Demographic, socioeconomic and disease knowledge factors, but not population mobility, associated with lymphatic filariasis infection in adult workers in American Samoa in 2014

Graves, Patricia M., Sheridan, Sarah, Fuimaono, Saipale, and Lau, Colleen L. (2020) Demographic, socioeconomic and disease knowledge factors, but not population mobility, associated with lymphatic filariasis infection in adult workers in American Samoa in 2014. Parasites & Vectors, 13. 125.

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Background: Prevalence of lymphatic filariasis (LF) antigen in American Samoa was 16.5% in 1999. Seven rounds of mass drug administration (MDA) programmes between 2000 and 2006 reduced antigen prevalence to 2.3%. The most efficient methods of surveillance after MDA are not clear, but testing specific at-risk groups such as adults may provide earlier warning of resurgence. The role of migration from LF endemic countries in maintaining transmission also needs investigation. Few studies have investigated knowledge about LF and how that relates to infection risk. This study aims to investigate associations between socio-demographics, population mobility, disease knowledge and LF infection risk.

Methods: In 2014, we surveyed 670 adults aged 16–68 years (62% female) at two worksites in American Samoa. Sera were tested for LF antigen and antibodies (Bm14 and Wb123) by rapid test and/or ELISA. Multivariate logistic regression was used to assess association between seromarkers and demographic factors, household socioeconomic status (SES), residence, travel history, and knowledge of LF.

Results: Overall, 1.8% of participants were positive for antigen, 11.8% for Bm14, 11.3% for Wb123 and 17.3% for at least one antibody. Recent travel outside American Samoa was not associated with positivity for any seromarker. Men had higher seroprevalence than women for all outcomes (any antibody: adjusted odds ratio (aOR) = 3.49 (95% CI: 2.21–5.49). Those aged over 35 years (compared to 15–24 years) had higher prevalence of Bm14 antibody (aOR = 3.75, 3.76 and 4.17 for ages 35–44, 45–54 and ≥ 55 years, respectively, P < 0.05). Lower SES was associated with seropositivity (antigen: aOR = 2.89, 95% CI: 1.09–7.69; either antibody: aOR = 1.51, 95% CI: 1.12–2.05). Those who knew that mosquitoes transmitted LF had lower Wb123 antibody prevalence (aOR = 0.55, 95% CI: 0.32–0.95).

Conclusions: Opportunistic sampling of adults at worksites provided an efficient and representative way to assess prevalence and risk factors for LF in American Samoa and in hindsight, foreshadowed the resurgence of transmission. Risk of LF infection, detected by one or more serological markers, was not related to recent travel history, but was strongly associated with male gender, older age, lower SES, and lack of knowledge about mosquito transmission. These results could guide future efforts to increase MDA participation.

Item ID: 66297
Item Type: Article (Research - C1)
ISSN: 1756-3305
Keywords: Lymphatic filariasis, American Samoa, Population mobility, Socioeconomic status, Disease knowledge, Sero-epidemiology, Surveillance, Mosquito
Copyright Information: © The Author(s) 2020. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creat ivecommons .org/licen ses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creat iveco mmons .org/publi cdoma in/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data
Funders: Australian Institute of Tropical Health and Medicine (AITHM), University of Queensland (UQ), National Health and Medical Research Council of Australia (NHMRC)
Projects and Grants: AITHM #13122014, NHMRC 1109035
Date Deposited: 25 Feb 2021 02:11
FoR Codes: 42 HEALTH SCIENCES > 4202 Epidemiology > 420202 Disease surveillance @ 34%
45 INDIGENOUS STUDIES > 4516 Pacific Peoples health and wellbeing > 451605 Pacific Peoples epidemiology @ 33%
32 BIOMEDICAL AND CLINICAL SCIENCES > 3207 Medical microbiology > 320704 Medical parasitology @ 33%
SEO Codes: 20 HEALTH > 2003 Provision of health and support services > 200303 Health surveillance @ 50%
20 HEALTH > 2005 Specific population health (excl. Indigenous health) > 200599 Specific population health (excl. Indigenous health) not elsewhere classified @ 50%
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