Efficacy of the Examination of Saliva Sample by Reverse Transcriptase-Polymerase Chain Reaction in Detection of SARS-CoV-2 in Al-Fallujah City, Iraq

Abstract

Saliva samples could be used as a non-invasive method to diagnose COVID-19. We aimed to assess the results of the reverse transcriptase-polymerase chain reaction (RT-PCR) of saliva specimens in the detection of COVID-19. We collected saliva and nasopharyngeal (NP) samples from consecutive COVID-19 suspects in Al-Fallujah Teaching Hospital, Anbar, Iraq from November 29, 2021 to February 15, 2022. The results of the two specimens were compared using RT-PCR. For the positive saliva tests, repetition of the test was undertaken at weekly intervals for four weeks from the time of the presentation. There were 55% men and 60% people ≤ 35 years. The majority of cases presented within 2-5 days (92%) and were of mild severity (89%). A hundred pairs of samples were taken. COVID-19 was diagnosed by NP swab RT-PCR in 56% and 31% of the saliva samples. The saliva samples had 100% sensitivity (95% confidence interval [CI] 60.4% e96.6%), 63.8% specificity (95% CI 96.1% e99.9%), and mild coefficient agreement (kappa coefficient = 0.522). The positive test for the saliva samples remained as such in all examined cases in the first and second weeks after the first test, 31/31 and 30/30, respectively. While half of them were positive in the third week (15/30). All cases became negative in the fourth week (0/15). We recommend not using the saliva swab as an alternative to the NP swab in the detection of the SARS-CoV-2 by RT-PCR. However, saliva sample can be used for the follow-up of the COVID-19 subjects, in children, elderly, and handicapped patients.

Impact of sampling site on diagnostic test accuracy of RT-PCR in diagnosing Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection since the emergence of omicron: a systematic review and meta-analysis

“…One identified study is not yet included in our analysis but is awaiting classification 20 . The study is a cohort type cross-sectional study, taking place in Iraq.…”

“…18,19 One study is still awaiting classification due to inconsistencies in reported data. 20 In total, three studies are included in the qualitative and quantitative synthesis (meta-analysis). [21][22][23] The PRISMA flow diagram with reasons for exclusion of studies is provided in Figure 1.…”

“…All three studies show slight differences in reported sensitivity/specificity and calculated sensitivity/specificity. One identified study is not yet included in our analysis but is awaiting classification 20 .…”

Testing the Efficiency of Silver Nanoparticles Manufactured Locally by the Alga Spirogyra in Inhibiting the Fungus Aspergillus flavus and Reduction of Aflatoxin B1

“…The results of Table (2) showed the efficiency of silver nanoparticles manufactured locally and biologically by the alga Spirogyra (T1) in preventing the fungus from producing aflatoxin B1 on stored wheat grains at all concentrations, all concentrations showed significant differences with the comparison treatment in which the toxin concentration was 88.4ppb, while the concentrations of AFB1 for the treatment (T1) and with concentrations of 1.5,2 and 3 amounted to 6.25ppb, ppb4.11 and ppb 0 respectively, as the HPLC device did not feel any concentration of toxins when Concentration 3 and the percentage of reduction of the concentrations used was 92.92%, 95.35% and 100%, respectively, while the concentrations of AFB1 in the commercial silver treatment (T2) were at the same concentrations of 2.15, 0 and 0 with a reduction rate of 97.56%, 100% and 100%, respectively, this is in agreement with some studies that indicated the efficiency of nanoparticles in AFB1 reduction [25]. Some studies have indicated the ability of nanoparticles to break down toxic chemicals, such as mycotoxins, including aflatoxin B1, as it can be used as an adsorbent [26,27,28], this results agreed with the findings of [29] who reported the efficiency of silver nanoparticles manufactured biologically and locally by fungi, which gave the reduction efficiency of aflatoxin B1 reached 94.61%, 100% and 100% for concentrations 0.2, 0.4 and 0.6, respectively, these results are also consistent with what was reached by [24], which indicated the efficiency of nano-algae in inhibiting the fungus Sclerotinia sclerotiorum, the nano-algae achieved an inhibition rate (18.24%, 74.31%, 100% and 100%) for the concentrations (0.5, 1,2 and 3), respectively, compared with normal algae, which achieved an inhibition rate of 10.00%, 9.41%, 9.41% and 9.41% for the same concentrations, respectively.…”

“…The problem of food contamination and its effects on humans and animals occur as a result of consuming food contaminated with fungi or their toxins, which is one of the most important global problems, especially in the field of nutrition [1]. Pathogens including fungi, nematodes, bacteria and viruses can severely damage agriculture by reducing commodity quality and quantity [2,3], which can have an effect on plants in storage or after harvest. Toxic aflatoxin B1-producing fungi grow naturally on different foods [4].…”