title: Surveillance of hepatitis A virus in urban sewages and comparison with cases notified in the course of an outbreak, Italy 2013.
abstract: BACKGROUND
  Over the past 20 years, Hepatitis A notifications in Italy have been in decline. Since the beginning of 2013 however, Italy has been experiencing a foodborne hepatitis A outbreak caused by genotype IA, involving hundreds of cases. Consumption of frozen mixed berries was deemed the potential vehicle of infection.We aimed to investigate the spread of hepatitis A virus (HAV) in Italy through the monitoring of urban sewages collected at Wastewater Treatment Plants (WTPs) and a subsequent comparison of environmental surveillance data with data from the clinical surveillance performed during the epidemic.
  
  
  METHODS
  The study covered 15 months, from July 2012 to September 2013, comprising the outbreak and the preceding six months. Environmental surveillance consisted of the analysis of urban sewage samples collected at 19 WTPs in seven of the Italian regions most affected by the epidemic. HAV isolates were detected and typed using a nested RT-PCR targeting the VP1/2A junction. Parallel clinical surveillance was performed by the sentinel surveillance system for acute viral hepatitis (SEIEVA) and by the ministerial Central Task Force on Hepatitis A, established with the purpose of determining the source of the outbreak and adopting appropriate outbreak control strategies.
  
  
  RESULTS
  A total of 38/157 wastewater samples (24.2%) were positive for HAV, 16 collected in 2012 and 22 in 2013. Several HAV strains were detected, including the IA variant implicated in the outbreak and isolated from clinical cases over the same period. The vast majority of sequences belonged to genotype IB. Interestingly however, although these included variants related to strains that had been involved in past Italian epidemics, none were detected in recent clinical samples, probably due to underreporting or asymptomatic circulation. Conversely, a number of sequences were identified in clinical samples that were not found in wastewaters.
  
  
  CONCLUSIONS
  The percentage of sewage samples detected as HAV-positive in this study are consistent with the classification of Italy as a country with low/intermediate endemicity. A combined environmental/clinical surveillance is able to provide a more complete picture of the spread of HAV and of the genotypes circulating in the population, allowing a better understanding of changes in disease trends.
authors: Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy. giuseppina.larosa@iss.it.
authors: Giuseppina
authors: G
authors: La Rosa
authors: Simonetta Della
authors: SD
authors: Libera
authors: Marcello
authors: M
authors: Iaconelli
authors: Anna Rita
authors: AR
authors: Ciccaglione
authors: Roberto
authors: R
authors: Bruni
authors: Stefania
authors: S
authors: Taffon
authors: Michele
authors: M
authors: Equestre
authors: Valeria
authors: V
authors: Alfonsi
authors: Caterina
authors: C
authors: Rizzo
authors: Maria Elena
authors: ME
authors: Tosti
authors: Maria
authors: M
authors: Chironna
authors: Luisa
authors: L
authors: Romanò
authors: Alessandro Remo
authors: AR
authors: Zanetti
authors: Michele
authors: M
authors: Muscillo
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D005260:Female; D006506:Hepatitis A / Q000453:epidemiology* / Q000821:virology; D030041:Hepatitis A virus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010802:Phylogeny; D011159:Population Surveillance; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018571:Sentinel Surveillance; D012722:Sewage / Q000821:virology*; D014504:Urban Health; D055815:Young Adult
chemical_list: D012722:Sewage