The infected metropolis

Discovery of Spilanthol Endoperoxide as a Redox Natural Compound Active against Mammalian Prx3 and Chlamydia trachomatis Infection

Chlamydia trachomatis (Ct) is a bacterial intracellular pathogen responsible for a plethora of diseases ranging from blindness to pelvic inflammatory diseases and cervical cancer. Although this disease is effectively treated with antibiotics, concerns for development of resistance prompt the need for new low-cost treatments. Here we report the activity of spilanthol (SPL), a natural compound with demonstrated anti-inflammatory properties, against Ct infections. Using chemical probes selective for imaging mitochondrial protein sulfenylation and complementary assays, we identify an increase in mitochondrial oxidative state by SPL as the underlying mechanism leading to disruption of host cell F-actin cytoskeletal organization and inhibition of chlamydial infection. The peroxidation product of SPL (SPL endoperoxide, SPL^E), envisioned to be the active compound in the cellular milieu, was chemically synthesized and showed more potent anti-chlamydial activity. Comparison of SPL and SPL^E reactivity with mammalian peroxiredoxins, demonstrated preferred reactivity of SPL^E with Prx3, and virtual lack of SPL reaction with any of the reduced Prx isoforms investigated. Cumulatively, these findings support the function of SPL as a pro-drug, which is converted to SPL^E in the cellular milieu leading to inhibition of Prx3, increased mitochondrial oxidation and disruption of F-actin network, and inhibition of Ct infection.

Optimal control of a multi-patch Dengue model under the influence of Wolbachia bacterium

In this work, a multi-patch model for dengue transmission dynamics including the bacterium Wolbachia is studied and by that the control efforts to minimize the disease spread by host and vector control are investigated. The multi-patch system models the host movement within the patches which coupled via a residence-time budgeting matrix P. Numerical results confirm that the control mechanism embedded in incidence rates of the disease transmission, effectively reduce the spread of the disease.

Public health and medical care for the world's factory: China's Pearl River Delta Region

While the growth of urbanization, worldwide, has improved the lives of migrants from the hinterland, it also raises health risks related to population density, concentrated poverty and the transmission of infectious disease. Will megacity regions evolve into socially infected breeding grounds for the rapid transmission of disease, or can they become critical spatial entities for the protection and promotion of population health? We address this question for the Pearl River Delta Region (PRD) based on recent data from Chinese sources, and on the experience of how New York, Greater London, Tokyo and Paris have grappled with the challenges of protecting population health and providing their populations with access to health care services. In some respects, there are some important lessons from comparative experience for PRD, notably the importance of covering the entire population for health care services and targeting special programs for those at highest risk for disease. In other respects, PRD's growth rate and sheer scale make it a unique megacity region that already faces new challenges and will require new solutions.

Superbugs II: how should economic evaluation be conducted for interventions which aim to contain antimicrobial resistance?

To date, there has been little examination of the problems associated with conducting economic evaluation for interventions designed to contain antimicrobial resistance. There are two quite different types of intervention aimed at containing antimicrobial resistance: interventions which are designed to avoid the emergence of resistant organisms; and interventions that are designed to avoid the transmission of resistance organisms. Four aspects of economic evaluation where the ease of assessment might be expected to differ across evaluations for these different types of intervention are examined: problems associated with the identification of diffuse impacts, problems associated with comparing current and future impacts, problems associated with uncertainty, and problems associated with difficulties in measurement and valuation. The paper suggests that it may be much easier to conduct rigorous economic evaluations for interventions designed to avoid transmission of resistance, than for those intended to avoid emergence. Unfortunately, the transmission policies, which are likely to be the easiest to evaluate, are not likely to produce an optimal long-term outcome given the apparent irreversibility of much resistance and the potentially severe harms which could be imposed as a result. Given the desirability of avoiding a scenario where, in the evidence-based medicine culture, the most rigorously evaluated policies are followed even though they may be less important, there is the need to consider carefully what, and how, economic evaluation should be conducted in the area of antimicrobial resistance. It is suggested that research should focus on the use of modelling as a means of evaluating optimal policy responses and on trying to resolve some of the difficulties associated with measurement and valuation.

Socioeconomic and behavioral factors leading to acquired bacterial resistance to antibiotics in developing countries

In developing countries, acquired bacterial resistance to antimicrobial agents is common in isolates from healthy persons and from persons with community-acquired infections. Complex socioeconomic and behavioral factors associated with antibiotic resistance, particularly regarding diarrheal and respiratory pathogens, in developing tropical countries, include misuse of antibiotics by health professionals, unskilled practitioners, and laypersons; poor drug quality; unhygienic conditions accounting for spread of resistant bacteria; and inadequate surveillance.