Applied Biosafety

The safe experimental handling of animals infected with a new Risk Category 4 virus posed significant biosafety challenges. Novel approaches for restraining, handling and inoculating horses, cats and large fruit-eating bats with equine morbillivirus were developed. Equipment was designed to allow staff working in encapsulating suits access to all parts of a large animal room capable of accommodating seven horses individually. Procedures were developed for the safe handling, anesthesia and euthanasia of experimental animals and for the disposal of infected horse carcasses. Comprehensive staff training for this demanding work included safety consciousness, teamwork and training in first aid and emergency procedures.

The potential for exposure to mycotoxins in indoor environments is of increasing concern. In order to evaluate the potential for mycotoxin production by toxigenic fungi growing on water-damaged building materials, two aflatoxin producing strains of Aspergillus flavus (American Type Culture Collection 16875 and 15547) were inoculated onto culture media, plain wallboard, and vinyl wallpapered wallboard (cellulose-based and wheat-based wallpaper paste) and incubated at high relative humidity and room temperature for up to 16 weeks. Each sample was extracted with 60% methanol and aflatoxins in the crude extract were collected by immunoaffinity chromatography and quantified by fluorometry. Analysis by high performance liquid chromatography was performed for confirmation. Varying degrees of fungal growth were evident on all tested substrate types. Up to 4800 ppb of aflatoxin was detected when strain ATCC 16875 was grown on potato dextrose agar. However, when inoculation was standardized to minimize initial aflatoxin concentration in the inoculum, aflatoxin production was not detected on any wallboard sample under any of the incubation conditions provided. The presence of a toxigenic fungal strain on an indoor substrate does not necessarily indicate that the fungus is producing mycotoxins and our data provide evidence that wet wallboard is unlikely to provide appropriate conditions for aflatoxin production.

Heightened interest in pathogens with the potential for aerosol transmission and for which prevention and medical treatment is not readily available has resulted in a need for more work environments that meet Biosafety Level 3 (BSL 3) criteria. Recognizing that the facility-based criteria for BSL 3 cannot be achieved by some existing laboratories, the Centers for Disease Control and Prevention (CDC) and National Institutes of Health (NIH) biological safety guidelines provide an option for attaining BSL 3 status through the use of Biosafety Level 2 (BSL 2) facilities and strict adherence to BSL 3 practices (BSL 2/3). Inherent to this provision is a greater emphasis on safe work practices. Since the extent to which this approach is actually used in practice is not known, a nationwide mail survey of medical academic and research institutions was conducted to provide an objective indication of the proportion of BSL 3 operations actually being carried out in the BSL 2/3 mode. The results obtained indicate that 2% of activities designated as BSL 3 in the study population actually achieve this level of protection using the BSL 2/3 approach. The findings quantitatively estimate for the first time the proportion of BSL 3 activities being carried out in this fashion, and can serve as a reference point for future studies to evaluate usage trends. The results also demonstrate the utility of flexible, performance-based health and safety guidelines, as a significant amount of clinical and research work is being accommodated with the BSL 2/3 provision.

Occupational transmission of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) has been documented. The risk of infection with HIV following one needlestick exposure is approximately 0.3% and ranges from 6% to 30% for FMV and from 3.3% to 10% for hepatitis C. The diversity of health care settings makes selection of a single sharps disposal container design inappropriate in many cases. No single sharps disposal container design meets all the disposal containment needs for an entire facility. Selection of any specific container(s) should be based on a comprehensive site-specific hazard analysis. Criteria for the design, selection, and appropriate use of sharps containers were developed. The sharps disposal container safety performance criteria are divided into four areas. First, containers should remain functional during their entire usage. Second, containers must be accessible to workers who use, maintain, or dispose of sharp devices. Third, containers should be visible o the workers who must use them. Last, container designs should provide accommodation to the user, the facility, and the environment. Although engineering controls, such as needleless IV systems and “safety” needles, will reduce injuries, proper selection and use of disposal containers is still important. Prevention strategies include implementation of engineering controls, use of personal protective equipment, training, and the involvement of occupational health professionals and workers.