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

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.

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

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0008854 ◽

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.

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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

10.1101/2020.04.07.20056549 ◽

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.

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The role of gender relations in uptake of mass drug administration for lymphatic filariasis in Alor District, Indonesia

Parasites & Vectors ◽

10.1186/s13071-018-2689-8 ◽

2018 ◽

Vol 11 (1) ◽

Cited By ~ 4

Author(s):

Alison Krentel ◽

Kaye Wellings

Keyword(s):

Lymphatic Filariasis ◽

Drug Administration ◽

Mass Drug Administration ◽

Gender Relations

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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

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0008916 ◽

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.

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

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0003297 ◽

2014 ◽

Vol 8 (11) ◽

pp. e3297 ◽

Cited By ~ 36

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

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

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0003087 ◽

2014 ◽

Vol 8 (8) ◽

pp. e3087 ◽

Cited By ~ 33

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

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The promise, problems and pitfalls of mass drug administration for malaria elimination: a qualitative study with scientists and policymakers

International Health ◽

10.1093/inthealth/ihy079 ◽

2018 ◽

Vol 11 (3) ◽

pp. 166-176 ◽

Cited By ~ 9

Author(s):

Nils Kaehler ◽

Bipin Adhikari ◽

Phaik Yeong Cheah ◽

Nicholas P J Day ◽

Daniel H Paris ◽

...

Keyword(s):

Drug Administration ◽

Mass Drug Administration ◽

Malaria Elimination ◽

Artemisinin Resistance ◽

Malaria Prevention ◽

Evidence Base ◽

World Health ◽

Pilot Studies ◽

Target Populations ◽

Health Organization

Abstract Background The emergence of artemisinin resistance in the Greater Mekong Subregion (GMS) has prompted urgent containment measures. One possible approach is mass drug administration (MDA). This article explores attitudes towards and perceptions of MDA for malaria elimination among policymakers and leading malariologists. Methods Thirty-two semistructured interviews (SSI) were conducted with policymakers (n=17) and principal investigators (n=15) selected based on their involvement in malaria prevention, control and elimination in the GMS. Interviews were audio recorded and transcribed for qualitative content (thematic) analysis using NVivo (QSR International, Doncaster, Victoria, Australia). Results Researchers and policymakers described reluctance and consequently delays to pilot MDA for malaria elimination. Most policymakers and some researchers reported concerns around the evidence base, citing a lack of data on its effectiveness and appropriate target populations. There were also worries about promoting resistance. Other issues included a previous lack of support from the World Health Organization, past MDAs, the remoteness of target populations and challenges explaining the rationale for MDA. Conclusions The complex rationale for MDA for malaria elimination, mistaking pilot studies for implementation, past experiences with MDA, difficulties in selecting appropriate sites and the WHO’s lack of clear backing undermined the support for MDA for malaria elimination.

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The Added Value of Water, Sanitation, and Hygiene Interventions to Mass Drug Administration for Reducing the Prevalence of Trachoma: A Systematic Review Examining

Journal of Environmental and Public Health ◽

10.1155/2013/682093 ◽

2013 ◽

Vol 2013 ◽

pp. 1-10 ◽

Cited By ~ 4

Author(s):

Anyess Travers ◽

Sheryl Strasser ◽

Stephanie L. Palmer ◽

Christine Stauber

Keyword(s):

Systematic Review ◽

Drug Administration ◽

Mass Drug Administration ◽

Added Value ◽

World Health ◽

Sanitation And Hygiene ◽

Pubmed Database ◽

Health Organization ◽

Hygiene Education ◽

The Impact

Trachoma is the leading cause of infectious blindness worldwide. The SAFE strategy, the World Health Organization-recommended method to eliminate blinding trachoma, combines developments in water, sanitation, surgery, and antibiotic treatment. Current literature does not focus on the comprehensive effect these components have on one another. The present systematic review analyzes the added benefit of water, sanitation, and hygiene education interventions to preventive mass drug administration of azithromycin for trachoma. Trials were identified from the PubMed database using a series of search terms. Three studies met the complete criteria for inclusion. Though all studies found a significant change in reduction of active trachoma prevalence, the research is still too limited to suggest the impact of the “F” and “E” components on trachoma prevalence and ultimately its effects on blindness.

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Lymphatic filariasis elimination endgame in an urban Indian setting: the roles of surveillance and residual microfilaremia after mass drug administration

Infectious Diseases of Poverty ◽

10.1186/s40249-021-00856-x ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Anjali Modi ◽

Keshav G. Vaishnav ◽

Kailash Kothiya ◽

Neal Alexander

Keyword(s):

High Risk ◽

Lymphatic Filariasis ◽

Drug Administration ◽

Mass Drug Administration ◽

Risk Groups ◽

Primary School Children ◽

World Health ◽

Urban Indian ◽

Indian Setting ◽

The Impact

Abstract Background To secure the gains of lymphatic filariasis (LF) elimination programs, attention is needed to the ‘residual microfilaremia phase’, in which high-risk populations may be crucial. The present study documents the impact of mass drug administration (MDA) in the urban Indian setting of Surat City, with high rates of in-migration. Methods Epidemiological assessment included National Filaria Control Program (NFCP) and World Health Organization recommended routine and pre-MDA microfilaremia surveys respectively. Routine filaria surveys were conducted around the year in approximately 2000–4000 people per month, while pre-MDA surveys were carried out annually among approximately 4000 people from four fixed and four random sites. In 2016, Transmission Assessment Survey (TAS) was done in primary school children. The outcomes were microfilaremia (Mf) and antigen prevalence; more specifically, microfilaremia according to place of birth, in pre-MDA and routine night blood smears (NBS) collected from 2008 to 2015. Prevalence ratios and confidence intervals were calculated. Results A total of 25 480 pre-MDA and 306 198 routine NBS were examined during the study. In 2008, the Mf prevalence in the routine survey was 63/18 814 (0.33%), declining to 23/39 717 (0.06%) in 2016. Pre-MDA surveys showed a similar decrease from 47/4184 (1.1%) in 2008 to 12/4042 (0.3%) in 2015. In those born outside Surat, microfilaremia decreased below transmission thresholds, but remained more than treble that of the remainder of the population, in both the pre-MDA surveys [prevalence ratio: 3.17, 95% confidence interval (CI): 1.15–8.72], and the routine surveys (3.31, 95% CI: 1.47–7.48). Though the TAS results indicated that MDA endpoints had been reached, sub-group analysis identified that 90% of antigenemic children were from families of high-risk groups. Conclusions Extensive long-term epidemiological monitoring suggests that all the urban population, including high-risk groups, have benefitted from the ELF program. To prevent re-establishment of infection in large urban areas with unsanitary conditions conducive to filarial vector breeding, there is need to identify residual microfilaremia by customized surveys in addition to pre-MDA monitoring and TAS. The present findings can be used to develop strategies to prioritize screening, surveillance and plan treatment of high-risk groups after achieving MDA endpoints.

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