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Lymphatic filariasis mapping by Immunochromatographic Test cards and baseline microfilaria survey prior to mass drug administration in Sierra Leone

Koroma, Joseph, Bangura, Momodu M, Hodges, Mary H, Bah, Mohamed, Zhang, Yaobi and Bockarie, Moses (2012) 'Lymphatic filariasis mapping by Immunochromatographic Test cards and baseline microfilaria survey prior to mass drug administration in Sierra Leone'. Parasites & Vectors, Vol 5, e10.

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National mapping of lymphatic filariasis (LF) was conducted using Immunochromatographic tests(ICT) in 2005 to determine endemicity and geographic spread of the disease. A baseline microfilaria survey was then conducted to determine LF prevalence and microfilaria intensity.


In 2005 1,982 persons of 15 years and over from 14 health districts were selected and fingertip blood samples were tested with ICT cards. In 2007-8 blood samples were taken between 10 p.m. and 2 a.m. and examined for microfilaria (mf) from 9,288 persons from 16 sentinel sites representing each district and 2 additional sites for districts with populations over 500,000 (Bo and Kenema).
Results: The overall LF prevalence by ICT cards was 21% (males 28%, females 15%). All districts had a prevalence
of Wuchereria bancrofti antigen > 1%. Distribution of LF prevalence showed a strong spatial correlation pattern
with high prevalence in a large area in the northeast gradually decreasing to a relatively low prevalence in the
southwest coast. High prevalence was found in the northeast, Bombali (52%), Koinadugu (46%), Tonkolili (37%) and Kono (30%). Low prevalence was found in the southwest, Bonthe (3%) and Pujehun (4%). The mf prevalence was
higher in the northeast: Bombali, 6.7%, Koinadugu 5.7%, Port Loko 4.4% and Kono 2.4%. Overall there was a
significant difference in mf prevalence by gender: males 2.9%, females 1.8% (p = 0.0002) and within districts in
Kailahun, Kono, Port Loko, Moyamba and Koinadugu (all p < 0.05). The mf prevalence was higher in people > 20
years (2.5%) than in people ≤ 20 years (1.7%) (p = 0.043). The overall arithmetic mean mf density was 50.30 mf/ml
among mf-positive individuals and 1.19 mf/ml in the population examined which varied significantly between


The ICT results showed that LF was endemic nationwide and that preventive chemotherapy (PCT) was justified across the country. Both the ICT and microfilaraemia surveys found that prevalence was greater in
males than females. The increase in microfilaraemia prevalence by age was evident when grouped as ≤ 20 versus
> 20 years demonstrating early exposure. Baseline LF microfilaria load will be used to monitor PCT program

Item Type: Article
Additional Information: The electronic version of this article is the complete one and can be found online at:
Subjects: QY Clinical Pathology > Diagnostic Tests > QY 250 Immunodiagnostic tests
WB Practice of Medicine > Therapeutics > WB 340 Drug Administration
WB Practice of Medicine > Medical Climatology > WB 710 Diseases of geographic areas
WC Communicable Diseases > Tropical and Parasitic Diseases > WC 880 Filariasis and related conditions (General)
Faculty: Department: Groups (2002 - 2012) > Disease Control Strategy Group
Digital Object Identifer (DOI):
Depositing User: Users 322 not found.
Date Deposited: 06 Feb 2012 12:37
Last Modified: 06 Feb 2018 13:04


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