Aged mice display an altered pulmonary host response to Francisella tularensis live vaccine strain (LVS) infections.

Aging is a complex phenomenon that has been shown to affect many organ systems including the innate and adaptive immune systems. The current study was designed to examine the potential effect of immunosenescence on the pulmonary immune response using a Francisella tularensis live vaccine strain (LVS) inhalation infection model. F. tularensis is a Gram-negative intracellular pathogen that can cause a severe pneumonia. In this study both young (8-12 week old) and aged (20-24 month old) mice were infected intranasally with LVS. Lung tissues from young and aged mice were used to assess pathology, recruitment of immune cell types and cytokine expression levels at various times post infection. Bacterial burdens were also assessed. Interestingly, the lungs of aged animals harbored fewer organisms at early time points of infection (day 1, day 3) compared with their younger counterparts. In addition, only aged animals displayed small perivascular aggregates at these early time points that appeared mostly mononuclear in nature. However, the kinetics of infiltrating polymorphonuclear neutrophils (PMNs) and increased cytokine levels measured in the bronchial alveolar lavage fluid (BALF) were delayed in infected aged animals relative to young infected animals with neutrophils appearing at day 5 post infection (PI) in the aged animals as opposed to day 3 PI in the young infected animals. Also evident were alterations in the ratios of mononuclear to PMNs at distinct post infection times. The above evidence indicates that aged mice elicit an altered immune response in the lung to respiratory F. tularensis LVS infections compared to their younger counterparts.

Effective models for medical and health response coordination: summary and action plan.

INTRODUCTION: To effectively respond to this relatively new, complex mandate, it is essential to find effective models of coordination to ensure that medical and health services can meet the standards now expected in a disaster situation. This theme explored various models, noting both the strengths that can be built on and the weaknesses that still need to be overcome. METHODS: Details of the methods used are provided in the preceding paper. The chairs moderated all presentations and produced a summary that was presented to an assembly of all of the delegates. Since the findings from the Theme 1 and Theme 4 groups were similar, the chairs of both groups presided over one workshop that resulted in the generation of a set of Action Plans that then were reported to the collective group of all delegates. RESULTS: The main points developed during the presentations and discussion included: (1) preplanning (predisaster goals), (2) information collection (assessment), (3) communication (materials and methods); and (4) response centres and personnel. There exists a need for institutionalization of processes for learning from experiences obtained from disasters. DISCUSSION: Action plans presented include: (1) creation of an information and data clearinghouse on disaster management, (2) identification of incentives and disincentives for readiness and develop strategies and interventions, and (3) action on lessons learned from evidence-based research and practical experience. CONCLUSIONS: There is an urgent need to proactively establish coordination and management procedures in advance of any crisis. A number of important insights for improvement in coordination and management during disasters emerged.