'Tausi Feagaiga: A Project to Train Caregivers and Empower the American Samoan Community.

The 'Tausi Feagaiga (Covenant Keeper) project was a partnership to support the traditional values of tausi matua (caring for one's elders). The partners included a non-governmental organization (Pacific Youth and Community Development), a faith-based organization (Roman Catholic Diocese of Samoa-Pago Pago), and an institute of higher education (University of Hawai'i John A. Burns School of Medicine). The project was created to address the lack of community-based health care such as home health or hospice, and families needing to work outside the home. A culturally based caregiving curriculum was developed to educate caregivers and improve their knowledge and skills. Using a train-the-trainer model, 125 caregivers were trained in family caregiving from 2016-2020. Training was conducted through an intensive workshop followed by practicum at Hope House, the Catholic Diocese home for the aged. Participants who expressed a willingness and competency were mentored to be trainers to continue the 'Tausi Feagaiga project. The mean self-rated confidence in caregiving improved significantly from 3.17 ± 1.02 (mean SD) pre workshop to 3.53 ± 0.71 post workshop (P = .001). Competence in geriatric syndromes was improved from 18.04 ± 4.27 to 21.31 ± 4.30 after attending the workshop (P < .001) and the feedback was extremely positive. Technical assistance was provided to obtain funding through American Samoa Medicaid State Agency to improve the existing infrastructure of Hope House, obtain much needed supplies, and increase ability to hire the participants. 'Tausi Feagaiga positively impacted the lives of the residents of Hope House, the course participants, the elders in the community, and those who care for them.

"There are still broken or fragmented systems": Qualitative assessment of needs to strengthen adolescent mental health services in American Samoa.

Mental health challenges appear common among adolescents in American Samoa. There is a community-identified need to better understand the health burden and identify opportunities to strengthen the mental health system to better meet adolescent mental health needs. The goal of this qualitative study was to gather community stakeholders' perceptions of common mental health problems among adolescents in American Samoa, identify existing services for adolescent mental health, and highlight strength-based opportunities to enhance care. Using the Fa'afaletui research framework, semi-structured in-depth interviews (n = 28) were conducted between October 2020 and February 2021 using Zoom. Key informants were adults living in American Samoa, sampled for diversity in profession, age, gender, education, and region of residence. Transcripts were coded in duplicate and analysed using deductive thematic analysis. Participants reported that suicide, depression, anxiety, and post-traumatic stress disorder are the conditions of highest burden. Participants identified an impressive amount of infrastructure and community mobilization, but also limitations in these services in addressing adolescents' health needs. Four themes arose related to the need to: (1) strengthen existing infrastructure; (2) reduce barriers to treatment access; (3) improve sustainability; and (4) encourage collaboration among leaders. Policymakers should prioritize the allocation of resources to strengthen infrastructure, public education, and stakeholder collaboration to improve adolescent mental health in American Samoa.

Research on the changes and predictions of the burden of type 2 diabetes mellitus in Pacific Island countries from 1990 to 2019.

AIMS: To assess the burden of type 2 diabetes in Pacific Island countries and predict future trends. METHODS: We analyzed and processed data using R and Excel software, performed Joinpoint 4.7.0 software analysis to investigate changing trends in disease burden, and used an autoregressive integrated moving average model to forecast future trends. RESULTS: Our study showed that from 1990 to 2019, the burden of type 2 diabetes in Pacific Island countries continues to increase, with the standardized incidence rate showing the most significant growth. Moreover, there were significant differences in the burden of type 2 diabetes between regions. In 2019, American Samoa had the highest standardized incidence rate, while Fiji had the highest standardized death rate and disability-adjusted life year rate. The standardized incidence rate peaked at ages 65-69 years, while the standardized death rate and disability-adjusted life year rate peaked at ages 95 years and 70-74 years respectively. Type 2 diabetes burden was higher among males than females. Based on our forecasting, from 2020 to 2030, the standardized incidence rate is expected to continue to rise, while the standardized death rate and disability-adjusted life year rate will slowly decline. CONCLUSIONS: Our study highlights that the burden of type 2 diabetes in Pacific Island countries has been increasing from 1990 to 2019. Therefore, it is imperative to strengthen disease prevention and control measures in the region.

Culturally Competent Interventions for Child Sexual Abuse: A Scoping Review of the Literature and the Implications for American Samoa.

Significant stigma regarding child sexual abuse exists in American Samoa. Although cultural interventions may help prevent child sexual abuse, very little is known about such interventions. Therefore, through a scoping review process, this study aimed to gain a broad understanding of past and current culturally tailored interventions to prevent child sexual abuse. Because no studies examine interventions to prevent child sexual abuse in American Samoa specifically, the reviewed literature investigates interventions in different cultures. The literature search initially identified 180 relevant articles. After applying inclusion and exclusion criteria, nine studies met the eligibility criteria for review. Extracted data from these articles included the country or population, sample, study methods, children's age, intervention type, and details about the intervention. Results suggest that culturally tailored interventions for preventing child sexual abuse exist in various countries and cultural contexts. Results highlight that child sexual abuse prevention interventions are effective if translated into the native language. Findings from this study highlight the importance of using a culturally tailored approach to addressing child sexual abuse and can help guide the development of new interventions. Although more research on the prevention of child sexual abuse in American Samoa is needed, the results of this study might inform the development of culturally tailored interventions for the region.

Spatial predictive risk mapping of lymphatic filariasis residual hotspots in American Samoa using demographic and environmental factors.

BACKGROUND: American Samoa successfully completed seven rounds of mass drug administration (MDA) for lymphatic filariasis (LF) from 2000-2006. The territory passed the school-based transmission assessment surveys in 2011 and 2015 but failed in 2016. One of the key challenges after the implementation of MDA is the identification of any residual hotspots of transmission. METHOD: Based on data collected in a 2016 community survey in persons aged ≥8 years, Bayesian geostatistical models were developed for LF antigen (Ag), and Wb123, Bm14, Bm33 antibodies (Abs) to predict spatial variation in infection markers using demographic and environmental factors (including land cover, elevation, rainfall, distance to the coastline and distance to streams). RESULTS: In the Ag model, females had a 26.8% (95% CrI: 11.0-39.8%) lower risk of being Ag-positive than males. There was a 2.4% (95% CrI: 1.8-3.0%) increase in the odds of Ag positivity for every year of age. Also, the odds of Ag-positivity increased by 0.4% (95% CrI: 0.1-0.7%) for each 1% increase in tree cover. The models for Wb123, Bm14 and Bm33 Abs showed similar significant associations as the Ag model for sex, age and tree coverage. After accounting for the effect of covariates, the radii of the clusters were larger for Bm14 and Bm33 Abs compared to Ag and Wb123 Ab. The predictive maps showed that Ab-positivity was more widespread across the territory, while Ag-positivity was more confined to villages in the north-west of the main island. CONCLUSION: The findings may facilitate more specific targeting of post-MDA surveillance activities by prioritising those areas at higher risk of ongoing transmission.

Lymphatic filariasis endgame strategies: Using GEOFIL to model mass drug administration and targeted surveillance and treatment strategies in American Samoa.

American Samoa underwent seven rounds of mass drug administration (MDA) for lymphatic filariasis (LF) from 2000-2006, but subsequent surveys found evidence of ongoing transmission. American Samoa has since undergone further rounds of MDA in 2018, 2019, and 2021; however, recent surveys indicate that transmission is still ongoing. GEOFIL, a spatially-explicit agent-based LF model, was used to compare the effectiveness of territory-wide triple-drug MDA (3D-MDA) with targeted surveillance and treatment strategies. Both approaches relied on treatment with ivermectin, diethylcarbamazine, and albendazole. We simulated three levels of whole population coverage for 3D-MDA: 65%, 73%, and 85%, while the targeted strategies relied on surveillance in schools, workplaces, and households, followed by targeted treatment. In the household-based strategies, we simulated 1-5 teams travelling village-to-village and offering antigen (Ag) testing to randomly selected households in each village. If an Ag-positive person was identified, treatment was offered to members of all households within 100m-1km of the positive case. All simulated interventions were finished by 2027 and their effectiveness was judged by their 'control probability'-the proportion of simulations in which microfilariae prevalence decreased between 2030 and 2035. Without future intervention, we predict Ag prevalence will rebound. With 3D-MDA, a 90% control probability required an estimated ≥ 4 further rounds with 65% coverage, ≥ 3 rounds with 73% coverage, or ≥ 2 rounds with 85% coverage. While household-based strategies were substantially more testing-intensive than 3D-MDA, they could offer comparable control probabilities with substantially fewer treatments; e.g. three teams aiming to test 50% of households and offering treatment to a 500m radius had approximately the same control probability as three rounds of 73% 3D-MDA, but used < 40% the number of treatments. School- and workplace-based interventions proved ineffective. Regardless of strategy, reducing Ag prevalence below the 1% target threshold recommended by the World Health Organization was a poor indicator of the interruption of LF transmission, highlighting the need to review blanket elimination targets.

Feasibility of Healthy Beverages Policies in American Samoa and Federated States of Micronesia: Water and Coconut Water Only Community Interventions.

American Samoa and the Federated States of Micronesia (FSM) are two small Pacific Island nations that have some of the highest noncommunicable disease (NCD) mortality rates in the world. Supported by church leaders to address obesity as an NCD risk factor, American Samoa, and Chuuk and Kosrae States of FSM selected the implementation of healthy beverages as a nutrition intervention through a water- and coconut water-only pledge in church events. The consumption of water and coconut water was tracked. Across 105 church events in the three jurisdictions, the count of water bottles before and after events decreased from 142.8 to 22.3, the number of coconuts before and after events decreased from 19.6 to 1.2, and cups of water before and after events decreased from 52.9 to 7.6. The promotion of healthy beverages in church settings holds promise in the Pacific as a feasible, accessible, and culturally responsive nutrition approach, given limited access to other nutritional alternatives, e.g., fresh fruits and vegetables. Supplemental health promotion messaging to maintain knowledge and attitudes about healthy is recommended for future scaling up.

Community Perspectives on Contraception in the Context of Zika Virus in American Samoa and the Commonwealth of the Northern Mariana Islands.

The prevention of unintended pregnancy was identified as a primary prevention strategy to reduce Zika-related adverse birth outcomes during the 2016-2017 Zika virus outbreak. The Centers for Disease Control and Prevention in partnership with local health agencies conducted formative research to guide the development of culturally appropriate messages and materials to increase awareness of the prevention of unintended pregnancy as a strategy to decrease Zika-related adverse outcomes in American Samoa and the Commonwealth of the Northern Mariana Islands (CNMI). Nine focus groups (N=71) were conducted with women and men aged 18-44 years living in American Samoa and CNMI. Semi-structured interview guides were used to explore participants' knowledge and perceptions of Zika, family planning, and contraception; barriers and facilitators to access contraception and use; and information sources and contraception decision-making. Trained staff from local organizations co-moderated each focus group. Thematic analysis was conducted with NVivo 10. Participants had mixed knowledge about Zika virus and its relation to pregnancy and birth defects. Women and men had varied knowledge of the full range of contraceptive methods available in their jurisdiction and identified barriers to contraceptive access. Social factors including stigma, gender roles, and religion often deterred participants from accessing contraceptive services. Participants highlighted the need for culturally appropriate and clear messaging about contraceptive methods. Results demonstrate the feasibility of conducting formative research as an effective strategy for understanding community perspectives on unintended pregnancy prevention in the context of the Zika virus outbreak to develop health communication materials.

Gestational Diabetes Mellitus Prevalence, Screening, and Treatment Practices in American Samoa, 2016.

Gestational diabetes mellitus (GDM) is a serious pregnancy complication and understudied public health issue in American Samoa. The goals of this study were to (1) estimate the prevalence of GDM in American Samoa, (2) evaluate current screening practices for GDM, and (3) evaluate obtainment of GDM treatments in 2016. This cross-sectional study used 3 data sources: electronic health records, a labor and delivery logbook, and the American Samoa Department of Health (ASDOH) Maternal and Children's Health (MCH) Postpartum database. Out of 995 women with a singleton birth in American Samoa during the study period, 60.1% (n=598) completed a glucose tolerance test for GDM. Of these women, 41.8% (n=250) completed the testing within the recommended 24-28 weeks gestation timeframe. The estimated prevalence of GDM was 14.0% (95% confidence interval: 11.2-16.8) but has many limitations due to missing data. There were 4 treatments analyzed: nutrition counseling, insulin, metformin, and diabetes counseling. Of all women diagnosed with GDM (n=84), 76% were prescribed any of the 4 treatments. However, only 52% of those women obtained the treatment prescribed. Access to testing and treatment needs to be expanded to provide adequate prenatal care to women in American Samoa.

Modelling lymphatic filariasis elimination in American Samoa: GEOFIL predicts need for new targets and six rounds of mass drug administration.

BACKGROUND: As part of the global effort to eliminate the debilitating mosquito-borne disease lymphatic filariasis (LF), seven rounds of two-drug (diethylcarbamazine and albendazole) mass drug administration (MDA) were conducted in American Samoa over 2000-2006. However subsequent surveys demonstrated ongoing transmission prompting further rounds of three-drug (diethylcarbamazine, albendazole, and ivermectin) MDA starting in 2018. METHODS: We extend GEOFIL, a spatially-explicit agent-based model of LF transmission to predict the probability and timing of the local elimination or resurgence of LF for different MDA scenarios starting in 2018: two-drug vs. three-drug MDA, two to seven annual rounds, and population coverage rates of 55-75%. We developed an interactive visualisation comparing the effect of MDA strategies on different outcomes. RESULTS: At least six annual rounds of three-drug MDA treating 75% of the population were required to achieve LF elimination in American Samoa by 2035 in > 50% of simulations. In scenarios where MDA did not achieve elimination, prevalence doubled approximately every three years, even if MDA reduced antigen prevalence to <1% (the target recommended by the World Health Organisation). Prevalence in six- and seven-year-old children was approximately one quarter of the prevalence in the general population. CONCLUSION: The three rounds of three-drug MDA conducted in 2018, 2019, and 2021 may have come close to WHO targets but are unlikely to interrupt LF transmission in American Samoa without further interventions. The recommended post-MDA surveillance strategy of testing primarily six and seven-year-old children will delay detection of resurgence compared to population representative surveys. The recommended elimination targets (reducing antigen prevalence below 0.5%, 1%, or 2%) may not be sufficient to interrupt transmission in countries with LF epidemiology like American Samoa. Alternative surveillance strategies and interventions designed to identify and eliminate spatially localized residual transmission may need to be considered. Interactive visualisations may assist decision-makers to choose locally appropriate strategies.

Lymphatic filariasis in 2016 in American Samoa: Identifying clustering and hotspots using non-spatial and three spatial analytical methods.

BACKGROUND: American Samoa completed seven rounds of mass drug administration from 2000-2006 as part of the Global Programme to Eliminate Lymphatic Filariasis (LF). However, resurgence was confirmed in 2016 through WHO-recommended school-based transmission assessment survey and a community-based survey. This paper uses data from the 2016 community survey to compare different spatial and non-spatial methods to characterise clustering and hotspots of LF. METHOD: Non-spatial clustering of infection markers (antigen [Ag], microfilaraemia [Mf], and antibodies (Ab [Wb123, Bm14, Bm33]) was assessed using intra-cluster correlation coefficients (ICC) at household and village levels. Spatial dependence, clustering and hotspots were examined using semivariograms, Kulldorf's scan statistic and Getis-Ord Gi* statistics based on locations of surveyed households. RESULTS: The survey included 2671 persons (750 households, 730 unique locations in 30 villages). ICCs were higher at household (0.20-0.69) than village levels (0.10-0.30) for all infection markers. Semivariograms identified significant spatial dependency for all markers (range 207-562 metres). Using Kulldorff's scan statistic, significant spatial clustering was observed in two previously known locations of ongoing transmission: for all markers in Fagali'i and all Abs in Vaitogi. Getis-Ord Gi* statistic identified hotspots of all markers in Fagali'i, Vaitogi, and Pago Pago-Anua areas. A hotspot of Ag and Wb123 Ab was identified around the villages of Nua-Seetaga-Asili. Bm14 and Bm33 Ab hotspots were seen in Maleimi and Vaitogi-Ili'ili-Tafuna. CONCLUSION: Our study demonstrated the utility of different non-spatial and spatial methods for investigating clustering and hotspots, the benefits of using multiple infection markers, and the value of triangulating results between methods.

Potential use of antibodies to provide an earlier indication of lymphatic filariasis resurgence in post-mass drug ad ministration surveillance in American Samoa.

BACKGROUND: Under the Global Programme to Eliminate Lymphatic Filariasis (LF), American Samoa conducted 7 rounds of mass drug administration (MDA) between 2000 and 2006. The territory passed transmission assessment surveys (TASs) in 2011 (TAS-1) and 2015 (TAS-2). In 2016, the territory failed TAS-3, indicating resurgence. This study aims to determine if antibodies (Abs) may have provided a timelier indication of LF resurgence in American Samoa. METHODS: We examined school-level antigen (Ag) and Ab status (presence/absence of Ag- and Ab-positive children) and prevalence of single and combined Ab responses to Wb123, Bm14, and Bm33 Ags at each TAS. Pearson chi-square test and logistic regression were used to examine associations between school-level Ab prevalence in TAS-1 and TAS-2 and school-level Ag status in TAS-3. RESULTS: Schools with higher prevalence of Wb123 Ab in TAS-2 had higher odds of being Ag-positive in TAS-3 (odds ratio [OR] 24.5, 95% confidence interval [CI] 1.2-512.7). Schools that were Ab-positive for WB123 plus Bm14, Bm33, or both Bm14 and Bm33 in TAS-2 had higher odds of being Ag-positive in TAS-3 (OR 16.0-24.5). CONCLUSION: Abs could provide earlier signals of resurgence and enable a timelier response. The promising role of Abs in surveillance after MDA and decision making should be further investigated in other settings.

Military Medicine in American Samoa-Connecting With Indo-Pacific Partners.

With the rise of great power competition in the Indo-Pacific, Global Health Engagement can facilitate positive foreign relations. Increasing military medical outreach in American Samoa will provide improved health care in the territory, offer relevant medical training in resource-limited environments, and build connections with a community that has many uniformed members.

Period Prevalence of Rheumatic Heart Disease and the Need for a Centralized Patient Registry in American Samoa, 2016 to 2018.

Background Rheumatic heart disease (RHD) is a severe, chronic complication of acute rheumatic fever, triggered by group A streptococcal pharyngitis. Centralized patient registries are recommended for RHD prevention and control, but none exists in American Samoa. Using existing RHD tracking systems, we estimated RHD period prevalence and the proportion of people with RHD documented in the electronic health record. Methods and Results RHD cases were identified from a centralized electronic health record system, which retrieved clinical encounters with RHD International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes, clinical problem lists referencing RHD, and antibiotic prophylaxis administration records; 3 RHD patient tracking spreadsheets; and an all-cause mortality database. RHD cases had ≥1 clinical encounter with RHD ICD-10-CM codes, a diagnostic echocardiogram, or RHD as a cause of death, or were included in RHD patient tracking spreadsheets. Period prevalence per 1000 population among children aged <18 years and adults aged ≥18 years from 2016 to 2018 and the proportion of people with RHD with ≥1 clinical encounter with an RHD ICD-10-CM code were estimated. From 2016 to 2018, RHD was documented in 327 people (57.2%: children aged <18 years). Overall RHD period prevalence was 6.3 cases per 1000 and varied by age (10.0 pediatric cases and 4.3 adult cases per 1000). Only 67% of people with RHD had ≥1 clinical encounter with an RHD ICD-10-CM code. Conclusions RHD remains a serious public health problem in American Samoa, and the existing electronic health record does not include all cases. A centralized patient registry could improve tracking people with RHD to ensure they receive necessary care.

Catchment to sea connection: Impacts of terrestrial run-off on benthic ecosystems in American Samoa.

Variation in water quality can directly affect the composition of benthic assemblages on coral reefs. Yet, few studies have directly quantified nutrient and suspended particulate matter (SPM) to examine their potential impacts on benthic community structure, especially around high oceanic islands. We assessed the spatio-temporal variation of nutrients and SPM across six sites in American Samoa over a 12-month period and used exploratory path analysis to relate dissolved inorganic nutrients, land use, and natural and anthropogenic drivers to benthic assemblages on adjacent shallow reefs. Multivariate analyses showed clear gradients in nutrient concentrations, sediment accumulation and composition, and benthic structure across watersheds. Instream nutrients and land uses positively influenced reef flat nutrient concentrations, while benthic assemblages were best predicted by wave exposure, runoff, stream phosphate and dissolved inorganic nitrogen loads. Identifying locality-specific drivers of water quality and benthic condition can support targeted management in American Samoa and in other high islands.

Relationship between patient understanding and timeliness of penicillin prophylaxis in rheumatic heart disease prevention programmes in American Samoa.

AIM: While mostly eradicated in developed nations, rheumatic heart disease (RHD) is still the leading cause of preventable cardiovascular disease in children. RHD and its antecedent acute rheumatic fever remain endemic in many low to middle income countries, as well as in vulnerable communities in wealthy ones. Evidence-based interventions are particularly important in resource-poor settings. We sought to determine if efforts directed at patient and family education impact degree of participation in community-based prevention measures, and with short-term disease progression. METHODS: We performed an observational, cross-sectional study of children with RHD aged 5-19 years, along with their parents, in American Samoa. A survey was administered in November 2016 to assess patient and parent knowledge of RHD. Scores were compared to percent timeliness of penicillin prophylaxis via chart review. RESULTS: We collected a total of 70 surveys of child-parent dyads with a patient mean age of 14.28 years ±2.71. An increased knowledge score was predictive of increased penicillin compliance for both children (12.70% increase in compliance per 1-unit increase in score (P = 0.0004)) and parents (10.10% increase in compliance per 1-unit increase in score (P = 0.0012)). CONCLUSIONS: A clear relationship exists between patient and parent knowledge of RHD and timeliness of penicillin prophylaxis doses. This study was the first to link patient understanding of RHD to engagement with preventative measures.

Dietary assessment methodology and reporting in Pacific Island research: a scoping review protocol.

OBJECTIVE: This scoping review aims to identify and describe the methods used to collect and analyze dietary intake data in residents of Pacific Island countries. INTRODUCTION: Dietary assessment explores associations between dietary factors and health outcomes. In regions, including the Pacific Islands, where diet-related, non-communicable diseases are increasing, this is a growing area of research. As this information is used to inform food and nutrition policies and practice, accurate collection, analysis, and interpretation of dietary assessment data relies on robust methods. A greater understanding of how nutrition studies are designed can strengthen the evidence on nutrition and health in Pacific Island settings and inform future research approaches. INCLUSION CRITERIA: The scoping review will consider studies published in peer-reviewed journals, including quantitative and qualitative study designs and gray literature, including government reports, research and technical reports, theses and dissertations that measure and/or assess dietary intake in resident populations of the Pacific Island member countries of the Secretariat of the Pacific Community: American Samoa, Commonwealth of the Northern Mariana Islands, the Cook Islands, the Federated States of Micronesia, French Polynesia, Guam, the Independent State of Papua New Guinea, the Independent State of Samoa, the Kingdom of Tonga, New Caledonia, Niue, Pitcairn Islands, the Republic of Fiji, the Republic of Kiribati, the Republic of the Marshall Islands, the Republic of Nauru, the Republic of Palau, the Republic of Vanuatu, Solomon Islands, Tokelau, Tuvalu, and Wallis and Futuna. METHODS: There will be no time limit and searches will be conducted in PubMed, CINAHL, CABI, Scopus, Cochrane Library, and Web of Science. Results will be limited to English-language articles. Data will be extracted independently by two reviewers into a charting table. Results will be presented graphically and with tables accompanied by a narrative summary.

Genetic epidemiology of lymphatic filariasis in American Samoa after mass drug administration.

Over 892 million people in 48 countries are at risk of infection by nematodes that cause lymphatic filariasis. As part of the Global Programme to Eliminate Lymphatic Filariasis, mass drug administration is distributed to communities until surveillance indicates infection rates are below target prevalence thresholds. In some countries, including American Samoa, lymphatic filariasis transmission persists despite years of mass drug administration and/or has resurged after cessation. Nothing is known about the population genetics of Wuchereria bancrofti worms in Polynesia, or whether local transmission is persisting and/or increasing due to inadequate mass drug administration coverage, expansion from residual hotspots, reintroduction from elsewhere, or a combination. We extracted DNA from microfilariae on blood slides collected during prevalence surveys in 2014 and 2016, comprising 31 pools of five microfilariae from 22 persons living in eight villages. We sequenced 1104 bp across three mitochondrial markers (ND4, COI, CYTB). We quantified parasite genetic differentiation using variant calls and estimated haplotypes using principal components analysis, F-statistics, and haplotype networks. Of the variants called, all but eight were shared across the main island of Tutuila, and three of those were from a previously described hotspot village, Fagali'i. Genotypic data did not support population genetic structure among regions or villages in 2016, although differences were observed between worms collected in Fagali'i in 2014 and those from 2016. Because estimated haplotype frequency varied between villages, these statistics suggested genetic differentiation, but were not consistent among villages. Finally, haplotype networks demonstrated American Samoan sequence clusters were related to previously published sequences from Papua New Guinea. These are, to our knowledge, the first reports of W. bancrofti genetic variation in Polynesia. The resurgent parasites circulating on the main island of American Samoa represent a single population. This study is the first step towards investigating how parasite population structure might inform strategies to manage resurgence and elimination of lymphatic filariasis.

Potential strategies for strengthening surveillance of lymphatic filariasis in American Samoa after mass drug administration: Reducing 'number needed to test' by targeting older age groups, hotspots, and household members of infected persons.

Under the Global Programme to Eliminate Lymphatic Filariasis (LF), American Samoa conducted mass drug administration (MDA) from 2000-2006. Despite passing Transmission Assessment Surveys (TAS) in 2011/2012 and 2015, American Samoa failed TAS-3 in 2016, with antigen (Ag) prevalence of 0.7% (95%CI 0.3-1.8%) in 6-7 year-olds. A 2016 community survey (Ag prevalence 6.2% (95%CI 4.4-8.5%) in age ≥8 years) confirmed resurgence. Using data from the 2016 survey, this study aims to i) investigate antibody prevalence in TAS-3 and the community survey, ii) identify risk factors associated with being seropositive for Ag and anti-filarial antibodies, and iii) compare the efficiency of different sampling strategies for identifying seropositive persons in the post-MDA setting. Antibody prevalence in TAS-3 (n = 1143) were 1.6% for Bm14 (95%CI 0.9-2.9%), 7.9% for Wb123 (95%CI 6.4-9.6%), and 20.2% for Bm33 (95%CI 16.7-24.3%); and in the community survey (n = 2507), 13.9% for Bm14 (95%CI 11.2-17.2%), 27.9% for Wb123 (95%CI 24.6-31.4%), and 47.3% for Bm33 (95%CI 42.1-52.6%). Multivariable logistic regression was used to identify risk factors for being seropositive for Ag and antibodies. Higher Ag prevalence was found in males (adjusted odds ratio [aOR] 3.01), age ≥18 years (aOR 2.18), residents of Fagali'i (aOR 15.81), and outdoor workers (aOR 2.61). Ag prevalence was 20.7% (95%CI 9.7-53.5%) in households of Ag-positive children identified in TAS-3. We used NNTestav (average number needed to test to identify one positive) to compare the efficiency of the following strategies for identifying persons who were seropositive for Ag and each antibody: i) TAS of 6-7 year-old children, ii) population representative surveys of older age groups, and iii) targeted surveillance of subpopulations at higher risk of being seropositive (older ages, householders of Ag-positive TAS children, and known hotspots). For Ag, NNTestav ranged from 142.5 for TAS, to <5 for households of index children. NNTestav was lower in older ages, and highest for Ag, followed by Bm14, Wb123 and Bm33 antibodies. We propose a multi-stage surveillance strategy, starting with population-representative sampling (e.g. TAS or population representative survey of older ages), followed by strategies that target subpopulations and/or locations with low NNTestav. This approach could potentially improve the efficiency of identifying remaining infected persons and residual hotspots. Surveillance programs should also explore the utility of antibodies as indicators of transmission.

Evolutionary history of Mycobacterium leprae in the Pacific Islands.

As one of the oldest known human diseases, leprosy or Hansen's disease remains a public health concern around the world with over 200 000 new cases in 2018. Most human leprosy cases are caused by Mycobacterium leprae, but a small number of cases are now known to be caused by Mycobacterium lepromatosis, a sister taxon of M. leprae. The global pattern of genomic variation in M. leprae is not well defined. Particularly, in the Pacific Islands, the origins of leprosy are disputed. Historically, it has been argued that leprosy arrived on the islands during nineteenth century colonialism, but some oral traditions and palaeopathological evidence suggest an older introduction. To address this, as well as investigate patterns of pathogen exchange across the Pacific Islands, we extracted DNA from 39 formalin-fixed paraffin-embedded biopsy blocks dating to 1992-2016. Using whole-genome enrichment and next-generation sequencing, we produced nine M. leprae genomes dating to 1998-2015 and ranging from 4-63× depth of coverage. Phylogenetic analyses indicate that these strains belong to basal lineages within the M. leprae phylogeny, specifically falling in branches 0 and 5. The phylogeographical patterning and evolutionary dating analysis of these strains support a pre-modern introduction of M. leprae into the Pacific Islands. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.