Camilla Puccinelli

Risks of water-borne disease outbreaks after extreme events

Climatic changes are associated with heat waves, droughts, and floods which have significant impacts on human health. Floods enhance the effects of water-borne pathogens increasing the concentration of biological agents in surface water. On the basis of national statistics collected by the Italian Ministry of Health, this work illustrates preliminary observations concerning outbreaks of water-borne diseases after flood events in Italy and presents options for an administrative response. The water-borne infectious diseases taken into account are Legionellosis, Salmonellosis, Hepatitis A, cutaneous and visceral Leishmaniasis, Leptospirosis, and Infectious Diarrhea. An association between these infectious diseases and flood events seems to exist in Italy, although further analysis should be carried out to confirm this relationship. Flood impacts can be distinguished into: immediate, medium term, and long term. Several factors are involved in determining the intensity and the severity of effects. Some vector-borne infectious diseases are likely to become more frequent due to changes in vector distribution and lifecycle dynamics associated with climate change. Health care systems should develop new strategies for a more comprehensive understanding of the impact of changing weather conditions on human health.

Molecular detection of a potentially toxic diatom species.

A few diatom species produce toxins that affect human and animal health. Among these, members of the Pseudo-nitzschia genus were the first diatoms unambiguously identified as producer of domoic acid, a neurotoxin affecting molluscan shell-fish, birds, marine mammals, and humans. Evidence exists indicating the involvement of another diatom genus, Amphora, as a potential producer of domoic acid. We present a strategy for the detection of the diatom species Amphora coffeaeformis based on the development of species-specific oligonucleotide probes and their application in microarray hybridization experiments. This approach is based on the use of two marker genes highly conserved in all diatoms, but endowed with sufficient genetic divergence to discriminate diatoms at the species level. A region of approximately 450 bp of these previously unexplored marker genes, coding for elongation factor 1-a (eEF1-a) and silicic acid transporter (SIT), was used to design oligonucleotide probes that were tested for specificity in combination with the corresponding fluorescently labeled DNA targets. The results presented in this work suggest a possible use of this DNA chip technology for the selective detection of A. coffeaeformis in environmental settings where the presence of this potential toxin producer may represent a threat to human and animal health. In addition, the same basic approach can be adapted to a wider range of diatoms for the simultaneous detection of microorganisms used as biomarkers of different water quality levels.

Diatoms in drowning cases in forensic veterinary context: a preliminary study

In this preliminary study, a digestive method used in forensic context to extract diatoms has been applied in organs taken from ten wildlife animals belonging three species of mammals (a deer, a roe and five otters) and one species of birds (two magpies). Only four carcasses were recovered from aquatic environments (bath trough for animals, bathtub irrigation, river) and only in three cases out of ten that the cause of death was ruled out as drowning. In seven cases, the death was due to other causes: gunshot injuries for one otter, blunt trauma for a magpie, and traumatic injuries followed by motor vehicle collision in other four otters and a roe. Post-mortem examination was performed in all carcasses. The diatom test protocol was performed according to the Italian guidelines for analysis of benthic diatoms for ecological status assessment of inland waters. Five grams of lung, liver, and kidney was taken from all the animal carcasses. In some cases, additional tissue samples were also available among which brain, heart, spleen, and bone marrow. In all four cases found in water, the drowning medium was also available. Hydrogen peroxide (H2O2) digestion was performed, and identification of 21 genera of diatoms was obtained. The method proved to be suitable for the identification of diatoms in the organs of the animals drowned supporting the final diagnosis of drowning. Only in otters, all died for causes other than drowning, diatoms did not prove to be suitable for the diagnosis of drowning since their presence in the internal organs was mainly related to their main diet based on fishmeal. The authors believe that this first trial is very promising, and the results suggest that diatom test can be easily applied in forensic veterinary context.

First isolation of Salmonella enterica serovar Napoli from wild birds in Italy

Salmonella enterica serovar Napoli (S. Napoli) is an emerging serovar in Italy. It accounts for 2-4% of all serovars isolated from human infections. The zoonotic origin of this serovar is still unknown and this makes difficult to apply any control intervention. We report here the isolation of S. Napoli from a river nightingale (Cettia cetti, Temminck 1820) which represents the first description of this serovar from wild birds. This finding adds knowledge to the ecology of S. Napoli and addresses further studies aimed to assess the epidemiologic link between S. Napoli isolated from wild birds, food, environmental sources and human infections.

Evaluation of two methods for the use of diatoms in drowning cases

In this study, we compare digestive methods used in a forensic context to extract diatoms (37xa0% hydrochloric acid) to a method recently described in Italian protocols for analysis of benthic diatoms for ecological assessment of surface water (hydrogen peroxide digestion). The two digestive methods were performed using 5xa0g of brain, lung, liver, kidney, and bone marrow taken from the bodies of 10 drowning victims recovered from three different aquatic environments (ocean, lakes, and rivers). Postmortem examination was performed on all bodies, but aquatic samples were only analyzed in two cases. Tissue digestion was equal by both methods. Hydrogen peroxide (H2O2) digestion resulted in better diatom preservation, enabling identification of nine genera in all samples examined versus three obtained using hydrochloride digestion. The ideal digestive method to provide evidence for corroboration of a diagnosis of drowning still needs to be established. However, the benthic diatoms protocol can be useful because it is less chemically hazardous to the laboratory operator and supports better diatom preservation for reliable taxonomic analysis.

A molecular approach for the impact assessment of fecal pollution in river ecosystems

Microbiological indicators such as Escherichia coli and Enterococci are commonly used to detect fecal pollution and presence of other pathogens, in the monitoring programs of sanitary surveillance of freshwater ecosystems. Clostridium perfringens (spores) is suggested as an alternative fecal indicator, it provides evidence of historical fecal contamination. This work aims at assessing the genetic variability of the anaerobic microbial community in river sediments and its relation to different fecal pollution sources. This can be obtained through a combined approach involving microbiological and molecular (16S rRNA) tools of isolated bacteria. The study was conducted on the river systems Foglia, Tevere, Astura, and Sitzerri located in three Italian regions. The frequencies of observed haplotypes proved to be remarkably different in the four sampling areas. The phylogenetic relationships among the species obtained from the comparison of the different genetic sequences made it possible to identify six homogeneous clusters, among which, five were attributed to the genus Clostridium and one to the genus Bacillus. The results of this study suggest a possible relation between different typologies of impacts and the presence of particular species of anaerobes. The research for sulfite reducing clostridia in river sediments could therefore have an essential role in the query for complete information on the quality state of river ecosystems.

Multi-criteria approach for the environmental impact assessment of inland aquaculture

Trout farming, that represents the most important sector for aquaculture inland production in Italy, can cause negative effects on aquatic ecosystems. Recently, in the framework of Water Frame Directive 2000/60/EC and national law DL 152/2006, concerning the sustainable uses of water resources, multi-criteria approaches have been suggested to evaluate the impact of fish farming on aquatic ecosystems. In this study trout farms of central Italy were selected to investigate the effects of their effluents, on receiving water bodies using a multi-criteria approach based on physicochemical parameters, microbiological and macrobenthonic indicators, detected in sampling stations located upstream/downstream the trout farm. Moreover, antibiotic susceptibility against antibiotics allowed and/or forbidden by current law (D.lgs 193/56/06) was tested on E. coli strains. The results indicate variations of chemical parameters and biological indicators from upstream to downstream sites in some of the investigated farms. Antibiotic resistance of E. coli strains suggested a large use of tetracycline and a possible past use of chloramphenicol. This study represents a first contribute to the knowledge of fish farm impacts on aquatic systems in Central Italy.