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ABSTRACT: Hepatitis E virus (HEV) is endemic in India and causes epidemics and sporadic cases. However, the exact transmission route for sporadic hepatitis E remains unclear. This study investigated HEV in sporadic hepatitis cases and sewage samples, as sewage is the major source of contamination of water in developing countries.
Monthly sampling and testing for HEV in sewage samples from Vellore, India was carried out for 1 year (November 2009-October 2010) and plasma and/or fecal samples from sporadic hepatitis cases presenting to a hospital in Vellore during 2006-2010 were tested for HEV RNA. A total of 144 raw sewage samples and 94 samples from sporadic hepatitis cases were tested for HEV RNA using RT-PCR.
The prevalence of HEV RNA in sewage and sporadic cases was 55.6% and 9.6%, respectively. HEV strains isolated from sewage showed 94-100% nucleotide sequence similarity with the HEV strains isolated from the sporadic hepatitis cases. HEV RNA in sewage was identified more often during the summer (81.2%) than the monsoon season (14.5%) (p < 0.001).
This study indicates that sewage may be a source of contamination for sporadic hepatitis and also underscores the need for preventive measures to protect drinking water from sewage contamination, particularly in the summer. GENBANK ACCESSION NUMBERS: HEV strains isolated from this study were deposited in GenBank under accession numbers JF972766-JF972773, JN705651-JN705659 and JN705660-JN705662.
Transactions of the Royal Society of Tropical Medicine and Hygiene 06/2013; 107(6):363-7. · 2.16 Impact Factor
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Rajiv Sarkar,
Sitara S R Ajjampur,
Ashok D Prabakaran,
Jayanthy C Geetha,
Thuppal V Sowmyanarayanan,
Anne Kane,
Joanne Duara,
Jayaprakash Muliyil,
Vinohar Balraj,
Elena N Naumova,
Honorine Ward, Gagandeep Kang
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ABSTRACT: Background. A quasi-experimental study was conducted to determine whether or not a protected water supply (bottled drinking water) could prevent or delay cryptosporidial infections among children residing in an endemic community. Methods. A total of 176 children residing in a semi-urban slum area in southern India were enrolled pre-weaning and received either bottled (n = 90) or municipal (n = 86) drinking water based on residence in specific streets. Weekly surveillance visits were conducted until children reached their second birthday. Stool samples were collected every month and during diarrheal episodes, and tested for the presence of Cryptosporidium spp. by PCR. Differences in the incidence of cryptosporidiosis between bottled and municipal water groups were compared using Poisson survival models, and a propensity score model was developed to adjust for the effect of potential confounders. Results. A total of 186 episodes of cryptosporidiosis, mostly asymptomatic, were observed in 118 (67%) children during the follow-up period at a rate of 0.59 episodes/child-year. Diarrhea associated with Cryptosporidium spp. tended to be longer in duration and more severe. Stunting at 6 months was associated with a higher risk of cryptosporidiosis (RR = 1.40, 95% CI, 1.03-1.91). A higher gastrointestinal disease burden was also seen in children with cryptosporidiosis. Drinking bottled water was not associated with a reduced risk of cryptosporidiosis (Adjusted RR = 0.86, 95% CI, .60-1.23). Conclusions. This study documented a high burden of cryptosporidiosis among children in an endemic Indian slum community. The lack of association between drinking bottled water and cryptosporidiosis suggests possible spread from asymptomatically infected individuals involving multiple transmission pathways.
Clinical Infectious Diseases 05/2013; · 9.15 Impact Factor
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ABSTRACT: Human and bovine norovirus virus-like particles were used to evaluate antibodies in Indian children at 6 and 36 months and their mothers. Antibodies to genogroup II viruses were acquired early and more prevalent than antibodies to genogroup I. Low levels of IgG antibodies against bovine noroviruses indicate possible zoonotic transmission.
Journal of clinical microbiology 04/2013; · 4.16 Impact Factor
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Sasirekha Ramani,
Nicolas W Cortes-Penfield,
Liya Hu,
Sue E Crawford,
Rita Czako,
David F Smith, Gagandeep Kang,
Robert F Ramig,
Jacques Le Pendu,
B V Venkataram Prasad,
Mary K Estes
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ABSTRACT: Naturally occurring bovine-human reassortant rotaviruses with a P [11] VP4 genotype exhibit a tropism for neonates. Interaction of the VP8* domain of the spike protein VP4 with sialic acid was thought to be the key mediator for rotavirus infectivity. However, recent studies indicate a role for non-sialylated glycoconjugates including histo-blood group antigens (HBGAs) in the infectivity of human rotaviruses. We sought to determine if the bovine rotavirus-derived VP8* of a reassortant neonatal G10P [11] virus interacts with hitherto uncharacterized glycans. In an array screen of >600 glycans, VP8* P [11] showed specific binding to glycans with the Galβ1-4GlcNAc motif, which forms the core structure of type II glycans and is the precursor of H type II HBGA. The specificity of glycan binding was confirmed through hemagglutination assays; GST-VP8* P [11] hemagglutinates type O, A and B red blood cells as well as pooled umbilical cord blood erythrocytes. Further, G10P [11] infectivity was significantly enhanced by the expression of H type II HBGA in CHO cells. The bovine origin VP4 was confirmed as essential for this increased infectivity using laboratory-derived reassortant viruses generated from sialic acid binding rotavirus SA11-4F and a bovine G10P [11] rotavirus B223. The binding to a core glycan unit has not been reported for any rotavirus VP4. Core glycan synthesis is constitutive in most cell types and modification of these glycans is thought to be developmentally regulated. These studies provide the first molecular basis for understanding neonatal rotavirus infections, indicating that glycan modification during neonatal development may mediate age-restricted infectivity of neonatal viruses.
Journal of Virology 04/2013; · 5.40 Impact Factor
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ABSTRACT: Noroviruses are a common cause of gastroenteritis worldwide, but outbreaks appear to be more common in industrialized countries than in developing countries, possibly reflecting differences in exposure and immunity. In this study, age-stratified sera from India and UK populations were analysed for the presence of norovirus-genogroup II specific IgG by a time resolved immunofluorescence assay and relative levels of antibodies in the two populations were compared. Antibody levels were higher among all age groups in India than in UK and increased with age in India, whereas in the UK, levels of antibody decreased in adulthood. These results indicate different patterns of exposure to noroviruses in the two countries. This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
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ABSTRACT: Noroviruses are a common cause of gastroenteritis worldwide, but outbreaks appear to be more common in industrialized countries than in developing countries, possibly reflecting differences in exposure and immunity. In this study, age-stratified sera from India and UK populations were analysed for the presence of norovirus-genogroup II specific IgG by a time resolved immunofluorescence assay and relative levels of antibodies in the two populations were compared. Antibody levels were higher among all age groups in India than in UK and increased with age in India, whereas in the UK, levels of antibody decreased in adulthood. These results indicate different patterns of exposure to noroviruses in the two countries.
PLoS ONE 02/2013; 8(2):e56239. · 4.09 Impact Factor
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ABSTRACT: BACKGROUND: India has seen rapid unorganized urbanization in the past few decades. However, the burden of childhood diseases and malnutrition in such populations is difficult to quantify. The morbidity experience of children living in semi-urban slums of a southern Indian city is described. METHODS: A total of 176 children were recruited pre-weaning from four geographically adjacent, semi-urban slums located in the western outskirts of Vellore, Tamil Nadu for a study on water safety and enteric infections and received either bottled or municipal drinking water based on their area of residence. Children were visited weekly at home and had anthropometry measured monthly until their second birthday. RESULTS: A total of 3932 episodes of illness were recorded during the follow-up period, resulting in an incidence of 12.5 illnesses/child-year, with more illness during infancy than in the second year of life. Respiratory, mostly upper respiratory infections, and gastrointestinal illnesses were most common. Approximately one third of children were stunted at 2 years of age, and two-thirds had at least one episode of growth failure during the two years of follow up. No differences in morbidity were seen between children who received bottled and municipal water. CONCLUSIONS: Our study found a high burden of childhood diseases and malnutrition among urban slum dwellers in southern India. Frequent illnesses may adversely impact children's health and development, besides placing an additional burden on families who need to seek healthcare and find resources to manage illness.
BMC Public Health 01/2013; 13(1):87. · 2.00 Impact Factor
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ABSTRACT: The rotavirus (RV) inner capsid protein VP6 is widely used to evaluate immune response during natural infection and in vaccine studies. Recombinant VP6 from the most prevalent circulating rotavirus strains in each subgroup (SG) identified in a birth cohort of children in southern India [SGII (G1P[8]) and SGI (G10P[11])] were produced. The purified proteins were used to measure VP6-specific antibodies in a Dissociation-Enhanced Lanthanide Fluorometric Immunoassay (DELFIA). The ability of the assay to detect a ≥ 2 fold rise in IgG level in a panel of serum samples from a longitudinal study was compared to a gold standard virus-capture ELISA. A strong association was observed between the assays (p<0.001; chi-squared test) with assay performances remaining similar when the samples were subdivided as having a fold change increase in VP6 antibody levels (a) within 90 days of RV RNA detection in stool or (b) if no RV RNA was detected within that time period This study demonstrates the suitability of using recombinant proteins to measure anti-RV immune responses and serves as a "proof of principle" to examine the antibody responses generated to other recombinant RV proteins and thereby possibly identify a correlate of protection.
Journal of virological methods 11/2012; · 2.13 Impact Factor
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ABSTRACT: OBJECTIVE: To estimate the number of rotavirus-associated deaths among Indian children younger than five years. METHODS: We surveyed more than 23 000 child deaths from a nationally representative survey of 1.1 million Indian households during 2001-2003. Diarrhoeal deaths were characterized by region, age and sex and were combined with the proportion of deaths attributable to rotavirus, as determined by hospital microbiologic data collected by the Indian Rotavirus Strain Surveillance Network from December 2005 to November 2007. Rotavirus vaccine efficacy data from clinical trials in developing countries were used to estimate the number of deaths preventable by a national vaccination programme. Data were analysed using Stata SE version 10. FINDINGS: Rotavirus caused an estimated 113 000 deaths (99% confidence interval, CI: 86 000-155 000); 50% (54 700) and 75% (85 400) occurred before one and two years of age, respectively. One child in 242 died from rotavirus infection before five years of age. Rotavirus-associated mortality rates overall, among girls and among boys were 4.14 (99% CI: 3.14-5.68), 4.89 (99% CI: 3.75-6.79) and 3.45 (99% CI: 2.58-4.66) deaths per 1000 live births, respectively. Rates were highest in Bihar, Uttar Pradesh and Madhya Pradesh, which together accounted for > 50% of deaths (64 400) nationally. Rotavirus vaccine could prevent 41 000-48 000 deaths among children aged 3-59 months. CONCLUSION: The burden of rotavirus-associated mortality is high among Indian children, highlighting the potential benefits of rotavirus vaccination.
Bulletin of the World Health Organisation 10/2012; 90(10):720-727. · 4.64 Impact Factor
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ABSTRACT: Background: Colorectal mucosal biopsies occasionally demonstrate the presence of bacteria adherent to the epithelium. This study evaluated the histological and ultrastructural correlates of such bacterial adherence. Materials and Methods: Rectal mucosal biopsies from eight patients in whom histopathological examination of biopsies had earlier demonstrated adherent bacteria were examined by electron microscopy and by bacterial culture. Colorectal biopsies of 69 patients with adherent bacteria detected histologically were retrospectively evaluated for histological changes at sites proximal and distant to adherent bacteria. Results: Escherichia coli of different serogroups were isolated from 7 of 8 rectal biopsies demonstrating bacterial adherence. All isolates showed diffuse or focal adherence to HEp-2 cell monolayers. Ultrastructural changes noted included microvillus damage, pedestal formation, actin web condensation, and protrusions of the apical cytoplasm of epithelial cells into the lumen towards the bacteria. Histological changes noted at light microscopy included reduction in epithelial cell height, focal epithelial cell degeneration, cryptitis and neutrophil infiltration at sites of bacterial adherence whereas these were usually absent at sites distant to adherent bacteria. Bacterial adherence was noted more often in biopsies from Crohn's disease patients than in patients without this diagnosis (P < 0.001). Conclusion: Adherent Escherichia coli in colorectal biopsies were associated with focal epithelial damage and showed an association with Crohn's disease.
Indian Journal of Pathology and Microbiology 10/2012; 55(4):485-9. · 0.68 Impact Factor
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ABSTRACT: Cryptosporidium spp. is under recognized as an important pathogen causing diarrhea in children and HIV-infected individuals with associated high morbidity and mortality. In endemic areas, most symptomatic infections are in childhood and in immunocompromised adults. The immune status of the host plays a critical role in determining the severity of cryptosporidiosis. Infection is self-limited in immunocompetent hosts, but can be severe and persistent in the immunocompromised such as AIDS patients or malnourished children. Cryptosporidiosis in developing countries is a major cause of acute and persistent diarrhea in children and is associated with subsequent impairment in growth, physical fitness, and cognitive function. Despite recognition of the importance of immune status, the correlates of protective immunity in cryptosporidiosis in humans are poorly understood, and treatment modalities are limited.
Tropical Parasitology. 07/2012; 2(2):91-8.
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ABSTRACT: Diarrhoeal disease is the fifth leading cause of all mortality globally. To this burden, rotavirus contributes over half a million deaths annually. This pilot study was conducted to determine the economic burden of diarrhoeal episodes on families from different geographical regions accessing medical facilities in India.
Participants were enrolled from four study sites with eight reporting hospitals, categorized as non-profit and low cost, private and government facilities between November 2008 and February 2009. Questionnaires detailing healthcare utilization, medical and non-medical expenditure and lost income were completed by families of children < 5 yr of age hospitalized for gastroenteritis. All available faecal samples were tested for rotavirus.
A total of 211 patients were enrolled. The mean total cost of a hospitalized diarrhoeal episode was ` 3633 (US$ 66.05) for all facilities, with a marked difference in direct costs between governmental and non-governmental facilities. Costs for rotavirus positive hospitalizations were slightly lower, at ` 2956 (US$ 53.75). The median cost of a diarrhoeal episode based on annual household expenditure was 6.4 per cent for all-cause diarrhoea and 7.6 per cent for rotavirus diarrhoea. Of the 124 samples collected, 66 (53%) were positive for rotavirus.
Data on direct costs alone from multiple facilities show that diarrhoeal disease constitutes a large economic burden on Indian families. Affordable, effective vaccines would greatly reduce the economic burden of severe gastroenteritis on patients, families and the government.
The Indian journal of medical research 07/2012; 136(1):68-73. · 1.84 Impact Factor
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ABSTRACT: Cryptosporidium spp. is under recognized as an important pathogen causing diarrhea in children and HIV-infected individuals with associated high morbidity and mortality. In endemic areas, most symptomatic infections are in childhood and in immunocompromised adults. The immune status of the host plays a critical role in determining the severity of cryptosporidiosis. Infection is self-limited in immunocompetent hosts, but can be severe and persistent in the immunocompromised such as AIDS patients or malnourished children. Cryptosporidiosis in developing countries is a major cause of acute and persistent diarrhea in children and is associated with subsequent impairment in growth, physical fitness, and cognitive function. Despite recognition of the importance of immune status, the correlates of protective immunity in cryptosporidiosis in humans are poorly understood, and treatment modalities are limited.
Tropical parasitology. 07/2012; 2(2):91-8.
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ABSTRACT: Although two oral rotavirus vaccines are licensed in many countries, multiple factors may affect decision-making regarding introduction into national immunization programs in developing countries. Financial and logistic challenges to introduction of rotavirus vaccines in countries with limited infrastructure and resources are accompanied by a perceived lack of need and evidence from recent vaccine trials, which demonstrated significantly lower efficacy in high burden countries. Nonetheless, even at a low efficacy, the use of existing vaccines in developing countries is predicted to alleviate considerable rotavirus disease burden and mortality. Potential alternate strategies for improving response to existing vaccines or the development of improved vaccines need to be considered to ensure that the remaining burden of mortality and morbidity can be addressed in the future.
Current opinion in virology. 06/2012; 2(4):443-8.
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Thuppal V Sowmyanarayanan,
Sasirekha Ramani,
Rajiv Sarkar,
Rajesh Arumugam,
Jubal P Warier,
Prabhakar D Moses,
Anna Simon,
Indira Agarwal,
Anuradha Bose,
Rashmi Arora, Gagandeep Kang
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ABSTRACT: The burden of rotavirus gastroenteritis is greatest in India and other developing countries. With the availability of two licensed vaccines and a number of additional vaccines in various stages of development and trial, analysis of detailed clinical information is essential for the development of a uniform method of severity assessment.
Diarrhoeal stool samples from 1001 children <5 years of age hospitalized with gastroenteritis were screened for rotavirus using a commercial enzyme immunoassay. Positive samples were confirmed by genotyping using hemi nested multiplex RT-PCR. Detailed clinical data was collected for gastroenteritis assessment for 934 children and extraintestinal presentations were analyzed in 470 children. Severity scoring was carried out for all children using the Vesikari score and in a subset by Clark's scoring system.
Rotavirus was detected in 35.4% of samples tested between December 2005 and November 2008. Clark's and Vesikari scores showed moderate correlation but varied greatly in the categorization of severe disease. Using Clark's scoring, only 1.6% were categorized as presenting with severe disease in comparison to 66.1% by the Vesikari score. Association of extraintestinal symptoms with rotavirus gastroenteritis was not documented in this study.
The assessment of disease severity using two common severity scoring systems highlights the difference in the categorization of "severe" disease. This underscores the need for a robust scoring system which is needed for vaccine trial and in post-licensure surveillance, because vaccine efficacy is estimated for protection against severe rotavirus gastroenteritis.
Vaccine 04/2012; 30 Suppl 1:A167-72. · 3.77 Impact Factor
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ABSTRACT: Of the estimated half-million deaths from rotavirus globally each year, approximately one-third (N = 160,000 deaths) occur in the Indian subcontinent (defined as India, Bangladesh, and Pakistan). Two commercial vaccines are available for use and recommended by WHO, although the prohibitive vaccine price has limited their introduction into routine childhood immunization programs. New rotavirus vaccines are in late clinical development, including two advanced candidates in India. As significant shifts in rotavirus strain diversity have occurred in the past three decades and questions remain regarding whether strain replacement may occur following introduction of rotavirus vaccines, it is important to understand the temporal and regional strain diversity profile before vaccine introduction. We reviewed 33 peer-reviewed manuscripts from the Indian subcontinent and found that the most common G-types (G1-4) and P-types (P[4] and P[8]) globally accounted for three-fourths of all strains in the subcontinent. However, strains varied by region, and temporal analysis showed the decline of G3 and G4 in recent years and the emergence of G9 and G12. Our findings underscore the large diversity of rotavirus strains in the Indian subcontinent and highlight the need to conduct surveillance on a regional scale to better understand strain diversity before and after rotavirus vaccine introduction.
Vaccine 04/2012; 30 Suppl 1:A131-9. · 3.77 Impact Factor
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ABSTRACT: The correlates of protective immunity to cryptosporidiosis are not well understood. This study was conducted to assess the effect of maternal serum IgG against Cryptosporidium gp15 on responses to this antigen in children with (cases) and without (controls) PCR-confirmed cryptosporidial diarrhea. Maternal sera (n = 129) and sera from cases (n = 39) and controls (n = 90) collected at 3.5, 9, and 24 months of age were tested for serum IgG against Cryptosporidium gp15 by enzyme-linked immunosorbent assay (ELISA). Seroconversion patterns were evaluated by estimating probabilities of seroconversion along three time points based on the transition pathways by using a first-order Markov chain process and empirical Bayesian estimates. There was no difference in serum IgG levels or seropositivity rates to gp15 between cases and controls across all time points in children or in IgG levels to this antigen between mothers of cases and controls. The most common transition pathway can be described as a seronegative child at 3.5 months who seroconverts at 9 months and remains seropositive at 24 months. This pattern remained stable irrespective of the serological status of the mother or the case or control status of the child. Children were most likely to be exposed to Cryptosporidium for the first time between the ages of 3 and 9 months, and most of the children seroconverted by 24 months. The high degree of seroconversion among control children is suggestive of high rates of asymptomatic transmission in this region.
Clinical and vaccine immunology: CVI 04/2012; 19(6):849-54. · 2.37 Impact Factor
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Anoli J Borad,
Geneve M Allison,
David Wang,
Sabeena Ahmed,
Mohammad M Karim,
Anne V Kane,
Joy Moy,
Patricia L Hibberd,
Sitara Swarna Rao Ajjampur, Gagandeep Kang,
Stephen B Calderwood,
Edward T Ryan,
Elena Naumova,
Wasif A Khan,
Honorine D Ward
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ABSTRACT: Cryptosporidium is a major cause of diarrhea in children in developing countries. However, there is no vaccine available and little is known about immune responses to protective antigens. We investigated antibody responses to p23, a putative vaccine candidate, in children in Bangladesh with cryptosporidiosis and diarrhea (cases) and uninfected children with diarrhea (controls), and p23 gene polymorphisms in infecting species. Serum IgM, IgG, and IgA responses to p23 were significantly greater in cases than controls after three weeks of follow-up. Cases with acute diarrhea had significantly greater serum IgA and IgM responses than those with persistent diarrhea, which suggested an association with protection from prolonged disease. The p23 sequences were relatively conserved among infecting species and subtype families. Although most children were infected with Cryptosporidium hominis, there was a cross-reactive antibody response to C. parvum antigen. These results support further development of p23 as a vaccine candidate.
The American journal of tropical medicine and hygiene 02/2012; 86(2):214-22. · 2.59 Impact Factor
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ABSTRACT: Human immunology is a growing field of research in which experimental, clinical, and analytical methods of many life science disciplines are utilized. Classic epidemiological study designs, including observational longitudinal birth cohort studies, offer strong potential for gaining new knowledge and insights into immune response to pathogens in humans. However, rigorous discussion of methodological issues related to designs and statistical analysis that are appropriate for longitudinal studies is lacking.
In this communication we address key questions of quality and validity of traditional and recently developed statistical tools applied to measures of immune responses. For this purpose we use data on humoral immune response (IR) associated with the first cryptosporidial diarrhea in a birth cohort of children residing in an urban slum in south India. The main objective is to detect the difference and derive inferences for a change in IR measured at two time points, before (pre) and after (post) an event of interest. We illustrate the use and interpretation of analytical and data visualization techniques including generalized linear and additive models, data-driven smoothing, and combinations of box-, scatter-, and needle-plots.
We provide step-by-step instructions for conducting a thorough and relatively simple analytical investigation, describe the challenges and pitfalls, and offer practical solutions for comprehensive examination of data. We illustrate how the assumption of time irrelevance can be handled in a study with a pre-post design. We demonstrate how one can study the dynamics of IR in humans by considering the timing of response following an event of interest and seasonal fluctuation of exposure by proper alignment of time of measurements. This alignment of calendar time of measurements and a child's age at the event of interest allows us to explore interactions between IR, seasonal exposures and age at first infection.
The use of traditional statistical techniques to analyze immunological data derived from observational human studies can result in loss of important information. Detailed analysis using well-tailored techniques allows the depiction of new features of immune response to a pathogen in longitudinal studies in humans. The proposed staged approach has prominent implications for future study designs and analyses.
BMC Medical Research Methodology 01/2012; 12:1. · 2.67 Impact Factor
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ABSTRACT: Rotavirus infection causes a significant proportion of diarrhea in infants and young children worldwide leading to dehydration, hospitalization, and in some cases death. Rotavirus infection represents a significant burden of disease in developing countries, such as those in South Asia.
We conducted a meta-analysis to examine how patterns of rotavirus infection relate to temperature and precipitation in South Asia. Monthly rotavirus data were abstracted from 39 published epidemiological studies and related to monthly aggregated ambient temperature and cumulative precipitation for each study location using linear mixed-effects models. We also considered associations with vegetation index, gathered from remote sensing data. Finally, we assessed whether the relationship varied in tropical climates and humid mid-latitude climates.
Overall, as well as in tropical and humid mid-latitude climates, low temperature and precipitation levels are significant predictors of an increased rate of rotaviral diarrhea. A 1°C decrease in monthly ambient temperature and a decrease of 10 mm in precipitation are associated with 1.3% and 0.3% increase above the annual level in rotavirus infections, respectively. When assessing lagged relationships, temperature and precipitation in the previous month remained significant predictors and the association with temperature was stronger in the tropical climate. The same association was seen for vegetation index; a seasonal decline of 0.1 units results in a 3.8% increase in rate of rotavirus.
In South Asia the highest rate of rotavirus was seen in the colder, drier months. Meteorological characteristics can be used to better focus and target public health prevention programs.
PLoS ONE 01/2012; 7(5):e38168. · 4.09 Impact Factor
