Adaptive Management and the Value of Information: Learning Via Intervention in Epidemiology

Optimal intervention for disease outbreaks is often impeded by severe scientific uncertainty. Adaptive management (AM), long-used in natural resource management, is a structured decision-making approach to solving dynamic problems that accounts for the value of resolving uncertainty via real-time evaluation of alternative models. We propose an AM approach to design and evaluate intervention strategies in epidemiology, using real-time surveillance to resolve model uncertainty as management proceeds, with foot-and-mouth disease (FMD) culling and measles vaccination as case studies. We use simulations of alternative intervention strategies under competing models to quantify the effect of model uncertainty on decision making, in terms of the value of information, and quantify the benefit of adaptive versus static intervention strategies. Culling decisions during the 2001 UK FMD outbreak were contentious due to uncertainty about the spatial scale of transmission. The expected benefit of resolving this uncertainty prior to a new outbreak on a UK-like landscape would be £45–£60 million relative to the strategy that minimizes livestock losses averaged over alternate transmission models. AM during the outbreak would be expected to recover up to £20.1 million of this expected benefit. AM would also recommend a more conservative initial approach (culling of infected premises and dangerous contact farms) than would a fixed strategy (which would additionally require culling of contiguous premises). For optimal targeting of measles vaccination, based on an outbreak in Malawi in 2010, AM allows better distribution of resources across the affected region; its utility depends on uncertainty about both the at-risk population and logistical capacity. When daily vaccination rates are highly constrained, the optimal initial strategy is to conduct a small, quick campaign; a reduction in expected burden of approximately 10,000 cases could result if campaign targets can be updated on the basis of the true susceptible population. Formal incorporation of a policy to update future management actions in response to information gained in the course of an outbreak can change the optimal initial response and result in significant cost savings. AM provides a framework for using multiple models to facilitate public-health decision making and an objective basis for updating management actions in response to improved scientific understanding

Interdisciplinary Differential Diagnosis and Care of a Patient with Atypical Delusional Parasitosis due to early HIV-related Dementia

<div><p><i>Objective</i>: To provide a differential diagnosis and recommendations for care for an individual with suspected delusional parasitosis secondary to human immunodeficiency virus (HIV). <i>Method</i>: A 62-year-old male with sexually acquired, chronic, and well-managed HIV infection was referred for neuropsychological evaluation and treatment recommendations following extensive self-manipulation of a sternoclavicular cystic mass and superficial skin lesions over most of his body. The patient reported that he had pulled long calcified tendrils out of the mass over a period of several weeks and that “encapsulated fat” was flowing beneath his skin. <i>Results</i>: Numerous lab panels were negative for any acute medical pathology. Clinical neuroimaging was unremarkable. Neuropsychological evaluation revealed a profile consistent with mild neurocognitive disorder due to HIV. Medical and behavioral recommendations were made for the management of delusional thought processes consistent with atypical delusional parasitosis and other symptoms. The patient was responsive to carefully crafted provider feedback and his delusional and somatic symptoms decreased significantly with risperidone. <i>Conclusions</i>: This case illustrates the utility of neuropsychological assessment and provider feedback in the diagnosis and care of HIV-related neurocognitive disorder, the context of a delusional disorder.</p></div