Assessing the capacity, feasibility, and acceptability of peer navigators to implement a malaria focal test and treat intervention targeting high-risk populations in Lao PDR

BACKGROUND: Forest-going and other high-risk populations (HRPs) contribute to sustained malaria transmission in the Greater Mekong Subregion. New strategies to increase access to malaria services for these populations are required if the 2030 regional elimination target is to be met. This study assessed the feasibility, acceptability, and provider capacity for a peer navigator-led malaria focal test and treat (FTAT) intervention targeting HRPs in Champasak Province in southern Lao People’s Democratic Republic (Lao PDR). METHODS: This research was conducted alongside a larger cluster-randomized controlled trial assessing the effectiveness of FTAT. Between April-November 2018, we conducted 38 interviews and 4 focus group discussions with diverse stakeholders, including HRPs, peer navigators, local health staff, and malaria officials, and 20 observations with a subset of 10 peer navigators. Using a hybrid deductive-inductive approach, data were thematically analyzed in Dedoose software and triangulated across methods, stakeholder types, and timepoints. The Consolidated Framework for Implementation Research guided the assessment, analysis, and interpretation of FTAT capacity, feasibility, and acceptability findings. RESULTS: Peer navigators were highly capable of and confident in conducting the FTAT intervention (malaria testing, treatment, education, and interviewing), and stakeholders perceived the intervention to be largely feasible and acceptable. Reported benefits of FTAT included increased HRP access to free, on-site malaria testing and treatment; increased malaria knowledge among HRPs; peer to peer learning; and increased access to real-time data for program planning. Identified challenges included high FTAT implementation costs, poor road and travel conditions, and initial fear or reluctance among some HRPs to participate in FTAT, while high HRP cooperability and demand for FTAT were key facilitators to FTAT feasibility. CONCLUSION: The peer navigator-led FTAT intervention is a feasible and acceptable approach to increasing access to malaria care among HRPs in southern Lao PDR. Demonstrated to be highly capable, effective, and accepted, lay or peer health workers could play an instrumental role in a broader strategy to achieve and sustain malaria elimination in the region. Adapting the intervention based on local resource availability may be required for programmatic scale-up, given the cost barrier

Characterizing the spatial distribution of multiple malaria diagnostic endpoints in a low-transmission setting in Lao PDR.

The epidemiology of malaria changes as prevalence falls in low-transmission settings, with remaining infections becoming more difficult to detect and diagnose. At this stage active surveillance is critical to detect residual hotspots of transmission. However, diagnostic tools used in active surveillance generally only detect concurrent infections, and surveys may benefit from sensitive tools such as serological assays. Serology can be used to interrogate and characterize individuals' previous exposure to malaria over longer durations, providing information essential to the detection of remaining foci of infection. We ran blood samples collected from a 2016 population-based survey in the low-transmission setting of northern Lao PDR on a multiplexed bead assay to characterize historic and recent exposures to Plasmodium falciparum and vivax. Using geostatistical methods and remote-sensing data we assessed the environmental and spatial associations with exposure, and created predictive maps of exposure within the study sites. We additionally linked the active surveillance PCR and serology data with passively collected surveillance data from health facility records. We aimed to highlight the added information which can be gained from serology as a tool in active surveillance surveys in low-transmission settings, and to identify priority areas for national surveillance programmes where malaria risk is higher. We also discuss the issues faced when linking malaria data from multiple sources using multiple diagnostic endpoints

Population Health Metrics Research Consortium gold standard verbal autopsy validation study: design, implementation, and development of analysis datasets

Background: Verbal autopsy methods are critically important for evaluating the leading causes of death in populations without adequate vital registration systems. With a myriad of analytical and data collection approaches, it is essential to create a high quality validation dataset from different populations to evaluate comparative method performance and make recommendations for future verbal autopsy implementation. This study was undertaken to compile a set of strictly defined gold standard deaths for which verbal autopsies were collected to validate the accuracy of different methods of verbal autopsy cause of death assignment.Methods: Data collection was implemented in six sites in four countries: Andhra Pradesh, India; Bohol, Philippines; Dar es Salaam, Tanzania; Mexico City, Mexico; Pemba Island, Tanzania; and Uttar Pradesh, India. The Population Health Metrics Research Consortium (PHMRC) developed stringent diagnostic criteria including laboratory, pathology, and medical imaging findings to identify gold standard deaths in health facilities as well as an enhanced verbal autopsy instrument based on World Health Organization (WHO) standards. A cause list was constructed based on the WHO Global Burden of Disease estimates of the leading causes of death, potential to identify unique signs and symptoms, and the likely existence of sufficient medical technology to ascertain gold standard cases. Blinded verbal autopsies were collected on all gold standard deaths.Results: Over 12,000 verbal autopsies on deaths with gold standard diagnoses were collected (7,836 adults, 2,075 children, 1,629 neonates, and 1,002 stillbirths). Difficulties in finding sufficient cases to meet gold standard criteria as well as problems with misclassification for certain causes meant that the target list of causes for analysis was reduced to 34 for adults, 21 for children, and 10 for neonates, excluding stillbirths. To ensure strict independence for the validation of methods and assessment of comparative performance, 500 test-train datasets were created from the universe of cases, covering a range of cause-specific compositions.Conclusions: This unique, robust validation dataset will allow scholars to evaluate the performance of different verbal autopsy analytic methods as well as instrument design. This dataset can be used to inform the implementation of verbal autopsies to more reliably ascertain cause of death in national health information systems

Using Verbal Autopsy to Measure Causes of Death: the Comparative Performance of Existing Methods.

Monitoring progress with disease and injury reduction in many populations will require widespread use of verbal autopsy (VA). Multiple methods have been developed for assigning cause of death from a VA but their application is restricted by uncertainty about their reliability. We investigated the validity of five automated VA methods for assigning cause of death: InterVA-4, Random Forest (RF), Simplified Symptom Pattern (SSP), Tariff method (Tariff), and King-Lu (KL), in addition to physician review of VA forms (PCVA), based on 12,535 cases from diverse populations for which the true cause of death had been reliably established. For adults, children, neonates and stillbirths, performance was assessed separately for individuals using sensitivity, specificity, Kappa, and chance-corrected concordance (CCC) and for populations using cause specific mortality fraction (CSMF) accuracy, with and without additional diagnostic information from prior contact with health services. A total of 500 train-test splits were used to ensure that results are robust to variation in the underlying cause of death distribution. Three automated diagnostic methods, Tariff, SSP, and RF, but not InterVA-4, performed better than physician review in all age groups, study sites, and for the majority of causes of death studied. For adults, CSMF accuracy ranged from 0.764 to 0.770, compared with 0.680 for PCVA and 0.625 for InterVA; CCC varied from 49.2% to 54.1%, compared with 42.2% for PCVA, and 23.8% for InterVA. For children, CSMF accuracy was 0.783 for Tariff, 0.678 for PCVA, and 0.520 for InterVA; CCC was 52.5% for Tariff, 44.5% for PCVA, and 30.3% for InterVA. For neonates, CSMF accuracy was 0.817 for Tariff, 0.719 for PCVA, and 0.629 for InterVA; CCC varied from 47.3% to 50.3% for the three automated methods, 29.3% for PCVA, and 19.4% for InterVA. The method with the highest sensitivity for a specific cause varied by cause. Physician review of verbal autopsy questionnaires is less accurate than automated methods in determining both individual and population causes of death. Overall, Tariff performs as well or better than other methods and should be widely applied in routine mortality surveillance systems with poor cause of death certification practices

The comparison of two temporally separated populations in Emmet County, Michigan: higher survivorship in Caucasian than Native American females.

Demography is a division of ecology that provides statistical information for a population of interest. Demography uses life tables to display how a population is age-structured and survivorship curves to compare rates of mortality between populations. The populations in interest in this study are Caucasian and Native American females. The purpose of this experimental study was to determine if there is a difference in mortality rates in Native American and Caucasian females in two time periods, 1900-1945 and 1946-2000, in Emmet County, northern lower Michigan, USA. I surveyed five cemeteries in Emmet County and recorded the year of death and age of death for Caucasian and Native American females. I divided the data into two time intervals and constructed life table and survivorship curves for each ethnic group in each time period. I performed Chi-squared Tests of Independence and t-tests on the mean age-specific mortality rates. The survivorship rates are statistically significantly different for Native American and Caucasian females in the 1900-1945 interval (X2 = 39.71, df = 2, P<0.05) and in the 1946-2000 interval (X2 = 17.21, df = 2, P<0.05). Female Native Americans were found to have a higher mortality rate than Caucasian females in the 1900-1945 period and in the 1946-2000. The mean age-specific mortality rate for Caucasian females in 1900-1945 is greater than in 1946-2000 (t = 1.363325, df = 42, P<0.05). The mean age-specific mortality rate for Native American females in the 1900-1945 was also greater than in 1946-2000 (t = 0.933101, df=42, P<0.05). There are several health factors that can explain the trend of lower survivorshiop of Native American females in relation to Caucasian females, such as their higher rates of chronic diseases, excessive consumption of alcohol and tobacco, poor health care system, and a high rate of infant mortality.http://deepblue.lib.umich.edu/bitstream/2027.42/54877/1/3318.pdfDescription of 3318.pdf : Access restricted to on-site users at the U-M Biological Station

Survivorship and size selection for smaller shells in the freshwater snail Campeloma decisum.

Selection is the driving force of evolutionary change. We studied selection on the freshwater snail Campeloma decisum. The purpose of this experimental study is to determine which phenotypic characters of C. decisum are selected for, and to explore the factors that lead to this selection. In order to examine survivorship, we collected both living and dead C. decisum along the shore of South Fishtail Bay in Douglas Lake, Cheboygan County, in northern lower Michigan. We took eight measurements of the shells, (overall width, aperture length, aperture width, distance from the last bar to the aperture, age, shell thickness, and number of whorls) of the live and dead snails, and we weighed shells of the dead snails. We performed several statistical analyses of the data, including F-tests, t-tests, and regressions to determine how the measurements were related and whether selection appeared to be occurring. The results of our statistical tests revealed that the living snails had consistently smaller average values for the shell measurements than the dead snails. We further discussed our results in the light of previous research on size-selection of snails by predators, environmental factors, and lifetime fitness.http://deepblue.lib.umich.edu/bitstream/2027.42/54872/1/3313.pdfDescription of 3313.pdf : Access restricted to on-site users at the U-M Biological Station

Study of two caucasian and native American populations of females from 1900-1945 to 1946-2000: comparison of death distributions, survivorship, and age-specific mortality rates.

Throughout the US, there are many distinct ethnic groups coexisting in the same geographic area that share access to resources. One would expect to find ethnic populations living in the same local area, to have similar demography. However, many factors outside of geography influence demography. These include differential access to resources and different lifestyle practices. We examined death distribution, survivorship, and age-specific mortality rates of Caucasian and Native American female populations in Emmet County, northern Michigan between 1900-1945 and 1946-2000. Both Caucasian and Native American female populations showed a significant difference in death distributions for 1900-1945 (X2 = 39.71, df 2, P <= 0.05) and 1946-2000 (X2 = 17.21, df 2, P <= 0.05). We also found that there was no statistical difference in mean age-specific mortality rates for Caucasian females (t = 1.363, df 42, P = 0.180) and for Native American females (t = 0.933, df 42, P = 0.356) for both periods. Based on past studies, we concluded that differential access and distinct lifestyle practices were more influential on demographic differences between Caucasian and Native American female populations from 1900-2000.http://deepblue.lib.umich.edu/bitstream/2027.42/54902/1/3343.pdfDescription of 3343.pdf : Access restricted to on-site users at the U-M Biological Station

Spatio-temporal associations between deforestation and malaria incidence in Lao PDR.

As countries in the Greater Mekong Sub-region (GMS) increasingly focus their malaria control and elimination efforts on reducing forest-related transmission, greater understanding of the relationship between deforestation and malaria incidence will be essential for programs to assess and meet their 2030 elimination goals. Leveraging village-level health facility surveillance data and forest cover data in a spatio-temporal modeling framework, we found evidence that deforestation is associated with short-term increases, but long-term decreases confirmed malaria case incidence in Lao People's Democratic Republic (Lao PDR). We identified strong associations with deforestation measured within 30 km of villages but not with deforestation in the near (10 km) and immediate (1 km) vicinity. Results appear driven by deforestation in densely forested areas and were more pronounced for infections with Plasmodium falciparum (P. falciparum) than for Plasmodium vivax (P. vivax). These findings highlight the influence of forest activities on malaria transmission in the GMS