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Secondary Transmission (secondary + transmission)
Selected AbstractsPopulation-based Triage Management in Response to Surge-capacity Requirements during a Large-scale Bioevent DisasterACADEMIC EMERGENCY MEDICINE, Issue 11 2006Frederick M. Burkle Jr MD Both the naturally occurring and deliberate release of a biological agent in a population can bring catastrophic consequences. Although these bioevents have similarities with other disasters, there also are major differences, especially in the approach to triage management of surge capacity resources. Conventional mass-casualty events use uniform methods for triage on the basis of severity of presentation and do not consider exposure, duration, or infectiousness, thereby impeding control of transmission and delaying recognition of victims requiring immediate care. Bioevent triage management must be population based, with the goal of preventing secondary transmission, beginning at the point of contact, to control the epidemic outbreak. Whatever triage system is used, it must first recognize the requirements of those Susceptible but not exposed, those Exposed but not yet infectious, those Infectious, those Removed by death or recovery, and those protected by Vaccination or prophylactic medication (SEIRV methodology). Everyone in the population falls into one of these five categories. This article addresses a population approach to SEIRV-based triage in which decision making falls under a two-phase system with specific measures of effectiveness to increase likelihood of medical success, epidemic control, and conservation of scarce resources. [source] Human prion diseases: biology and transmission by bloodISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue 1 2006J. W. Ironside Human prion diseases are a group of rare fatal transmissible neurodegenerative disorders that occur in sporadic, acquired and familial forms. In 1996, a new type of human prion disease, variant Creutzfeldt-Jakob disease (vCJD), was first identified and has subsequently been identified in 10 additional countries. vCJD results from human exposure to the bovine spongiform encephalopathy (BSE) agent, most likely through the consumption of BSE-contaminated meat products. Unlike other human prion diseases, both infectivity and the disease-associated form of the prion protein are readily detected in lymphoid tissues in vCJD, suggesting that infectivity may also be present in blood. Three recent cases of apparent iatrogenic vCJD infection by blood transfusion have occurred in the UK, following red blood cell transfusions from asymptomatic donors who subsequently died from vCJD. The first and third cases resulted in a clinical illness identical to vCJD, while the second case was an asymptomatic infection only detected at autopsy. There are no current means of detecting vCJD infection in asymptomatic donors, so continuing surveillance is required in the UK and other countries to monitor the incidence of vCJD and further cases of secondary transmission by blood transfusion. [source] Experience of Severe Acute Respiratory Syndrome in Singapore: Importation of Cases, and Defense Strategies at the AirportJOURNAL OF TRAVEL MEDICINE, Issue 5 2003Annelies Wilder-Smith Background The importation of SARS was responsible for the outbreaks in Singapore, Hong Kong, Vietnam and Canada at a time when this new disease had not been identified. We report the incidence and impact of cases of SARS imported to Singapore between 25 February and 31 May 2003, and describe national measures to prevent further importation. Methods Information on imported cases of SARS and measures taken at entry points to Singapore was retrieved from the Ministry of Health and the Civil Aviation Authority of Singapore. Results Of the 6 imported cases, which all occurred before screening measures were implemented at the airport, only the first resulted in extensive secondary transmission. Of 442,973 air passengers screened after measures were implemented, 136 were sent to a designated hospital for further SARS screening; none was diagnosed as having SARS. Conclusions The SARS outbreak in Singapore can be traced to the first imported case. The absence of transmission from the other imported cases was probably a result of relatively prompt identification and isolation of cases, together with a low potential for transmission. New imported SARS cases therefore need not lead to major outbreaks if systems are in place to identify and isolate them early. Screening at entry points is costly, has a low yield and is not sufficient in itself, but may be justified in light of the major economic, social and international impact which even a single imported SARS case may have. [source] Improved infection control in the prevention of variant Creutzfeldt-Jakob disease in Australia: costs and benefitsAUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH, Issue 6 2004Trang Vu Objective: To evaluate the costs and benefits of infection control strategies to prevent the transmission of variant Creutzfeldt-Jakob disease (vCJD) in ophthalmic surgery in Australia. Methods: The reduction in the risk of iatrogenic transmission of vCJD from feasible infection control strategies was calculated using decision analytic models. A static model calculated the direct secondary transmission for surgical eye procedures, and a simple dynamic model estimated the change in the risk of a subsequent sustained epidemic over the longer term. The expected number of vCJD infections, their cost of care and years of life lost and the estimated cost of strategies included the direct costs of infection control measures were calculated taking a health system perspective. Results: The dynamic model (Markov process) predicted that from a hypothetical pool of as many as 100 primary vCJD cases there would be less than five iatrogenic infections in the next 30 years. If there are fewer than five primary cases the model predicted no secondary cases of vCJD. The costs of providing care for a vCJD case is estimated to be about 50,000, subject to considerable uncertainty. The minimum cost for using a partial infection control strategy to prevent an iatrogenic infection is likely to be in the order of several millions of dollars. Conclusions: Substantial public health investment would need to be made in order to reduce a low risk of iatrogenic transmission of vCJD. Given the likely number of cases of iatrogenic infection, and the order of magnitude of the costs of caring for cases of vCJD, it may be difficult to justify the high cost of risk reduction strategies. [source] | ||||||||||