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Background: Path quality has not been well studied as a correlate of active transport to school. We hypothesize that for urban-dwelling children the environment between home and school is at least as important as the environment immediately surrounding their homes and/or schools when exploring walking to school behavior. Methods: Tools from spatial statistics and geographic information systems (GIS) were applied to an assessment of street blocks to create a walking path quality measure based on physical and social disorder (termed "incivilities") for each child. Path quality was included in a multivariate regression analysis of walking to school status for a sample of 362 children. Results: The odds of walking to school for path quality was 0.88 (95% CI: 0.72-1.07), which although not statistically significant is in the direction supporting our hypothesis. The odds of walking to school for home street block incivility suggests the counter intuitive effect (OR = 1.10, 95% CI: 1.08-1.19). Conclusions: Results suggest that urban children living in communities characterized by higher incivilities are more likely to walk to school, potentially placing them at risk for adverse health outcomes because of exposure to high incivility areas along their route. Results also support the importance of including path quality when exploring the influence of the environment on walking to school behavior. [ABSTRACT FROM AUTHOR]

Background: Reactive case detection (RCD) seeks to enhance malaria surveillance and control by identifying and treating parasitaemic individuals residing near index cases. In Zambia, this strategy starts with passive detection of symptomatic incident malaria cases at local health facilities or by community health workers, with subsequent home visits to screen-and-treat residents in the index case and neighbouring (secondary) households within a 140-m radius using rapid diagnostic tests (RDTs). However, a small circular radius may not be the most efficient strategy to identify parasitaemic individuals in low-endemic areas with hotspots of malaria transmission. To evaluate if RCD efficiency could be improved by increasing the probability of identifying parasitaemic residents, environmental risk factors and a larger screening radius (250 m) were assessed in a region of low malaria endemicity. Methods: Between January 12, 2015 and July 26, 2017, 4170 individuals residing in 158 index and 531 secondary households were enrolled and completed a baseline questionnaire in the catchment area of Macha Hospital in Choma District, Southern Province, Zambia. Plasmodium falciparum prevalence was measured using PfHRP2 RDTs and quantitative PCR (qPCR). A Quickbird™ high-resolution satellite image of the catchment area was used to create environmental risk factors in ArcGIS, and generalized estimating equations were used to evaluate associations between risk factors and secondary households with parasitaemic individuals. Results: The parasite prevalence in secondary (non-index case) households was 0.7% by RDT and 1.8% by qPCR. Overall, 8.5% (n = 45) of secondary households had at least one resident with parasitaemia by qPCR or RDT. The risk of a secondary household having a parasitaemic resident was significantly increased in proximity to higher order streams and marginally with increasing distance from index households. The adjusted OR for proximity to third- and fifth-order streams were 2.97 (95% CI 1.04–8.42) and 2.30 (95% CI 1.04–5.09), respectively, and that for distance to index households for each 50 m was 1.24 (95% CI 0.98–1.58). Conclusion: Applying proximity to streams as a screening tool, 16% (n = 3) more malaria-positive secondary households were identified compared to using a 140-m circular screening radius. This analysis highlights the potential use of environmental risk factors as a screening strategy to increase RCD efficiency. [ABSTRACT FROM AUTHOR]

Background: Walking to school is an important source of physical activity among children. There is a paucity of research exploring environmental determinants of walking to school among children in urban areas. Methods: A cross-sectional secondary analysis of baseline data (2007) from 365 children in the "Multiple Opportunities to Reach Excellence" (MORE) Study (8 to 13 years; Mean 9.60 years, SD 1.04). Children and caregivers were asked about walking to school and perceived safety. Objective measures of the environment were obtained using a validated environmental neighborhood assessment. Results: Over half (55.83%) of children reported walking to school most of the time. High levels of neighborhood incivilities were associated with lower levels of perceived safety (OR: 0.39, 95% CI: 0.21 to 0.72). Living on a block above the median in incivilities was associated with a 353% increase in odds of walking to school (OR: 3.53; 95% CI: 1.68 to 7.39). Conclusions: Children residing in neighborhoods high in incivilities are more likely to walk to school, in spite of lower levels of perceived safety. As a high proportion of children residing in disadvantaged neighborhoods walk to school, efforts should be directed at minimizing exposure to neighborhood hazards by ensuring safe routes to and from school. [ABSTRACT FROM AUTHOR]

The weekly samples of recreational bathing waters were examined during summer months for human-virulent microsporidian spores and water quality parameters in association with high and low bather numbers during weekends and week days respectively. Findings reveal that bathing in public waters results in exposure to potentially viable microsporidian spores.

Background: Southern Province, Zambia has experienced a dramatic decline in Plasmodium falciparum malaria transmission in the past decade and is targeted for elimination. Zambia's National Malaria Elimination Program recommends reactive case detection (RCD) within 140 m of index households to enhance surveillance and eliminate remaining transmission foci.Methods: To evaluate whether RCD captures local transmission, we genotyped 26 microsatellites from 106 samples collected from index (n = 27) and secondary (n = 79) cases detected through RCD in the Macha Hospital catchment area between January 2015 and April 2016.Results: Participants from the same RCD event harbored more genetically related parasites than those from different RCD events, suggesting that RCD captures, at least in part, infections related through local transmission. Related parasites clustered in space and time, up to at least 250 m from index households. Spatial analysis identified a putative focal transmission hotspot.Conclusions: The current RCD strategy detects focal transmission events, although programmatic guidelines to screen within 140 m of index households may fail to capture all secondary cases. This study highlights the utility of parasite genetic data in assessing programmatic interventions, and similar approaches may be useful to malaria elimination programs seeking to tailor intervention strategies to the underlying transmission epidemiology. [ABSTRACT FROM AUTHOR]

The 1993 U.S. hantavirus pulmonary syndrome (HPS) outbreak was attributed to environmental conditions and increased rodent populations caused by unusual weather in 1991-92. In a case-control study to test this [...]

Background: As malaria transmission declines in many regions of sub-Saharan Africa, interventions to identify the asymptomatic reservoir are being deployed with the goals of improving surveillance and interrupting transmission. Reactive case detection strategies, in which individuals with clinical malaria are followed up at their home and household residents and neighbours are screened and treated for malaria, are increasingly used as part of malaria elimination programmes. Methods: A reactive screen-and-treat programme was implemented by the National Malaria Control Centre in Southern Province, Zambia, in which individuals residing within 140 m of an index case were screened with a malaria rapid diagnostic test (RDT) and treated if positive. The operational challenges during the early stages of implementing this reactive screen-and-treat programme in the catchment area of Macha Hospital in Southern Province, Zambia were assessed using rural health centre records, ground truth evaluation of community health worker performance, and data from serial cross-sectional surveys. The proportion of individuals infected with Plasmodium falciparum who were identified and treated was estimated by simulating reactive screen-and-treat and focal drug administration cascades. Results: Within the 1st year of implementation, community health workers followed up 32 % of eligible index cases. When index cases were followed up, 66 % of residents were at home in the index households and 58 % in neighbouring households. Forty-one neighbouring households of 26 index households were screened, but only 13 (32 %) were within the 140-m screening radius. The parasite prevalence by RDT was 22 % in index households and 5 % in neighbouring households. In a simulation model with complete follow-up, 22 % of the total infected population would be detected with reactive screen-and-treat but 57 % with reactive focal drug administration. Conclusions: With limited resources, coverage and diagnostic tools, reactive screen-and-treat will likely not be sufficient to achieve malaria elimination in this setting. However, high coverage with reactive focal drug administration could be efficient at decreasing the reservoir of infection and should be considered as an alternative strategy. [ABSTRACT FROM AUTHOR]

Background: The scale-up of malaria control interventions has resulted in substantial declines in transmission in some but not all regions of sub-Saharan Africa. Understanding factors associated with persistent malaria transmission despite control efforts may guide targeted interventions to high-risk areas and populations. Methods: Household malaria surveys were conducted in Nchelenge District, Luapula Province, in northern Zambia. Structures that appeared to be households were enumerated from a high-resolution satellite image and randomly sampled for enrollment. Households were enrolled into cross-sectional (single visit) or longitudinal (visits every other month) cohorts but analyses were restricted to cross-sectional visits and the first visit to longitudinal households. During study visits, a questionnaire was administered to adults and caretakers of children and a blood sample was collected for a malaria rapid diagnostic test (RDT) from all household residents. Characteristics associated with RDT positivity were analyzed using multi-level models. Results: A total of 2,486 individuals residing within 742 households were enrolled between April 2012 and July 2015. Over this period, 51% of participants were RDT positive. Forty-three percent of all RDT positive individuals were between the ages of 5 and 17 years although this age group comprised only 30% of study participants. In a multivariable model, the odds being RDT positive were highest in 5–17 year olds and did not vary by season. Children 5–17 years of age had 8.83 higher odds of being RDT positive compared with those >18 years of age (95% CI: 6.13, 12.71); there was an interaction between age and report of symptoms, with an almost 50% increased odds of report of symptoms with decreasing age category (OR = 1.49; 95% CI 1.11, 2.00). Conclusions: Children and adolescents between the ages of 5 and 17 were at the highest risk of malaria infection throughout the year. School-based programs may be effective at targeting this high-risk group. [ABSTRACT FROM AUTHOR]