The factors affecting household transmission dynamics and community compliance with Ebola control measures: a mixed-methods study in a rural village in Sierra Leone.

BACKGROUND: Little is understood of Ebola virus disease (EVD) transmission dynamics and community compliance with control measures over time. Understanding these interactions is essential if interventions are to be effective in future outbreaks. We conducted a mixed-methods study to explore these factors in a rural village that experienced sustained EVD transmission in Kailahun District, Sierra Leone. METHODS: We reconstructed transmission dynamics using a cross-sectional survey conducted in April 2015, and cross-referenced our results with surveillance, burial, and Ebola Management Centre (EMC) data. Factors associated with EVD transmission were assessed with Cox proportional hazards regression. Following the survey, qualitative semi-structured interviews explored views of community informants and households. RESULTS: All households (n = 240; 1161 individuals) participated in the survey. 29 of 31 EVD probable/confirmed cases died (93·5% case fatality rate); six deaths (20·6%) had been missed by other surveillance systems. Transmission over five generations lasted 16 weeks. Although most households had ≤5 members there was a significant increase in risk of Ebola in households with > 5 members. Risk of EVD was also associated with older age. Cases were spatially clustered; all occurred in 15 households. EVD transmission was better understood when the community experience started to concord with public health messages being given. Perceptions of contact tracing changed from invading privacy and selling people to ensuring community safety. Burials in plastic bags, without female attendants or prayer, were perceived as dishonourable. Further reasons for low compliance were low EMC survival rates, family perceptions of a moral duty to provide care to relatives, poor communication with the EMC, and loss of livelihoods due to quarantine. Compliance with response measures increased only after the second generation, coinciding with the implementation of restrictive by-laws, return of the first survivor, reduced contact with dead bodies, and admission of patients to the EMC. CONCLUSIONS: Transmission occurred primarily in a few large households, with prolonged transmission and a high death toll. Return of a survivor to the village and more effective implementation of control strategies coincided with increased compliance to control measures, with few subsequent cases. We propose key recommendations for management of EVD outbreaks based on this experience.

Spatiotemporal patterns of Aedes aegypti populations in Cairns, Australia: assessing drivers of dengue transmission.

OBJECTIVES: To identify the meteorological drivers of dengue vector density and determine high- and low-risk transmission zones for dengue prevention and control in Cairns, Australia. METHODS: Weekly adult female Ae. aegypti data were obtained from 79 double sticky ovitraps (SOs) located in Cairns for the period September 2007-May 2012. Maximum temperature, total rainfall and average relative humidity data were obtained from the Australian Bureau of Meteorology for the study period. Time series-distributed lag nonlinear models were used to assess the relationship between meteorological variables and vector density. Spatial autocorrelation was assessed via semivariography, and ordinary kriging was undertaken to predict vector density in Cairns. RESULTS: Ae. aegypti density was associated with temperature and rainfall. However, these relationships differed between short (0-6 weeks) and long (0-30 weeks) lag periods. Semivariograms showed that vector distributions were spatially autocorrelated in September 2007-May 2008 and January 2009-May 2009, and vector density maps identified high transmission zones in the most populated parts of Cairns city, as well as Machans Beach. CONCLUSION: Spatiotemporal patterns of Ae. aegypti in Cairns are complex, showing spatial autocorrelation and associations with temperature and rainfall. Sticky ovitraps should be placed no more than 1.2 km apart to ensure entomological coverage and efficient use of resources. Vector density maps provide evidence for the targeting of prevention and control activities. Further research is needed to explore the possibility of developing an early warning system of dengue based on meteorological and environmental factors.

Ebola management centre proximity associated with reduced delays of healthcare of Ebola Virus Disease (EVD) patients, Tonkolili, Sierra Leone, 2014-15.

Between August-December 2014, Ebola Virus Disease (EVD) patients from Tonkolili District were referred for care to two Médecins Sans Frontières (MSF) Ebola Management Centres (EMCs) outside the district (distant EMCs). In December 2014, MSF opened an EMC in Tonkolili District (district EMC). We examined the effect of opening a district-based EMC on time to admission and number of suspect cases dead on arrival (DOA), and identified factors associated with fatality in EVD patients, residents in Tonkolili District. Residents of Tonkolili district who presented between 12 September 2014 and 23 February 2015 to the district EMC and the two distant EMCs were identified from EMC line-lists. EVD cases were confirmed by a positive Ebola PCR test. We calculated time to admission since the onset of symptoms, case-fatality and adjusted Risk Ratios (aRR) using Binomial regression. Of 249 confirmed Ebola cases, 206 (83%) were admitted to the distant EMCs and 43 (17%) to the district EMC. Of them 110 (45%) have died. Confirmed cases dead on arrival (n = 10) were observed only in the distant EMCs. The median time from symptom onset to admission was 6 days (IQR 4,8) in distant EMCs and 3 days (IQR 2,7) in the district EMC (p<0.001). Cases were 2.0 (95%CI 1.4-2.9) times more likely to have delayed admission (>3 days after symptom onset) in the distant compared with the district EMC, but were less likely (aRR = 0.8; 95%CI 0.6-1.0) to have a high viral load (cycle threshold ≤22). A fatal outcome was associated with a high viral load (aRR 2.6; 95%CI 1.8-3.6) and vomiting at first presentation (aRR 1.4; 95%CI 1.0-2.0). The opening of a district EMC was associated with earlier admission of cases to appropriate care facilities, an essential component of reducing EVD transmission. High viral load and vomiting at admission predicted fatality. Healthcare providers should consider the location of EMCs to ensure equitable access during Ebola outbreaks.

Successful Control of Ebola Virus Disease: Analysis of Service Based Data from Rural Sierra Leone.

INTRODUCTION: The scale and geographical distribution of the current outbreak in West Africa raised doubts as to the effectiveness of established methods of control. Ebola Virus Disease (EVD) was first detected in Sierra Leone in May 2014 in Kailahun district. Despite high case numbers elsewhere in the country, transmission was eliminated in the district by December 2014. We describe interventions underpinning successful EVD control in Kailahun and implications for EVD control in other areas. METHODS: Internal service data and published reports from response agencies were analysed to describe the structure and type of response activities, EVD case numbers and epidemic characteristics. This included daily national situation reports and District-level data and reports of the Sierra Leone Ministry of Health and Sanitation, and Médecins Sans Frontières (MSF) patient data and internal epidemiological reports. We used EVD case definitions provided by the World Health Organisation over the course of the outbreak. Characteristics assessed included level of response activities and epidemiological features such as reported exposure (funeral-related or not), time interval between onset of illness and admission to the EVD Management Centre (EMC), work-related exposures (health worker or not) and mortality. We compared these characteristics between two time periods--June to July (the early period of response), and August to December (when coverage and quality of response had improved). A stochastic model was used to predict case numbers per generation with different numbers of beds and a varying percentage of community cases detected. RESULTS: There were 652 probable/confirmed EVD cases from June-December 2014 in Kailahun. An EMC providing patient care opened in June. By August 2014 an integrated detection, treatment, and prevention strategy was in place across the district catchment zone. From June-July to August-December 2014 surveillance and contact tracing staff increased from 1.0 to 8.8 per confirmed EVD case, EMC capacity increased from 32 to 100 beds, the number of burial teams doubled, and health promotion activities increased in coverage. These improvements in response were associated with the following changes between the same periods: the proportion of confirmed/probable cases admitted to the EMC increased from 35% to 83% (χ(2) p-value<0·001), the proportion of confirmed patients admitted to the EMC <3 days of symptom onset increased from 19% to 37% (χ(2) p-value <0·001), and reported funeral contact in those admitted decreased from 33% to 16% (χ(2) p-value <0·001). Mathematical modelling confirmed the importance of both patient management capacity and surveillance and contact tracing for EVD control. DISCUSSION: Our findings demonstrate that control of EVD can be achieved using established interventions based on identification and appropriate management of those who are at risk of and develop EVD, including in the context of ongoing transmission in surrounding regions. Key attributes in achieving control were sufficient patient care capacity (including admission to specialist facilities of suspect and probable cases for assessment), integrated with adequate staffing and resourcing of community-based case detection and prevention activities. The response structure and coverage targets we present are of value in informing effective control in current and future EVD outbreaks.

Clinical and radiological follow-up of laparoscopic adjustable gastric bands, 1998 and 2000: a comparison of two techniques.

BACKGROUND: Concerns still exist about the long-term effectiveness and rate of retention of the laparoscopic adjustable gastric band (LAGB). Furthermore, esophageal dilatation has been suggested as a long-term complication for LAGB. We therefore sought to objectively analyze our follow-up results in patients with LAGB performed in 1998 by perigastric technique and 2000 by pars flaccida technique. We also offered patients for 1998 a barium esophagram to assess dilatation. METHODS: Data on all 2,300 LAGBs performed since 1996 have been prospectively collected in LapBase. This data was accessed for 1998 and 2000, for follow-up complication, band removal, weight loss and comorbidity reduction. Patients were offered barium esophagrams. RESULTS: 123 patients (mean weight 127 kg, mean BMI 44.5 kg/m2) had LAGB in 1998, and 162 patients (mean weight 123 kg, mean BMI 44) had LAGB in 2000. Follow-up was a mean 67 months in 88% for 1998 and 94% at 34 months for 2000. Mean %EWL for 1998 was 51.2% with mean BMI 31.9. Slippage occurred in 9.5% in 1998 compared to 4.3% in 2000 (P<0.01). 20 of 23 diabetics are off all treatment. 1 of 34 patients had esophageal dilatation on barium esophagram, which resolved on band deflation. CONCLUSION: LAGB is a safe and effective at midterm follow-up. Less slippage occurred after the pars flaccida technique. No evidence of permanent esophageal dilatation was found on barium studies.

Laparoscopic adjustable gastric banding in severely obese adolescents.

BACKGROUND: Severely obese adolescents are suffering all the consequences well known in adults. A decision was made to offer laparoscopic adjustable gastric band surgery to severely obese adolescents. METHODS: This retrospective study reviewed the outcomes of 41 adolescents aged 12-19 years (mean 15.6 years) who underwent laparoscopic adjustable gastric band surgery. At surgery, their mean weight was 125 +/- 9 kg (range 83-220), and the mean body mass index was 42.4 +/- 8.2 kg/m(2) (range 31-71). The comorbidities included 2 patients with diabetes, 1 with sleep apnea requiring continuous positive airway pressure, 2 with hypertension, and 1 with Perthe's disease of the hip. RESULTS: No operative or 60-day morbidity or mortality occurred. One patient was lost to follow-up, but returned at 3 years. The mean follow-up was 33.8 +/- 19 months (range 1-70). Eighteen patients have had a Lap-Band for at least 3 years. Compliance was excellent, with 12.2 visits per child (range 7-22) at 2 years. At 3 years, the mean body mass index had decreased to 29 +/- 6 kg/m(2) (range 23-47), which was maintained at 5 years. Of the 41 adolescents, 83% were no longer obese, with a BMI <30 kg/m(2). The estimated weight loss was 70% +/- 21% (range 37-101%) and was maintained at 5 years. CONCLUSION: Laparoscopic adjustable gastric band surgery is a valid option for the care of severely obese adolescents.

Poor weight loss despite biliopancreatic diversion and subsequent revision to a 30-cm common channel after initial laparoscopic adjustable gastric banding: an analysis of 8 cases.

BACKGROUND: Laparoscopic adjustable gastric banding (LAGB) fails in 5% of patients due to band-related complications or patient intolerance. A subset of patients subsequently managed with biliopancreatic diversion (BPD) have failed to achieve a percentage of excess weight loss (%EWL) > 50% or a body mass index (BMI) < 35 kg/m(2) even after a further procedure shortening the common channel to 30 cm. METHOD: A computerized obesity database was used to identify the study group and collect preoperative and outcome data. Patient outcomes were analyzed in 2 groups: LAGB removed either because of a failure to lose weight (FTLW) or because of a band-related complication (eg, recurrent gastric prolapse, gastric erosion, intractable dysphagia). RESULTS: A total of 2300 patients underwent LAGB between 1996 and 2003. LAGB failed in 95 (4%) of these patients, 79 of whom had subsequent BPD. Of these 79 patients, 8 (10%) failed to lose further weight and had their common channel shortened to 30 cm. Six patients were identified who, despite this revision surgery, still had a BMI > 35 kg/m(2) or %EWL < 50 and are considered failures. Two further patients failed to lose any weight after revision for what they saw as an unsatisfactory outcome. There was minimal evidence of malabsorption in these 8 patients, and 4 had slow intestinal transit down the alimentary limb of the BPD. CONCLUSION: The reasons for the failure of malabsorption and restrictive surgery in these patients appear to be physiological, not psychological. Uncontrolled hunger, particularly in the patients with FTLW, and an abnormally slow metabolism are likely to be important.

Characterising the spatial dynamics of sympatric Aedes aegypti and Aedes albopictus populations in the Philippines.

Entomological surveillance and control are essential to the management of dengue fever (DF). Hence, understanding the spatial and temporal patterns of DF vectors, Aedes (Stegomyia) aegypti (L.) and Ae. (Stegomyia) albopictus (Skuse), is paramount. In the Philippines, resources are limited and entomological surveillance and control are generally commenced during epidemics, when transmission is difficult to control. Recent improvements in spatial epidemiological tools and methods offer opportunities to explore more efficient DF surveillance and control solutions: however, there are few examples in the literature from resource-poor settings. The objectives of this study were to: (i) explore spatial patterns of Aedes populations and (ii) predict areas of high and low vector density to inform DF control in San Jose village, Muntinlupa city, Philippines. Fortnightly, adult female Aedes mosquitoes were collected from 50 double-sticky ovitraps (SOs) located in San Jose village for the period June-November 2011. Spatial clustering analysis was performed to identify high and low density clusters of Ae. aegypti and Ae. albopictus mosquitoes. Spatial autocorrelation was assessed by examination of semivariograms, and ordinary kriging was undertaken to create a smoothed surface of predicted vector density in the study area. Our results show that both Ae. aegypti and Ae. albopictus were present in San Jose village during the study period. However, one Aedes species was dominant in a given geographic area at a time, suggesting differing habitat preferences and interspecies competition between vectors. Density maps provide information to direct entomological control activities and advocate the development of geographically enhanced surveillance and control systems to improve DF management in the Philippines.

Geographical information systems for dengue surveillance.

This review provides details on the role of Geographical Information Systems (GIS) in current dengue surveillance systems and focuses on the application of open access GIS technology to emphasize its importance in developing countries, where the dengue burden is greatest. It also advocates for increased international collaboration in transboundary disease surveillance to confront the emerging global challenge of dengue.