Home About us Contact
|
Home About us Contact | ||
|
|
||
Transmission Risk (transmission + risk)
Selected AbstractsModeling the effect of high dead-space syringes on the human immunodeficiency virus (HIV) epidemic among injecting drug usersADDICTION, Issue 8 2010Georgiy V. Bobashev ABSTRACT Aims To illustrate the impact of different proportions of injecting drug users (IDUs) sharing high dead-space syringes (HDSS) or low dead-space syringes (LDSS) on the probability of human immunodeficiency virus (HIV) transmission; and thus the impact on injection-related HIV prevalence and incidence. Design A stochastic mathematical model was used to evaluate the impact of HDSS use in high- and low-risk IDU populations. Model parameters were obtained from peer-reviewed publications. Analytical solutions of a simplified deterministic model were obtained to explain the effect of HDSS on HIV endemic states. Findings Simulation analysis shows that the HIV epidemic could be sustained even when a small percentage of sharing (10%) involved HDSS. The effect is much stronger in high-risk compared with low-risk populations. Steady state HIV prevalence increases with the proportion of HDSS, and for high- and low-risk populations reaches around 80% and 20%, respectively. For low-risk populations, the use of LDSS could result in the virtual elimination of HIV. These results are dependent upon an evidence-supported assumption of a significant difference in HIV transmission risk associated with HDSS versus LDSS. Conclusions Our models suggest that injection-related HIV epidemics may not occur when most (e.g. 95% or more) IDUs use LDSS. While these results are based on indirect risk measures and a number of simplifying assumptions, the effect of blood retained in high dead-space syringes on HIV prevalence seems to be very strong, even using relatively conservative assumptions. The findings have potential implications for needle exchange programs and the types of syringes produced and distributed world-wide. [source] Nucleic Acid Testing (NAT) of Organ Donors: Is the ,Best' Test the Right Test?AMERICAN JOURNAL OF TRANSPLANTATION, Issue 4 2010A Consensus Conference Report Nucleic acid testing (NAT) for HIV, HBV and HCV shortens the time between infection and detection by available testing. A group of experts was selected to develop recommendations for the use of NAT in the HIV/HBV/HCV screening of potential organ donors. The rapid turnaround times needed for donor testing and the risk of death while awaiting transplantation make organ donor screening different from screening blood-or tissue donors. In donors with no identified risk factors, there is insufficient evidence to recommend routine NAT, as the benefits of NAT may not outweigh the disadvantages of NAT especially when false-positive results can lead to loss of donor organs. For donors with identified behavioral risk factors, NAT should be considered to reduce the risk of transmission and increase organ utilization. Informed consent balancing the risks of donor-derived infection against the risk of remaining on the waiting list should be obtained at the time of candidate listing and again at the time of organ offer. In conclusion, there is insufficient evidence to recommend universal prospective screening of organ donors for HIV, HCV and HBV using current NAT platforms. Further study of viral screening modalities may reduce disease transmission risk without excessive donor loss. [source] Donor-Derived Disease Transmission Events in the United States: Data Reviewed by the OPTN/UNOS Disease Transmission Advisory CommitteeAMERICAN JOURNAL OF TRANSPLANTATION, Issue 8 2009M. G. Ison Donor-derived disease transmission is increasingly recognized as a source of morbidity and mortality among transplant recipients. Policy 4.7 of the Organ Procurement and Transplantation Network (OPTN) currently requires reporting of donor-derived events. All potential donor-derived transmission events (PDDTE) reported to OPTN/UNOS were reviewed by the Disease Transmission Advisory Committee (DTAC). Summary data from January 1, 2005,December 31, 2007, were prepared for presentation. Reports of PDDTE have increased from 7 in 2005, the first full year data were collected, to 60 in 2006 and to 97 in 2007. More detailed information is available for 2007; a classification system for determining likelihood of donor-derived transmission was utilized. In 2007, there were four proven and one possible donor-derived malignancy transmissions and four proven, two probable and six possible donor-derived infectious diseases transmissions. There were nine reported recipient deaths attributable to proven donor transmissions events arising from eight donors during 2007. Although recognized transmission events resulted in significant morbidity and mortality, transmission was reported in only 0.96% of deceased donor donations overall. Improved reporting, through enhanced recognition and communication, will be critical to better estimate the transmission risk of infection and malignancy through organ transplantation. [source] Ingestion of multiple veterinary drugs and associated impact on vulture health: implications of livestock carcass elimination practicesANIMAL CONSERVATION, Issue 6 2009G. Blanco Abstract Veterinary drugs present in livestock carcasses may be ingested by scavengers and may cause important declines in their populations, as reported for diclofenac in Asia. Drug content of carcasses may depend on the prevailing livestock operations and legal regulations for carcass elimination. In Spain, the main stronghold of vultures in Europe, legal measures to mitigate the spread of bovine spongiform encephalopathy (BSE) have caused the lack or scarcity of unstabled livestock carcasses available for avian scavengers, and the parallel increase in use of dumps of livestock carcasses supplied by farms, especially of intensively medicated pigs and poultry. We evaluated temporal trends in the presence and concentration of antibiotics and other veterinary drugs, and their associated health impacts on three vulture species, due to the ban of abandoning unstabled livestock carcasses in the countryside since the BSE crisis. An increasing presence and concentration of antibiotics since the BSE crisis, and residues of three non-steroidal anti-inflammatories (NSAIDs) and four anti-parasitics were found in the vultures. Quinolones were associated with infection by opportunistic pathogens in the three species and with generalized damage to internal organs in the cinereous vulture, but no clear health impacts of NSAIDs and anti-parasitics were found. Given that there is no evidence of BSE transmission risk due to the abandonment of unstabled livestock carcasses in the countryside, this traditional practice in the Mediterranean region should be legalized in order to increase the availability, dispersion and quality of food for threatened scavengers. Once legalized, this practice should be prioritized over the spatially concentrated disposal of large amounts of carcasses from medicated stabled livestock to reduce the risk and effects of drug ingestion and acquisition and transmission of pathogens by vultures. [source] Implications of and perspectives on HIV surveillance using a serological method to measure recent HIV infections in newly diagnosed individuals: results from a pilot study in Berlin, Germany, in 2005,2007HIV MEDICINE, Issue 4 2009J Bätzing-Feigenbaum Objectives This cross-sectional study was designed to pilot the analysis of clinical data, knowledge about and attitudes towards HIV/AIDS, and prevention and risk behaviour in persons recently infected with HIV. Methods Blood samples and demographic, laboratory, clinical and behavioural data were collected from patients with newly diagnosed HIV infections. The BED IgG-capture ELISA (BED-CEIA) was used to determine the recency of infection. Results Recent HIV infections contributed 54% [95% confidence interval (CI) 45; 64%] of infections in men who have sex with men (MSM) and 16% (95% CI 0; 39%) of infections in patients with other transmission risks (P=0.041). Recently infected MSM were characterized by younger age and higher viral load as compared with MSM who had longstanding infections (P=0.011 and 0.005, respectively). Symptoms during primary infection and patients' assumptions with regard to time of infection were significantly correlated with test results indicating whether or not the HIV infection was recently acquired (P<0.001). Conclusions Cross-sectional surveillance of recent HIV infections proved to be relevant to the identification of current risks for acquiring HIV infection. The high proportion of recent HIV infections in MSM and the even higher proportion in MSM younger than 30 years indicate ongoing HIV transmission in this group. The method will be used in future national HIV surveillance in Germany. [source] Associations of Rural Residence With Timing of HIV Diagnosis and Stage of Disease at Diagnosis, South Carolina 2001-2005THE JOURNAL OF RURAL HEALTH, Issue 2 2010Kristina E. Weis PhD Abstract Context: Rural areas in the southern United States face many challenges, including limited access to health care services and stigma, which may lead to later HIV diagnosis among rural residents. Purpose: To investigate the associations of rural residence with timing of HIV diagnosis and stage of disease at diagnosis. Methods: Timing of HIV diagnosis was categorized as a diagnosis of acquired immune deficiency syndrome within 1 year of a first positive HIV test or HIV-only. Stage of disease was based on initial CD4+ T-cell count taken within 1 year of diagnosis. County of residence at HIV diagnosis was classified as urban if the population of the largest city was at least 25,000; it was classified as rural otherwise. Logistic regression was used to analyze timing of HIV diagnosis, and analysis of covariance was used to analyze stage of disease. Findings: From 2001 to 2005, 4,137 individuals were diagnosed with HIV infection. Of these, 1,129 (27%) were rural and 3,008 (73%) were urban residents. Among rural residents, 533 (47%) were diagnosed late, compared with 1,258 (42%) urban residents. Rural residents were significantly more likely to be diagnosed late (OR 1.19 [95% CI, 1.02-1.38]). Rural residence was associated with lower initial CD4+ T-cell count in crude analysis (P= .01) but not after adjustment (P > .05). Conclusions: Rural residence is a risk factor for late HIV diagnosis. This may lead to reduced treatment response to antiretroviral medications, increased morbidity and mortality, and greater HIV transmission risks among rural residents. New testing strategies are needed that address challenges to HIV testing and diagnosis specific to rural areas. [source] | ||||||||||