Molecular characterization of a nosocomial outbreak of influenza B virus in an acute care hospital setting.

AIM: To describe a hospital outbreak of influenza B virus (InfB) infection during season 2015/2016 by combining clinical and epidemiological data with molecular methods. METHODS: Twenty patients diagnosed with InfB from a hospital outbreak over a four-week-period were included. Nasopharyngeal samples (NPS) positive for InfB by multiplex real-time polymerase chain reaction were sent for lineage typing and whole genome sequencing (WGS). Medical records were reviewed retrospectively for data regarding patient characteristics, localization, exposure and outcome, and assembled into a timeline. In order to find possible connections to the hospital outbreak, all patients with a positive NPS for influenza from the region over an extended time period were also reviewed. FINDINGS: All 20 cases of InfB were of subtype B/Yamagata, and 17 of 20 patients could be linked to each other by either shared room or shared ward. WGS was successful or partially successful for 15 of the 17 viral isolates, and corroborated the epidemiological link supporting a close relationship. In the main affected ward, 19 of 75 inpatients were infected with InfB during the outbreak period, resulting in an attack rate of 25%. One probable case of influenza-related death was identified. CONCLUSION: InfB may spread within an acute care hospital, and advanced molecular methods may facilitate assessment of the source and extent of the outbreak. A multi-faceted approach, including rapid diagnosis, early recognition of outbreak situations, simple rules for patient management and the use of regular infection control measures, may prevent nosocomial transmission of influenza virus.

Air bag-induced corneal flap folds after laser in situ keratomileusis.

PURPOSE: We describe a case of air bag-induced ocular trauma resulting in folds in the corneal flap 3 weeks after laser in situ keratomileusis. METHODS: Case report. Three weeks after laser in situ keratomileusis, a 20-year-old man was involved in a motor vehicle accident and sustained blunt trauma to the right eye, which caused corneal flap folds, corneal edema, anterior chamber cellular reaction, and Berlin retinal edema. RESULTS: Six weeks after laser in situ keratomileusis, persistent flap folds necessitated re-operation with lifting of the flap and repositioning. One week after the procedure, the visual acuity improved to 20/20-2, and the folds had cleared. CONCLUSION: Trauma after laser in situ keratomileusis may produce folds in the corneal flap. With persistence of these folds, management by lifting and repositioning the corneal flap may be necessary to permit recovery of visual acuity.

Posterior polymorphous dystrophy associated with astigmatism and amblyopia in children.

BACKGROUND: Posterior polymorphous dystrophy has been described in the scientific literature as having more than a casual association with keratoconus in adults. We studied four consecutive children with posterior polymorphous dystrophy who had coexisting astigmatism. In our patients, the posterior changes appeared to be associated with the corneal astigmatism, as evidenced by videokeratography. METHODS: Four consecutive cases of posterior polymorphous dystrophy in children were found over a 3-year period by one of the authors (PD). They presented with varying degrees of amblyopia in the eyes with the greater amount of posterior polymorphous dystrophy. Cycloplegic refractions and keratometry readings were performed. The more affected eyes had greater degrees of astigmatism, presumably causing the amblyopia. Whenever possible, the results were supplemented by confirmation by a corneal specialist, specular microscopy, slit-lamp photographs and videokeratography. RESULTS: Greater asymmetry of posterior polymorphous dystrophy was associated with greater astigmatism in the more affected eye. When more astigmatic anisometropia was present there was a greater amblyopia. Videokeratography of one of the patients showed that an area of confluent blebs forming a crescent shape compared exactly with a steep cylinder along the same axis. With-the-rule astigmatism was associated with a more diffuse pattern of blebs. CONCLUSION: Decreases in visual acuity in children with posterior polymorphous dystrophy may sometimes be due to an amblyopia caused by the astigmatism of asymmetric disease.

On the distribution of completed parities when fertility is heritable.

"Over the last one hundred years, there has been, in many developed countries, a demographic convergence towards the two child family. The possible implications for population growth of such a tendency are considered in this paper in terms of both family limitation and also the intergenerational transmission of fertility. These two effects interact so that as the proportion of two-child families increases, the possible influence of mother-daughter fertility associations on population growth decreases, though even now it could override otherwise significant changes in either or both of the birth and death intensities. In particular, it is shown that according...to how fertility is transmitted through generations, it is still possible to have zero growth rates consistently with a widely dispersed stable distribution of family size as well as a typical mortality regime." (SUMMARY IN FRE)

Population growth with variable family size.

"The Sharpe-Lotka continuous time deterministic model of population growth is developed to take account of some possible forms of mother-daughter fertility association.... Model specific results relating the intergenerational fertility effect to the long term population growth rate and magnitude are established. The quantitative implications of the theory are illustrated by a consideration of a general bilinear form of A and in this context numerical results illustrating the finite time growth and also the long term distribution of fertility levels in the stable female population are obtained. In particular, it is shown that different fertility specific subpopulations can coexist indefinitely."

The imaging photopolarimeter experiment on pioneer 11.

For 2 weeks continuous imaging, photometry, and polarimetry observations were made of Jupiter and the Galilean satellites in red and blue light from Pioneer 11. Measurements of Jupiter's north and south polar regions were possible because the spacecraft trajectory was highly inclined to the planet's equatorial plane. One of the highest resolution images obtained is presented here along with a comparison of a sample of our photometric and polarimetric data with a simple model. The data seem consistent with increased molecular scattering at high latitudes.