A large ongoing outbreak of hepatitis A predominantly affecting young males in Lazio, Italy; August 2016 - March 2017.

Simone Lanini,Maria Rosaria Loffredo,Paola Scognamiglio,Alessio Pendenza,Alessandro Agresta,Vincenzo Puro,Alimuddin Zumla,Claudia Minosse,Francesco Vairo,Virginia Di Bari,Giovanni Rezza,Maria Rosaria Capobianchi,Giuseppe Ippolito,Annarosa Garbuglia,Vincenzo Panella,Maria Lina Tornesello

doi:10.1371/journal.pone.0185428

Abstract

The hepatitis A virus (HAV) is mainly transmitted through the faecal-oral route. In industrialized countries HAV infection generally occurs as either sporadic cases in travelers from endemic areas, local outbreak within closed/semi-closed population and as foodborne community outbreak. Recently, an increasing number of HAV infection clusters have been reported among young men-who-have-sex-with-men (MSM).The Lazio Regional Service for the epidemiology and control for infectious diseases (SeRESMI) has noticed an increase of acute hepatitis A (AHA) since September 2016. Temporal analysis carried out with a discrete Poisson model using surveillance data between January 2016 and March 2017 evidenced an ongoing outbreak of AHA that started at the end of August. Molecular investigation carried out on 130 out of 513 cases AHA reported until March 2017 suggests that this outbreak is mainly supported by an HAV variant which is currently spreading within MSM communities across Europe (VRD_521_2016).The report confirms that AHA is an emerging issue among MSM. In addition through the integration of standard (case based) surveillance with molecular investigation we could discriminate, temporally concomitant but epidemiologically unrelated, clusters due to different HAV variants. As suggested by the WHO, in countries with low HAV circulation, vaccination programmes should be tailored on the local epidemiological patterns to prevent outbreaks among high risk groups and eventual spillover of the infection in the general population.

Highlights

Acute hepatitis A (AHA) is usually a self-limiting disease caused by the hepatitis A virus (HAV)
HAV infection was laboratory confirmed in 509 patients, while 4 cases were reported because presenting with acute hepatitis after close contact with a confirmed case
Our study provides strong evidence that a large AHA epidemic is currently ongoing in Lazio, mainly involving young men living in Rome

Summary

Introduction

Acute hepatitis A (AHA) is usually a self-limiting disease caused by the hepatitis A virus (HAV). HAV is mainly transmitted through the faecal-oral route either by direct person-toperson contacts or by contaminated water and/or food products. [2,3] The diagnosis of AHA is usually based on the detection of anti-HAV IgM; in addition, viral genomes can be detected in blood and stools. Infected persons are most likely to transmit HAV from 1–2 weeks before the onset of illness, when HAV concentration in stool is at the highest level. Asymptomatic disease is relatively common in children aged less than 6 years; in contrast, about 70% of adults develop acute hepatitis with increased liver enzymes and often jaundice. [5] Recently, an increasing number of HAV infection clusters have been reported among young men-who-have-sex-with-men (MSM). Asymptomatic disease is relatively common in children aged less than 6 years; in contrast, about 70% of adults develop acute hepatitis with increased liver enzymes and often jaundice. [4] In industrialized countries HAV infection generally occurs as either sporadic cases in travelers form endemic areas, local outbreak within closed/semi-closed populations (primary schools, ethnic minority, religious groups, people who inject drugs, marginalized groups) and as foodborne community outbreak. [5] Recently, an increasing number of HAV infection clusters have been reported among young men-who-have-sex-with-men (MSM). [2,6,7]

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Conclusion