Persistence of a strain of Mycobacterium tuberculosis in a prison system.

SETTING: A prison system with an average year-end census of 9084 inmates. OBJECTIVE: To determine transmission dynamics of tuberculosis over a long period; to establish whether Mycobacterium tuberculosis strains responsible for disease in a prison system persist; and to determine whether patients in a community whose isolates cluster with those in a prison system are linked. DESIGN: Retrospective epidemiologic analysis was performed on tuberculosis cases reported in a prison system over a 9-year period. In addition, IS6110 RFLP patterns of M. tuberculosis isolates obtained from prisoners were compared with those of other cases from the state at large. The results of the RFLP analysis and the epidemiologic investigation were compared. RESULTS: Approximately 80% of tuberculosis cases in the prison system were clustered. Over 9 years, a single strain of M. tuberculosis accounted for more than 50% of cases. Patients from the community at large who were infected with the same strain were linked to the prison system. CONCLUSION: In spite of intensive tuberculosis control efforts, a single strain of M. tuberculosis has persisted in the prison system. Its persistence is accounted for by activation of latent infection in patients who, prior to being diagnosed and treated, infected other patients, who then sustained the transmission chain.

Variation in vulnerability to tuberculosis in America today: random, or legacies of different ancestral epidemics?

OBJECTIVE: To test the hypothesis that vulnerability to infection by Mycobacterium tuberculosis is the norm for mankind but innate resistance to the infection is common in the USA today as a legacy of TB epidemics survived by one's ancestors. MEASUREMENTS: A reaction of 10 mm or more to a tuberculin skin test (TST) was used to determine the prevalence of infection following community outbreaks of the disease. For further information, a survey was conducted of prevalence of tuberculin reactivity among health-care workers with frequent exposures to tuberculosis patients during bronchoscopy and sputum collection. RESULTS: Sixty per cent of African Americans exposed in 26 community outbreaks were TST positive compared to only 40% of whites following comparable exposures. Similarly only 56 (41.2%) of 136 heavily exposed white health-care workers were TST positive. CONCLUSIONS: When considered in conjunction with contrasting ancestral histories of exposure to TB, these observations suggest a difference in frequency of an innate ability to respond protectively to M. tuberculosis and to mount an effective mechanism to destroy it. This is best explained as a process of natural selection among largely separate heavily exposed ancestors. Several recent reports have identified genetically mediated mechanisms of immunity that could be involved with reduced vulnerability to tuberculosis. An understanding of these processes could aid in the development of immunomodulatory agents or vaccines.

Integration and beyond: linking information from disparate sources and into workflow.

The vision of integrating information-from a variety of sources, into the way people work, to improve decisions and process-is one of the cornerstones of biomedical informatics. Thoughts on how this vision might be realized have evolved as improvements in information and communication technologies, together with discoveries in biomedical informatics, and have changed the art of the possible. This review identified three distinct generations of "integration" projects. First-generation projects create a database and use it for multiple purposes. Second-generation projects integrate by bringing information from various sources together through enterprise information architecture. Third-generation projects inter-relate disparate but accessible information sources to provide the appearance of integration. The review suggests that the ideas developed in the earlier generations have not been supplanted by ideas from subsequent generations. Instead, the ideas represent a continuum of progress along the three dimensions of workflow, structure, and extraction.

Health informatics: linking investment to value.

Informatics and information technology do not appear to be valued by the health industry to the degree that they are in other industries. The agenda for health informatics should be presented so that value to the health system is linked directly to required investment. The agenda should acknowledge the foundation provided by the current health system and the role of financial issues, system impediments, policy, and knowledge in effecting change. The desired outcomes should be compelling, such as improved public health, improved quality as perceived by consumers, and lower costs. Strategies to achieve these outcomes should derive from the differentia of health, opportunities to leverage other efforts, and lessons from successes inside and outside the health industry. Examples might include using logistics to improve quality, mass customization to adapt to individual values, and system thinking to change the game to one that can be won. The justification for the informatics infrastructure of a virtual health care data bank, a national health care knowledge base, and a personal clinical health record flows naturally from these strategies.

The networked health enterprise: a vision for 2008.

Informatics and information technology hold the promise of a consumer-centered health enterprise--one that provides quality care at a cost society is willing to pay; one where need-based, adaptive, competency-based learning results in cost-effectiveness of health education; one where team-based health and learning on demand, coupled with monitoring of process outcomes and network access to expertise, guarantee quality. The barriers to this promise are the professional guilds, the cross-subsidies that support the health enterprise of 1998, and the lack of respect for privacy. Collectively, the informatics community needs to develop a compelling vision that will galvanize the health community to action. If the health community does not step up to this challenge, consumers will take advantage of disintermediation. Empowered by the network, they will go outside the system into hands that meet their needs.