First evidence of spatial clustering of lymphatic filariasis in an Aedes polynesiensis endemic area

Joseph, Hayley, Moloney, James, Maiava, Fuatai, McClintock, Shannon, Lammie, Patrick, and Melrose, Wayne (2011) First evidence of spatial clustering of lymphatic filariasis in an Aedes polynesiensis endemic area. Acta Tropica, 120 (Supplement 1). S39-S47.

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Abstract

Successful elimination of lymphatic filariasis (LF) requires accurate identification of residual foci of transmission and stringent surveillance strategies to combat potential resurgence. This is challenging in areas where the day-biting Aedes polynesiensis is endemic, such as Samoa, since in previous studies no geographical clustering of infection has been demonstrated. Another challenge for this low prevalence phase is the choice of diagnostic assay as testing for circulating filarial antigen (CFA) or microfilariae (Mf) alone may not have adequate sensitivity. This could be solved by using the commercially available filariasis Cellabs enzyme linked immunosorbent assay (CELISA) to measure antibody. In the current study five Samoan villages were chosen based on previous epidemiological assessments to represent a range of infection prevalences. CFA, Mf, and antibody levels in children ≤10 years had been recorded and results linked to household of residence and/or primary school of attendance. To ascertain the location of exposure, two scenarios based on potential foci of transmission around communities and schools were explored. Both scenarios revealed significant spatial clusters of households with infected individuals and a relationship to antibody positive children when they were included in the spatial analysis. Fasitoo-Tai had the highest LF prevalence and largest geographical spatial clusters for both scenarios. In Falefa, spatial clusters were detected only for the primary school scenario. In Tafua, which spanned an area of 19.5 km2, no spatial clusters were detected. Lastly, in Siufaga, the village with the lowest LF prevalence, significant clustering of infected individuals was observed and, for the primary school scenario, this was geographically related to exposure. These promising findings are the first published evidence of spatial clustering of LF in a day-biting Ae. polynesiensis endemic area.

Item ID: 15315
Item Type: Article (Refereed Research - C1)
Keywords: filariasis CELISA; Samoa; serology; spatial clustering; SaTScan™; Wuchereria
ISSN: 1873-6254
Date Deposited: 07 Apr 2011 01:59
FoR Codes: 11 MEDICAL AND HEALTH SCIENCES > 1107 Immunology > 110705 Humoural Immunology and Immunochemistry @ 5%
11 MEDICAL AND HEALTH SCIENCES > 1117 Public Health and Health Services > 111706 Epidemiology @ 70%
11 MEDICAL AND HEALTH SCIENCES > 1117 Public Health and Health Services > 111711 Health Information Systems (incl Surveillance) @ 25%
SEO Codes: 92 HEALTH > 9202 Health and Support Services > 920203 Diagnostic Methods @ 10%
92 HEALTH > 9204 Public Health (excl. Specific Population Health) > 920404 Disease Distribution and Transmission (incl. Surveillance and Response) @ 90%
Citation Count from Web of Science Web of Science 2
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