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 Potential strategies for strengthening surveillance of lymphatic filariasis in American Samoa after mass drug administration: targeting older age groups, hotspots, and household members of infected persons

2020 ◽  
Author(s):  
Colleen Lau ◽  
Meru Sheel ◽  
Katie Gass ◽  
Saipale Fuimaono ◽  
Michael David ◽  
...  
Keyword(s):  
High Risk ◽  
Lymphatic Filariasis ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Disease Transmission ◽  
Parasitic Infection ◽  
American Samoa ◽  
Community Survey ◽  
World Health ◽  
Surveillance Strategy

ABSTRACTBackgroundUnder 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. Here, we explore the potential of targeted strategies to strengthen post-MDA surveillance.Methodology/Principal FindingsUsing Ag data plus new antibody data (Wb123, Bm14, Bm33) from the 2016 surveys, we identified risk factors for seropositivity using multivariable logistic regression. We compared TAS with strategies that targeted high-risk subpopulations (older ages, householders of Ag-positive TAS children [index children]) and/or known hotspots, and used NNTestav (average number needed to test to identify one positive) to compare sampling efficiency.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%). Ag prevalence was 20.7% (95%CI 9.7-53.5%) in households of index children. 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). Using 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.Conclusions/SignificanceWe propose a multi-stage surveillance strategy, starting with population-representative sampling (e.g. TAS), followed by targeted strategies in subgroups and locations with low NNTestav. This approach could potentially improve the efficiency of identifying remaining infected persons and residual hotspots. The utility of antibodies in surveillance should also be explored.AUTHOR SUMMARYLymphatic filariasis (LF) is a parasitic infection transmitted by mosquito bites. Globally, tens of millions are infected, with many disfigured and disabled by severe damage to their lymphatic systems, such as severe swelling of the legs (elephantiasis) or scrotum (hydrocele). The Global Programme to Eliminate LF (GPELF) aims to interrupt disease transmission through mass drug administration (MDA), and to control illness and suffering in affected persons. The World Health Organization recommends conducting Transmission Assessment Surveys (TAS) in school children aged 6 to 7 years, to determine if infection rates have dropped to levels where disease transmission is no longer sustainable. From 2000-2006, American Samoa conducted MDA and made significant progress towards eliminating LF. However, despite passing TAS in 2011/2012 and 2015, surveys in 2016 showed evidence of resurgence. Our study explored alternative surveillance strategies and compared their efficiency with TAS. Based on our findings, we recommended that in addition to TAS, strategies that target high-risk populations and hotspots would strengthen surveillance and help countries achieve their goals of LF elimination.

scholarly journals Risk factors for lymphatic filariasis and mass drug administration non-participation in Mandalay Region, Myanmar

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Benjamin F. R. Dickson ◽  
Patricia M. Graves ◽  
Ni Ni Aye ◽  
Thet Wai Nwe ◽  
Tint Wai ◽  
...  
Keyword(s):  
Risk Factors ◽  
Lymphatic Filariasis ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Survey Design ◽  
Age Groups ◽  
Household Survey ◽  
Male Gender ◽  
Night Time ◽  
Cross Sectional

Abstract Background Myanmar commenced a lymphatic filariasis (LF) elimination programme in 2000. Whilst the country has made considerable progress since then, a number of districts have demonstrated persistent transmission after many rounds of mass drug administration (MDA). The causes of unsuccessful MDA have been examined elsewhere; however, there remains little information on the factors that contribute in Myanmar. Methods We conducted an analysis of factors associated with persistent infection, LF-related hydrocoele and MDA participation in an area with ongoing transmission in 2015. A cross-sectional household survey was undertaken in 24 villages across four townships of Mandalay Region. Participants were screened for circulating filarial antigen (CFA) using immunochromatographic tests and, if positive, for microfilaria by night-time thick blood slide. Individuals 15 year and older were assessed for filariasis morbidity (lymphoedema and, if male, hydrocoele) by ultrasound-assisted clinical examination. A pre-coded questionnaire was used to assess risk factors for LF and for non-participation (never taking MDA). Significant variables identified in univariate analyses were included in separate step-wise multivariate logistic regressions for each outcome. Results After adjustment for covariates and survey design, being CFA positive was significantly associated with age [odds ratio (OR) 1.03, 95% CI 1.01–1.06), per year], male gender (OR 3.14, 1.27–7.76), elevation (OR 0.96, 0.94–0.99, per metre) and the density of people per household room (OR 1.59, 1.31–1.92). LF-related hydrocoele was associated with age (OR 1.06, 1.03–1.09, per year) and residing in Amarapura Township (OR 8.93, 1.37–58.32). Never taking MDA was associated with male gender [OR 6.89 (2.13–22.28)] and age, particularly in females, with a significant interaction term. Overall, compared to those aged 30–44 years, the proportion never taking MDA was higher in all age groups (OR highest in those < 5 years and > 60 years, ranging from 3.37 to 12.82). Never taking MDA was also associated with residing in Amarapura township (OR 2.48, 1.15–5.31), moving to one’s current village from another (OR 2.62, 1.12–6.11) and ever having declined medication (OR 11.82, 4.25–32.91). Decreased likelihood of never taking MDA was associated with a higher proportion of household members being present during the last MDA round (OR 0.16, 0.03–0.74) and the number visits by the MDA programme (OR 0.69, 0.48–1.00). Conclusions These results contribute to the understanding of LF and MDA participation-related risk factors and will assist Myanmar to improve its elimination and morbidity management programmes.

scholarly journals Prevalence and risk factors associated with lymphatic filariasis in American Samoa after mass drug administration

2017 ◽  
Vol 45 (1) ◽  
Author(s):  
Shaun P. Coutts ◽  
Jonathan D. King ◽  
Molisamoa Pa’au ◽  
Saipale Fuimaono ◽  
Joseph Roth ◽  
...  
Keyword(s):  
Risk Factors ◽  
Lymphatic Filariasis ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
American Samoa ◽  
Factors Associated

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 A community survey of coverage and adverse events following country-wide triple-drug mass drug administration for lymphatic filariasis elimination, Samoa 2018

2020 ◽  
Vol 14 (11) ◽  
pp. e0008854
Author(s):  
Gabriela A. Willis ◽  
Helen J. Mayfield ◽  
Therese Kearns ◽  
Take Naseri ◽  
Robert Thomsen ◽  
...  
Keyword(s):  
Adverse Events ◽  
Lymphatic Filariasis ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Total Population ◽  
Community Survey ◽  
World Health ◽  
Cross Sectional ◽  
Eligible Population ◽  
Health Organization

The Global Programme to Eliminate Lymphatic Filariasis has made considerable progress but is experiencing challenges in meeting targets in some countries. Recent World Health Organization guidelines have recommended two rounds of triple-drug therapy with ivermectin, diethylcarbamazine (DEC), and albendazole (IDA), in areas where mass drug administration (MDA) results with two drugs (DEC and albendazole) have been suboptimal, as is the case in Samoa. In August 2018, Samoa was the first country in the world to implement countrywide triple-drug MDA. This paper aims to describe Samoa’s experience with program coverage and adverse events (AEs) in the first round of triple-drug MDA. We conducted a large cross-sectional community survey to assess MDA awareness, reach, compliance, coverage and AEs in September/October 2018, 7–11 weeks after the first round of triple-drug MDA. In our sample of 4420 people aged ≥2 years (2.2% of the population), age-adjusted estimates indicated that 89.0% of the eligible population were offered MDA, 83.9% of the eligible population took MDA (program coverage), and 80.2% of the total population took MDA (epidemiological coverage). Overall, 83.8% (2986/3563) reported that they did not feel unwell at all after taking MDA. Mild AEs (feeling unwell but able to do normal everyday things) were reported by 13.3% (476/3563) and moderate or severe AEs (feeling unwell and being unable to do normal everyday activities such as going to work or school) by 2.9% (103/3563) of participants. This study following the 2018 triple-drug MDA in Samoa demonstrated a high reported program awareness and reach of 90.8% and 89.0%, respectively. Age-adjusted program coverage of 83.9% of the total population showed that MDA was well accepted and well tolerated by the community.

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.

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 Risk factors for Lymphatic Filariasis and Mass Drug Administration non-Participation in Mandalay Region, Myanmar

2020 ◽  
Author(s):  
Benjamin Felix Rothschild Dickson ◽  
Patricia M. Graves ◽  
Ni Ni Aye ◽  
Thet Wai Nwe ◽  
Tint Wai ◽  
...  
Keyword(s):  
Risk Factors ◽  
Lymphatic Filariasis ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Survey Design ◽  
Household Survey ◽  
Male Gender ◽  
Night Time ◽  
Cross Sectional ◽  
Separate Step

Abstract Background: Myanmar commenced a lymphatic filariasis (LF) elimination program in 2000. Whilst the country has made considerable progress since then, a number of districts have demonstrated persistent transmission after many rounds of mass drug administration (MDA). The causes of unsuccessful MDA have been examined elsewhere, however, there remains little information on the factors that contribute in Myanmar. Methods: We conducted an analysis of factors associated with persistent infection, LF-related hydrocoele and MDA participation in an area with ongoing transmission in 2015. A cross-sectional household survey was undertaken in 24 villages across four townships of Mandalay Region. Participants were screened for circulating filarial antigen (CFA) using immunochromatographic tests and if positive, for microfilaria by night-time thick blood slide. Individuals 15 year and older were assessed for filariasis morbidity (lymphoedema and if male, hydrocoele) by ultrasound-assisted clinical examination. A pre-coded questionnaire was used to assess risk factors for LF and for never-taking MDA. Significant variables identified in univariate analyses were included in separate step-wise multivariate logistic regressions for each outcome. Results: After adjustment for covariates and survey design, being CFA positive was significantly associated with age (odds ratio (OR) 1.03, 95% CI 1.01 – 1.06), per year), male gender (OR 3.11, 1.23 – 7.87), elevation (OR 0.97, 0.94 – 1.00, per metre) and the density of people per household room (OR 1.56, 1.26 – 1.93). LF-related hydrocoele was associated with age (OR 1.06, 1.02 – 1.09, per year) and residing in Amarapura Township (OR 8.56, 1.33 – 55.22). Never-taking MDA was associated with age (less than 15 years: OR 2.89, 1.11 – 7.51; greater than 60 years: OR 4.00, 1.53 – 10.48), male gender (OR 1.85, 1.05 – 3.25), residing in Amarapura township (OR 2.99, 1.39 – 6.43), moving to one’s current village from another (OR 2.84, 1.15 – 7.02) and ever having declined medication (OR 13.76, 4.79 – 39.58). Decreased likelihood of never taking MDA was associated with a higher proportion of household members being present during the last MDA round (OR 0.18, 0.04 – 0.96)). Conclusions: These results contribute to the understanding of LF and MDA participation related risk factors, and will assist Myanmar improve its elimination and morbidity management programs.

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