Association of host, agent and environment characteristics and the duration of incubation and symptomatic periods of norovirus gastroenteritis.

We analysed the reported duration of incubation and symptomatic periods of norovirus for a dataset of 1022 outbreaks, 64 of which reported data on the average incubation period and 87 on the average symptomatic period. We found the mean and median incubation periods for norovirus to be 32·8 [95% confidence interval (CI) 30·9-34·6] hours and 33·5 (95% CI 32·0-34·0) hours, respectively. For the symptomatic period we found the mean and median to be 44·2 (95% CI 38·9-50·7) hours and 43·0 (95% CI 36·0-48·0) hours, respectively. We further investigated how these average periods were associated with several reported host, agent and environmental characteristics. We did not find any strong, biologically meaningful associations between the duration of incubation or symptomatic periods and the reported host, pathogen and environmental characteristics. Overall, we found that the distributions of incubation and symptomatic periods for norovirus infections are fairly constant and showed little differences with regard to the host, pathogen and environmental characteristics we analysed.

A rare case of Moraxella lacunata producing combined native mitral and aortic valve endocarditis.

We describe a case of infective endocarditis due to Moraxella lacunata involving the native mitral and aortic valves, complicated by cerebral emboli and resultant hemiparesis. The patient was treated with ceftriaxone and gentamicin and improved. This appears to be the first case reported in the medical literature of native multivalvular endocarditis produced by this rare organism.