Norovirus in symptomatic and asymptomatic individuals: cytokines and viral shedding.

Noroviruses (NoV) are the most common cause of epidemic gastroenteritis world-wide. NoV infections are often asymptomatic, although individuals still shed large amounts of NoV in their stool. Understanding the differences between asymptomatic and symptomatic individuals would help in elucidating mechanisms of NoV pathogenesis. Our goal was to compare the serum cytokine responses and faecal viral RNA titres of asymptomatic and symptomatic NoV-infected individuals. We tested serum samples from infected subjects (n = 26; 19 symptomatic, seven asymptomatic) from two human challenge studies of GI.1 NoV for 16 cytokines. Samples from prechallenge and days 1-4 post-challenge were tested for these cytokines. Cytokine levels were compared to stool NoV RNA titres quantified previously by reverse transcription-polymerase chain reaction (RT-qPCR). While both symptomatic and asymptomatic groups had similar patterns of cytokine responses, the symptomatic group generally exhibited a greater elevation of T helper type 1 (Th1) and Th2 cytokines and IL-8 post-challenge compared to the asymptomatic group (all P < 0·01). Daily viral RNA titre was associated positively with daily IL-6 concentration and negatively with daily IL-12p40 concentration (all P < 0·05). Symptoms were not associated significantly with daily viral RNA titre, duration of viral shedding or cumulative shedding. Symptomatic individuals, compared to asymptomatic, have greater immune system activation, as measured by serum cytokines, but they do not have greater viral burden, as measured by titre and shedding, suggesting that symptoms may be immune-mediated in NoV infection.

Human norovirus infection and the acute serum cytokine response.

Noroviruses (NoV) are the most common cause of epidemic gastroenteritis worldwide. The acute immune response to NoV in humans is poorly understood, hindering research on prevention and treatment. To elucidate the acute immune response and test for cytokine predictors of susceptibility to infection, serum samples from two human NoV challenge studies were tested for 16 cytokines. Subjects who became infected (n = 26) were age-matched with subjects who remained uninfected following NoV challenge (n = 26). Samples were tested from prechallenge and days 1-4 post-challenge. Cytokine responses were compared between infected and uninfected groups. Overall, infected individuals exhibited an elevation in T helper type 1 (Th1) and Th2 cytokines, as well as chemokines interleukin (IL)-8 and monocyte chemoattractant protein (MCP-1), compared to uninfected individuals (all P < 0.05). Most cytokines peaked on day 2 post-challenge in infected subjects, and tumour necrosis factor (TNF)-α, IL-8, and IL-10 remained elevated to day 3. The only cytokine elevated significantly among infected subjects to day 4 post-challenge was IL-10 (P = 0.021). Prechallenge cytokine concentrations were not predictive of infection status post-challenge. There were no significant changes in serum cytokines among NoV-challenged subjects who remained uninfected. These results suggest that NoV infection elicits a Th1-type response, with some Th2 activation. Persistent elevation of IL-10 among infected subjects is consistent with activation of adaptive immune responses, such as B cell expansion, as well as down-regulation of Th1 cytokines. This study presents the first comprehensive description of the acute cytokine response to GI.1 NoV in humans.

The impact of socioeconomic status on foodborne illness in high-income countries: a systematic review.

Foodborne illness is a major cause of morbidity and loss of productivity in developed nations. Although low socioeconomic status (SES) is generally associated with negative health outcomes, its impact on foodborne illness is poorly understood. We conducted a systematic review to examine the association between SES and laboratory-confirmed illness caused by eight important foodborne pathogens. We completed this systematic review using PubMed for all papers published between 1 January 1980 and 1 January 2013 that measured the association between foodborne illness and SES in highly developed countries and identified 16 studies covering four pathogens. The effect of SES varied across pathogens: the majority of identified studies for Campylobacter, salmonellosis, and E. coli infection showed an association between high SES and illness. The single study of listeriosis showed illness was associated with low SES. A reporting bias by SES could not be excluded. SES should be considered when targeting consumer-level public health interventions for foodborne pathogens.

Extending a critical path for patients who are ventilator dependent: nursing case management in the home setting.

A case management model is prepared to extend nursing care of the patient who is ventilator dependent from the hospital to the home setting. The model focuses on decreasing the hospital length of stay and major critical pathway elements. Effective discharge planning is emphasized.

Body image dissatisfaction in homosexual and heterosexual males.

A nonclinical sample of 43 homosexual and 32 heterosexual men completed two self-report inventories regarding weight, body satisfaction, eating attitudes, and behaviors. Subjects were also asked to select their current and ideal figures, the weight they felt would be most attractive to a potential partner, and the weight to which they would be most attracted in a potential partner from figures representing very thin to very heavy physiques. Heterosexual men were significantly heavier than homosexual men and desired a significantly heavier ideal weight. Although the current and ideal physiques selected by the homosexual and heterosexual men were almost identical, homosexual men were more likely to desire an underweight ideal. A heightened pursuit of thinness may place homosexual men at an increased risk for developing eating disorders.