At the end of July 2006, an unusually high number of patients with acute diarrhoea were reported by the accident and emergency departments in Taranto, Apulia. Subsequently, a field  investigation was conducted jointly by the Apulia Regional Epidemiological Observatory and the  Regional Reference Laboratory in Bari, and the Epidemiological Department of Taranto Local  Health Unit. The outbreak investigation carried out between July and October 2006, involving hospitals in the  whole province of Taranto, included a case ascertainment and descriptive epidemiology. A case was defined as a patient with  diarrhoea (at least three loose or liquid stools in a day) and one or more of the following  symptoms: fever >= 38C, headache, vomit, abdominal pain, nausea [1,2]. Five out of six hospitals in the province of Taranto provided information on patients with  acute gastroenteritis. Data were collected retrospectively for the period between May and  July and prospectively for August and September 2006. In addition, the special medical facilities set up for tourists in the summer season (June-August) in the province of Taranto  were also asked to report cases. The outbreak investigation included microbiological investigation of stool samples of hospitalized patients. It also included microbiological investigation of environmental samples (including tap water, sea water and  shellfish) [1-4].  G     Case control study performed between 1 August and 15 September 2006 in order to  identify the possible sources of infection. From 1 May to 30 September 2006, a total of 2,860 patients with gastroenteritis symptoms were  either admitted to hospital or seen by the hospitals outpatient accident and emergency units.  This significantly exceeded the number reported in the same period in 2005, when a total of 586  patients with gastroenteritis were treated by the same hospitals. The epidemic curve is shown in  Figure 1.  Figure 1. Number of patients with gastroenteritis seeking hospital care, by week. Taranto  province, 1 May-30 September, 2005 and 2006 The first peak in incidence was observed at the end of June (26 week of the year), followed by a  second peak at the end of July (weeks 29 and 30). The number of patients with gastroenteritis  seeking hospital care decreased in the following weeks. By mid-September, the number of cases  per week was similar to that seen in the same period of 2005. Patients mean age was 25 years; 19% of the cases were under 5 years of age, 16% were 5 to 15  years old, and 65% were above 15 years of age. Incubation time was not calculated because it  was not possible to determine the exact time of exposure.  Incidence by town of residence was highest in the city of Taranto (9.5 cases per 1,000  inhabitants) (Figure 2).  http://www.eurosurveillance.org/ViewArticle.aspx?PublicationType=W&Volume=12&Issue=16&OrderNumber=1 (2 di 5)19/05/2008 10.16.21 http://www.eurosurveillance.org/ViewArticle.aspx?PublicationType=W&Volume=12&Issue=16&OrderNumber=1 Figure 2. Number of patients with gastroenteritis seeking hospital care, by town of residency per  1,000 inhabitants. Taranto province, 1 May-30 September 2006 Data collected by the tourist medical facilities in Taranto province showed a total of 361 cases of  acute gastroenteritis, significantly more than a year before. Hence the same trend was observed  as in the case of hospital data.  Microbiological analysis  A total of 70 stool samples from patients affected by the outbreak were collected and analysed.  Results by age group are reported in Table 1. Table 1. Stool samples collected from patients and tested by the Regional Reference Laboratory  (U.O.C. Igiene, Azienda Ospedaliera Policlinico), Bari, August  September 2006  Age Number of  samples  Rotavirus () Norovirus (*) < 15 51 32 (62%) 19 (37%) >= 15 7 1 (14%) 4 (57%) Unknown 12 1 (8%) 5 (41%) Total 70 34 (48%) 28 (40%)   () Nested PCR in VP7 region  (*) Nested PCR in the polymerase gene  Stool samples were also examined with respect to gastrointestinal bacteria and parasites. No  samples examined were positive for the entire range of pathogens tested.  Further genotyping of the samples is currently being done. Environmental samples, systematically collected for microbiological analyses, were tap water from  the water distribution system across the whole area affected by the outbreak, sea water and  shellfish. The water samples were collected at the local waterworks, from major water pipelines  and wells, and from tap water in pubs.  No faecal indicator bacteria and endotoxins were detected in the environmental samples of tap  water collected in Taranto city. Of 44 samples tested, four (9%) were positive for norovirus and  11 (25%) for rotavirus (Table 2). The tests were performed using molecular techniques. http://www.eurosurveillance.org/ViewArticle.aspx?PublicationType=W&Volume=12&Issue=16&OrderNumber=1 (3 di 5)19/05/2008 10.16.21 http://www.eurosurveillance.org/ViewArticle.aspx?PublicationType=W&Volume=12&Issue=16&OrderNumber=1 Table 2. Drinkable tap water samples collected and tested  Regional Reference Laboratory (U.O. C. Igiene, Azienda Ospedaliera Policlinico), Bari, August  September 2006  Date Number of  samples  Norovirus Rotavirus Both 31.07.2006 2 1 1 0 2.08.2006 3 0 2 0 8-9.08.2006 3 0 0 0 12.09.2006 4 1 1 0 14.09.2006 2 0 0 0 18-19.09.2006 8 1 3 1 12.10.2006 6 1 2 0 19.10.2006 13 0 2 0 27.10.2006 3 0 0 0 Total 44 4 (9%) 11 (25%) 1 (2%) Molecular profiles of rotavirus and norovirus identified in some tap water samples were the same  as the ones found in some patients stool samples. Sequence analysis showed the new norovirus  strain GGII.4 2006a and rotavirus genotype G9. The laboratory investigations, however, are still  ongoing and more results are expected in the future.  Of 12 sea water samples tested, four (33%) were positive for norovirus and one (8,3%) for  rotavirus.  No shell fish samples were positive for bacteria or viruses.  Case control study  A case control study was performed in order to find an association between the occurrence of  gastroenteritis and the exposure to one or more risk factors.   A case was defined as a patient with at least 3 loose or liquid stools in a day and one or more of  the following symptoms: fever >= 38C, headache, vomit, abdominal pain, nausea.   166 cases were selected among patients treated at the accident and emergency departments of  the hospitals in Taranto province, in the period between 1 August and 15 September 2006. The  control group consisted of 146 non-hospitalised healthy individuals who during the study period  were resident in the same area as the case patients. Cases and controls were age-matched. A standard questionnaire was used for the interview.  Risk factors which were shown to be significantly associated with the onset of acute diarrhoea/ gastroenteritis were the use of tap water (OR= 2; 95% CI: 1,23-3,36), and the use of water of  uncertain origin in the 72 hours before the onset of the symptoms (OR= 3,9; 95% CI: 1,41- 10,54). The epidemiological investigation and the laboratory tests showed that the possible source of  infection was the drinkable tap water contaminated with (at least) rota- and noroviruses. An extra  chlorination treatment for household water supplies was therefore performed starting from the  34th week of the year in order to stop a possible contamination of the water.  Systematic technical and microbiological investigations of the pipelines and wells of the water  distribution system did not reveal the source of contamination even though technical problems at  the local chlorination treatment facilities could not have been excluded.   http://www.eurosurveillance.org/ViewArticle.aspx?PublicationType=W&Volume=12&Issue=16&OrderNumber=1 (4 di 5)19/05/2008 10.16.21 http://www.eurosurveillance.org/ViewArticle.aspx?PublicationType=W&Volume=12&Issue=16&OrderNumber=1 To date, the outbreak of viral gastroenteritis described in this paper is probably the largest one  associated with drinking tap water in Italy. Acknowledgements  A. Mincuzzi, T. Battista, R. Mongelli, M.T. Balducci, C. Ladalardo, A. Fusco, S. Tafuri, A.  Panebianco, F. Fortunato, A. Arbore, L. Lamarina (Department of Biomedical Science and Human  Oncology, Hygiene Section, University of Bari - Apulia Regional Epidemiological Observatory); A.  Pesare, S. Minerba, G. Grassi, M. Rollo, D. Zuppiroli (Taranto Local Health Unit); F. Portincasa, P.  Montemurro, G. Vitucci (Apulia Water Distribution Company Ente Acquedotto Pugliese) References: 1.  Chironna M, Prato R. Lopalco PL, Germinario C, Sallustio A, Barbuti S, Quarto M. Norovirus GI e GII in corso  di epidemia di gastroenterite acuta associata al consumo di molluschi bivalvi in Puglia. Rapporti ISTISAN  2003; 3/C5: 39.  2.  Prato R, Lopalco PL, Chironna M, Barbuti G, Germinario C, Quarto M. Norovirus gastroenteritis general  outbreak associated with raw shellfish consumption in South Italy. BMC Infectious Diseases, 2004; 4: 37.  3.  Liang JL, Dziuban EJ, Craun GF, Hill V, Moore MR, Gelting RJ, Calderon RL, Beach MJ, Roy SL. Surveillance  for waterborne disease and outbreaks associated with drinking water and water not intended for drinking,  United States, 2003-2004. In: Surveillance Summaries, MMWR, 2006; 55: 31-58.  4.  Boccia D, Tozzi AE, Cotter B, Rizzo C, Russo T, Buttinelli G, Caprioli A, Marziano ML, Ruggeri FM.  Waterborne Outbreak of Norwalk-Like Virus Gastroenteritis at a Tourist Resort, Italy. Emerging Infection  Diseases, 2002; 8(6):563-568.  back to top    Back to Table of Contents  Next   To top |   Recommend this page  Disclamer:The opinions expressed by authors contributing to Eurosurveillance do not necessarily reflect the opinions of the European Centre for Disease Prevention and Control (ECDC) or the Editorial team or the institutions with  which the authors are affiliated. Neither the ECDC nor any person acting on behalf of the ECDC is responsible for the use which might be made of the information in this journal.   Eurosurveillance [ISSN] - 2008 All rights reserved      http://www.eurosurveillance.org/ViewArticle.aspx?PublicationType=W&Volume=12&Issue=16&OrderNumber=1 (5 di 5)19/05/2008 10.16.21 View publication stats View publication stats 

{'answer_start': [519], 'text': ['case ascertainment and descriptive epidemiology']}