Jennifer Stevenson

Quantifying travel behavior for infectious disease research: a comparison of data from surveys and mobile phones

Human travel impacts the spread of infectious diseases across spatial and temporal scales, with broad implications for the biological and social sciences. Individual data on travel patterns have been difficult to obtain, particularly in low-income countries. Travel survey data provide detailed demographic information, but sample sizes are often small and travel histories are hard to validate. Mobile phone records can provide vast quantities of spatio-temporal travel data but vary in spatial resolution and explicitly do not include individual information in order to protect the privacy of subscribers. Here we compare and contrast both sources of data over the same time period in a rural area of Kenya. Although both data sets are able to quantify broad travel patterns and distinguish regional differences in travel, each provides different insights that can be combined to form a more detailed picture of travel in low-income settings to understand the spread of infectious diseases.

Hope predicts positive functional role outcomes in acute rehabilitation populations

PURPOSE/OBJECTIVE The purpose of this study was to examine the association between facilitating psychological variables and functional rehabilitation outcomes following acute medical rehabilitation. RESEARCH METHOD/DESIGN Using a longitudinal design and correlational and regression analyses, we studied 174 adults who were participating in inpatient rehabilitation for acute spinal cord dysfunction, stroke, amputation, or orthopedic surgery recovery. All participants completed the Hope Scale, Positive and Negative Affect Schedule, and Functional Independence Measure (FIM) during the first days of their inpatient stay, and then were contacted 3 months after discharge to complete the Craig Hospital Assessment and Reporting Technique (CHART) and FIM. RESULTS Hope accounted for a statistically significant amount of the variance in the prediction of functional role participation at 3 months postdischarge (as measured by the CHART) above and beyond the variance accounted for by demographic and severity variables. In contrast, positive affect was not found to contribute to the prediction of functional role participation, and neither hope nor positive affect contributed to the prediction of functional skill level (FIM). CONCLUSIONS/IMPLICATIONS The results indicate that positive psychological variables present during the rehabilitation stay, such as hopefulness, may contribute to the prediction of functional outcomes after discharge in rehabilitation populations. These findings suggest that incorporating interventions that enhance hope and build on the individuals psychological strengths may be useful to improve participation outcomes following acute medical rehabilitation.

The Impact of Hotspot-Targeted Interventions on Malaria Transmission in Rachuonyo South District in the Western Kenyan Highlands: A Cluster-Randomized Controlled Trial.

Background Malaria transmission is highly heterogeneous, generating malaria hotspots that can fuel malaria transmission across a wider area. Targeting hotspots may represent an efficacious strategy for reducing malaria transmission. We determined the impact of interventions targeted to serologically defined malaria hotspots on malaria transmission both inside hotspots and in surrounding communities. Methods and Findings Twenty-seven serologically defined malaria hotspots were detected in a survey conducted from 24 June to 31 July 2011 that included 17,503 individuals from 3,213 compounds in a 100-km2 area in Rachuonyo South District, Kenya. In a cluster-randomized trial from 22 March to 15 April 2012, we randomly allocated five clusters to hotspot-targeted interventions with larviciding, distribution of long-lasting insecticide-treated nets, indoor residual spraying, and focal mass drug administration (2,082 individuals in 432 compounds); five control clusters received malaria control following Kenyan national policy (2,468 individuals in 512 compounds). Our primary outcome measure was parasite prevalence in evaluation zones up to 500 m outside hotspots, determined by nested PCR (nPCR) at baseline and 8 wk (16 June–6 July 2012) and 16 wk (21 August–10 September 2012) post-intervention by technicians blinded to the intervention arm. Secondary outcome measures were parasite prevalence inside hotpots, parasite prevalence in the evaluation zone as a function of distance from the hotspot boundary, Anopheles mosquito density, mosquito breeding site productivity, malaria incidence by passive case detection, and the safety and acceptability of the interventions. Intervention coverage exceeded 87% for all interventions. Hotspot-targeted interventions did not result in a change in nPCR parasite prevalence outside hotspot boundaries (p ≥ 0.187). We observed an average reduction in nPCR parasite prevalence of 10.2% (95% CI −1.3 to 21.7%) inside hotspots 8 wk post-intervention that was statistically significant after adjustment for covariates (p = 0.024), but not 16 wk post-intervention (p = 0.265). We observed no statistically significant trend in the effect of the intervention on nPCR parasite prevalence in the evaluation zone in relation to distance from the hotspot boundary 8 wk (p = 0.27) or 16 wk post-intervention (p = 0.75). Thirty-six patients with clinical malaria confirmed by rapid diagnostic test could be located to intervention or control clusters, with no apparent difference between the study arms. In intervention clusters we caught an average of 1.14 female anophelines inside hotspots and 0.47 in evaluation zones; in control clusters we caught an average of 0.90 female anophelines inside hotspots and 0.50 in evaluation zones, with no apparent difference between study arms. Our trial was not powered to detect subtle effects of hotspot-targeted interventions nor designed to detect effects of interventions over multiple transmission seasons. Conclusions Despite high coverage, the impact of interventions targeting malaria vectors and human infections on nPCR parasite prevalence was modest, transient, and restricted to the targeted hotspot areas. Our findings suggest that transmission may not primarily occur from hotspots to the surrounding areas and that areas with highly heterogeneous but widespread malaria transmission may currently benefit most from an untargeted community-wide approach. Hotspot-targeted approaches may have more validity in settings where human settlement is more nuclear. Trial registration ClinicalTrials.gov NCT01575613

Unexpected diversity of Anopheles species in Eastern Zambia: implications for evaluating vector behavior and interventions using molecular tools

The understanding of malaria vector species in association with their bionomic traits is vital for targeting malaria interventions and measuring effectiveness. Many entomological studies rely on morphological identification of mosquitoes, limiting recognition to visually distinct species/species groups. Anopheles species assignments based on ribosomal DNA ITS2 and mitochondrial DNA COI were compared to morphological identifications from Luangwa and Nyimba districts in Zambia. The comparison of morphological and molecular identifications determined that interpretations of species compositions, insecticide resistance assays, host preference studies, trap efficacy, and Plasmodium infections were incorrect when using morphological identification alone. Morphological identifications recognized eight Anopheles species while 18 distinct sequence groups or species were identified from molecular analyses. Of these 18, seven could not be identified through comparison to published sequences. Twelve of 18 molecularly identified species (including unidentifiable species and species not thought to be vectors) were found by PCR to carry Plasmodium sporozoites - compared to four of eight morphological species. Up to 15% of morphologically identified Anopheles funestus mosquitoes in insecticide resistance tests were found to be other species molecularly. The comprehension of primary and secondary malaria vectors and bionomic characteristics that impact malaria transmission and intervention effectiveness are fundamental in achieving malaria elimination.

General anxiety symptoms after acute lung injury: Predictors and correlates

OBJECTIVE Acute lung injury (ALI) is common in the intensive care unit (ICU), typically requiring life support ventilation. Survivors often experience anxiety after hospital discharge. We evaluated general anxiety symptoms 3 months after ALI for: (1) associations with patient characteristics and ICU variables, and (2) cross-sectional associations with physical function and quality of life (QOL). METHODS General anxiety was assessed as part of a prospective cohort study recruiting patients from 13 ICUs at four hospitals in Baltimore, MD using the Hospital Anxiety and Depression Scale--Anxiety Subscale (HAD-A), with associations evaluated using multivariable linear and logistic regression models. RESULTS Of 152 patients, 38% had a positive screening test for general anxiety (HAD-A≥8). Pre-ICU body mass index and psychiatric comorbidity were associated with general anxiety (OR, 95% confidence interval (CI): 1.06 (1.00, 1.13) and 3.59 (1.25, 10.30), respectively). No ICU-related variables were associated with general anxiety. General anxiety was associated with the number of instrumental ADL dependencies (Spearmans rho=0.22; p=0.004) and worse overall QOL as measured by EQ-5D visual analog scale (VAS) (rho=-0.34; p<0.001) and utility score (rho=-0.30; p<0.001), and by the SF-36 mental health domain (rho=-0.70; p<0.001) and Mental Component Summary score (rho=-0.73; p<0.001). CONCLUSION Many patients have substantial general anxiety symptoms 3 months after ALI. General anxiety was associated with patient characteristics and impaired physical function and quality of life. Early identification and treatment of general anxiety may enhance physical and emotional function in patients surviving critical illnesses.

Developing, testing, and sustaining rehabilitation interventions via participatory action research.

Few published intervention studies in the rehabilitation literature have included consumers in the research process other than as study participants. This lack of consumer involvement in intervention research may contribute to the challenges encountered developing, translating, disseminating, and sustaining evidence-based rehabilitation interventions in clinical practice. The overall objective of this article is to promote the integration of participatory action research (PAR) into rehabilitation intervention research as a mechanism for addressing these gaps. First, we outline essential components of a PAR model across 5 key phases of intervention research, specifically: agenda setting, methods, implementation, diffusion/dissemination, and sustainability. Second, we describe the use of PAR in rehabilitation intervention research within each of these phases by reviewing relevant literature and by providing an illustrative research example from a randomized controlled trial that integrated PAR throughout the research process. Finally, we conclude with a discussion of 5 specific recommendations for promoting the integration of PAR into rehabilitation intervention research.

Focal Screening to Identify the Subpatent Parasite Reservoir in an Area of Low and Heterogeneous Transmission in the Kenya Highlands

BACKGROUND Mass screening and treatment currently fails to identify a considerable fraction of low parasite density infections, while mass treatment exposes many uninfected individuals to antimalarial drugs. Here we test a hybrid approach to screen a sentinel population to identify clusters of subpatent infections in the Kenya highlands with low, heterogeneous malaria transmission. METHODS Two thousand eighty-two inhabitants were screened for parasitemia by nested polymerase chain reaction (nPCR). Children aged ≤ 15 years and febrile adults were also tested for malaria by rapid diagnostic test (RDT) and served as sentinel members to identify subpatent infections within the household. All parasitemic individuals were assessed for multiplicity of infections by nPCR and gametocyte carriage by nucleic acid sequence-based amplification. RESULTS Households with RDT-positive individuals in the sentinel population were more likely to have nPCR-positive individuals (odds ratio: 1.71, 95% confidence interval, 1.60-1.84). The sentinel population identified 64.5% (locality range: 31.6%-81.2%) of nPCR-positive households and 77.3% (locality range: 24.2%-91.0%) of nPCR-positive individuals. The sensitivity of the sentinel screening approach was positively associated with transmission intensity (P = .037). CONCLUSIONS In this low endemic area, a focal screening approach with RDTs prior to the high transmission season was able to identify the majority of the subpatent parasite reservoirs.

Comparative assessment of diverse strategies for malaria vector population control based on measured rates at which mosquitoes utilize targeted resource subsets

BackgroundEliminating malaria requires vector control interventions that dramatically reduce adult mosquito population densities and survival rates. Indoor applications of insecticidal nets and sprays are effective against an important minority of mosquito species that rely heavily upon human blood and habitations for survival. However, complementary approaches are needed to tackle a broader diversity of less human-specialized vectors by killing them at other resource targets.MethodsImpacts of strategies that target insecticides to humans or animals can be rationalized in terms of biological coverage of blood resources, quantified as proportional coverage of all blood resources mosquito vectors utilize. Here, this concept is adapted to enable impact prediction for diverse vector control strategies based on measurements of utilization rate s for any definable, targetable resource subset, even if that overall resource is not quantifiable.ResultsThe usefulness of this approach is illustrated by deriving utilization rate estimates for various blood, resting site, and sugar resource subsets from existing entomological survey data. Reported impacts of insecticidal nets upon human-feeding vectors, and insecticide-treated livestock upon animal-feeding vectors, are approximately consistent with model predictions based on measured utilization rates for those human and animal blood resource subsets. Utilization rates for artificial sugar baits compare well with blood resources, and are consistent with observed impact when insecticide is added. While existing data was used to indirectly measure utilization rates for a variety of resting site subsets, by comparison with measured rates of blood resource utilization in the same settings, current techniques for capturing resting mosquitoes underestimate this quantity, and reliance upon complex models with numerous input parameters may limit the applicability of this approach.ConclusionsWhile blood and sugar consumption can be readily quantified using existing methods for detecting natural markers or artificial tracers, improved techniques for labelling mosquitoes, or other arthropod pathogen vectors, will be required to assess vector control measures which target them when they utilize non-nutritional resources such as resting, oviposition, and mating sites.

Thinking outside the box: Intensive care unit diaries to improve psychological outcomes in family members

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Focal screening and treatment for malaria: defining the sentinel population

Background Mass screening and treatment campaigns have had limited success in curbing malaria transmission, possibly as a consequence of the high prevalence of subpatent infections that are missed using the currently available field based diagnostic tools. It has been shown that subpatent malaria infections are more likely to occur in households where patent infections are identified suggesting that it may be possible to employ a more focal approach to treatment campaigns using sentinel cases as markers for the presence of a subpatent reservoir. However, it is not known which definition of sentinel case to rely on for initiation of treatment would provide optimal coverage of the parasite reservoir.