Astrovirus MLB1 Is Not Associated with Diarrhea in a Cohort of Indian Children

University of Hong Kong, Hong Kong
PLoS ONE (Impact Factor: 3.23). 12/2011; 6(12):e28647. DOI: 10.1371/journal.pone.0028647
Source: PubMed


Astroviruses are a known cause of human diarrhea. Recently the highly divergent astrovirus MLB1 (MLB1) was identified in a stool sample from a patient with diarrhea. It has subsequently been detected in stool from individuals with and without diarrhea. To determine whether MLB1 is associated with diarrhea, we conducted a case control study of MLB1. In parallel, the prevalence of the classic human astroviruses (HAstVs) was also determined in the same case control cohort. 400 cases and 400 paired controls from a longitudinal birth cohort in Vellore, India were analyzed by RT-PCR. While HAstVs were associated with diarrhea (p = 0.029) in this cohort, MLB1 was not; 14 of the controls and 4 cases were positive for MLB1. Furthermore, MLB1 viral load did not differ significantly between the cases and controls. The role of MLB1 in human health still remains unknown and future studies are needed.

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Available from: Priya Rajendran, Jul 25, 2014
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    • "In humans, for example, there are currently four identified species that can be further subdivided into numerous serotypes and subtypes. These serotypes and subtypes have been found, in some situations, to differ in their virulence (Caballero et al., 2003 Holtz et al., 2011). There have also been reports that particular AstVs differ in their tissue tropism with some being associated specifically with 0378-1135/ ã 2015 Published by Elsevier B.V. "
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    ABSTRACT: Astroviruses (AstV) are single-stranded, positive-sense RNA viruses and one of the major causes of infant diarrhoea worldwide. Diarrhoea is a common and important cause of morbidity and mortality in calves; therefore, we investigated whether the presence of AstV is associated with calf diarrhoea. We identified diverse AstV lineages from faecal samples of both healthy and diarrhoeic calves and healthy adult cattle in South West Scotland. AstV was common in calves (present in 74% (85/115) of samples) but uncommon in adult cattle (present in 15% (3/20) of samples). No association was found between the presence of AstV and calf diarrhoea or the presence of a specific AstV lineage and calf diarrhoea. AstV was strongly associated with the presence of rotavirus Group A (RVA), and a protective effect of age was evident for both AstV and RVA. Co-infections with multiple AstV lineages were detected in several calves and serial infection with different viruses could also be seen by longitudinal sampling of individuals. In summary, our study found genotypically diverse AstV in the faeces of calves in South West Scotland. However, no association was identified between AstV and calf diarrhoea, which suggests the virus does not play a primary role in the aetiology of calf diarrhoea in the group studied. Copyright © 2015. Published by Elsevier B.V.
    Full-text · Article · May 2015 · Veterinary Microbiology
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    • "Wider geographic sampling of human fecal samples will likely continue to increase the known diversity of human astroviruses. Case-control studies of unexplained diarrhea will help determine whether any of these novel astroviruses has pathogenic potential [25] although their occasional pathogenicity in highly susceptible individuals [20] such as immunosuppressed patients will remain a possibility irrespective of their associations or lack thereof with diarrhea or other enteric condition. The GenBank accession numbers for human astrovirus BF34 is KF859964. "
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    ABSTRACT: Background A significant fraction of cases of diarrhea, a leading cause of childhood mortality worldwide, remain unexplained. Objectives To identify viruses in unexplained cases of diarrhea using an unbiased metagenomics approach. Study design Viral nucleic acids were enriched from the feces from 48 cases of unexplained diarrhea from Burkina Faso, sequenced, and compared against all known viral genomes. Results The full genome of a highly divergent astrovirus was sequenced in a sample co-infected with parechovirus 1. RT-PCR identified a single astrovirus infection in these 48 patients indicating a low prevalence. Human astrovirus-BF34 was most closely related to mamastrovirus species 8 and 9 also found in human with which it shared 62%, 74%, and 57% amino acid identities over its protease, RNA dependent RNA polymerase and capsid proteins, respectively. Conclusions Burkina Faso astrovirus is proposed as prototype for a novel species in the genus Mamastrovirus, here tentatively called Mamastrovirus 20, representing the fifth human astrovirus species.
    Full-text · Article · Jun 2014 · Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology
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    • "Stool samples from a cohort of Indian children A previously described cohort (Holtz et al., 2011a) of 400 specimens collected from children experiencing acute diarrhea and 400 stool specimens collected from the same children while asymptomatic was analyzed using an astrovirus consensus RT-PCR assay (Finkbeiner, 2009). The 400 diarrhea samples were negative for the following enteric pathogens: rotavirus by ELISA and PCR; norovirus using PCR; bacterial pathogens (Vibrio cholerae , enteropathogenic Escherichia coli, Salmonella, Shigella, Aeromonas and Plesiomonas) by culture, biochemical reactions and serogrouping where appropriate; and parasitic pathogens using routine saline and iodine preparations and modified acid fast stain (Ajjampur et al., 2008). "
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    ABSTRACT: Eight serotypes of human astroviruses (the classic human astroviruses) are causative agents of diarrhea. Recently, five additional astroviruses belonging to two distinct clades have been described in human stool, including astroviruses MLB1, MLB2, VA1, VA2 and VA3. We report the discovery in human stool of two novel astroviruses, astroviruses MLB3 and VA4. The complete genomes of these two viruses and the previously described astroviruses VA2 and VA3 were sequenced, affording seven complete genomes from the MLB and VA clades for comparative analysis to the classic human astroviruses. Comparison of the genetic distance, number of synonymous mutations per synonymous site (dS), number of non-synonymous mutations per non-synonymous site (dN) and the dN/dS ratio in the protease, polymerase and capsid of the classic human, MLB and VA clades suggests that the protease and polymerase of the classic human astroviruses are under distinct selective pressure.
    Full-text · Article · Oct 2012 · Virology
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