Emergence of New Norovirus Variants on Spring Cruise Ships and Prediction of Winter Epidemics

A reporting system could provide early warning

Viruses transmitted through the food chain : A review of the latest developments

The emergence of severe acute respiratory syndrome (SARS), Nipah virus and H5N1 has sparked fears of food-borne dissemination of viruses, resulting in an increased focus on microbiological food safety. Norovirus (NoV) and hepatitis A virus (HAV) have been recognized as priorities based on their illness burden, and as models for prevention studies. In addition, hepatitis E virus is considered an emerging food-borne pathogen. Systematic surveillance for food-borne viral diseases, where present, has to deal with underreporting, with available data biased towards developed countries, making true estimates of the burden of illness challenging. Nevertheless, food-borne viral outbreaks are often reported, whereas current measures undertaken by food safety management organizations are focused primarily on bacterial contamination and are insufficient for viruses in food. There has been a shift towards molecular techniques for the diagnosis and detection of viruses in food, but a definite link to food is still hard to establish owing to the low levels of viruses in foods. Moreover, multiple strains may be involved in sewagecontaminated foods, with the risk of recombination and development of novel strains after ingestion. To enable monitoring of food and food safety, sensitive routine methods are needed, and methods for detection of NoV and HAV in risk foods (shellfish, soft fruit and leafy greens) are currently validated. Norovirus cannot be cultured, but the murine NoV may be a surrogate for studying NoV survival. In all, significant progress has been made in understanding food-borne viral infections, but clear data gaps still exist and should be the focus of future research.</p

Modulation of IL-6 production and IL-1 activity by keratinocyte-fibroblast interaction

The present study was undertaken to investigate whether modulation of interleukin-6 and interleukin-1 production occurs owing to keratinocyte-fibroblast interaction. Normal human keratinocytes or squamous carcinoma cells were cultured either alone or in the presence of human foreskin fibroblasts or murine 3T3 cells. All cells tested produced interleukin-6, and interleukin-6 levels were markedly increased when normal or malignant keratinocytes were co-cultured with fibroblasts. The bioassay (species independent) and enzyme-linked immunosorbent assay (specific for human interleukin-6) together with use of complementary DNA probes specific for human or murine interleukin-6 revealed that fibroblasts are responsible for increased interleukin-6 levels. Moreover, interleukin-6 levels were increased when fibroblasts were cultured in conditioned media derived from normal human keratinocytes and squamous carcinoma cells-4 cultures. Interleukin-1α secreted by normal human keratinocytes and squamous carcinoma cells-4 cells was mainly responsible for the increased interleukin-6 production in fibroblasts. Although interleukin-1 activity increased linearly with the incubation time in squamous carcinoma cells-4 mono-cultures, interleukin-1 activity was low and remained unchanged in squamous carcinoma cells-4/3T3 co-cultures. Low interleukin-1 activity was most probably not due to inhibition of interleukin-1α production in squamous carcinoma cells-4/3T3 co-cultures because interleukin-lα messenger RNA expression in squamous carcinoma cells-4 cells remained unchanged in the presence of 3T3 cells. Furthermore, when 3T3 cells were incubated in conditioned medium derived from squamous carcinoma cells-4 cells, high interleukin-1 activity decreased to an undetectable level, suggesting that fibroblasts are involved in the suppression of interleukin-1 activity. The remaining interleukin-1 activity, however, was sufficient for maximal induction of interleukin-6 production in fibroblasts. These results suggest that the interaction between epithelial and mesenchymal cells is at least partly initiated by interleukin-lα secreted by the activated epithelial cell during skin injury or tumor invasion. Interleukin-1 in turn can induce modulation of the synthesis of various pro-inflammatory mediators and proteases in surrounding fibroblasts. An enhanced proteolytic activity and/or a possible induced production of an interleukin-1 inhibitor in fibroblasts and/or a receptor-mediated interleukin-1 consumption by fibroblasts will cause a decrease in interleukin-1 activity and thus exert a negative feedback

Induction of HSP27 nuclear immunoreactivity during stress is modulated by vitamin C

For the investigation of the skin irritancy potential of chemicals in an in vitro model it is necessary to have sensitive endpoints that predict the effects of those compounds on native human skin. Recently, we have identified that 27-kDa heat shock protein (HSP27) can serve as a sensitive marker of skin irritation, as exposure of human skin to sodium lauryl sulfate (SLS) both in vitro and in vivo induced relocalization of HSP27 from the cytoplasm to the cell nucleus. The aim of the present study was to determine whether nuclear localization of HSP27 could be used as a parameter for evaluation of potential skin irritants in screening assays in vitro. For this purpose, human skin equivalent consisting of epidermis reconstructed on de-epidermized dermis was exposed to SLS or UV light. Stress-induced nuclear relocalization of HSP27 was observed in excised skin exposed to SLS or UV light and in reconstructed epidermis only when the latter was generated in the absence of vitamin C. The omission of vitamin C results in an impaired barrier function. In the presence of vitamin C, however, the barrier function was comparable with excised skin, suggesting that vitamin C may control the response to stress in the reconstructed epidermis. Besides the presence of vitamin C, the response of skin equivalents may strongly depend on other conditions under which they are generated, because the stress-induced HSP27 relocalization was not detected in the commercially available epidermal kit EpiDerm. The results of the present study show that HSP27 nuclear staining can serve as a sensitive marker for skin irritation or cellular stress in excised skin as well as in certain well-characterized human skin equivalents in vitro.</p

Emergence of new norovirus variants on spring cruise ships and prediction of winter epidemics.

In June 2006, reported outbreaks of norovirus on cruise ships suddenly increased; 43 outbreaks occurred on 13 vessels. All outbreaks investigated manifested person-to-person transmission. Detection of a point source was impossible because of limited investigation of initial outbreaks and data sharing. The most probable explanation for these outbreaks is increased norovirus activity in the community, which coincided with the emergence of 2 new GGII.4 variant strains in Europe and the Pacific. As in 2002, a new GGII.4 variant detected in the spring and summer corresponded with high norovirus activity in the subsequent winter. Because outbreaks on cruise ships are likely to occur when new variants circulate, an active reporting system could function as an early warning system. Internationally accepted guidelines are needed for reporting, investigating, and controlling norovirus illness on cruise ships in Europe

Surveillance study of hepatitis A virus RNA on fig and date samples

A total of 91 fig and 185 date samples were analyzed by reverse transcription (RT) real-time PCR for the presence of hepatitis A virus (HAV) RNA. Two batches of dates tested positive, and theHAVRNAdetected was genotyped as IA. These findings warrant further development of methods applicable to food which is consumed untreated and is exported from countries in whichHAVis endemic

Human papillomavirus type 5 is commonly present in immunosuppressed and immunocompetent individuals

DNA of a wide spectrum of epidermodysplasia verruciformis-associated human papillomavirus (HPV) types (EV-HPV) has been detected in skin lesions and plucked hairs from both immunosuppressed and a considerable proportion of non-immunosuppressed persons. Recently, the skin of psoriatic patients was claimed to be an important reservoir for a particular EV-HPV type, HPV 5, which is considered as a high-risk HPV type for skin carcinomas. In the present study, we analysed plucked hairs from immunosuppressed renal transplant patients and immunocompetent individuals, utilizing an HPV 5- specific nested polymerase chain reaction. HPV 5 was detected in hairs derived from 14 of 31 (45%) immunosuppressed patients and 21 of 135 (16%) immunocompetent individuals. Both the immunosuppressed and the immunocompetent groups consisted of individuals with and without non-melanoma skin cancer. HPV 5 DNA was detected in similar proportions of hair samples plucked from individuals with and without skin cancer in either group. Our results indicate that HPV 5 is commonly present in the population. The role of HPV 5 in the pathogenesis of skin carcinomas and psoriasis remains to be established.</p

Norovirus on swabs taken from hands illustrate route of transmission: A case study

Abstract Recently, environmental swabs from kitchen and bathroom surfaces have been described as an additional tool for the detection of norovirus in outbreak settings. This article describes an outbreak investigation in response to the reporting of gastroenteritis in three unrelated groups of 6, 12, and 13 adults approximately 30 h after having meals in the same restaurant. Fecal samples were collected from 13 patients and six food handlers, and environmental swabs were taken from the soap dispenser, working bench, doorknobs of cupboards, and the grip of a knife in the kitchen and in bathrooms as well as from the hands of each of three employees on the day of inspection. Clinical and environmental samples were analyzed separately in time and location for the presence of norovirus by real-time reverse transcription PCR. Structured interviews revealed that all staff members had suffered from gastroenteritis, one after the other. Norovirus RNA (GGI.6) was detected in 17 of 19 fecal samples as well as in 4 environmental samples, including a swab sample from the hands of a staff member who was preparing ready-to-eat food. Sequences obtained from clinical and environmental samples showed an identity of 100% (235 nucleotides). To our knowledge, this is the first case study to directly demonstrate the presence of norovirus RNA on a food handler's hands in an outbreak setting. This finding provides direct evidence for the feasibility of transmission of norovirus by a food handler to food. Education of food handlers on the infectivity of norovirus and updating of hygienic codes are strongly recommended.</p