Leptospirosis, caused by a spirochete of genus Leptospira, is considered the most widespread zoonosis in the world. It has a global distribution with a higher incidence in the tropics and subtropics, ...ranging from 10 to 100 human cases per 100,000 individuals. Leptospirosis is considered an “emerging” zoonosis due to increased contact between animals and humans and the resulting human encroachment into wildlife habitat. Climate change and its associated environmental shifts can affect the degree of transmission of leptospirosis. Surveillance for leptospirosis is important for early detection of cases because early treatment is crucial to decrease morbidity and mortality. In June 2012, the Council of State and Territorial Epidemiologists approved reinstatement of leptospirosis as a Nationally Notifiable Condition. Reinstatement of national surveillance will facilitate the assessment of the incidence, geographic distribution, trends, and risk factors associated with human cases and the identification of outbreaks and potential new animal reservoirs.
•Leptospirosis is caused by a spirochete of genus Leptospira.•Leptospirosis is considered an emerging zoonosis.•Climate change can affect the degree of transmission of leptospirosis.•Leptospirosis was recently reinstated as a Nationally Notifiable Condition.
Leptospirosis Guerra, Marta A
Journal of the American Veterinary Medical Association,
2009-Feb-15, Letnik:
234, Številka:
4
Journal Article
Recenzirano
Leptospirosis has recently been classified as an emerging disease because of large clusters of cases resulting from exposure during recreational activities and natural disasters. In addition to their ...involvement in the prevention, diagnosis, and treatment of leptospirosis in animals, veterinarians serve an important role in public health by providing guidance and information on risk factors and prevention and control measures.
A small percentage of persons with leptospirosis, a reemerging zoonosis, experience severe complications that require hospitalization. The number of leptospirosis cases in the United States is ...unknown. Thus, to estimate the hospitalization rate for this disease, we analyzed US hospital discharge records for 1998-2009 for the total US population by using the Nationwide Inpatient Sample. During that time, the average annual rate of leptospirosis-associated hospitalizations was 0.6 hospitalizations/1,000,000 population. Leptospirosis-associated hospitalization rates were higher for persons >20 years of age and for male patients. For leptospirosis-associated hospitalizations, the average age of patients at admission was lower, the average length of stay for patients was longer, and hospital charges were higher than those for nonleptospirosis infectious disease-associated hospitalizations. Educating clinicians on the signs and symptoms of leptospirosis may result in earlier diagnosis and treatment and, thereby, reduced disease severity and hospitalization costs.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
An appropriate maintenance policy is essential to reduce expenses and risks related to equipment failures. A fundamental aspect to be considered when specifying such policies is to be able to predict ...the reliability of the systems under study, based on a well fitted model. In this paper, the classes of models Arithmetic Reduction of Age and Arithmetic Reduction of Intensity are explored. Likelihood functions for such models are derived, and a graphical method is proposed for model selection. A real data set involving failures in trucks used by a Brazilian mining is analyzed considering models with different memories. Parameters, namely, shape and scale for Power Law Process, and the efficiency of repair were estimated for the best fitted model. Estimation of model parameters allowed us to derive reliability estimators to predict the behavior of the failure process. These results are a valuable information for the mining company and can be used to support decision making regarding preventive maintenance policy.
•Likelihood functions for imperfect repair models are derived.•A goodness-of-fit technique is proposed as a tool for model selection.•Failures in trucks owned by a Brazilian mining are modeled.•Estimation allowed deriving reliability predictors to forecast the future failure process of the trucks.
•The history of the system is considered in order to decide whether to maintain it.•The equipment is maintained whenever the failure intensity goes above a threshold.•This random policy will incur in ...lower costs than the periodical, fixed age policy.•Estimation for imperfect repair models uses maximum likelihood and bootstrap methods.•Application to a data set regarding failures of engines of off-road trucks is shown.
A preventive maintenance policy that considers information provided by observing the failure history of a repairable system is proposed. For a system that is to be operated for a long time, it is shown that the proposed policy will have a lower expected cost than a periodical one which does not take into account the failure history. Statistical inference using both maximum likelihood point estimates and bootstrap confidence intervals is discussed. The proposed policy is applied to a real situation involving maintenance of off-road engines owned by a Brazilian mining company. A simulation study compares the performance between the maintenance policy proposed and the periodical one.
Since 1981, an epizootic of raccoon rabies has spread throughout the eastern United States. A concomitant increase in reported rabies cases in skunks has raised concerns that an independent ...maintenance cycle of rabies virus in skunks could become established, affecting current strategies of wildlife rabies control programs. Rabies surveillance data from 1981 through 2000 obtained from the health departments of 11 eastern states were used to analyze temporal and spatial characteristics of rabies epizootics in each species. Spatial analysis indicated that epizootics in raccoons and skunks moved in a similar direction from 1990 to 2000. Temporal regression analysis showed that the number of rabid raccoons predicted the number of rabid skunks through time, with a 1-month lag. In areas where the raccoon rabies virus variant is enzootic, spatio-temporal analysis does not provide evidence that this rabies virus variant is currently cycling independently among skunks.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In the repairable systems literature one can find a great number of papers that propose maintenance policies under the assumption of minimal repair after each failure (such a repair leaves the system ...in the same condition as it was just before the failure-as bad as old). This article derives a statistical procedure to estimate the optimal Preventive Maintenance (PM) periodic policy, under the following two assumptions: (i) perfect repair at each PM action (i.e., the system returns to the as-good-as-new state) and (ii) imperfect system repair after each failure (the system returns to an intermediate state between as bad as old and as good as new). Models for imperfect repair have already been presented in the literature. However, an inference procedure for the quantities of interest has not yet been fully studied. In the present article, statistical methods, including the likelihood function, Monte Carlo simulation, and bootstrap resampling methods, are used in order to (i) estimate the degree of efficiency of a repair and (ii) obtain the optimal PM check points that minimize the expected total cost. This study was motivated by a real situation involving the maintenance of engines in off-road vehicles.
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