Bacillus anthracis contamination and inhalational anthrax in a mail processing and distribution center.

AIMS: Four inhalational anthrax cases occurred in a large mail processing and distribution center in Washington, DC, after envelopes containing Bacillus anthracis spores were processed. This report describes the results of sampling for B. anthracis spores during investigations conducted in October and December 2001. METHODS AND RESULTS: Wet swabs, wet wipes, vacuum sock, and air-filter samples were collected throughout the facility to characterize the extent of building contamination. The results showed widespread contamination of B. anthracis spores, particularly associated with one delivery bar code sorter (DBCS) machine that had sorted the spore-containing envelopes and an area where the envelopes were handled by postal workers. Spore concentrations decreased as distance from the DBCS machine increased, but spores were widely dispersed into surrounding areas. CONCLUSION: The spatial distribution of culture positive samples was closely related to the work areas of the inhalational anthrax cases and supported epidemiological evidence that the workers became ill from exposure to B. anthracis spores in areas where the contaminated envelopes had travelled. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this investigation were used to guide decontamination efforts and provided baseline spore concentrations for follow-up measurements after the building had been cleaned. Implementing methods to reduce aerosolization and dispersion of dust within the facility would reduce postal workers' potential exposures to bioterrorism agents.

Levels of carbon dioxide in helmet systems used during orthopaedic operations.

The use of isolation helmets has gained popularity as a method of possible protection of the operating-room personnel from diseases that can be transmitted during operative procedures. However, the use of these systems has been associated with a variety of symptoms, including fatigue, diaphoresis, nausea, headache, and irritability. These symptoms have often been attributed to the mental stress of the operative procedure or the physical discomfort of the helmet. As far as we know, no manufacturers include the measured levels of carbon dioxide or the rate of air exchange of their helmet system. A possible common cause of discomfort with helmet systems is the level of carbon dioxide to which the person wearing the device is exposed. We measured the levels of carbon dioxide in four helmet systems from three different manufacturers during light exercise designed to approximate the exertion during an orthopaedic operation. All but one unit failed to meet the exposure limits recommended by the National Institute for Occupational Safety and Health and the Occupational Safety and Health Administration regarding exposure to carbon dioxide. One unit, the Stackhouse Freedom Aire self-contained system, did meet these standards, but the levels of carbon dioxide in this helmet were more than 1000 per cent greater than the ambient levels in air (440 parts per million compared with 4939 parts per million). Isolation systems must be evaluated carefully not only for comfort but also for the physiological effects caused by exposure to elevated levels of carbon dioxide. Operating-room personnel who use such systems should be aware that many of the physical symptoms that they experience may be associated with elevated levels of carbon dioxide.

An outbreak of pruritic skin lesions in a group of laboratory workers--a case report.

In May 1993, an outbreak of pruritic skin lesions occurred among a group of employees located in four laboratories in the basement of an office building. Medical interviews with the affected workers were performed and an industrial hygiene survey of the site was conducted. Workers commonly reported a pricking sensation on exposed skin. Four of the workers had small (< 5mm) erythematous papules on their forearms. Just prior to the outbreak, the installation of fibrous glass insulation had commenced in the mechanical rooms which provided air to the basement of the building. Because of the nature of the symptoms and the temporal relationship with the nearby insulation work, direct skin contact with fibrous glass fibres was thought to be the cause of the outbreak. The poorly maintained air handling unit supplying air to the laboratories probably contributed to this outbreak by inefficient filtering of the circulating air.

Warts: benign or malignant?

The number of identifiable types of human papillomavirus (HPV), based on deoxyribonucleic acid (DNA) sequence, has steadily increased in recent years. Although at one time verruca vulgaris was considered a benign reactive proliferation, current evidence submits that this is not the case; some types of HPV are malignant.