Zoonoses in the European Union: origin, distribution and dynamics - the EFSA-ECDC summary report 2009.

We present a summary of the main findings of the latest report of the European Food Safety Authority and European Centre for Disease Prevention and Control on zoonoses, zoonotic agents and food-borne outbreaks in the European Union (EU), based on data from 2009. Zoonoses are prevalent and widely distributed across several countries in the EU. The most important highlight of this report was the continuous decrease of human salmonellosis since 2005, probably due to effective control programmes in livestock.

Norovirus outbreaks linked to oyster consumption in the United Kingdom, Norway, France, Sweden and Denmark, 2010.

This paper reports on several simultaneous outbreaks of norovirus infection linked to the consumption of raw oysters. Since January 2010, 334 cases in 65 clusters were reported from five European countries: the United Kingdom, Norway, France, Sweden and Denmark. The article describes the available epidemiological and microbiological evidence of these outbreaks.

Zoonotic infections in Europe in 2007: a summary of the EFSA-ECDC annual report.

The European Food Safety Authority and the European Centre for Disease Prevention and Control have just published their Community Zoonoses Report for 2007, analysing the occurrence of infectious diseases transmittable from animals to humans. Campylobacter infections still topped the list of zoonotic diseases in the European Union and the number of Salmonella infections in humans decreased for the fourth year in a row. Cases of listeriosis remained at the same level as in 2006, but due to the severity of the disease, more studies on transmission routes are warranted. The report highlights the importance of continued co-operation between veterinarians and public health specialists, both at the EU level and within Member States.

Characterization of drinking water treatment for virus risk assessment.

Removal or inactivation of viruses in drinking water treatment processes can be quantified by measuring the concentrations of viruses or virus indicators in water before and after treatment. Virus reduction is then calculated from the ratio of these concentrations. Most often only the average reduction is reported. That is not sufficient when treatment efficiency must be characterized in quantitative risk assessment. We present three simple models allowing statistical analysis of series of counts before and after treatment: distribution of the ratio of concentrations, and distribution of the probability of passage for unpaired and paired water samples. Performance of these models is demonstrated for several processes (long and short term storage, coagulation/filtration, coagulation/sedimentation, slow sand filtration, membrane filtration, and ozone disinfection) using microbial indicator data from full-scale treatment processes. All three models allow estimation of the variation in (log) reduction as well as its uncertainty; the results can be easily used in risk assessment. Although they have different characteristics and are present in vastly different concentrations, different viruses and/or bacteriophages appear to show similar reductions in a particular treatment process, allowing generalization of the reduction for each process type across virus groups. The processes characterized in this paper may be used as reference for waterborne virus risk assessment, to check against location specific data, and in case no such data are available, to use as defaults.

Removal of noro- and enteroviruses, Giardia cysts, Cryptosporidium oocysts, and fecal indicators at four secondary wastewater treatment plants in Sweden.

The aim of this study was to investigate variation in the occurrence and removal of enteroviruses, noroviruses, Giardia cysts, Cryptosporidium oocysts, and the most commonly used fecal indicators in four Swedish secondary wastewater treatment plants (WWTPs). Paired samples were taken from the inlet and outlet of each WWTP. (Oo)cysts and indicators were enumerated with standard methods and viruses with a reverse transcriptase polymerase chain reaction. Giardia cysts and enteroviruses were constantly detected (mean numbers were 10(3.31) cysts and 10(4.44) polymerase chain reaction (PCR) units L(-1), respectively). Oocysts were found in 5 out of 19 samples (mean number was 20 L(-1)). Noroviruses were found between November and February, with an average titer of 10(3.29( L(-1). Mean cyst removal was 2.6 log, while noroviruses and enteroviruses were removed by 0.9 and 1.3 log, respectively. There was no correlation between the removals of pathogens and indicators (p > 0.05). Coliphage removal resembled human viral removal better than did F-specific phage.

QMRA (quantitative microbial risk assessment) and HACCP (hazard analysis and critical control points) for management of pathogens in wastewater and sewage sludge treatment and reuse.

Hazard Analysis and Critical Control Points (HACCP) was applied for identifying and controlling exposure to pathogenic microorganisms encountered during normal sludge and wastewater handling at a 12,500 m3/d treatment plant utilising tertiary wastewater treatment and mesophilic sludge digestion. The hazardous scenarios considered were human exposure during treatment, handling, soil application and crop consumption, and exposure via water at the wetland-area and recreational swimming. A quantitative microbial risk assessment (QMRA), including rotavirus, adenovirus, haemorrhagic E. coli, Salmonella, Giardia and Cryptosporidium, was performed in order to prioritise pathogen hazards for control purposes. Human exposures were treated as individual risks but also related to the endemic situation in the general population. The highest individual health risk from a single exposure was via aerosols for workers at the belt press for sludge dewatering (virus infection risk = 1). The largest impact on the community would arise if children ingested sludge at the unprotected storage site, although in the worst-case situation the largest number of infections would arise through vegetables fertilised with sludge and eaten raw (not allowed in Sweden). Acceptable risk for various hazardous scenarios, treatment and/or reuse strategies could be tested in the model.

A theoretical approach to assess microbial risks due to failures in drinking water systems.

A failure in treatment or in the distribution network of a surface water-works could have serious consequences due to the variable raw water quality in combination with an extended distribution. The aim of this study was to examine the theoretical impact of incidents in the drinking water system on the annual risk of infection in a population served by a large water treatment plant in Sweden. Reported incidents in the system were examined and a microbial risk assessment that included three pathogens, Cryptosporidium parvum, rotavirus and Campylobacter jejuni, was performed. The main risk incidents in water treatment were associated with sub-optimal particle removal or disinfection malfunction. Incidents in the distribution network included cross-connections and microbial pollution of reservoirs and local networks. The majority of the annual infections were likely to be due to pathogens passing treatment during normal operation and not due to failures, thus adding to the endemic rate. Among the model organisms, rotavirus caused the largest number of infections. Decentralised water treatment with membranes was also considered in which failures upstream fine-pored membranes would have little impact as long as the membranes were kept intact.