Age-stratified adeno-associated virus serotype 3 neutralizing and total antibody prevalence in hemophilia A patients from India.

Gene therapy using an adeno-associated virus (AAV) vector offers a new treatment option for individuals with monogenetic disorders. The major bottleneck is the presence of pre-existing anti-AAV antibodies, which impacts its use. Even very low titers of neutralizing antibodies (NAb) to capsids from natural AAV infections have been reported to inhibit the transduction of intravenously administered AAV in animal models and are associated with limited efficacy in human trials. Assessing the level of pre-existing NAb is important for determining the primary eligibility of patients for AAV vector-based gene therapy clinical trials. Techniques used to screen AAV-antibodies include AAV capsid enzyme-linked immunosorbent assay (ELISA) and transduction inhibition assay (TIA) for detecting total capsid-binding (TAb) and Nab, respectively. In this study, we screened 521 individuals with hemophilia A from India for TAb and NAb using ELISA and TIA, respectively. The prevalence of TAb and NAb in hemophilia A patients from India were 96% and 77.5%, respectively. There was a significant increase in anti-AAV3 NAb prevalence with age in the hemophilia A patient group from India. There was a trend in anti-AAV3 TAb positivity between the pediatric age group (94.4%) and the adult age group (97.4%).

Performance of molecular and serologic tests for the diagnosis of scrub typhus.

Diagnosis of scrub typhus, caused by the bacterium Orientia tsutsugamushi, is challenging because of the overlap of its non-specific symptoms with other infections coupled with the lack of sufficient data on the performance of diagnostic tests. Early diagnosis of scrub typhus is crucial to improve outcomes and this study evaluates the diagnostic performance of various tests. The present study aims at assessing the accuracy of various rapid diagnostic tests, serologic tests, and nucleic acid amplification methods on well-characterized patient samples. Adult patients with acute febrile illness and manifestations suggestive of scrub typhus confirmed by positive PCR in the blood, eschar or tissue were characterized as cases. Patients with acute febrile illness and a confirmed alternate etiology such as culture-confirmed typhoid, smear/PCR positive for malaria, PCR/NS1 antigen positive for dengue, PCR positive for influenza, PCR/MAT positive for leptospirosis, PCR positive for spotted fever were characterized as controls with other infections. The healthy controls consisted of subjects from the same geographic region. We performed the following tests on blood samples for scrub typhus and calculated the sensitivity, specificity, positive predictive value, and negative predictive value: (1) Quantitative real time PCR using 47kDa gene (qPCR); (2) Conventional PCR using 56kDa gene (cPCR); (3) Loop-mediated isothermal amplification assay (LAMP assay); (4) Immunofluorescence assay (IFA); (5) Enzyme-linked immunosorbent assay (ELISA); (6) Weil-Felix test(WF test); and (7) Immunochromatographic Rapid Diagnostic Test (RDT).Among the 316 participants, 158 had confirmed scrub typhus (cases) and 158 were controls. ELISA and RDT detecting Orientia tsutsugamushi specific IgM antibodies had excellent discriminative potential with sensitivities and specificities of 92%, 94% and 92%, 92% respectively. The sensitivity and specificity of IFA were found to be 95% and 74% respectively. IgM serology had a false positivity rate of 8% with other acute febrile illnesses such as dengue, leptospirosis and spotted fever due to the nonspecific binding of the pentavalent IgM. LAMP assay had 91.7% sensitivity and 77.2% specificity while qPCR provided excellent sensitivity (97%) and perfect specificity. In conclusion, ELISA and RDT detecting Orientia tsutsugamushi specific IgM antibodies have excellent sensitivity and specificity while the accuracy of IFA is suboptimal for the diagnosis of scrub typhus. Given its perfect specificity and superior sensitivity, qPCR is preferred for diagnostic confirmation in reference laboratories particularly for diagnosis of early disease with less than 7 days duration. This study provides a comprehensive evaluation of all currently available diagnostic tests for scrub typhus.

BK virus characterisation among HIV-1-Infected individuals and its association with immunosuppression.

Purpose: BK virus (BKV) is an opportunistic pathogen which causes significant morbidity and mortality in individuals who are immunodeficient. We aimed to quantitate and characterise BKV and to correlate with the degree of immunosuppression among human immunodeficiency virus (HIV)-1-infected individuals. Methods: BKV DNA detection was carried out using an in-house quantitative real-time polymerase chain reaction on paired whole-blood and urine samples collected from 187 antiretroviral therapy (ART)-naïve HIV-1-infected individuals and 93 healthy individuals who served as controls. Sequencing was performed for a proportion of high BK viral load (VL) samples to observe non-coding control region (NCCR) rearrangements. Results: BKV positivity in urine was 25.6% among HIV-infected individuals and 10.7% in control individuals (P = 0.03). The BK VL showed a significant negative correlation with CD4+ T-cell counts, a positive correlation with WHO clinical staging and no significant correlation with HIV-1 VL. Of 42 BKVs from urine samples sequenced, two showed rearrangements without clinically severe disease or high VL. Their NCCR and VP1 sequence-based genotyping revealed genotype I. In a small subset of individuals (n = 8) on ART who were being followed up, six individuals showed either decrease or complete clearance of virus with ART. Conclusion: There was a higher frequency of BK viruria in HIV-1-infected individuals than among healthy controls and the positivity correlated with the degree of immunosuppression. There was no association of high VL with NCCR rearrangements in urine.

The effect of probiotics and zinc supplementation on the immune response to oral rotavirus vaccine: A randomized, factorial design, placebo-controlled study among Indian infants.

BACKGROUND: Strategies are needed to improve oral rotavirus vaccine (RV), which provides suboptimal protection in developing countries. Probiotics and zinc supplementation could improve RV immunogenicity by altering the intestinal microbiota and immune function. METHODS: Infants 5weeks old living in urban Vellore, India were enrolled in a randomized, double-blind, placebo-controlled trial with a 4-arm factorial design to assess the effects of daily zinc (5mg), probiotic (1010Lactobacillus rhamnosus GG) or placebo on the immunogenicity of two doses of RV (Rotarix®, GlaxoSmithKline Biologicals) given at 6 and 10weeks of age. Infants were eligible for participation if healthy, available for the study duration and without prior receipt of RV or oral poliovirus vaccine other than the birth dose. The primary outcome was seroconversion to rotavirus at 14weeks of age based on detection of VP6-specific IgA at ≥20U/ml in previously seronegative infants or a fourfold rise in concentration. RESULTS: The study took place during July 2012 to February 2013. 620 infants were randomized equally between study arms and 551 (88.9%) completed per protocol. Seroconversion was recorded in 54/137 (39.4%), 42/136 (30.9%), 40/143 (28.0%), and 37/135 (27.4%) infants receiving (1) probiotic and zinc, (2) probiotic and placebo, (3) placebo and zinc, (4) two placebos. Seroconversion showed a modest improvement among infants receiving probiotic (difference between groups 1, 2 and 3, 4 was 7.5% (97.5% Confidence Interval (CI): -1.4%, 16.2%), p=0.066) but not zinc (difference between groups 1, 3 and 2, 4 was 4.4% (97.5% CI: -4.4%, 13.2%), p=0.272). 16 serious adverse events were recorded, none related to study interventions. CONCLUSIONS: Zinc or probiotic supplementation did not significantly improve the low immunogenicity of rotavirus vaccine given to infants in a poor urban community in India. A modest effect of combined supplementation deserves further investigation. TRIAL REGISTRATION: The trial was registered in India (CTRI/2012/05/002677).

Clinical Profile and Predictors of Mortality of Severe Pandemic (H1N1) 2009 Virus Infection Needing Intensive Care: A Multi-Centre Prospective Study from South India.

BACKGROUND: This multi-center study from India details the profile and outcomes of patients admitted to the intensive care unit (ICU) with pandemic Influenza A (H1N1) 2009 virus [P(H1N1)2009v] infection. MATERIALS AND METHODS: Over 4 months, adult patients diagnosed to have P(H1N1)2009v infection by real-time RT-PCR of respiratory specimens and requiring ICU admission were followed up until death or hospital discharge. Sequential organ failure assessment (SOFA) scores were calculated daily. RESULTS: Of the 1902 patients screened, 464 (24.4%) tested positive for P(H1N1)2009v; 106 (22.8%) patients aged 35±11.9 (mean±SD) years required ICU admission 5.8±2.7 days after onset of illness. Common symptoms were fever (96.2%), cough (88.7%), and breathlessness (85.9%). The admission APACHE-II and SOFA scores were 14.4±6.5 and 5.5±3.1, respectively. Ninety-six (90.6%) patients required ventilation for 10.1±7.5 days. Of these, 34/96 (35.4%) were non-invasively ventilated; 16/34 were weaned successfully whilst 18/34 required intubation. Sixteen patients (15.1%) needed dialysis. The duration of hospitalization was 14.0±8.0 days. Hospital mortality was 49%. Mortality in pregnant/puerperal women was 52.6% (10/19). Patients requiring invasive ventilation at admission had a higher mortality than those managed with non-invasive ventilation and those not requiring ventilation (44/62 vs. 8/44, P<0.001). Need for dialysis was independently associated with mortality (P=0.019). Although admission APACHE-II and SOFA scores were significantly (P<0.02) higher in non-survivors compared with survivors on univariate analysis, individually, neither were predictive on multivariate analysis. CONCLUSIONS: In our setting, a high mortality was observed in patients admitted to ICU with severe P(H1N1)2009v infection. The need for invasive ventilation and dialysis were associated with a poor outcome.

Virological investigation of hand, foot, and mouth disease in a tertiary care center in South India.

CONTEXT: Hand, foot, and mouth disease (HFMD) remains a common problem in India, yet its etiology is largely unknown as diagnosis is based on clinical characteristics. There are very few laboratory-based molecular studies on HFMD outbreaks. AIM: The aim of this study was to characterize HFMD-related isolates by molecular techniques. SETTINGS AND DESIGN: Between 2005 and 2008, during two documented HFMD outbreaks, 30 suspected HFMD cases presented at the Outpatient Unit of the Department of Dermatology, Christian Medical College (CMC), Vellore. Seventy-eight clinical specimens (swabs from throat, mouth, rectum, anus, buttocks, tongue, forearm, sole, and foot) were received from these patients at the Department of Clinical Virology, CMC, for routine diagnosis of hand, foot, and mouth disease. MATERIALS AND METHODS: Samples from these patients were cultured in Vero and rhabdomyosarcoma (RD) cell lines. Isolates producing enterovirus-like cytopathogenic effect (CPE) in cell culture were identified by a nested reverse transcription-based polymerase chain reaction (RT-PCR) and sequenced. The nucleotide sequences were analyzed using the BioEdit sequence program. Homology searches were performed using the Basic Local Alignment Search Tool (BLAST) algorithm. STATISTICAL ANALYSIS USED: The statistical analysis was performed using Epi Info version 6.04b and Microsoft Excel 2002 (Microsoft Office XP). RESULTS: Of the 30 suspected HFMD cases, only 17 (57%) were laboratory confirmed and Coxsackievirus A16 (CVA16) was identified as the etiological agent in all these cases. CONCLUSIONS: Coxsackievirus A16 (CVA16) was identified as the virus that caused the HFMD outbreaks in Vellore between 2005 and 2008. Early confirmation of HFMD helps to initiate control measures to interrupt virus transmission. In the laboratory, classical diagnostic methods, culture and serological tests are being replaced by molecular techniques. Routine surveillance systems will help understand the epidemiology of HFMD in India.

Multisite virological influenza surveillance in India: 2004-2008.

BACKGROUND: Influenza surveillance is important to identify circulating, emerging/reemerging strains and unusual epidemiological trends. With these objectives, a multisite human influenza surveillance network was initiated in India in 2004. METHODS: Epidemiologic data and throat swabs for laboratory testing were collected from patients with influenza-like illness (ILI) and severe acute respiratory infections (SARI). Virus isolation was carried out in Madin-Darby canine kidney cells and strains identified by hemagglutination inhibition assay. Meteorological data were collected. RESULTS: From September 2004 to December 2008, 617 (4·43%) of 13928 cases yielded isolates: 27·8% were influenza A(H1N1), 29·8% were type A(H3N2), and 42·3% were type B. The yearly type and subtype distribution varied significantly from site to site. Peak influenza activity was observed from June to August in Delhi, Pune, and Kolkata and October to December in Chennai. Maximum influenza activity was seen during the rains in Delhi, Pune, Chennai, and Kolkata in correlation with virus isolations. Multivariate analysis of ILI cases showed chill/rigors, cough, fatigue, and ILI in family, correlated positively with isolation. Genetic analysis of Indian isolates revealed that viruses matched with vaccine strains by and large. Overlapping between circulating and vaccine component strains of consecutive years was also observed. CONCLUSIONS: Seasonal influenza A(H1N1), H3N2, and type B co-circulated in all regions without any particular pattern of movement of any subtype. Year-round limited influenza activity with peaks during rains was observed. Genetic drifts and varying seasonality in different parts of the country suggest that a staggered timing of vaccination may be appropriate for India.

Gap in the prevalence of neutralising antibodies to polioviruses in antenatal women in southern India.

With the disappearance of circulating wild poliovirus and improved sanitation, protective antibody levels may wane over time following oral poliovirus vaccine (OPV) administration. This study evaluated the seroprevalence of neutralising antibodies to vaccine polioviruses among young Indian women who had received at least three doses of OPV as primary immunisation. Of 60 women studied, 27 (45%) had antibody titres of <1:8 to one or more polioviruses, with the lowest levels for poliovirus types 3 and 1. These findings represent a possible immunity gap and this needs to be confirmed with further studies, which could include a challenge with vaccine virus.

Acute kidney injury in tropical acute febrile illness in a tertiary care centre--RIFLE criteria validation.

BACKGROUND: Acute febrile illnesses are a common cause of tropical acute kidney injury (AKI). The incidence and severity of AKI in tropical febrile illnesses and validity of RIFLE classification are unclear. METHODS: Consecutive adult inpatients of a tertiary hospital in southern India with tropical acute febrile illness between January 2007 and January 2008 were prospectively studied for the incidence and severity of AKI based on RIFLE classification and its association with mortality and dialysis requirement. RESULTS: The 367 patients (mean age 39.7±16.9 years; 60% males) with tropical acute febrile illness due to scrub typhus (51.2%), falciparum malaria (10.4%), enteric fever (8.7%), dengue (7.6%), mixed malaria (6.5%), leptospirosis (3.3%), undifferentiated acute febrile illness (8.4%) and others (3.8%) (spotted fever, vivax malaria and Hantaan virus infection) had an overall mortality rate of 12.3%. The incidence of AKI was 41.1%; of which, 17.4%, 9.3% and 14.4% were in the Risk, Injury and Failure classes, respectively. Of the patients, 7.9% required dialysis. Among the Risk, Injury and Failure groups, there was an incremental risk of mortality (OR 6.9, 20.2 and 25.6; P<0.001) and dialysis requirement (OR 3.4, 28.8 and 178.8; P<0.001). CONCLUSIONS: The incidence of AKI in the common tropical acute febrile illnesses in our study such as scrub typhus, falciparum malaria, enteric fever, dengue and leptospirosis is 41.1%. RIFLE classification is valid and applicable in AKI related to tropical acute febrile illnesses, with an incremental risk of mortality and dialysis requirement.