Molecular Diagnosis of COVID-19

The SARS-CoV-2 coronavirus causes COVID-19. Nucleic acid amplification tests (NAAT), could be used to detect the presence of SARS-CoV-2 viral RNA in clinical samples. Several real-time reverse transcriptase-polymerase chain reaction (rRT-PCR) assays are being used by many laboratories for confirming COVID-19. We have outlined the characteristics of the available SARS-Cov-2 rRT-PCR assays and discussed its clinical utility

Favipiravir in Covid-19

The SARS-Cov-2 virus, emerged in December 2019 in Wuhan, China and has now spread to all parts of the world. Many research groups are carrying out intense research on drugs and vaccines to treat or prevent Covid-19. We have outlined aspects relating to Favipiravir, in treating RNA viral infections and its potential role in controlling SARS-Cov-2 infections

Immunomodulatory Activity of a Traditional Sri Lankan Concoction of Coriandrum sativum L. and Coscinium fenestratum G.

Objective. To investigate the immunomodulatory activity of a traditional Sri Lankan concoction of Coriandrum sativum L. and Coscinium fenestratum (Gaertn.) Colebr., which is a Sri Lankan traditional medicine used to relieve inflammation and cold. Methods. In vivo anti-inflammatory activity was tested using carrageenan-induced rat paw-edema model. Mechanism of anti-inflammatory activity was assessed by investigating the production of nitric oxide (NO), expression of iNOS enzyme, and reactive oxygen species (ROS) by rat peritoneal cells. The membrane stabilizing activity was also tested. The antibody response was determined by assessing the specific haemagglutination antibodies raised against sheep red blood cells. Results. The three doses of freeze-dried concoction used ((human equivalent dose (HED)—183 mg/kg) 2 × HED and 1/2HED; n = 6 rats/group) showed significant inhibition of paw edema compared to water control at 3rd–5th hours (p<0.05). Both HED and 1/2HED exhibited marked anti-inflammatory activity (72–83% inhibition at 4th-5th hours; p<0.05). The HED of the concoction showed significant inhibition of NO (77.5 ± 0.73%, p<0.001) and ROS production (26.9 ± 2.55%; p<0.01) by rat peritoneal cells. Inhibition of NO production in the concoction treated rat peritoneal cells was confirmed by the lack of iNOS expression. The concoction also exhibited significant membrane stabilizing activity (IC50 = 0.0006 μg/ml; p=0.001). HED resulted in a significantly high induction of specific antibody production against SRBC antigens as detected by SRBC haemagglutination assay (mean day 14 titers 253.3 compared to control: 66.7) (p<0.01). Conclusions. The traditional Sri Lankan concoction of C. sativum and C. fenestratum demonstrated potent in vivo anti-inflammatory activity, significant reduction of ROS, and NO production by rat peritoneal cells and the lack of iNOS expression confirmed the low NO production. The increased membrane stability also supports the anti-inflammatory activity of the concoction. Further, this concoction induced a significantly high antibody response reflecting its immunostimulatory activity. Together these results scientifically validate the therapeutic use of the concoction of C. sativum and C. fenestratum in Sri Lankan traditional medicinal system for immunomodulatory effects

Multilocus sequence typing reveals diverse known and novel genotypes of Leptospira spp. circulating in Sri Lanka.

BackgroundLeptospirosis has gained much attention in Sri Lanka since its large outbreak in 2008. However, most of the cases were clinically diagnosed and information on Leptospira genotypes and serotypes currently prevailing in the country is lacking.Methodology/principal findingsWe retrospectively analyzed 24 Leptospira strains from human patients as well as isolated and characterized three Leptospira strains from black rats using the microscopic agglutination test with antisera for 19 serovars and multilocus sequence typing. The isolates were identified as Leptospira borgpetersenii sequence types (STs) 143 and 144; L. interrogans STs 30, 34, 43, 44, 74, 75, 80, 308, 313, 314, 316, and 317; and L. kirschneri ST318. Six of the 15 STs were identified for the first time in this study. Five serogroups such as Autumnalis, Grippotyphosa, Hebdomadis, Javanica, and Pyrogenes were detected among the isolates. Contrary to previous studies, various genotypes including novel STs were isolated during an outbreak in Southern Province. L. borgpetersenii serogroup Javanica ST143 was isolated both from a human and black rat.Conclusions/significanceThis study revealed that genetically diverse Leptospira strains currently circulate in Sri Lanka: some genotypes have been circulating and others have emerged recently, which may explain the recent surge of leptospirosis patients with varying clinical manifestations and frequent outbreaks of leptospirosis. Black rats were identified as the source of infection for humans, but reservoir animals for other genotypes remain unknown

Diagnosis of Human Leptospirosis: Comparison of Microscopic Agglutination Test with Recombinant LigA/B Antigen-Based In-House IgM Dot ELISA Dipstick Test and Latex Agglutination Test Using Bayesian Latent Class Model and MAT as Gold Standard

Leptospirosis is a spirochaetal infection that possesses a broad host range affecting almost all mammals. In the present study, the microscopic agglutination test (MAT) was compared with recombinant LigA/B antigen-based point-of-care diagnostics such as the in-house IgM dot ELISA dipstick test (IgM- DEDT) and the latex agglutination test (LAT) for the serodiagnosis of human leptospirosis. The comparison of the MAT with these two point&ndash;of-care diagnostics was performed using the MAT as the gold standard test and using Bayesian latent class modelling (BLCM), which considers all diagnostic tests as imperfect. The N-terminal conserved region of the LigA/B protein spanning the first to fifth big tandem repeat domains (rLigA/BCon1-5) was employed as a serodiagnostic marker in both of the bedside assays. A total of 340 serum samples collected from humans involved in high risk occupations were screened using the MAT, IgM DEDT and LAT. During the early phase of leptospirosis, BLCM analysis showed that the IgM DEDT and LAT had similar sensitivities (99.6 (96.0&ndash;100)) and (99.5 (95.2&ndash;100)), respectively, while the single acute phase MAT had the lowest sensitivity (83.3 (72.8&ndash;91.3)). Both the IgM DEDT and the LAT may be superior to the single acute phase MAT in terms of sensitivity during the early phase of infection and may be suitable for the early diagnosis of leptospirosis. However, BLCM analysis revealed that the use of both acute and convalescent samples substantially increased the sensitivity of the final MAT (98.2% (93.0&ndash;99.8%)) as a test to diagnose human leptospirosis. Both the IgM DEDT and LAT can be employed as bedside spot tests in remote locations where the MAT is not easily accessible

Levels of carbonylated serum proteins and hydroperoxidated lipids.

<p>(A) Serum protein carbonyl levels (μmol/ mg protein) and (B) serum lipid hydroperoxide levels (μM) in CL (n = 110; collectively both SL and ML), SL (n = 60), ML (n = 50), DC and HC (n = 30/ group). *—p<0.05 between SL and ML, ●—p<0.05 between any of leptospirosis category (CL, SL and ML) with DC respectively, †—p<0.05 between any of patient category (CL, SL, ML and DC) with HC respectively. The intra-assay coefficient of variability (% CV) was 1.9% and inter-assay % CV was 0.6% for the FOX2 assay, indicating high reproducibility of the test in the laboratory conditions.</p

Receiver operating characteristic curves of protein carbonyl levels between severe leptospirosis and critical phase dengue patients.

<p>Arrow head shows the cut-off of 13 μmol/mg protein.</p

Serum uric acid, total bilirubin and cumulative anti-oxidant capacities.

<p>(A) Serum uric acid levels (mg/ dL), (B) serum total bilirubin levels (mg/ dL) and (C) Serum anti-oxidant capacity (μmol/ mg protein) among CL (n = 110; collectively both SL and ML), SL (n = 60), ML (n = 50), DC and HC (n = 30/ group). *—p<0.05 between SL and ML, ●—p<0.05 between any of leptospirosis category (CL, SL and ML) with DC respectively, †—p<0.05 between any of patient category (CL, SL, ML and DC) with HC respectively. The ABTS decolourization method had good intra-assay % CV (7.9%) and inter-assay % CV (6.9%).</p

Haematological and biochemical parameters in SL, ML and DC patients.

<p>Haematological and biochemical parameters in SL, ML and DC patients.</p