The transmission of hepatitis B virus (HBV) in clinical laboratory areas was delineated by the use of hepatitis B surface antigen (HBsAg) as presumptive evidence for the presence of the infective agent. Twenty-six (34%) of 76 environmental surfaces sampled were positive for HBsAg. The outer surfaces of blood- and serum-specimen containers had HBsAg contamination rates of 55% (six of 11) and 44% (four of nine), respectively. Subsequent handling of pipetting aids, marking devices, and other items led to their contamination and further dissemination of HBsAg. An assay instrument for complete determinations of blood cell counts was observed to splatter and drip blood during its operation. The contamination rate for environmental surfaces associated with this instrument was 15%. The data indicate that transmission of HBV in the clinical laboratory is subtle and mainly via hand contact with contaminated items during the various steps of blood processing. These data support the concept that the portal of entry of HBV is through inapparent breaks in skin and mucous membranes.

is recognized as an important cause of acute illness in human beings. Community-wide waterborne outbreaks of giardiasis. h a v e b e e n d o c u m e n t e d w i t h i n c r e a s i n g f r e q u e n c y , '-' and backpackers have become ill after drinking water from mountain streams. 6'7 Giardiasis has also occurred among travelers to foreign countries, although the methods of transmission in these situations are not clear." Person-to-person transmission has been demonstrated in mental institutions,"-" in day-care centers," 15 and among male homosexuals.' 6-' 8 To our knowledge, fecally contaminated food has not been documented to be a vehicle for the transmission of giardiasis, even though the fecal-oral route of transmission has been well established." We report here an outbreak of foodborne giardiasis. On December 13, 1979, a physician notified the Minnesota Department of Health (MDH) that two employees of the Goodhue, Minnesota Public School System were being treated for giardiasis. The physician also reported that the ill employees had estimated that more than half the other employees of the school had a similar diarrheal illness. After a discussion with local school and public-health officials, the MDH initiated an investigation. Goodhue is a farming community in southeastern Minnesota with a population of 630. The major employer in the community is the consolidated rural school system, which serves 649 students in kindergarten through grade 12 and retains 60 employees. The community is served by a chlorinated but unfiltered public water system. The source of the water is a municipal well; there was no evidence of contamination during the two years before the outbreak. The school consists of one building built in 1935 and three additions that were built in 1953, 1960, and 1970. The employees have access to either of the two employee lounges, designated for smokers and nonsmokers. One is located in the original building, and the other is in the section added in 1960. A central kitchen facility, located in the building, provides approximately 500 daily lunches for employees and students in all grades. The school is connected to the public water system. From the divisions of Disease Prevention and Control and the Medical Laboratories, Minnesota Department of Health, and the Minneapolis Center for Microbiological investigations, U.S. Food and Drug Administration, Minneapolis.

This paper describes the development of an autonomous vehicle system that participated in the 2005 DARPA Grand Challenge event. After a brief description of the event, the architecture, based on version 3.2 of the Department of Defense Joint Architecture for Unmanned Systems, and the design of the system are presented in detail. In particular, the “smart sensor” concept is introduced which provided a standardized means for each sensor to present data for rapid integration and arbitration. Information about the vehicle design, system localization, perception sensors, and the dynamic planning algorithms that were used is then presented in detail. Subsequently, testing results and performance results are presented. © 2006 Wiley Periodicals, Inc.