Antonio Alfredo Azara

Prevalence study of Legionella spp. contamination in ferries and cruise ships

BackgroundIn the last years, international traffic volume has significantly increased, raising the risk for acquisition of infectious diseases. Among travel-associated infections, increased incidence of legionellosis has been reported among travellers.Aim of our study was: to describe the frequency and severity of Legionella spp. contamination in ferries and cruise ships; to compare the levels of contamination with those indicated by the Italian ministerial guidelines for control and prevention of legionellosis, in order to assess health risks and to adopt control measures.MethodA prevalence study was carried out on 9 ships docked at the seaports of northern Sardinia in 2004. Water samples were collected from critical sites: passenger cabins, crew cabins, kitchens, coffee bars, rooms of the central air conditioning system. It was performed a qualitative and quantitative identification of Legionella spp. and a chemical, physical and bacteriological analysis of water samples.ResultsForty-two percent (38/90) water samples were contaminated by Legionella spp.. Positive samples were mainly drawn from showers (24/44), washbasins (10/22). L. pneumophila was isolated in 42/44 samples (95.5%), followed by L. micdadei (4.5%).Strains were identified as L. pneumophila serogroup 6 (45.2%; 19 samples), 2–14 (42.9%), 5 (7.1%) and 3 (4.8%). Legionella spp. load was high; 77.8% of the water samples contained > 104 CFU/L.Low residual free chlorine concentration (0–0,2 mg/L) was associated to a contamination of the 50% of the water samples.ConclusionLegionella is an ubiquitous bacterium that could create problems for public health.We identified Legionella spp. in 6/7 ferries. Microbial load was predominantly high (> 104 CFU/L or ranging from 103 to 104 CFU/L). It is matter of concern when passengers are subjects at risk because of Legionella spp. is an opportunist that can survive in freshwater systems; high bacterial load might be an important variable related to diseases occurrence.High level of contamination required disinfecting measures, but does not lead to a definitive solution to the problem. Therefore, it is important to identify a person responsible for health safety in order to control the risk from exposure and to apply preventive measures, according to European and Italian guidelines.

IS200 fingerprint of Salmonella enterica serotype Typhimurium human strains isolated in Sardinia

A collection of Salmonella enterica serotype Typhimurium human strains isolated in Northern Sardinia (Italy) was examined for the insertion sequence IS200, phage type, antibiotic profile, ribotyping polymorphisms and plasmid profile. All clinical isolates studied contained from 4 to 10 copies of the IS200 element. IS200 permitted to discriminate Typhimurium strains and to identify five IS200 types, some of them circulating in Sardinia at least since 1900. Strains belonging to phage DT104 predominated and correlated with a specific IS200 pattern.

Indoor Radon Exposure in Italian Schools

Background: The aim of the study was to assess radon concentration in schoolrooms in a city located in the midwest of Italy. Methods: A two-phase environmental study was carried out in 19 school buildings of 16 primary, secondary, and tertiary schools. Results: Median (interquartile range—IQR) indoor radon concentration in schoolrooms was 91.6 (45.0–140.3) Bq/m3. The highest (median 952.8 Bq/m3) radon concentration was found in one (3.6%) classroom, located in a building of a primary school whose median concentration was 185 Bq/m3. Radon concentration was significantly correlated with the number of students and teachers, foundation wall construction material, and with the absence of underground floors. A geopedological survey was performed close to the building with highest radon level, showing the presence of granite and tonalithic granodiorite in the soil. Conclusions: Radon levels should be routinely assessed where individuals live or work. Schools are susceptible targets, because of childhood stay and the long daily stay of occupants. Low-cost interventions, such as implementation of natural air ventilation and school maintenance, can reduce radon levels, limiting individual exposure.

In the Digital Era, Is Community Outrage a Feasible Proxy Indicator of Emotional Epidemiology? The Case of Meningococcal Disease in Sardinia, Italy

The aims of this study were (i) to evaluate the relationship between official data on invasive meningococcal disease cases in Sardinia and the reporting of the cases by a regional online newspaper and (ii) to identify indicators useful for understanding the community outrage related to health events. Cases of meningococcal disease, selected from articles published between 1999 and 2016 on a regional newspaper database, were compared to those reported to the Infectious Disease Information Service. In order to evaluate the equality of the two distribution records, the Kolgomorov Smirnov test for two samples was applied. A community outrage indicator was obtained by calculating the number of published articles for each case of meningococcal disease identified. The outrage indicator was evaluated in comparison with other phenomena: drinking water supply limitation and domestic accidents. Overall, 2724 articles on meningitis/sepsis referring to 89 cases related to meningococcal disease were considered. Significant differences between the distribution of cases officially reported and those found in the newspaper (combined K-S = 0.39; p = 0.08) were not observed. The meningococcal disease outrage indicator showed an average of seven items per case. Comparing the meningococcal disease outrage indicator with those regarding the limitation of drinking water supplies and domestic accidents, a different risk perception by the reference media was found, with the highest outrage for meningococcal disease. The present study supports the role played by emotional factors as behavioral determinants in emerging threats to public health. The analysis of the data allowed us to highlight that the proposed outrage indicator could be a feasible proxy of emotional epidemiology. Finally, data confirm that meningitis is perceived as a highly outrageous health threat.

Evaluation of radon levels in indoor gymnasia of Palermo (Sicily) and Sassari (Sardinia)

Background : In the last decades, there has been increased worldwide interest in the management of health risks from indoor radon. Methods : From 2006 to 2008, a survey on air radon levels was carried out in a total of 57 indoor gymnasia respectively located in the urban area of Palermo (Sicily) and Sassari (Sardinia). Results : The indoor radon levels were generally low with different geometric means in the two geographic areas (14.3 Bq/m3 in Palermo and 36 Bq/m3 in Sassari, respectively). Overall, in both groups increasing values of radon were found during the night and the early morning, with radon concentrations significantly lower during working time than at other times. The analysis of structural parameters showed that direct contact with the soil significantly correlated with increased levels of radon in gymnasia located in Palermo’s area (p<0.05). Furthermore, higher radon levels in Sicilian structures were also associated, although not significantly, with lack of sumps (19.3 vs 12.9 Bq/m3), location below the ground level (18.8 vs 8.7 Bq/m3), lack of windows (25 vs 13.2 Bq/m3), presence of forced ventilation (15.5 vs 7.3 Bq/m3) and with cracks or moisture tracks (15.7 vs 13.2 Bq/m3). Conclusions : Radon tends to accumulate in indoor sites and it’s monitoring, especially in buildings with potentially overcrowded conditions, could be of public health interest. Mitigation measures and minimization of the number of structural and functional risk parameters should be strongly encouraged in order to limit radon accumulation especially in countries with higher radium concentration in the soil.

Cloriti e clorati nelle acque potabili della Sardegna centro-settentrionale

Introduzione: l’approvvigionamento idropotabile della Sardegna e basato quasi esclusivamente su acqua superficiale particolarmente esposta a contaminazione ambientale per il cui trattamento sono richiesti complessi sistemi di potabilizzazione. In questo contesto, l’utilizzo del biossido di cloro in sostituzione dell’ipoclorito di sodio, pur determinando la significativa riduzione dei THM, potrebbe generare ioni clorito e clorato potenzialmente dannosi per l’uomo. Obiettivi: e stata condotta un‘indagine al fine di valutare la presenza di cloriti e clorati e rilevare indicazioni utili al loro contenimento nelle acque in uscita dagli impianti di potabilizzazione della Sardegna centro-settentrionale. Materiali e metodi: in due distinte serie di campionamenti, sono stati rilevate sia concentrazioni di disinfettante in pre ed in post clorazione sia, mediante cromatografia liquida per scambio ionico secondo la procedura EPA Metodo 300.0, cloriti e clorati nei vari step della potabilizzazione di 12 impianti. Risultati: il dosaggio medio totale di ClO2 e stato di 4,63 mg/l (2,87 mg/l in preclorazione e 1,93 in postclorazione). La percentuale media di abbattimento dei cloriti da parte dei filtri a carbone attivo ha evidenziato un calo di efficacia, essendo passata da un 62,3% rilevato nel primo campionamento ad un 23,6% rilevato nel secondo campionamento. La concentrazione media di cloriti e clorati in uscita dagli impianti e stata rispettivamente di 1,66 mg/l (min. 0,72 mg/l, max. 2,98 mg/l, dev. st. 0,69) e di 1,05 mg/l (min. 0,47 mg/l, max. 1,58 mg/l, dev. st. 0,36). La concentrazione media di cloro residuo attivo libero (C.R.A.L.) e stata di 0,59 mg/l (min. 0,19 mg/l, max. 1,26 mg/l). Conclusioni: Le concentrazioni di cloriti rilevate appaiono piuttosto elevate rispetto al valore di parametro del D.L.vo 31/2001 e, unitamente alle concentrazioni dei clorati, sono indicative della necessita di adottare, quanto prima, articolati e specifici interventi per il loro contenimento.