Patients with coronavirus disease‐2019 may be discharged based on clinical resolution of symptoms, and evidence for viral RNA clearance from the upper respiratory tract. Understanding the severe ...acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) viral clearance profile is crucial to establish a re‐testing plan on discharge and ending isolation of patients. We aimed to evaluate the number of days that a patient needed to achieve undetectable levels of SARS‐CoV‐2 in upper respiratory tract specimens (nasopharyngeal swab and/or an oropharyngeal swab). The clearance and persistence of viral RNA was evaluated in two groups of positive patients: those who achieved two negative reverse transcription‐polymerase chain reaction (RT‐PCR) tests and those who kept testing positive. Patients were organized thereafter in two subgroups, mild illness patients discharged home and inpatients who had moderate to severe illness. Results from RT‐PCR tests were then correlated with results from the evaluation of the immune response. The study evidenced that most patients tested positive for more than 2 weeks and that persistence of viral RNA is not necessarily associated with severe disease but may result from a weaker immune response instead.
Highlights
Viral RNA was evaluated in two groups of patients: those who achieved two negative RT‐PCR tests and those who kept testing positive.
Patients were organized thereafter in two subgroups, mild and moderate/severe illness patients.
Most patients from either group tested positive for more than two weeks.
Mild illness patients maintained viral RNA for a longer period of time and presented lower IgG titers than moderate/severe illness patients.
We hypothesize that the exposition of mild illness patients to SARS‐CoV‐2 did not elicit an effective immune response, explaining the need of more time to viral RNA clearance.
A prospective cohort study was conducted during the Delta and Omicron severe acute respiratory syndrome coronavirus type 2 (SARS‐CoV‐2) epidemic waves from paired nasopharyngeal swab (NPS or NP swab) ...and saliva samples taken from 624 participants. The study aimed to assess if any differences among participants from both waves could be observed and if any difference in molecular diagnostic performance could be observed among the two sample types. Samples were transported immediately to the laboratory to ensure the highest possible sample quality without any freezing and thawing steps before processing. Nucleic acids from saliva and NPS were prospectively extracted and SARS‐CoV‐2 was detected using a real‐time reverse‐transcription polymerase chain reaction. All observed results were statistically analyzed. Although the results obtained with NP and saliva agreed overall, higher viral loads were observed in NP swabs regardless of the day of specimen collection in both SARS‐CoV‐2 epidemic waves. No significant difference could be observed between the two epidemic waves characterized by Delta or Omicron SARS‐CoV‐2. To note, Delta infection resulted in higher viral loads both in NP and saliva and more symptoms, including rhinorrhea, cough, and dyspnea, whereas Omicron wave patients more frequently reported sore throat. An increase in the mean log RNA of SARS‐CoV‐2 was observed with the number of expressed symptoms in both waves, however, the difference was not significant. Data confirmed that results from saliva were concordant with those from NP swabs, although saliva proved to be a challenging sample with frequent inhibitions that required substantial retesting.
•Cyt b gene a potential molecular tool to identify Cow leathers.•Primers and probes designed are unique and specific.•Low levels of mtDNA extracted from finished cow leathers facilitate PCR ...amplification.
Authentication of true (genuine) cow leathers is in high demand to promote merchandise and economic growth. The present study employs RT-PCR-based TaqMan assay to facilitate the identification. Species-specific primers and probes were designed utilizing the existing NCBI data on mitochondrial DNA (mtDNA) genes, particularly the cytochrome b region (Cyt b). Mitochondrial DNA extracted from leather samples of both Bos taurus and Bos indicus and analyzed following the appropriate procedures. The RT-PCR results showed the designed primers and probes are exceptionally precise for cow leather samples. The established detection limit for the assay is estimated as 0.1 ng of DNA. In summary, the amplifiable mtDNA extracted from finished leather enables the identification of authentic cow leathers using the RT-PCR TaqMan assay, representing a pioneering report in this field.
Background and Objectives
Although about 80% of coronavirus disease‐2019 (COVID‐19) cases are reported to be mild, the remaining 20% of cases often result in severe disease with the potential of ...crushing already overstrained health care services. There has been sustainable growth of COVID‐19 cases worldwide since mid‐May 2020. To keep tabs on community transmission of COVID‐19 infection screening of the samples from a large population is needed which includes asymptomatic/symptomatic individuals along with the migrant population. This requires extra resources, man power, and time for detection of severe acute respiratory syndrome coronavirus 2 by real‐time polymerase chain reaction (RT‐PCR). In the current scenario, the pooled sample testing strategy advocated by the Indian Council of Medical Research, New Delhi is a new approach that is very promising in resource‐limited settings. In this study, we have evaluated the pooled strategy in terms of accurate testing results, utilization of consumables, and identification of borderline positive cases.
Materials and Methods
Between April and June 2020, we performed COVID‐19 testing by RT‐PCR from areas with varying prevalence of population referred to COVID laboratory, Dr Ram Manohar Lohia Institute of Medical Sciences, Lucknow. In the first step, the samples are collated into pools of 5 or 10. These pools are tested by RT‐PCR. Negative pools were reported as negative whereas positive pools of 5 and 10 are then deconvoluted and each sample is tested individually.
Results
In the present study, we tested 4620 samples in 462 pools of 10 and 14 940 samples in 2990 pools of 5. Among 10 samples pool, 61 (13%) pools flagged positive in the first step. In the second step, among 61 pools (610 samples) deconvoluted strategy was followed in which 72 individual samples came positive. The pooled‐sample testing strategy helps saves substantial resources and time during surge testing and enhanced pandemic surveillance. This approach requires around 76% to 93% fewer tests done in low to moderate prevalence settings and group sizes up to 5–10 in a population, compared to individual testing.
Conclusions
Pooled‐sample PCR analysis strategies can save substantial resources and time for COVID‐19 mass testing in comparison with individual testing without compromising the resulting outcome of the test. In particular, the pooled‐sample approach can facilitate mass screening in the early coming stages of COVID‐19 outbreaks, especially in low‐ and middle‐income settings, and control the spread by meticulous testing of all risk groups.
Background: Hemoglobin plays a vital role in tissue oxygenation. Hence anemia might significantly affect the prognosis of COVID 19 pneumonia, where in there is development of tissue hypoxia due to ...the disease pathogenesis.
Aims and Objectives: To correlate the severity of anemia in COVID 19 patients with disease outcomes in patients admitted in a tertiary care setting.
Materials and Methods: The prospective single-center study considered adults patients of both the gender, diagnosed with COVID-19 infection by RT-PCR technique. Necessary demographic, clinical data and Hemoglobin level were collected and selected subjects were followed-up until discharge or death. Subjects were classified as those who survived and succumbed to death. t-test was used for comparing continuous variables and chi-square test for categorical data between the groups.
Results: The study included 1212 patients, where in there was a statistically significant correlation between low hemoglobin level and the disease outcome. The hemoglobin levels were significantly lower in patients who died than the patients who were discharged.
Conclusion: Severe anemia as noted by low hemoglobin level was associated with higher mortality than subjects with normal hemoglobin.
•We describe the presence of 24 respiratory pathogens as co-infections in COVID-19 patients.•Most of these co-infections occurred 1–4 days after the onset of disease in COVID-19 patients.•The ...proportion of viral co-infections, fungal co-infections and bacterial-fungal co-infections were the highest in severe COVID-19 cases.
Accumulating evidence shows that microbial co-infection increases the risk of disease severity in humans. There have been few studies about SARS-CoV-2 co-infection with other pathogens. In this retrospective study, 257 laboratory-confirmed COVID-19 patients in Jiangsu Province were enrolled from January 22 to February 2, 2020. They were re-confirmed by real-time RT-PCR and tested for 39 respiratory pathogens. In total, 24 respiratory pathogens were found among the patients, and 242 (94.2 %) patients were co-infected with one or more pathogens. Bacterial co-infections were dominant in all COVID-19 patients, Streptococcus pneumoniae was the most common, followed by Klebsiella pneumoniae and Haemophilus influenzae. The highest and lowest rates of co-infections were found in patients aged 15–44 and below 15, respectively. Most co-infections occurred within 1–4 days of onset of COVID-19 disease. In addition, the proportion of viral co-infections, fungal co-infections and bacterial-fungal co-infections were the highest severe COVID-19 cases. These results will provide a helpful reference for diagnosis and clinical treatment of COVID-19 patients.
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