diagnosis, RT-PCR, using 177 nasopharyngeal RNA samples. For viral loads above 100 copies, the RT-LAMP assay had a sensitivity of 100% and a specificity of 96.1%. Additionally, we set up a RNA extraction-free RT-LAMP test capable of detecting SARS-CoV-2 directly from saliva samples, albeit with lower sensitivity. The saliva was self-collected and the collection tube remained closed until inactivation, thereby ensuring the protection of the testing personnel. As expected, RNA extraction from saliva samples increased the sensitivity of the test. To lower the costs associated with RNA extraction, we performed this step using an alternative protocol that uses plasmid DNA extraction columns. We also produced the enzymes needed for the assay and established an in-house-made RT-LAMP test independent of specific distribution channels. Finally, we developed a new colorimetric method that allowed the detection of LAMP products by the visualization of an evident color shift, regardless of the reaction pH.


Subject(s)
COVID-19 Testing/methods , COVID-19/virology , Colorimetry/methods , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/methods , SARS-CoV-2/isolation & purification , COVID-19/diagnosis , Humans , Pandemics , Portugal/epidemiology , RNA, Viral/genetics , SARS-CoV-2/genetics , Saliva/chemistry , Saliva/virology , Sensitivity and Specificity
8.
Sci Rep ; 11(1): 16051, 2021 08 06.
Article in English | MEDLINE | ID: covidwho-1345585

ABSTRACT

With an increasing body of evidence that SARS-CoV-2 is an airborne pathogen, droplet character formed during speech, coughs, and sneezes are important. Larger droplets tend to fall faster and are less prone to drive the airborne transmission pathway. Alternatively, small droplets (aerosols) can remain suspended for long time periods. The small size of SARS-CoV-2 enables it to be encapsulated in these aerosols, thereby increasing the pathogen's ability to be transmitted via airborne paths. Droplet formation during human respiratory events relates to airspeed (speech, cough, sneeze), fluid properties of the saliva/mucus, and the fluid content itself. In this work, we study the fluidic drivers (fluid properties and content) and their influence on factors relating to transmissibility. We explore the relationship between saliva fluid properties and droplet airborne transmission paths. Interestingly, the natural human response appears to potentially work with these drivers to mitigate pathogen transmission. In this work, the saliva is varied using two approaches: (1) modifying the saliva with colloids that increase the viscosity/surface tension, and (2) stimulating the saliva content to increased/decreased levels. Through modern experimental and numerical flow diagnostic methods, the character, content, and exposure to droplets and aerosols are all evaluated. The results indicate that altering the saliva properties can significantly impact the droplet size distribution, the formation of aerosols, the trajectory of the bulk of the droplet plume, and the exposure (or transmissibility) to droplets. High-fidelity numerical methods used and verify that increased droplet size character enhances droplet fallout. In the context of natural saliva response, we find previous studies indicating natural human responses of increased saliva viscosity from stress and reduced saliva content from either stress or illness. These responses both favorably correspond to reduced transmissibility. Such a finding also relates to potential control methods, hence, we compared results to a surgical mask. In general, we find that saliva alteration can produce fewer and larger droplets with less content and aerosols. Such results indicate a novel approach to alter SARS-CoV-2's transmission path and may act as a way to control the COVID-19 pandemic, as well as influenza and the common cold.


Subject(s)
COVID-19/transmission , SARS-CoV-2/isolation & purification , Saliva/virology , Aerosols/chemistry , Air Microbiology , Colloids/chemistry , Cough , Humans , Pandemics , Saliva/chemistry , Sneezing , Viscosity
9.
PLoS One ; 16(8): e0255690, 2021.
Article in English | MEDLINE | ID: covidwho-1344158

ABSTRACT

Saliva is an attractive specimen type for asymptomatic surveillance of COVID-19 in large populations due to its ease of collection and its demonstrated utility for detecting RNA from SARS-CoV-2. Multiple saliva-based viral detection protocols use a direct-to-RT-qPCR approach that eliminates nucleic acid extraction but can reduce viral RNA detection sensitivity. To improve test sensitivity while maintaining speed, we developed a robotic nucleic acid extraction method for detecting SARS-CoV-2 RNA in saliva samples with high throughput. Using this assay, the Free Asymptomatic Saliva Testing (IGI FAST) research study on the UC Berkeley campus conducted 11,971 tests on supervised self-collected saliva samples and identified rare positive specimens containing SARS-CoV-2 RNA during a time of low infection prevalence. In an attempt to increase testing capacity, we further adapted our robotic extraction assay to process pooled saliva samples. We also benchmarked our assay against nasopharyngeal swab specimens and found saliva methods require further optimization to match this gold standard. Finally, we designed and validated a RT-qPCR test suitable for saliva self-collection. These results establish a robotic extraction-based procedure for rapid PCR-based saliva testing that is suitable for samples from both symptomatic and asymptomatic individuals.


Subject(s)
COVID-19 Testing/methods , RNA, Viral/isolation & purification , SARS-CoV-2/genetics , Adult , COVID-19/diagnosis , Female , Humans , Male , Mass Screening/methods , RNA/genetics , RNA/isolation & purification , RNA, Viral/genetics , Real-Time Polymerase Chain Reaction/methods , Robotics/methods , Saliva/chemistry , Specimen Handling/methods
10.
Eur J Clin Microbiol Infect Dis ; 40(10): 2199-2206, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1338226

ABSTRACT

BACKGROUND: The current practice of COVID-19 diagnosis worldwide is the use of oro-nasopharyngeal (ONP) swabs. Our study aim was to explore mouthwash (MW) as an alternative diagnostic method, in light of the disadvantages of ONP swabs. METHODS: COVID-19 outpatients molecular-confirmed by ONP swab were repeatedly examined with ONP swab and MW with normal saline (0.9%). Other types of fluids were compared to normal saline. The Cq values obtained with each method were compared. RESULTS: Among 137 pairs of ONP swabs and MW samples, 84.6% (116/137) of ONP swabs were positive by at least one of the genes (N, E, R). However MW detected 70.8% (97/137) of samples as positive, which means 83.6% (97/116) out of positive ONP swabs, missing mainly Cq value > 30. In both methods, the N gene was the most sensitive one. Therefore, MW samples targeting N gene, which was positive in 95/137 (69.3%), are comparable to ONP swabs targeting E and R genes which gave equal results-95/137 (69.3%) and 90/137 (65.7%), respectively. Comparing saline MW to distilled water gave equal results, while commercial mouth-rinsing solutions were less sensitive. CONCLUSIONS: MW with normal saline, especially when tested by N gene, can effectively detect COVID-19 patients. Furthermore, this method was not inferior when compared to R and E genes of ONP swabs, which are common targets in many laboratories around the world.


Subject(s)
COVID-19/diagnosis , Mouthwashes/analysis , SARS-CoV-2/isolation & purification , Saliva/virology , Adult , Aged , COVID-19/virology , COVID-19 Nucleic Acid Testing , Female , Humans , Male , Middle Aged , Prospective Studies , SARS-CoV-2/genetics , Saliva/chemistry , Young Adult
11.
FASEB J ; 35(8): e21745, 2021 08.
Article in English | MEDLINE | ID: covidwho-1288103

ABSTRACT

Studies are needed to identify useful biomarkers to assess the severity and prognosis of COVID-19 disease, caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2) virus. Here, we examine the levels of various plasma species of the SARS-CoV-2 host receptor, the angiotensin-converting enzyme 2 (ACE2), in patients at different phases of the infection. Human plasma ACE2 species were characterized by immunoprecipitation and western blotting employing antibodies against the ectodomain and the C-terminal domain, using a recombinant human ACE2 protein as control. In addition, changes in the cleaved and full-length ACE2 species were also examined in serum samples derived from humanized K18-hACE2 mice challenged with a lethal dose of SARS-CoV-2. ACE2 immunoreactivity was present in human plasma as several molecular mass species that probably comprise truncated (70 and 75 kDa) and full-length forms (95, 100, 130, and 170 kDa). COVID-19 patients in the acute phase of infection (n = 46) had significantly decreased levels of ACE2 full-length species, while a truncated 70-kDa form was marginally higher compared with non-disease controls (n = 26). Levels of ACE2 full-length species were in the normal range in patients after a recovery period with an interval of 58-70 days (n = 29), while the 70-kDa species decreased. Levels of the truncated ACE2 species served to discriminate between individuals infected by SARS-CoV-2 and those infected with influenza A virus (n = 17). In conclusion, specific plasma ACE2 species are altered in patients with COVID-19 and these changes normalize during the recovery phase. Alterations in ACE2 species following SARS-CoV-2 infection warrant further investigation regarding their potential usefulness as biomarkers for the disease process and to asses efficacy during vaccination.


Subject(s)
Angiotensin-Converting Enzyme 2/blood , COVID-19/blood , SARS-CoV-2 , Adult , Aged , Aged, 80 and over , Angiotensin-Converting Enzyme 2/cerebrospinal fluid , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/urine , Biomarkers/blood , Brain Chemistry , Colon/chemistry , Female , Humans , Liver/chemistry , Male , Middle Aged , Saliva/chemistry
12.
Psychoneuroendocrinology ; 132: 105345, 2021 10.
Article in English | MEDLINE | ID: covidwho-1284482

ABSTRACT

Loneliness is associated with multiple forms of psychopathology in youth. However, we do not yet know how loneliness gets "under the skin" in ways that may impact the long-term health and development of early adolescents. In particular, loneliness may influence youths' patterns of diurnal cortisol, an index of hypothalamic-pituitary-adrenal (HPA) axis functioning and a central predictor of health across the lifespan. The current severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2, or COVID-19) pandemic represents a salient period in which to study the consequences of loneliness, as recent work has provided evidence that the physical-distancing measures put in place to contain the virus have resulted in greater loneliness, particularly among youth. Thus, the current study aimed to examine the prospective association between loneliness during the COVID-19 pandemic and diurnal cortisol in early adolescents. We found that greater loneliness was associated with higher levels of cortisol at waking and a blunted cortisol awakening response (CAR). These results held even when controlling for covariates that can influence diurnal trajectories of cortisol. Critically, this pattern of HPA-axis functioning increases risk for adverse mental and physical health outcomes across adolescence and into adulthood. This study is the first to examine the prospective association between loneliness and diurnal cortisol in early adolescence, and the first to identify mechanisms that contribute to biological markers of distress during the COVID-19 pandemic. Findings underscore the importance of developing and distributing strategies to mitigate feelings of loneliness among youth.


Subject(s)
COVID-19 , Circadian Rhythm , Hydrocortisone/metabolism , Hypothalamo-Hypophyseal System/metabolism , Loneliness/psychology , Pituitary-Adrenal System/metabolism , Adolescent , Female , Humans , Hydrocortisone/analysis , Male , Pituitary-Adrenal Function Tests , SARS-CoV-2 , Saliva/chemistry
13.
Angew Chem Int Ed Engl ; 60(31): 17102-17107, 2021 07 26.
Article in English | MEDLINE | ID: covidwho-1245354

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in an unprecedented need for diagnostic testing that is critical in controlling the spread of COVID-19. We propose a portable infrared spectrometer with purpose-built transflection accessory for rapid point-of-care detection of COVID-19 markers in saliva. Initially, purified virion particles were characterized with Raman spectroscopy, synchrotron infrared (IR) and AFM-IR. A data set comprising 171 transflection infrared spectra from 29 subjects testing positive for SARS-CoV-2 by RT-qPCR and 28 testing negative, was modeled using Monte Carlo Double Cross Validation with 50 randomized test and model sets. The testing sensitivity was 93 % (27/29) with a specificity of 82 % (23/28) that included positive samples on the limit of detection for RT-qPCR. Herein, we demonstrate a proof-of-concept high throughput infrared COVID-19 test that is rapid, inexpensive, portable and utilizes sample self-collection thus minimizing the risk to healthcare workers and ideally suited to mass screening.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , Saliva/chemistry , Animals , Chlorocebus aethiops , Cohort Studies , Discriminant Analysis , Humans , Least-Squares Analysis , Monte Carlo Method , Point-of-Care Testing , Proof of Concept Study , SARS-CoV-2 , Sensitivity and Specificity , Specimen Handling , Spectrophotometry, Infrared , Vero Cells
14.
PLoS One ; 16(5): e0250202, 2021.
Article in English | MEDLINE | ID: covidwho-1216953

ABSTRACT

Diagnosis of any infectious disease is vital for opportune treatment and to prevent dissemination. RT-qPCR tests for detection of SARS-CoV-2, the causative agent for COVID-19, are ideal in a hospital environment. However, mass testing requires cheaper and simpler tests, especially in settings that lack sophisticated machinery. The most common current diagnostic method is based on nasopharyngeal sample collection, RNA extraction, and RT-qPCR for amplification and detection of viral nucleic acids. Here, we show that samples obtained from nasopharyngeal swabs in VTM and in saliva can be used with or without RNA purification in an isothermal loop-mediated amplification (LAMP)-based assay, with 60-93% sensitivity for SARS-CoV-2 detection as compared to standard RT-qPCR tests. A series of simple modifications to standard RT-LAMP published methods to stabilize pH fluctuations due to salivary acidity resulted in a significant improvement in reliability, opening new avenues for efficient, low-cost testing of COVID-19 infection.


Subject(s)
COVID-19/diagnosis , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/methods , RNA, Viral/analysis , SARS-CoV-2/genetics , Saliva/chemistry , COVID-19/virology , False Positive Reactions , Humans , Hydrogen-Ion Concentration , Limit of Detection , Nasopharynx/virology , SARS-CoV-2/isolation & purification , Sensitivity and Specificity
15.
PLoS One ; 16(4): e0250158, 2021.
Article in English | MEDLINE | ID: covidwho-1183679

ABSTRACT

While the world awaits a widely available COVID-19 vaccine, availability of testing is limited in many regions and can be further compounded by shortages of reagents, prolonged processing time and delayed results. One approach to rapid testing is to leverage the volatile organic compound (VOC) signature of SARS-CoV-2 infection. Detection dogs, a biological sensor of VOCs, were utilized to investigate whether SARS-CoV-2 positive urine and saliva patient samples had a unique odor signature. The virus was inactivated in all training samples with either detergent or heat treatment. Using detergent-inactivated urine samples, dogs were initially trained to find samples collected from hospitalized patients confirmed with SARS-CoV-2 infection, while ignoring samples collected from controls. Dogs were then tested on their ability to spontaneously recognize heat-treated urine samples as well as heat-treated saliva from hospitalized SARS-CoV-2 positive patients. Dogs successfully discriminated between infected and uninfected urine samples, regardless of the inactivation protocol, as well as heat-treated saliva samples. Generalization to novel samples was limited, particularly after intensive training with a restricted sample set. A unique odor associated with SARS-CoV-2 infection present in human urine as well as saliva, provides impetus for the development of odor-based screening, either by electronic, chemical, or biological sensing methods. The use of dogs for screening in an operational setting will require training with a large number of novel SARS-CoV-2 positive and confirmed negative samples.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , Working Dogs/psychology , Animals , COVID-19/urine , Dogs , Female , Humans , Male , Mass Screening , Proof of Concept Study , SARS-CoV-2/isolation & purification , Saliva/chemistry , Specimen Handling/methods , Volatile Organic Compounds/chemistry
16.
Front Cell Infect Microbiol ; 11: 632646, 2021.
Article in English | MEDLINE | ID: covidwho-1167304

ABSTRACT

A major bottleneck in scaling-up COVID-19 testing is the need for sophisticated instruments and well-trained healthcare professionals, which are already overwhelmed due to the pandemic. Moreover, the high-sensitive SARS-CoV-2 diagnostics are contingent on an RNA extraction step, which, in turn, is restricted by constraints in the supply chain. Here, we present CASSPIT (Cas13 Assisted Saliva-based & Smartphone Integrated Testing), which will allow direct use of saliva samples without the need for an extra RNA extraction step for SARS-CoV-2 detection. CASSPIT utilizes CRISPR-Cas13a based SARS-CoV-2 RNA detection, and lateral-flow assay (LFA) readout of the test results. The sample preparation workflow includes an optimized chemical treatment and heat inactivation method, which, when applied to COVID-19 clinical samples, showed a 97% positive agreement with the RNA extraction method. With CASSPIT, LFA based visual limit of detection (LoD) for a given SARS-CoV-2 RNA spiked into the saliva samples was ~200 copies; image analysis-based quantification further improved the analytical sensitivity to ~100 copies. Upon validation of clinical sensitivity on RNA extraction-free saliva samples (n = 76), a 98% agreement between the lateral-flow readout and RT-qPCR data was found (Ct<35). To enable user-friendly test results with provision for data storage and online consultation, we subsequently integrated lateral-flow strips with a smartphone application. We believe CASSPIT will eliminate our reliance on RT-qPCR by providing comparable sensitivity and will be a step toward establishing nucleic acid-based point-of-care (POC) testing for COVID-19.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , CRISPR-Cas Systems , RNA, Viral/isolation & purification , SARS-CoV-2/isolation & purification , Saliva/chemistry , Humans , Molecular Diagnostic Techniques/methods , Point-of-Care Testing , Real-Time Polymerase Chain Reaction , SARS-CoV-2/genetics , Sensitivity and Specificity , Smartphone , Specimen Handling/methods , Workflow
17.
J Photochem Photobiol B ; 217: 112168, 2021 Apr.
Article in English | MEDLINE | ID: covidwho-1117166

ABSTRACT

Worldwide shortages of personal protective equipment during COVID-19 pandemic has forced the implementation of methods for decontaminating face piece respirators such as N95 respirators. The use of UV irradiation to reduce bioburden of used respirators attracts attention, making proper testing protocols of uttermost importance. Currently artificial saliva is used but its comparison to human saliva from the UV disinfection perspective is lacking. Here we characterize UV spectra of human and artificial saliva, both fresh and after settling, to test for possible interference for UV-based disinfection. ASTM 2720 artificial saliva recipe (with either porcine or bovine mucin) showed many discrepancies from average (N = 18) human saliva, with different mucins demonstrating very different UV absorbance spectra, resulting in very different UV transmittance at different wavelength. Reducing porcine mucin concentration from 3 to 1.7 g/L brought UVA254 in the artificial saliva to that of average human saliva (although not for other wavelengths), allowing 254 nm disinfection experiments. Phosphate saline and modified artificial saliva were spiked with 8.6 log CFU/ml B. subtilis spores (ATCC 6633) and irradiated at dose of up to 100 mJ/cm2, resulting in 5.9 log inactivation for a saline suspension, and 2.8 and 1.1 log inactivation for ASTM-no mucin and ASTM-1.7 g/L porcine mucin 2 µL dried droplets, respectively. UVC irradiation of spores dried in human saliva resulted in 2.3 and 1.5 log inactivation, depending on the size of the droplets (2 vs 10 µL, respectively) dried on a glass surface. Our results suggest that in the presence of the current standard dried artificial saliva it is unlikely that UVC can achieve 6 log inactivation of B. subtilis spores using a realistic UV dose (e.g. less than 2 J/cm2) and the ATSM saliva recipe should be revised for UV decontamination studies.


Subject(s)
Disinfection/methods , Saliva/chemistry , Saliva/radiation effects , Animals , Bacillus subtilis/radiation effects , Canada , Cattle , Decontamination/methods , Female , Humans , Israel , Male , Mucins/chemistry , N95 Respirators , Saliva/microbiology , Specimen Handling/methods , Spectrophotometry, Ultraviolet , Spores, Bacterial/radiation effects , Ultraviolet Rays
18.
Sci Rep ; 11(1): 4943, 2021 03 02.
Article in English | MEDLINE | ID: covidwho-1114729

ABSTRACT

The pandemic of COVID-19 is continuously spreading, becoming a worldwide emergency. Early and fast identification of subjects with a current or past infection must be achieved to slow down the epidemiological widening. Here we report a Raman-based approach for the analysis of saliva, able to significantly discriminate the signal of patients with a current infection by COVID-19 from healthy subjects and/or subjects with a past infection. Our results demonstrated the differences in saliva biochemical composition of the three experimental groups, with modifications grouped in specific attributable spectral regions. The Raman-based classification model was able to discriminate the signal collected from COVID-19 patients with accuracy, precision, sensitivity and specificity of more than 95%. In order to translate this discrimination from the signal-level to the patient-level, we developed a Deep Learning model obtaining accuracy in the range 89-92%. These findings have implications for the creation of a potential Raman-based diagnostic tool, using saliva as minimal invasive and highly informative biofluid, demonstrating the efficacy of the classification model.


Subject(s)
COVID-19/diagnosis , Saliva/chemistry , Spectrum Analysis, Raman/methods , Aged , Aged, 80 and over , Antibodies, Viral/analysis , Comorbidity , Computational Biology , Deep Learning , Female , Humans , Male , Middle Aged , Normal Distribution , Reproducibility of Results , Sensitivity and Specificity
19.
Clin Chim Acta ; 517: 54-59, 2021 Jun.
Article in English | MEDLINE | ID: covidwho-1091904

ABSTRACT

BACKGROUND AND AIM: SARS-CoV-2 quick testing is relevant for the containment of new pandemic waves. Antigen testing in self-collected saliva might be useful. We compared salivary and naso-pharyngeal swab (NPS) SARS-CoV-2 antigen detection by a rapid chemiluminescent assay (CLEIA) and two different point-of-care (POC) immunochromatographic assays, with results of molecular testing. METHODS: 234 patients were prospectively enrolled. Paired self-collected saliva (Salivette) and NPS were obtained to perform rRT-PCR, chemiluminescent (Lumipulse G) and POC (NPS: Fujirebio and Abbott; saliva: Fujirebio) for SARS-CoV-2 antigen detection. RESULTS: The overall agreement between NPS and saliva rRT-PCR was 78.7%, reaching 91.7% at the first week from symptoms. SARS-CoV-2 CLEIA antigen was highly accurate in distinguishing positive and negative NPS (ROC-AUC = 0.939, 95%CI:0.903-0.977), with 81.6% sensitivity and 93.8% specificity. This assay on saliva reached the optimal value within 7 days from symptoms onset (Sensitivity: 72%; Specificity: 97%). Saliva POC antigen was limited in sensitivity (13%), performing better in NPS (Sensitivity: 48% and 66%; Specificity: 100% and 99% for Espline and Abbott respectively), depending on viral loads. CONCLUSIONS: Self-collected saliva is a valid alternative to NPS for SARS-CoV-2 detection by molecular, but also by CLEIA antigen testing, which is therefore potentially useful for large scale screening.


Subject(s)
Antigens, Viral/analysis , COVID-19/diagnosis , Saliva/chemistry , Humans , Luminescent Measurements , Nasopharynx/virology , Pandemics , Point-of-Care Testing , Prospective Studies , SARS-CoV-2 , Sensitivity and Specificity
20.
BMC Infect Dis ; 20(1): 536, 2020 Jul 23.
Article in English | MEDLINE | ID: covidwho-1072981

ABSTRACT

BACKGROUND: As the COVID-19 pandemic continues to spread, early, ideally real-time, identification of SARS-CoV-2 infected individuals is pivotal in interrupting infection chains. Volatile organic compounds produced during respiratory infections can cause specific scent imprints, which can be detected by trained dogs with a high rate of precision. METHODS: Eight detection dogs were trained for 1 week to detect saliva or tracheobronchial secretions of SARS-CoV-2 infected patients in a randomised, double-blinded and controlled study. RESULTS: The dogs were able to discriminate between samples of infected (positive) and non-infected (negative) individuals with average diagnostic sensitivity of 82.63% (95% confidence interval [CI]: 82.02-83.24%) and specificity of 96.35% (95% CI: 96.31-96.39%). During the presentation of 1012 randomised samples, the dogs achieved an overall average detection rate of 94% (±3.4%) with 157 correct indications of positive, 792 correct rejections of negative, 33 incorrect indications of negative or incorrect rejections of 30 positive sample presentations. CONCLUSIONS: These preliminary findings indicate that trained detection dogs can identify respiratory secretion samples from hospitalised and clinically diseased SARS-CoV-2 infected individuals by discriminating between samples from SARS-CoV-2 infected patients and negative controls. This data may form the basis for the reliable screening method of SARS-CoV-2 infected people.


Subject(s)
Betacoronavirus/isolation & purification , Coronavirus Infections/diagnosis , Coronavirus Infections/virology , Mass Screening/methods , Odorants/analysis , Pneumonia, Viral/diagnosis , Pneumonia, Viral/virology , Animals , Bronchi/chemistry , Bronchi/virology , COVID-19 , Case-Control Studies , Dogs , Double-Blind Method , Humans , Pandemics/prevention & control , Pilot Projects , SARS-CoV-2 , Saliva/chemistry , Saliva/virology , Sensitivity and Specificity
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