UV Inactivation of Common Pathogens and Surrogates Under 222 nm Irradiation from KrCl* Excimer Lamps.

Germicidal ultraviolet (UV) devices have been widely used for pathogen disinfection in water, air, and on food and surfaces. Emerging UV technologies, like the krypton chloride (KrCl*) excimer emitting at 222 nm, are rapidly gaining popularity due to their minimal adverse effects on skin and eyes compared with conventional UV lamps emitting at 254 nm, opening opportunities for UV disinfection in occupied public spaces. In this study, inactivation of seven bacteria and five viruses, including waterborne, foodborne and respiratory pathogens, was determined in a thin-film aqueous solution using a filtered KrCl* excimer emitting primarily at 222 nm. Our results show that the KrCl* excimer can effectively inactivate all tested bacteria and viruses, with most microorganisms achieving more than 4-log (99.99%) reduction with a UV dose of 10 mJ cm-2 . Compared with conventional UV lamps, the KrCl* excimer lamp exhibited better disinfection performance for viruses but was slightly less effective for bacteria. The relationships between UV sensitivities at 222 and 254 nm for bacteria and viruses were evaluated using regression analysis, resulting in factors that could be used to estimate the KrCl* excimer disinfection performance from well-documented UV kinetics using conventional 254 nm UV lamps. This study provides fundamental information for pathogen disinfection when employing KrCl* excimers.

Men who have sex with men and also inject drugs-profiles of risk related to the synergy of sex and drug injection behaviors.

OBJECTIVES: Men who have sex with men and also inject drugs (MSM-IDU) are among the groups at highest risk for acquiring and transmitting HIV in Colorado and the US. We conducted formative research and a survey among MSM-IDU in Denver to better understand sexual and drug HIV risk behaviors and how they interact. METHODS: Formative data were collected with 30 persons who work, live or otherwise interact with MSM-IDU using a semi-structured interview instrument. Survey data on sexual and drug risk behaviors were collected with 100 MSM-IDU; eligible participants have had sex with men and injected drugs within the past six months. RESULTS: Results from formative research were used to generate the survey instrument. The survey results demonstrate high-risk sexual behaviors with multiple partners of both genders; 82% of the sample had primary and non-primary male partners, 20% had non-primary female partners, and 15% exchanged money or drugs for sex. Condom use was inconsistent and infrequent for all types of sex (vaginal, anal and oral) and with all types of partners. Drug risk behaviors highlight that the injection drugs of choice for this sample (90% shoot cocaine and 59% shoot methamphetamine) stimulate sexual desire and cocaine injection increases opportunities for injection risk behavior. Forty-five percent of the sample were HIV-infected. Significant differences between HIV infected and non-infected men were not observed with regard to many sexual and drug risk behaviors. CONCLUSIONS: These data show that MSM-IDU are engaging in multiple risk behaviors that may have a synergistic effect on HIV transmission, and that their injection drug of choice contributes to their risk. That there do not appear to be consistent differences in preventive behaviors between men with or without HIV infection suggests a greatly increased risk for HIV transmission in this group of men and their partners. Because MSM-IDU do not identify strongly with either MSM because they may not gay identify or IDU because they do not use heroin, targeted HIV prevention strategies for this group are urgently needed.