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Detailed investigation of ongoing subclinical hepatitis E virus infections; occurring in outbreak settings of North India
Author(s) -
Majumdar Manasi,
Singh Mini P.,
Goyal Kapil,
Chawla Yogesh,
Ratho Radha K.
Publication year - 2015
Publication title -
liver international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.873
H-Index - 110
eISSN - 1478-3231
pISSN - 1478-3223
DOI - 10.1111/liv.12568
Subject(s) - subclinical infection , hepatitis e virus , avidity , outbreak , medicine , virology , viral load , viremia , index case , viral hepatitis , immunology , context (archaeology) , virus , biology , antibody , genotype , paleontology , biochemistry , gene
Background & Aims Every year globally WHO reports 20 million Hepatitis E virus ( HEV ) infections. The disease occurs as sporadic cases or focused outbreaks and has potentials to cause massive epidemics. The reservoir of HEV during inter‐epidemic period is not well characterized. The sporadic cases usually lack history of contact with clinically overt HEV patients. In the present context we evaluated the occurrence of subclinical HEV as a possible reservoir in endemic region. Methods Blood samples were collected from 67 apparently healthy individuals and 10 acute viral hepatitis ( AVH ) patients during two HEV outbreaks in North India. The serum samples were tested for anti‐ HEV IgM, IgG, HEV ‐IgG avidity index, HEV viral load and conventional‐ PCR followed by sequencing and phylogenetic analysis. Results A total of 14 (20.89%) apparently healthy individuals showed the presence of anti‐ HEV IgM and IgG. Of 14 based on HEV ‐IgG avidity index, 9 (64.28%) had secondary‐exposure, 4 (28.57%) had primary exposure, while one patient had intermediate avidity. Subclinical subjects with primary exposure had significantly higher anti‐ HEV IgM index as compared to secondary‐exposure ( P = 0.0028). Viral load in clinically jaundiced patients was significantly higher as compared to subclinical subjects ( P < 0.0001). Phylogenetic analysis showed HEV sequences retrieved from subclinical individuals clustered along with AVH patients, suggesting matched source. The significantly low viral load in subclinical subjects hints towards the dose dependency for progression of clinical manifestation. Conclusion We document subclinical HEV with low level viremia occurs during outbreak settings and goes un‐noticed, which helps maintaining the virus in nature possibly leading to its endemicity.