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Virus diffusion in isolation rooms.

In hospitals, the ventilation of isolation rooms operating under closed-door conditions is vital if the spread of viruses and infection is to be contained. Engineering simulation, which employs computational fluid dynamics, provides a convenient means of investigating airflow behaviour in isolation rooms for various ventilation arrangements. A cough model was constructed to permit the numerical simulation of virus diffusion inside an isolation room for different ventilation system configurations. An analysis of the region of droplet fallout and the dilution time of virus diffusion of coughed gas in the isolation room was also performed for each ventilation arrangement. The numerical results presented in this paper indicate that the parallel-directional airflow pattern is the most effective means of controlling flows containing virus droplets. Additionally, staggering the positions of the supply vents at the door end of the room relative to the exhaust vents on the wall behind the bed head provides effective infection control and containment. These results suggest that this particular ventilation arrangement enhances the safety of staff when performing medical treatments within isolation rooms.

Adult↗

[Occupational risk for blood exposure and staff behaviour: a cross-sectional study in 3 Moroccan healthcare centers].

OBJECTIVE: As in other countries, Moroccan health-care workers are exposed to occupational blood exposure (OBE) hazards. The purpose of this study was to estimate the occupational safety and hygiene conditions determining the OBE risk for health-care workers. WORKERS AND METHODS: In March 2000, a multicentric study was carried out in Morocco on 420 health-care workers, with an anonymous questionnaire. The study included health-care workers in the Taza and Temara hospitals and health centers, as well as in a Rabat public medical analysis laboratory. RESULTS: The participation rate was 67.8% (285/420). The population was mainly female (61%) with a mean age of 41.4 years (+/-7 years). Health-care workers answered that: occupational hygiene and safety were inadequate (55.1%); wearing single-use gloves was rare (34.5%); resheathing used needles was frequent (74.5%); safe containers were often missing (67%). In 1999, the annual average incidence of OBE was 1.5 (+/-4.3) per capita. If we consider the whole career of health-care workers, the incidence reached about 14.3+/-28.1 per capita. The absence of post-exposure chemoprophylaxis was the rule. CONCLUSION: The study shows that there is a need to improve occupational hygiene and safety conditions for Moroccan health-care workers in order to reduce OBE hazards.

Adult↗

[Are isolation measures needed in the hospital management of Acinetobacter baumannii colonizations-infections?].

UNLABELLED: Until 2001, the infection control department of the Besançon university hospital (France) recommended isolation precautions for all patients colonized-infected by Acinetobacter baumannii (Ab) whatever the antibiotic susceptibility of the strain. These systematic isolation procedures were given up at the beginning of 2002 since the number of colonized-infected patients remained stable from 1998 to 2001. OBJECTIVE: The aim of this study was to evaluate the impact of this decision on the risk of Ab infection. METHOD: Incidence rates of colonization-infections that were observed during years 2002 and 2003 were compared with expected incidence rate, based on data from 1998-2001 period. Infection control practices and antibiotics consumption were evaluated for each ward of hospitalisation. Genotyping made it possible to determine diversity of clones inside each unit and the whole hospital. RESULTS: The expected incidence per 1000 patients-days was 0.22 in comparison with observed data in 2002, 0.34 (CI(95%) [0.28-0.42]), and in 2003, 0.53 (CI(95%) [0.45-0.63]). The expected number of Ab bloodstream infections, about two per year compared with the observed numbers in 2002 and 2003 respectively seven and 17. The number of unit with more than three cases per year increased from seven in 1999 to 18 in 2003. Antibiotics consumption did not change significantly. CONCLUSION: Genotyping results show the importance of cross-transmission in these units. Finally, observed results suggest that some measures of isolation precautions in addition to standard precautions are needed to prevent outbreaks of Ab.

Acinetobacter Infections↗

[Hospital practice and prion risks].

Procedures applicable in France for the prevention of prion diseases were first implemented in 1995, resulting from the threat of an epidemic extension of Creutzfeldt-Jakob Disease (CJD) following contamination resulting from the use of extracted growth hormone. It was found later that the bovine disease could infect humans via foodstuffs, and the human variant of the disease (v-CJD) transmissible through lymphoid formations was described in 1996. This led to generalizing precautions to a larger number of medical interventions, taking into account the risk for a population more broadly exposed to contamination. The principles for managing these new risks are described, as well for the use of medical devices or in patient as pathology laboratories.

Animals↗

[Legal framework relating to human tissues used for research ends].

Development in cell and tissue engineering needs human tissue samples. If French jurisdiction concerning the human tissue sample collected in a therapeutic goal is well established, the French and European legal context concerning the scientific research is not clear and controversial. In our lab, we aim to conjugate the professional and the moral duty and to impose on our researchers the respect of strictly defined procedures. In order to organize the management of these biological resources, we chose not only to take into account the present legal context concerning the collection of tissues for research purposes, but also to precede the French legal framework by inspiring from good practice, concerning on one hand the conservation, the transformation and the transport of human tissues used to therapeutic ends (decree of December 29, 1998) and on the other hand, from the ethical recommendations of the european directives. It is why, we put some procedures in place to guarantee the donor's information, the staff's security, the confidentiality as well as the tracability.

Biopsy↗

Development of a head-out plethysmograph system for non-human primates in an Animal Biosafety Level 3 facility.

INTRODUCTION: The term 'select agent' (SA) refers to a list of microorganisms and toxins and are defined as those that have the potential to pose a severe threat to public health and safety (42 C.F.R. Part 73). In order to carry out a research with SAs, an Animal Biosafety Level 3 (ABSL3) containment facility is required. Our newly completed ABSL3 facility is developing protocols for implementing safety and efficacy studies of therapeutics for SAs. METHODS: The primary purpose of this study was to develop methods for exposing non-human primates (NHP) to aerosolized SAs in the ABSL3 and systematically measure specific ventilatory endpoints (frequency, tidal volume, minute volume, and accumulated volume) using a head-out plethysmograph to more precisely control dosimetry. This report details the equipment and protocols used to conduct such studies within a containment facility. RESULTS: After validating the performance of the plethysmography system, we successfully exposed NHPs to an agent using the integrated plethysmography system. The system enabled an acquisition and analysis of ventilatory characteristics, facilitating accurate estimations of the inhaled dose. DISCUSSION: This system will have clear uses in the development of novel therapeutics and vaccines for the treatment of SAs in NHPs.

Administration, Inhalation↗

Plasma alpha-MSH and acetylated beta-endorphin levels following stress vary according to CRH sensitivity of the pituitary melanotropes in common carp, Cyprinus carpio.

Pituitary melanotropes release alpha-melanocyte-stimulating hormone (alpha-MSH) and acetylated beta-endorphin (NAc beta-end) during stress responses. However, effects of stressors on plasma concentrations of these hormones are highly inconsistent among fish species. Here, we show that also within a species, the common carp (Cyprinus carpio), fish sometimes respond with elevated alpha-MSH and NAc beta-end plasma levels, and at other times not. The origin of this variable response was investigated by (1) studying the effects of corticotropin-releasing hormone (CRH) on alpha-MSH and NAc beta-end release in vitro, (2) establishing where in the second messenger pathway coupled to CRH receptors melanotrope responsiveness is determined, and (3) testing modulatory actions of other hypothalamic factors (here opioid beta-endorphin). Melanotropes were in a high or low responsive state to CRH in vitro, which was especially evident when tissue was tested from fish kept at higher ambient water temperatures, and this correlates with the variability in alpha-MSH and NAc beta-end responses in vivo. Relative rates of alpha-MSH and NAc beta-end release following stimulation with CRH in vitro match plasma level changes in vivo, and this indicates that the CRH pathway does act in vivo. cAMP did not stimulate melanotropes in the low responsive state to release hormones in vitro. Thus, the mechanism that determines the cell status, occurs downstream of cAMP accumulation. Opioid beta-endorphin differentially modulated the actions of CRH, as NAc beta-end, but not alpha-MSH, release was inhibited. This response was not observed in the stress paradigms studied. We conclude that the variation in alpha-MSH and NAc beta-end stress responses in vivo correlates with many CRH responses in vitro; whether a cell is in a high or low responsive state to CRH is determined downstream of accumulation of the second messenger. We propose that melanotropes have to be in the high responsive state to be activated by CRH during stress in carp and other teleosts.

Acetylation↗

Survival of endospores of Bacillus subtilis on spacecraft surfaces under simulated martian environments: implications for the forward contamination of Mars.

Experiments were conducted in a Mars simulation chamber (MSC) to characterize the survival of endospores of Bacillus subtilis under high UV irradiation and simulated martian conditions. The MSC was used to create Mars surface environments in which pressure (8.5 mb), temperature (-80, -40, -10, or +23 degrees C), gas composition (Earth-normal N2/O2 mix, pure N2, pure CO2, or a Mars gas mix), and UV-VIS-NIR fluence rates (200-1200 nm) were maintained within tight limits. The Mars gas mix was composed of CO2 (95.3%), N2 (2.7%), Ar (1.7%), O2 (0.2%), and water vapor (0.03%). Experiments were conducted to measure the effects of pressure, gas composition, and temperature alone or in combination with Mars-normal UV-VIS-NIR light environments. Endospores of B. subtilis, were deposited on aluminum coupons as monolayers in which the average density applied to coupons was 2.47 x 10(6) bacteria per sample. Populations of B. subtilis placed on aluminum coupons and subjected to an Earth-normal temperature (23 degrees C), pressure (1013 mb), and gas mix (normal N2/O2 ratio) but illuminated with a Mars-normal UV-VIS-NIR spectrum were reduced by over 99.9% after 30 sec exposure to Mars-normal UV fluence rates. However, it required at least 15 min of Mars-normal UV exposure to reduce bacterial populations on aluminum coupons to non-recoverable levels. These results were duplicated when bacteria were exposed to Mars-normal environments of temperature (-10 degrees C), pressure (8.5 mb), gas composition (pure CO2), and UV fluence rates. In other experiments, results indicated that the gas composition of the atmosphere and the temperature of the bacterial monolayers at the time of Mars UV exposure had no effects on the survival of bacterial endospores. But Mars-normal pressures (8.5 mb) were found to reduce survival by approximately 20-35% compared to Earth-normal pressures (1013 mb). The primary implications of these results are (a) that greater than 99.9% of bacterial populations on sun-exposed surfaces of spacecraft are likely to be inactivated within a few tens of seconds to a few minutes on the surface of Mars, and (b) that within a single Mars day under clear-sky conditions bacterial populations on sun-exposed surfaces of spacecraft will be sterilized. Furthermore, these results suggest that the high UV fluence rates on the martian surface can be an important resource in minimizing the forward contamination of Mars.

Atmospheric Pressure↗

Rates and risks of transmission of smallpox and mechanisms of prevention.

In 1980, the World Health Organization declared smallpox eradicated from the world; the last known natural case had occurred in Somalia in 1977, and the United States had stopped routinely vaccinating its citizens in 1972. However, with increasing concerns regarding domestic and international terrorism, smallpox has resurfaced as a potential threat to global health. We review the direct and indirect modes of smallpox transmission and how patterns of transmission vary substantially, depending on the severity of circulating disease, vaccination status, environmental and socioeconomic factors, and the setting of an outbreak. We examine mechanisms for controlling outbreaks of disease and preventing further transmission in the event of an outbreak, with an emphasis on smallpox vaccination.

Containment of Biohazards↗

Hantaviral biosafety issues in the autopsy room and laboratory: concerns and recommendations.

The need to perform autopsies on and examine laboratory specimens from patients with hantavirus pulmonary syndrome (HPS) has raised questions about biosafety. Human illness associated with hantaviruses is usually the result of exposure to infectious aerosols from saliva or excreta of wild rodents. It is unclear whether or nor certain autopsy and laboratory procedures can also generate similar potentially infectious aerosols. As the biosafety information developed for the HPS agent is limited and the consequences of infection are serious we recommend a cautious approach. Autopsy prosectors should use N-95 particulate respirators as a minimum standard. If aerosols will be generated they should use N-100 particulate respirators or powered air purifying respirators with high-efficiency particulate air (HEPA) filters. Centrifugation and cytocentrifugation of blood or body fluid samples should be performed in bio-contained systems and these specimen containers should be opened in a class II biological safety cabinet.

Autopsy↗

The viability of Mycobacterium tuberculosis in formalin-fixed pulmonary autopsy tissue: review of the literature and brief report.

Formalin is commonly thought to decrease the risk of Mycobacterium tuberculosis infection. However, the true disinfection efficacy of formalin for tissue infected with M tuberculosis is unclear. We reviewed all pertinent literature from 1900 until the present regarding the disinfection efficacy of formalin for tissue infected with M tuberculosis. We also retrospectively cultured five cases of M tuberculosis from formalin-fixed archival pulmonary tissue. All cultures from our archived tissue were negative. The literature review revealed limited and contradictory information concerning the viability of M tuberculosis in formalin-fixed human tissue. There are no studies which specifically address the viability of M tuberculosis in tissue exclusively fixed in 10% buffered formalin. The disinfection efficacy of formalin for tuberculosis infected tissue remains unclear. Larger, prospective studies using current methodologies are needed to establish guidelines to ensure the safety for those handling infected, fixed tissue.

Autopsy↗

Critical issues in connection with human planetary missions: protection of and from the environment.

Activities associated with human missions to the Moon or to Mars will interact with the environment in two reciprocal ways: (i) the mission needs to be protected from the natural environmental elements that can be harmful to human health, the equipment or to their operations: (ii) the specific natural environment of the Moon or Mars should be protected so that it retains its value for scientific and other purposes. The following environmental elements need to be considered in order to protect humans and the equipment on the planetary surface: (i) cosmic ionizing radiation, (ii) solar particle events; (iii) solar ultraviolet radiation; (iv) reduced gravity; (v) thin atmosphere; (vi) extremes in temperatures and their fluctuations; (vii) surface dust; (viii) impacts by meteorites and micrometeorites. In order to protect the planetary environment. the requirements for planetary protection as adopted by COSPAR for lander missions need to be revised in view of human presence on the planet. Landers carrying equipment for exobiological investigations require special consideration to reduce contamination by terrestrial microorganisms and organic matter to the Greatest feasible extent. Records of human activities on the planet's surface should be maintained in sufficient detail that future scientific experimenters can determine whether environmental modifications have resulted from explorations. Grant numbers: 14056/99/NL/PA.

Aerospace Medicine↗

The Suess-Urey mission (return of solar matter to Earth).

The Suess-Urey (S-U) mission has been proposed as a NASA Discovery mission to return samples of matter from the Sun to the Earth for isotopic and chemical analyses in terrestrial laboratories to provide a major improvement in our knowledge of the average chemical and isotopic composition of the solar system. The S-U spacecraft and sample return capsule will be placed in a halo orbit around the L1 Sun-Earth libration point for two years to collect solar wind ions which implant into large passive collectors made of ultra-pure materials. Constant Spacecraft-Sun-Earth geometries enable simple spin stabilized attitude control, simple passive thermal control, and a fixed medium gain antenna. Low data requirements and the safety of a Sun-pointed spinner, result in extremely low mission operations costs.

Astronomy↗