Hepatitis C prevalence and risk behavior of injecting drug users in Sydney: a continuing concern.

This study examines patterns of injecting drug use and hepatitis C (HCV) risk behavior among injecting drug users. A survey of injecting drug users attending needle and syringe programs (NSPs) in the Sydney metropolitan area and members of NSW Users and AIDS Association (NUAA) yielded 336 responses. Demographic, behavioral and drug-use information was collected from injecting drug users aged from 14 to 64 years. The majority of respondents (66%) were HCV positive, 28% had tested negative and 5% did not know their status. Prevalence was higher among men than among women (54% vs 44%). Two thirds of respondents (72%) reported frequent heroin injection. Multivariate analysis identified the following significant risk factors for hepatitis C: being more than 30 years of age, an injecting history of five years or more, and having shared drug injecting equipment with a HCV positive user. The most significant factor associated with needle sharing was having unprotected sex with sexual partners and having a positive hepatitis C test result. Early identification of these factors should be a component of HCV prevention programs. Our data indicate that the promotion of safer injecting continues to be an important public health issue with regard to reducing HCV infections.

A molecular line study of NGC 1333/IRAS 4.

Molecular line surveys and fully sampled spectral line maps at 1.3 and 0.87 mm are used to examine the physical and chemical characteristics of the extreme Class I sources IRAS 4A and 4B in the L1450/NGC 1333 molecular cloud complex. A very well collimated, jetlike molecular outflow emanates from IRAS 4A, with a dynamical age of a few thousand years. Symmetric, clumpy structure along the outflow lobes suggests that there is considerable variability in the mass-loss rate or wind velocity even at this young age. Molecular emission lines toward IRAS 4A and 4B are observed to be weak in the velocity range corresponding to quiescent material surrounding the young stellar objects (YSOs). Depletion factors of 10-20 are observed for all molecules, including CO, even for even for very conservative mass estimates from the measured millimeter and submillimeter dust continuum. However, abundances scaled with respect to CO are similar to other dark molecular cloud cores. Such depletions could be mimicked by high dust optical depths or increased grain emissivities at the observing frequencies of 230 and 345 GHz, but the millimeter and submillimeter spectral energy distributions suggest that this is unlikely over the single-dish size scales of 5000-10,000 AU. Dense, outflowing gas is found to be kinematically, but not spatially, distinct from the quiescent material on these size scales. If CO is used as a chemical standard for the high-velocity gas, we find substantial enhancements in the abundances of several molecules in outflowing material, most notably CS, SiO, and CH3OH. The SiO emission is kinematically well displaced from the bulk cloud velocity and likely arises from directly shocked material. As is the case for CO, however, the outflow features from more volatile species are centered near the cloud velocity and are often characterized by quite low rotational temperatures. We suggest that grain-grain collisions induced by velocity shear zones surrounding the outflow axes transiently desorb the grain mantles, resulting in large abundance enhancements of selected species. Similar results have recently been obtained in several other low-mass YSOs, where the outflowing gas is often both kinematically and spatially distinct, and are illustrative of the ability of accretion and outflow processes to simultaneously modify the composition of the gas and dust surrounding young stars.