Hepatitis E virus seroprevalence in Polish soldiers serving in harsh environmental conditions.

BACKGROUND: Hepatitis E virus (HEV) is an under-recognised aetiological factor of viral hepatitis; it is most commonly transmitted via the oral-faecal route, but can also be transmitted by blood or blood products, vertically from an infected mother to the foetus or by transplanted organs. The aim of the study was to present the current seroprevalence of HEV among soldiers from the Polish Special Forces deployed on military operations carried out in harsh environmental conditions. MATERIALS AND METHODS: The research conducted between October and November 2016 involved 253 active duty soldiers, 237 men and 16 women, aged 26-57, without clinical symptoms of infection, participants in military operations in Asia and Africa. Accurate HEV diagnosis required the implementation of a two-phase diagnostic protocol. During the first phase, immunoenzymatic ELISA method was used to detect specific anti-HEV antibodies (IgM and IgG) in blood serum samples indicating contact with an infectious agent in the past. During the second phase, serum samples obtained from subjects with positive or inconclusive test results were tested again using confirmatory recomLine HEV IgM/IgG immunoassay. RESULTS: Immunoenzymatic assay found anti-HEV antibodies (IgM and/or IgG) in blood serum samples obtained from 18 soldiers. Confirmatory tests were carried out among soldiers tested positive with ELISA or those with inconclusive test results; the confirmatory tests showed anti-HEV antibodies (IgM and/or IgG) in 16 of the studied soldiers, i.e. 6.3% of the study group. CONCLUSIONS: The occurrence of HEV infections in Polish soldiers justifies the need for the introduction of screening tests for HEV in the military environment, especially among blood donors and in cases of whole blood or blood products transfusion.

Characterisation and validation of insertions and deletions in 173 patient exomes.

Recent advances in genomics technologies have spurred unprecedented efforts in genome and exome re-sequencing aiming to unravel the genetic component of rare and complex disorders. While in rare disorders this allowed the identification of novel causal genes, the missing heritability paradox in complex diseases remains so far elusive. Despite rapid advances of next-generation sequencing, both the technology and the analysis of the data it produces are in its infancy. At present there is abundant knowledge pertaining to the role of rare single nucleotide variants (SNVs) in rare disorders and of common SNVs in common disorders. Although the 1,000 genome project has clearly highlighted the prevalence of rare variants and more complex variants (e.g. insertions, deletions), their role in disease is as yet far from elucidated.We set out to analyse the properties of sequence variants identified in a comprehensive collection of exome re-sequencing studies performed on samples from patients affected by a broad range of complex and rare diseases (N = 173). Given the known potential for Loss of Function (LoF) variants to be false positive, we performed an extensive validation of the common, rare and private LoF variants identified, which indicated that most of the private and rare variants identified were indeed true, while common novel variants had a significantly higher false positive rate. Our results indicated a strong enrichment of very low-frequency insertion/deletion variants, so far under-investigated, which might be difficult to capture with low coverage and imputation approaches and for which most of study designs would be under-powered. These insertions and deletions might play a significant role in disease genetics, contributing specifically to the underlining rare and private variation predicted to be discovered through next generation sequencing.