First detection of hepatitis E virus in Central Argentina: Environmental and serological survey

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Highlights

  • This is the first detection of HEV in Córdoba.

  • Genotype 3 (subtypes 3a, 3b and 3c) was detected.

  • Seroprevalence in healthy adult population of Córdoba is 4.4%.

  • Detection of HEV should be included in the diagnosis algorithm of viral hepatitis.

Abstract

Background

The hepatitis E virus (HEV) is an emergent causative agent of acute hepatitis worldwide, transmitted by fecal-oral route. In Argentina it is considered rare, so differential laboratory testing is not routinely performed. Besides, in Argentina's central area epidemiological and molecular characteristics of HEV are still unknown.

Objectives

Provide evidence of local circulation of HEV by molecular detection on environmental samples and by serological survey in healthy adult population of Córdoba city, Argentina.

Study design

Environmental surveillance was conducted in river and sewage samples collected between 2007 and 2009–2011. Viral detection was performed by RT-Nested PCR of ORF-1 and ORF-2 partial regions. Anti-HEV IgG was determined by EIA in 433 serum samples collected between 2009 and 2010.

Results

HEV was detected in 6.3% of raw sewage samples and in 3.2% of riverine samples. Nucleotide sequencing analyses revealed that all isolates belonged to genotype 3, subtypes a, b and c. The prevalence of IgG anti-HEV was 4.4%. Seroprevalence increased with the age of the individuals (OR: 3.50; 95% CI 1.39–8.87; p = 0.0065) and, although the prevalence was higher in low income population, no statistical relation was found between anti-HEV and socioeconomic level.

Conclusions

The environmental findings added to serological results, demonstrate that HEV circulates in central Argentina. Contamination of water with HEV could represent a route of transmission for local populations, which have a high number of susceptible individuals. This fact alerts local health care systems in order to include detection of HEV in the diagnostic algorithm of viral hepatitis.

Section snippets

Background

The hepatitis E virus (HEV) (Hepevirus, Hepeviridae) is the causative agent of human acute hepatitis E with a worldwide distribution [1], [2], responsible for both sporadic cases and large hepatitis epidemics in developing countries [3], [4]. It is a single strand, positive sense, RNA non-enveloped virus which is classified into 4 genotypes of mammalian HEV [5]. HEV is mostly transmitted by fecal-oral routes following ingestion of contaminated water or consumption of fruits and vegetables that

Objectives

The aim of this study was to provide evidence of HEV circulation in central region of Argentina. For that, molecular detection of HEV was performed on environmental samples, as well as detection of IgG-anti HEV in healthy adult population of Córdoba city.

Environmental samples collection

Wastewater samples (n = 48) were monthly collected in the years 2007, 2009, 2010 and 2011 from the main pipe that enters the treatment plant which receives sewage discharges from about 61% of the population of Córdoba city (1,330,023 inhabitants, census 2010). Samples of the Suquía River (n = 31) were collected seasonally during 2010 in eight sampling points that cover the whole of its course across Córdoba city. During spring, point 7 could not be sampled (Fig. 1).

For each sample, 1500 mL of water

Environmental surveillance

HEV was detected in 6.3% of sewage samples (3/48: April-2007, September-2010 and March-2011) and in 3.2% of river samples (1/31: Spring-2010) by amplification of ORF 2 genomic region. From these, only one sample tested positive to ORF 1 amplification, probably due to a low sensitivity of the technique. The nucleotide sequencing analysis of both regions allowed assigning all HEV strains as Gnt-3. All samples formed distinct sequence clusters with high nucleotide similarity (Fig. 2). No

Discussion

The epidemiology of viral hepatitis has changed in several parts of the world since the introduction of hepatitis A and hepatitis B immunization programs and the incidence of acute infections caused by these viruses has been declining [25]. Hepatitis E virus has been worldwide recognized as an increasingly important cause of acute hepatitis, but testing is not widely available.

This study reports, for the first time in Argentina, the presence of Gnt-3 HEV on environmental samples. Having found

Funding

This study was supported by grants from: Secyt-Universidad Nacional de Córdoba (Secyt UNC-05/H343), Agencia Nacional de Promoción Científica y Tecnológica-Foncyt (PICT 2012-0998), Ministerio de Ciencia y Tecnología, Gobierno de la Provincia de Córdoba (MINCyT-Cba PIO 170/11 and 198/11-CICAL 175/10). SIV-Universidad Católica de Córdoba and Alberto J. Roemmers Fundation. PAB and VER are members of the researcher career from Consejo Nacional de Investigaciones Científicas – CONICET – Argentina.

Competing interests

None declared.

Ethical approval

Ethics committee of the Health Ministry of the Province of Cordoba.

Authors’ contributions

MMW designed the study, collection the data, performed the statistical analysis and drafted the manuscript; MBP, PAB and PDG contributed to the acquisition of samples and data. VER participated in revised the analysis plan, the data analysis and revised critically the manuscript. SVN, OCE, JMO and MAP revised the analysis plan and made an important intellectual contribution in the content. All authors read and approved the final version of this manuscript.

Acknowledgments

We thank Lorena Spinsanti for allowing the use of serum samples and to LACE Laboratories and Vanella Virology Institute for the use of facilities and equipment necessary for the development part of this study.

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