Role of Viral Load and Host Cytokines in Determining the Disease Severity of Respiratory Syncytial Virus-Associated Acute Lower Respiratory Tract Infections in Children.

Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory tract infections (ALRTIs). In this study, we aimed to evaluate the role of viral load, cytokines, matrix metalloproteinase 9 (MMP-9), and tissue inhibitor of metalloproteinase 1 (TIMP-1) in determining the severity of RSV disease and identify potential biomarkers of disease severity. A total of 142 patients with RSV infection (aged between 2 months and 5 years) who presented with ALRTI between December 2013 and March 2016 were enrolled. Their nasopharyngeal aspirates were subjected to RSV viral load quantification, and local cytokine levels of interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), IL-17A, interferon γ (IFN-γ), and IL-10 were determined using a cytokine bead array. The levels of MMP-9 and TIMP-1 in 109 aspirates were calculated using Quantikine ELISA. These parameters were compared for different disease severity categories. A higher viral load and increased levels of TNF-α, MMP-9, and MMP-9:TIMP-1 were associated with greater severity of disease; whereas levels of IL-17A, IFN-γ, and IFN-γ:IL-10 were associated with disease resolution. When defining the transition from non-severe to severe disease, MMP-9 had a sensitivity and specificity of 89.7% and 85.4%, respectively. Moreover, MMP-9:TIMP-1 had a sensitivity and specificity of 87.2% and 76.8%, respectively. Hence, MMP-9, MMP-9:TIMP-1, TNF-α, and IL-10 could serve as potential biomarkers for disease progression in RSV-infected children.

Comparative Analysis of Epidemiology, Clinical Features, and Cytokine Response of Respiratory Syncytial and Human Metapneumovirus Infected Children with Acute Lower Respiratory Infections.

Both human respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) cause immune-mediated under-five acute respiratory infections (ARIs), but differences in their disease pathogenesis, if any, are not well-known. This study was undertaken to analyze the epidemiological and immunological features of RSV and hMPV infections. Nasopharyngeal aspirates from children (aged 2 months to 5 years) with ARI, presenting to our tertiary care center between December 2013 and March 2016, were subjected to real-time polymerase chain reaction for the detection of RSV and hMPV. Positive samples were analyzed for co-infection and cytokine levels. Of the 349 nasopharyngeal aspirates, RSV was detected in 40.68% (142/349), hMPV in 6.59% (23/349), and both in 1.4% (5/349). Co-infections were common, with rhinovirus being the most common co-offender. The demographic and clinical parameters of RSV- and hMPV-infected children were comparable. The MMP-9/TIMP-1 ratio was significantly higher in RSV-mediated ARI and IFN-γ in hMPV-mediated ARI. Both RSV and hMPV are common among North Indian children with ARI, and coinfections are common. Their clinical features are non-discriminatory, and molecular diagnosis should be utilized to ascertain their individual epidemiology. The differences in their immune-pathogenesis (MMP-9/TIMP-1 ratio in RSV and IFN-γ in hMPV) could serve as useful tools for developing newer drugs.

Correlation of SARS-CoV-2 Viral Load in Different Population Subsets: A Study from a Tertiary Care North Indian Hospital.

BACKGROUND: The correlation of SARS-CoV-2 viral load with disease severity in different population subsets is still elusive. There is a scarcity of literature regarding this aspect in Indian Population. AIM: To study retrospectively the risk factors and the role of viral load with disease severity among different age groups of North Indian population. METHODS: Here we quantified the viral load of 239 positive participants and collected data retrospectively from April 2020 to May 2020 and categorised the patients as per disease severity and population subsets. RESULTS: Asymptomatic patients were found to have higher viral load than the symptomatic patients, though the difference was not found to be statistically significant. The logistic regression analysis showed that contact with laboratory confirmed cases, SARI and ILI were independent risk factors for acquiring COVID-19 infection. CONCLUSION: SARS-CoV-2 viral load is not significantly associated with disease severity among different population subsets. However, there is a need to carry out more studies with a larger number of patients to validate and confirm the above findings.

Molecular characterization of hepatitis A virus strains in a tertiary care health set up in north western India.

BACKGROUND & OBJECTIVES: Hepatitis A virus usually causes acute viral hepatitis (AVH) in the paediatric age group with a recent shift in age distribution and disease manifestations like acute liver failure (ALF). This has been attributed to mutations in 5'non-translated region (5'NTR) which affects the viral multiplication. The present study was aimed to carry out the molecular detection and phylogenetic analysis of hepatitis A virus strains circulating in north western India. METHODS: Serum samples from in patients and those attending out patient department of Pediatric Gastroenterology in a tertiary care hospital in north India during 2007-2011 with clinically suspected AVH were tested for anti-hepatitis A virus (HAV) IgM antibodies. Acute phase serum samples were subjected to nested PCR targeting the 5'NTR region followed by sequencing of the representative strains. RESULTS: A total of 1334 samples were tested, 290 (21.7%) were positive for anti-HAV IgM antibody. Of these, 78 serum samples (< 7 days old) were subjected to PCR and 47.4% (37/78) samples showed the presence of HAV RNA. Children < 15 yr of age accounted for majority (94%) of cases with highest seropositivity during rainy season. Sequencing of 15 representative strains was carried out and the circulating genotype was found to be III A. The nucleotide sequences showed high homology among the strains with a variation ranging from 0.1-1 per cent over the years. An important substitution of G to A at 324 position was shown by both AVH and ALF strains. The cumulative substitution in AVH strains Vs ALF strains as compared to GBM, Indian and prototype strain in the 200-500 region of 5' NTR was comparable. INTERPRETATION & CONCLUSION: Our results showed hepatitis A still a disease of children with III A as a circulating genotype in this region. The mutations at 5'NTR region warrant further analysis as these affect the structure of internal ribosomal entry site which is important for viral replication.

Epidemiologic lessons: chickenpox outbreak investigation in a rural community around Chandigarh, North India.

PURPOSE: Primary infection with Varicella Zoster virus (VZV) leads to Varicella or chickenpox. The epidemiology of Varicella has changed dramatically since the introduction of the Varicella vaccine in 1995. The routine childhood immunization in a few countries in the western world like Germany and the United States has reduced the incidence of the disease, associated complications, hospital admissions and deaths related to its complications. However, chickenpox outbreaks are common in naive unvaccinated communities in India. MATERIALS AND METHODS: We report an outbreak of chickenpox that occurred in a village situated on the outskirts of Chandigarh city in North India in the winter of 2007. The outbreak was confirmed by the detection of VZV IgM by enzyme-linked immunosorbent assay (ELISA) on serum samples from the patients. In patients showing active lesions, Giemsa and indirect immunofluorescence was carried out on scrapings from vesicular lesions. RESULTS: A total of 162 cases occurred in the present outbreak. The serum samples were collected from 20 patients, and all of them showed positive serology for VZV IgM antibodies while 19 showed a positive VZV IgG result by ELISA. The scrapings were collected from two patients showing active lesions, and both were positive by the Tzanck smear examination, and VZV antigen could be demonstrated by immunofluorescence. CONCLUSIONS: There is an urgent need to identify naive communities and unvaccinated individuals at risk. Also, there is a need for regular training programmes of health workers posted in peripheral centers so that highly contagious communicable diseases can be picked up in time and such outbreaks can be prevented.

NS1 antigen as an early diagnostic marker in dengue: report from India.

Detection of specific IgM antibodies by ELISA forms the mainstay for diagnosis of dengue infection. However, IgM antibodies develop after 4 to 5 days of infection. The methods for early diagnosis include virus isolation and reverse transcriptase polymerase chain reaction (RT-PCR) which need a sophisticated laboratory. Another alternative that has recently come up is NS1 antigen detection. The present study compared IgM antibody detection with NS1 antigen for the diagnosis of acute dengue in 87 samples. NS1 antigen could be detected with good sensitivity (71-100%) till day 3 of fever, whereas IgM had a sensitivity of 0% to 50% at this time. On day 4 of illness, both the tests had comparative sensitivity. Beyond day 4, IgM antibody detection was superior to NS1. Both these diagnostic modalities were also compared with RT-PCR in 40 acute samples. NS1 detected additional 15 samples, which were missed by PCR. NS1 antigen is an early diagnostic marker that is feasible in a routine diagnostic laboratory.

Herpetic meibomianitis: an unusual case report.

Herpes simplex virus (HSV) infection of the eye can vary from mild blepharitis to sight threatening choreoretinitis. Primary infection of the eye is usually sub-clinical but reactivation of a latent infection can lead to recurrent disease. Although, herpetic blepharitis is a well documented entity, this virus has so far not been incriminated in the causation of meibomianitis, an inflammatory condition of the meibomian gland. This paper reports a case of meibomianitis due to Herpes simplex virus.

Otosclerosis--do we have a viral aetiology?

The etiology of otosclerosis remains an enigma though there are evidences suggesting a viral involvement. This study aimed to find out the relationship between viral infections and otosclerosis. Twenty two patients with otosclerosis and 10 healthy controls were included in the study. IgM antibodies to varicella zoster virus (VZV), measles, rubella, human cytomegalovirus (HCMV) and herpes simplex virus (HSV) were detected using micro ELISA. Paul Bunnel Davidsohn test was performed to rule out Ebstein Barr virus (EBV) infection. Overall, 5(22.7%) patients showed antibodies to one or more viruses. IgM antibodies against measles and VZV could be demonstrated in 4(18.1%) and 1(4.5%) patients respectively. None of the samples were found to be positive for HSV, HCMV, rubella and EBV antibodies. Controls were negative for all the viruses tested. The difference in seropositivity between the patient and control group was not statistically significant (p>0.05). Thus, this study suggests that otosclerosis is not commonly associated with a systemic viral infection.