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Foodborne Snow Mountain agent gastroenteritis with secondary person-to-person spread in a retirement community.

A variety of small round-structured viruses are being recognized with increasing frequency as a cause of gastroenteritis in the community, but have rarely been reported to cause outbreaks in hospitals or extended-care facilities. From March 20 through April 15, 1988, an outbreak of gastroenteritis occurred in a retirement facility in the San Francisco Bay area. Illness was characterized by diarrhea, nausea, and vomiting; two residents died. Attack rates were 46% (155 of 336) in residents and 37% (28 of 75) in employees. During the initial outbreak period, illness among residents was associated with two shrimp meals served in the facility dining hall (odds ratio = 6.7). Person-to-person transmission probably occurred: The risk of becoming ill one or two days after a roommate became ill was significantly greater than that of becoming ill at other times during the outbreak (risk ratio = 6.5). Microbiologic examinations for bacterial and parasitic enteric pathogens were negative; however, 27-nm viral particles were detected by immune electron microscopy and by blocking enzyme immunoassay to Snow Mountain agent in stools obtained at the onset of illness from one of six ill residents. Seroconversion (greater than fourfold antibody rise) to Snow Mountain agent was detected in acute- and convalescent-phase serum specimens from five of six ill residents as measured by enzyme immunoassay, but not for Norwalk agent as measured by radioimmunoassay. This report of an outbreak of Snow Mountain agent gastroenteritis in an extended-care facility documents that these difficult-to-identify 27-nm viruses can cause outbreaks in inpatient settings.

Aged↗

John Snow's practice of obstetric anesthesia.

The influence of Queen Victoria on the acceptance of obstetric anesthesia has been overstated, and the role of John Snow has been somewhat overlooked. It was his meticulous, careful approach and his clinical skills that influenced many of his colleagues, Tyler-Smith and Ramsbotham and the Queen's own physicians. The fact that the Queen received anesthesia was a manifestation that the conversion of Snow's colleagues had already taken place. This is not to say that this precipitated a revolution in practice. Medical theory may have changed, but practice did not, and the actual number of women anesthetized for childbirth remained quite low. This, however, was a reflection of economic and logistical problems, too few women were delivered of newborn infants during the care of physicians or in hospitals. Conversely, it is important to recognize that John Snow succeeded in lifting theoretical restrictions on the use of anesthesia.

Anesthesia, Obstetrical↗

Treatment of nevus Ota: combined skin abrasion and carbon dioxide snow method.

Thirty-seven patients with nevus Ota were treated by skin abrasion-carbon dioxide snow therapy. Data obtained from 24 patients (including 5 infants) who completed treatment were analyzed to determine the number of treatment courses and to assess the outcome by color and histologic type. The 5 infants completing treatment received a mean of 10 courses of carbon dioxide snow therapy. Excluding these infants, the mean number of treatment courses was 3 for skin abrasion and 16 for carbon dioxide snow therapy. The therapeutic outcome was satisfactory, being graded as "excellent" in 6 patients, "excellent to good" in 6 patients, "good" in 10 Patients, and "fair" in 2 patients. None of the patients had a "poor" outcome. Darker lesions were generally less responsive to treatment. Lesions with melanocytes in the superficial dermis showed a better response with fewer courses of treatment. Those with melanocytes throughout the whole dermis generally had a poorer outcome. The results confirm that the benefits of this procedure are limited by the associated pain and the need for great skill and a long treatment duration.

Adolescent↗

Patterns in melting snow and vapor deposited layers.

We have observed a natural periodic pattern occurring in partially melted snow lying on the ground under certain atmospheric conditions. We explain this phenomenon quantitatively by considering heat flow through this layer coexisting in two phases (snow and water). Our model equations exhibit a range of patterns depending on the average density of snow. Strikingly similar patterns have been observed by Plass and co-workers in monolayer depositions of Pb on heated PbCu substrates. We argue that the physics of the two phenomena, differing in length scales by 7 orders of magnitude, is similar.

Journal Article↗

Subclass-specific serum antibody responses to recombinant Norwalk virus capsid antigen (rNV) in adults infected with Norwalk, Snow Mountain, or Hawaii virus.

Subclass-specific antibody responses to the Norwalk virus capsid protein in adults challenged with Norwalk, Snow Mountain, or Hawaii virus were evaluated by solid-phase enzyme immunoassay using recombinant Norwalk virus capsid antigen (rNV). Fourfold or greater serum immunoglobulin G (IgG) antibody responses to rNV were detected in 15 of 20 volunteers challenged with Norwalk virus, and serum IgA and IgM antibody responses to rNV were seen in almost all subjects who had rNV IgG responses. Serum rNV IgG antibody responses also were detected in 6 of 15 volunteers challenged with Snow Mountain virus and 2 of 12 volunteers challenged with the Hawaii virus. However, the magnitude of antibody response and the geometric mean postchallenge rNV IgG antibody titers were lower in subjects challenged with Snow Mountain or Hawaii virus, and serum IgA and IgM responses generally did not occur.

Adult↗

The Wood Library-Museum's 1858 edition of John Snow's On chloroform and other anaesthetics.

The original 1858 edition of John Snow's On Chloroform and Other Anaesthetics, from which came the Wood Library-Museum of Anesthesiology reprints in 1971 and 1989, was donated to the Wood Library-Museum by Ralph Waters of Madison, Wisconsin, in 1967. The book contains a message of appreciation to Waters, dated October 1937, with the signatures of J. Blomfield, Charles King, and R.R. Macintosh as representatives of anesthesiology in England. Correspondence exists in the archives of the University of Wisconsin-Madison between Macintosh, Professor of Anaesthetics in Oxford, and Waters, Associate Professor in Madison. This reveals that Waters, during his visit to England in 1936, inspired British anesthetists to discover more of Snow's early contributions to anesthesiology, even though Waters himself did not possess On Chloroform and Other Anaesthetics. King, a manufacturer of anesthetic equipment, found a copy in the hands of Blomfield, an anesthetist at St. George's Hospital, London, where John Snow had worked. It was this copy that they presented to Waters, and that was delivered to Waters by hand when Waters' resident, Ivan Taylor, returned from Oxford to Madison. Blomfield's ownership of the book, in addition to his position as president of the Association of Anaesthetists of Great Britain and Ireland, explains why the inscription is in his handwriting.

Anesthesiology↗

Magnetic orientation of snow buntings (Plectrophenax nivalis), a species breeding in the high Arctic: passage migration through temperate-zone areas

Orientation tests were conducted with snow buntings (Plectrophenax nivalis) exposed to artificially manipulated magnetic fields, during both spring and autumn migration. Experiments were run under clear sunset skies and under simulated complete overcast. The birds closely followed experimental shifts of the magnetic fields during both seasons regardless of whether they had access to celestial cues. Clear-sky tests in vertical magnetic fields resulted in a significant bimodal orientation, the directionality of which was almost identical during spring and autumn. When the snow buntings were deprived of celestial directional information and tested in vertical magnetic fields, they failed to show any statistically significant mean directions in either spring or autumn. The results demonstrate that snow buntings possess a magnetic compass and suggest that magnetic cues are of primary importance for their migratory orientation while on passage through temperate-zone areas. However, the axial orientation in vertical magnetic fields under clear skies may indicate an involvement of celestial cues as an auxiliary source of directional information.

Journal Article↗

Assessment of the accuracy of snow surface direct beam spectral albedo under a variety of overcast skies derived by a reciprocal approach through radiative transfer simulation.

With radiative transfer simulations it is suggested that stable estimates of the highly anisotropic direct beam spectral albedo of snow surface can be derived reciprocally under a variety of overcast skies. An accuracy of +/- 0.008 is achieved over a solar zenith angle range of theta0 < or = 74 degrees for visible wavelengths and up to theta0 < or = 63 degrees at the near-infrared wavelength lambda = 862 nm. This new method helps expand the database of snow surface albedo for the polar regions where direct measurement of clear-sky surface albedo is limited to large theta0's only. The enhancement will assist in the validation of snow surface albedo models and improve the representation of polar surface albedo in global circulation models.

Journal Article↗

Visible and near-ultraviolet absorption spectrum of ice from transmission of solar radiation into snow.

Snow is a scattering-dominated medium whose scattering is independent of wavelength at 350-600 nm. The attenuation of solar radiation in snow can be used to infer the spectral absorption coefficient of pure ice, by reference to a known value at 600 nm. The method is applied to clean Antarctic snow; the absorption minimum is at 390 nm, and the inferred absorption coefficient is lower than even the lowest values of the Antarctic Muon and Neutrino Detector Array (AMANDA) experiment on glacier ice: The absorption length is at least 700 m, by comparison with 240 m for AMANDA and 10 m from laboratory attenuation measurements.

Journal Article↗

Scaling constant and its determination from simultaneous measurements of light reflection and methane adsorption by snow samples.

We describe a fast and accurate method for the determination of the specific surface area of snow samples based on the measurements of the snow reflection function at a single wavelength and geometry. The method is less sensitive to the assumed shape of particles as compared with other techniques. The concept of the snow scaling constant is introduced, and its value is derived from simultaneous measurements of light reflectance and methane adsorption.

Journal Article↗

Snow on cholera--the special lecture in the Second British Epidemiology and Public Health Course at Kansai Systems Laboratory on 24 August 1996.

The Second British Epidemiology and Public Health Course was held from 19 to 25 August 1996 in Osaka as a satellite meeting for the 14th International Scientific Meeting of the International Epidemiological Association. Thirty-three researchers from 10 countries participated in the course. Professor Walter W Holland gave a special lecture about Snow on cholera during the course, and the lecture revealed that Henry Whitehead who was a junior priest at that time contributed to Snow's work to prevent the cholera outbreak in Golden Square in 1854. What John Snow did in his life are reviewed in detail in this paper.

Cholera↗

Monitoring the prevalence of the parasitic dinoflagellate Hematodinium sp. in snow crabs Chionoecetes opilio from Conception Bay, Newfoundland.

Bitter crab disease (BCD) of snow crabs Chionoecetes opilio is caused by a parasitic dinoflagellate, Hematodinium sp. In Newfoundland's commercial fishery, infected snow crabs are identified using visual, macroscopic signs of disease for separation prior to processing. We estimated the sensitivity and specificity of gross, macroscopic diagnosis of Hematodinium sp. by comparing these results with microscopic examination of prepared hemolymph smears. The sensitivity of a diagnostic test is the probability that the test will yield a positive result given that the animal has the disease. The specificity is the probability of a negative result given the animal is not diseased. In October 1998, we conducted a design-based survey using cluster sampling in 2 strata. Over 10 000 snow crabs from pot and trawl surveys were examined macroscopically for BCD. In addition, over 350 crabs were randomly examined microscopically for disease. The double sampling resulted in an estimated sensitivity of 52.7% and an estimated specificity of 100%. That is, a positive result from macroscopic examination is definitive, if the observer is well trained, but macroscopic examination will fail to detect infections in crabs with borderline clinical signs of disease. The prevalence estimated from macroscopic observations (p(st) = 2.24%) was corrected for misclassification by dividing p(st) by the estimated sensitivity (0.527), giving a corrected estimate of 4.25%. The use of double sampling provides for efficient estimation of prevalence in that large numbers of crabs can be quickly examined for gross signs of infection and the results corrected for misclassification based on a limited number of observations with a better, but time-consuming test. In addition, the prevalence of macroscopically infected male crabs was lower in a trap survey (0.57%) compared to a trawl survey (1.59%). In the trawl survey, female crabs had a significantly higher prevalence of macroscopically diagnosed infections than males (6.34%). The prevalence of BCD has shown an alarming increase since it was first detected in Newfoundland during the early 1990s. Transmission and mortality studies are warranted to better understand the effect of the disease on its commercially important host.

Animals↗

Epidemiology of bitter crab disease (Hematodinium sp.) in snow crabs Chionoecetes opilio from Newfoundland, Canada.

The parasitic dinoflagellate Hematodinium sp. causes a condition known as bitter crab disease (BCD) in snow crabs Chionoecetes opilio and Tanner crabs C. bairdi. As the name of the condition implies, crabs infected with BCD are unmarketable due to their bitter flavor. We surveyed the distribution of BCD in 3 regions within the snow crab fishery of Newfoundland from 1997 to 2003. Over time, the disease has become firmly established in Conception and Bonavista Bays and persists at low levels on the Avalon fishing grounds. An epizootic occurred within Bonavista and Conception Bays in 1999 and persisted in Conception Bay in 2000, reaching prevalences of over 2% to 9% in trapped and trawled male crabs and from 19 to 26% in trawled and trapped female crabs, respectively. Infections were highest in females and small males, i.e. the unfished and pre-recruit portions of the fishery. In a mortality study, all of the naturally infected crabs died and 50% of the experimentally inoculated crabs died. Patterns in the molting cycle and prevalence of infection indicate that transmission occurs during the post-molt condition, and that overt infections probably develop 2 to 4 mo later with mortalities occurring at least 3 to 4 mo thereafter. The hydrography of this bay may have contributed to the epizootic as infections were centered within the deeper confines of the bay. Analysis of various abiotic factors uncovered a significant positive association between prevalence, depth and mud/sand substrates; the nature of this relationship was not apparent but may be related to diet or alternate hosts. Lastly, given the increase in BCD in snow crabs in Newfoundland, we recommend that fishery management programs for Chionoecetes fisheries employ non-selective gear to monitor for Hematodinium infections in female and juvenile crabs because these under-sampled members of the population may forewarn of impending recruitment declines that might otherwise remain unexplained.

Animals↗

Antibodies against Pasteurella multocida in snow geese in the western Arctic.

To determine if lesser snow geese (Chen caerulescens caerulescens) are a potential reservoir for the Pasteurella multocida bacterium that causes avian cholera, serum samples and/or pharyngeal swabs were collected from > 3,400 adult geese breeding on Wrangel Island (Russia) and Banks Island (Canada) during 1993-1996. Pharyngeal swab sampling rarely (> 0.1%) detected birds that were exposed to P. multocida in these populations. Geese with serum antibody levels indicating recent infection with P. multocida were found at both breeding colonies. Prevalence of seropositive birds was 3.5% at Wrangel Island, an area that has no recorded history of avian cholera epizootics. Prevalence of seropositive birds was 2.8% at Banks Island in 1994, but increased to 8.2% during 1995 and 1996 when an estimated 40,000-60,000 snow geese were infected. Approximately 50% of the infected birds died during the epizootic and a portion of the surviving birds may have become carriers of the disease. This pattern of prevalence indicated that enzootic levels of infection with P. multocida occurred at both breeding colonies. When no avian cholera epizootics occurred (Wrangel Island, Banks Island in 1994), female snow geese (4.7%) had higher antibody prevalence than males (2.0%).

Animals↗

[Dr Stockmann and Dr Snow--two heroes of public health].

Dr Thomas Stockmann, the main character of An enemy of the people by Henrik Ibsen (1828-1906), has been described as a hero of public health. In spite of his idealism and high principles, he was, however, not able to do anything about the contaminated water supply of the baths in the town where he lived. Important differences may be noticed if we compare the fictional Dr Stockmann with Dr John Snow (1813-58), a real hero of public health famous for his handling of a cholera epidemic in London in 1854. While Dr Snow carried out extensive investigations of the relation between water supply and illness and still was humble when presenting his findings, the fictional Dr Stockmann took only one sample of water for examination and was bombastic in his conclusion. And while Dr Snow had a simple suggestion for solving the problem, Dr Stockmann seemed more eager to dramatize the situation. Scientific documentation and a practical attitude to problem solving continue to be important in order to achieve results in the field of public health.

Disease Outbreaks↗

Outbreak of cyclosporiasis associated with snow peas--Pennsylvania, 2004.

During June-July 2004, public health officials in Pennsylvania were notified of cases of the parasitic disease cyclosporiasis among persons associated with a residential facility (e.g., residents, staff, and volunteers). CDC confirmed the diagnosis of Cyclospora cayetanensis infection by examining stool specimens from multiple patients. By early July, local public health officials had been notified of approximately 50 potential cases of cyclosporiasis associated with the facility; onsets of illness were from early June through early July. This report describes the findings of the epidemiologic and traceback investigations, which determined the cases were linked to consumption of raw Guatemalan snow peas at five special events, for which food was prepared by the facility staff, from late May through late June. This is the first documented outbreak of cyclosporiasis linked to snow peas. The Food and Drug Administration (FDA) and CDC are working with Guatemalan officials to determine the sources of the snow peas and possible modes of contamination.

Cluster Analysis↗

Variation of POP concentrations in fresh-fallen snow and air on an Alpine glacier (Monte Rosa).

To understand better the mechanisms ruling the fate of POPs (persistent organic pollutants) in cold environments, a field campaign sampling fresh-fallen snow and air on an Alpine glacier was carried out during Summer 2003. The concentrations of all analyzed chemicals in fresh-fallen snow show a sharp decrease over time, particularly for the more volatile POPs, confirming the rather limited literature evidence of a rapid decline of such substances from the snowpack and/or ice. Even if the results presented here are preliminary and should be confirmed by further studies, some evidence of the influence of a night/day cycle of temperature on POP deposition and revolatilization mechanisms has been highlighted. Finally, the role of cold condensation and long-range atmospheric transport in the contamination of higher altitudes in this Alpine system has been substantiated, particularly for OC pesticides.

Air Pollutants↗

Snow sports related head and spinal injuries: an eight-year survey from the neurotrauma centre for the Snowy Mountains, Australia.

Neurotrauma from snow-sports related injuries is infrequently documented in the literature. In Australia no collective data has ever been published. The aim of this study is to document the injury pattern of snow sports related neurotrauma admissions to The Canberra Hospital, the regional trauma centre for the Snowy Mountains. A computerised hospital record search conducted between January 1994 and July 2002 revealed 25 head and 66 spinal injury admissions. The incidence of severe injuries requiring referral to tertiary trauma hospital was estimated to be 7.4 per 100,000 skier-days and for head and spinal injury 1.8 per 1,000,000 skier-days and 5.6 per 1,000,000 skier-days, respectively. Collision with a stationary object was disproportionately associated with head injury ( [Formula: see text] ) and falling forward with spinal injury ( [Formula: see text] ). Snowboarders tended to sustain cervical fractures more often than skiers ( [Formula: see text] ). The importance of helmet usage in buffering the impact of head-on collision and the proposition of having both feet fastened to a snowboard in leading to cervical injury were highlighted.

Adolescent↗