Salmonella risk to consumers via pork is related to the Salmonella prevalence in pig feed.

Pigs are an important source of human infections with Salmonella, one of the most common causes of sporadic gastrointestinal infections and foodborne outbreaks in the European region. Feed has been estimated to be a significant source of Salmonella in piggeries in countries of a low Salmonella prevalence. To estimate Salmonella risk to consumers via the pork production chain, including feed production, a quantitative risk assessment model was constructed. The Salmonella prevalence in feeds and in animals was estimated to be generally low in Finland, but the relative importance of feed as a source of Salmonella in pigs was estimated as potentially high. Discontinuation of the present strict Salmonella control could increase the risk of Salmonella in slaughter pigs and consequent infections in consumers. The increased use of low risk and controlled feed ingredients could result in a consistently lower residual contamination in pigs and help the tracing and control of the sources of infections.

Norovirus transmission between hands, gloves, utensils, and fresh produce during simulated food handling.

Human noroviruses (HuNoVs), a leading cause of food-borne gastroenteritis worldwide, are easily transferred via ready-to-eat (RTE) foods, often prepared by infected food handlers. In this study, the transmission of HuNoV and murine norovirus (MuNoV) from virus-contaminated hands to latex gloves during gloving, as well as from virus-contaminated donor surfaces to recipient surfaces after simulated preparation of cucumber sandwiches, was inspected. Virus transfer was investigated by swabbing with polyester swabs, followed by nucleic acid extraction from the swabs with a commercial kit and quantitative reverse transcription-PCR. During gloving, transfer of MuNoV dried on the hand was observed 10/12 times. HuNoV, dried on latex gloves, was disseminated to clean pairs of gloves 10/12 times, whereas HuNoV without drying was disseminated 11/12 times. In the sandwich-preparing simulation, both viruses were transferred repeatedly to the first recipient surface (left hand, cucumber, and knife) during the preparation. Both MuNoV and HuNoV were transferred more efficiently from latex gloves to cucumbers (1.2% ± 0.6% and 1.5% ± 1.9%) than vice versa (0.7% ± 0.5% and 0.5% ± 0.4%). We estimated that transfer of at least one infective HuNoV from contaminated hands to the sandwich prepared was likely to occur if the hands of the food handler contained 3 log10 or more HuNoVs before gloving. Virus-contaminated gloves were estimated to transfer HuNoV to the food servings more efficiently than a single contaminated cucumber during handling. Our results indicate that virus-free food ingredients and good hand hygiene are needed to prevent HuNoV contamination of RTE foods.

Outbreak of gastroenteritis caused by norovirus GII.4 Sydney variant after a wedding reception at a resort/activity centre, Finland, August 2012.

In August 2012, an outbreak of gastroenteritis occurred among 88 persons attending a wedding reception at a resort/activity centre in Ylöjärvi, Finland. Of 39 interviewed guests, 23 met the case definition. Two persons were hospitalized. Epidemiological, laboratory and environmental investigations were conducted to characterize the outbreak and to recommend control measures. Investigation confirmed the presence of a new strain of norovirus GII.4 Sydney variant in stool specimens obtained from two wedding guests and on several environmental surfaces in the centre. In the questionnaire study, none of the foods or beverages served during the reception were significantly associated with the illness. Additional cases of gastroenteritis that occurred at the centre before and after the wedding reception supported the hypothesis of environmental transmission of norovirus. After thorough cleansing and disinfection and 1 week's quarantine, no new cases with symptoms typical for norovirus infection were identified at the centre.

The Presence of Norovirus and Adenovirus on Environmental Surfaces in Relation to the Hygienic Level in Food Service Operations Associated with a Suspected Gastroenteritis Outbreak.

Norovirus (NoV) gastroenteritis outbreaks appear frequently in food service operations (FSOs), such as in restaurants and canteens. In this study the presence of NoV and adenovirus (AdV) genomes was investigated on the surfaces of premises, especially in kitchens, of 30 FSOs where foodborne gastroenteritis outbreaks were suspected. The objective was to establish a possible association between the presence of virus genomes on surfaces and a visual hygienic status of the FSOs. NoV genome was found in 11 and AdV genome in 8 out of 30 FSOs. In total, 291 swabs were taken, of which 8.9% contained NoV and 5.8% AdV genome. The presence of NoV genomes on the surfaces was not found to associate with lower hygiene level of the premises when based on visual inspection; most (7/9) of the FSOs with NoV contamination on surfaces and a completed evaluation form had a good hygiene level (the best category). Restaurants had a significantly lower proportion of NoV-positive swabs compared to other FSOs (canteens, cafeteria, schools etc.) taken together (p = 0.00014). The presence of a designated break room for the workers was found to be significantly more common in AdV-negative kitchens (p = 0.046). Our findings suggest that swabbing is necessary for revealing viral contamination of surfaces and emphasis of hygiene inspections should be on the food handling procedures, and the education of food workers on virus transmission.

Nitric oxide synthase increases in hypothalamic magnocellular neurons after salt loading in the rat. An immunohistochemical and in situ hybridization study.

Magnocellular hypothalamic neurons of the paraventricular (PVN) and supraoptic (SON) nuclei have been shown to contain a wide variety of messenger molecules in addition to vasopressin and oxytocin, including the nitric oxide (NO)-synthesizing enzyme (NOS). In this paper we have investigated the effects of salt loading on the expression of NOS by means of immunohistochemistry and in-situ hybridization. The results show an increase in the number of NOS-immunoreactive (IR) neurons both in the PVN and the SON after 5 and 14 days of salt loading. Several of these neurons were double labelled with vasopressin antiserum. In situ hybridization showed a marked increase in the number of neurons expressing NOS mRNA and a stronger signal in individual neurons. The present results suggest a role for NO in the magnocellular hypothalamic system after salt loading.

Ultraviolet Light Inactivation of Murine Norovirus and Human Norovirus GII: PCR May Overestimate the Persistence of Noroviruses Even When Combined with Pre-PCR Treatments.

Transmission of gastroenteritis-causing noroviruses may be significant via contaminated surfaces. Measures for control, e.g. disinfection with ultraviolet irradiation (UV), are therefore necessary for interrupting this transmission. Human norovirus (HuNoV) GII.4 and Murine norovirus (MuNoV) were used to study the efficacy of UV for virus inactivation on dry glass surfaces. MuNoV inactivation was measured using viability assay and the reduction in viral RNA levels for both viruses using reverse transcription quantitative PCR (RT-QPCR). For each UV dose, two parallel sample groups were detected using RT-QPCR: one group was enzymatically pre-PCR treated with Pronase and RNAse enzymes, while the other was not treated enzymatically. In the viability assay, loss of infectivity and a 4-log reduction of MuNoV were observed when the viruses on glass slides were treated with a UV dose of 60 mJ/cm(2) or higher. In the RT-QPCR assay, a steady 2-log decline of MuNoV and HuNoV RNA levels was observed when UV doses were raised from 0 to 150 mJ/cm(2). A distinct difference in RNA levels of pretreated and non-pretreated samples was observed with UV doses of 450-1.8 × 10(3) mJ/cm(2): the RNA levels of untreated samples remained over 1.0 × 10(3) PCR units (pcr-u), while the RNA levels of enzyme-treated samples declined below 100 pcr-u. However, the data show a prominent difference between the persistence of MuNoV observed with the infectivity assay and that of viral RNA detected using RT-QPCR. Methods based on genome detection may overestimate norovirus persistence even when samples are pretreated before genome detection.