Lymphatic Filariasis in 2016 in American Samoa: Identifying Clustering and Hotspots Using Non-Spatial and Three Spatial Analytical Methods

2020 ◽  
Author(s):  
Kinley Wangdi ◽  
Meru Sheel ◽  
Saipale Fuimaono ◽  
Patricia M. Graves ◽  
Colleen L. Lau
Keyword(s):  
Lymphatic Filariasis ◽  
Analytical Methods ◽  
American Samoa

scholarly journals 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

2020 ◽  
Vol 14 (12) ◽  
pp. e0008916
Author(s):  
Colleen L. Lau ◽  
Meru Sheel ◽  
Katherine Gass ◽  
Saipale Fuimaono ◽  
Michael C. David ◽  
...  
Keyword(s):  
Risk Factors ◽  
Lymphatic Filariasis ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Age Groups ◽  
American Samoa ◽  
Community Survey ◽  
Older Age ◽  
Antibody Prevalence ◽  
Surveillance Strategy

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.

scholarly journals Seroprevalence and Spatial Epidemiology of Lymphatic Filariasis in American Samoa after Successful Mass Drug Administration

2014 ◽  
Vol 8 (11) ◽  
pp. e3297 ◽  
Author(s):  
Colleen L. Lau ◽  
Kimberly Y. Won ◽  
Luke Becker ◽  
Ricardo J. Soares Magalhaes ◽  
Saipale Fuimaono ◽  
...  
Keyword(s):  
Lymphatic Filariasis ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Spatial Epidemiology ◽  
American Samoa

scholarly journals Molecular Xenomonitoring Using Mosquitoes to Map Lymphatic Filariasis after Mass Drug Administration in American Samoa

2014 ◽  
Vol 8 (8) ◽  
pp. e3087 ◽  
Author(s):  
Mark A. Schmaedick ◽  
Amanda L. Koppel ◽  
Nils Pilotte ◽  
Melissa Torres ◽  
Steven A. Williams ◽  
...  
Keyword(s):  
Lymphatic Filariasis ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
American Samoa ◽  
Molecular Xenomonitoring

scholarly journals Potential use of antibodies to provide an earlier indication of lymphatic filariasis resurgence in post-mass drug administration surveillance, American Samoa

2021 ◽  
Author(s):  
Angela M. Cadavid Restrepo ◽  
Katherine Gass ◽  
Kimberly Y. Won ◽  
Meru Sheel ◽  
Keri Robinson ◽  
...  
Keyword(s):  
Lymphatic Filariasis ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
American Samoa ◽  
School Level ◽  
World Health ◽  
Chi Squared ◽  
Health Organization ◽  
Potential Use

AbstractObjectivesUnder the Global Programme to Eliminate Lymphatic Filariasis (LF), American Samoa conducted seven rounds of mass drug administration between 2000 and 2006. The territory passed transmission assessment surveys (TAS) in 2011 (TAS-1) and 2015 (TAS-2) based on World Health Organization guidelines. In 2016, the territory failed TAS-3, indicating resurgence. This study aims to determine if antibodies (Ab) may have provided a timelier indication of LF resurgence in American Samoa.MethodsWe examined school-level Ag and Ab status (presence/absence of Ag- and Ab- positive children) and prevalence of single and combined Ab responses to Wb123, Bm14, Bm33 Ags at each TAS. Pearson’s chi-squared tests 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.ResultsSchools 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% 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).ConclusionAnti-filarial Abs could provide earlier signals of resurgence and enable a timelier response. The promising role of Abs in post-MDA surveillance and decision making should be further investigated in other settings.

scholarly journals Improving community participation to eliminate lymphatic filariasis in American Samoa

Acta Tropica ◽  
2011 ◽  
Vol 120 ◽  
pp. S48-S54 ◽  
Author(s):  
Jonathan D. King ◽  
Emily Zielinski-Gutierrez ◽  
Molisamoa Pa’au ◽  
Patrick Lammie
Keyword(s):  
Lymphatic Filariasis ◽  
Community Participation ◽  
American Samoa

Assessing Transmission of Lymphatic Filariasis Using Parasitologic, Serologic, and Entomologic Tools after Mass Drug Administration in American Samoa

2009 ◽  
Vol 80 (5) ◽  
pp. 769-773 ◽  
Author(s):  
Janice M. Mladonicky ◽  
Mark Bradley ◽  
Jennifer L. Liang ◽  
Molisamoa Pa’au ◽  
Thomas R. Burkot ◽  
...  
Keyword(s):  
Lymphatic Filariasis ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
American Samoa

scholarly journals Detecting and confirming residual hotspots of lymphatic filariasis transmission in American Samoa 8 years after stopping mass drug administration

2017 ◽  
Vol 11 (9) ◽  
pp. e0005914 ◽  
Author(s):  
Colleen L. Lau ◽  
Sarah Sheridan ◽  
Stephanie Ryan ◽  
Maureen Roineau ◽  
Athena Andreosso ◽  
...  
Keyword(s):  
Lymphatic Filariasis ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
American Samoa

scholarly journals Lymphatic Filariasis Elimination in American Samoa: Evaluation of Molecular Xenomonitoring as a Surveillance Tool in the Endgame

2016 ◽  
Vol 10 (11) ◽  
pp. e0005108 ◽  
Author(s):  
Colleen L. Lau ◽  
Kimberly Y. Won ◽  
Patrick J. Lammie ◽  
Patricia M. Graves
Keyword(s):  
Lymphatic Filariasis ◽  
American Samoa ◽  
Molecular Xenomonitoring
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