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Impact of three rounds of mass drug administration on lymphatic filariasis in areas previously treated for onchocerciasis in Sierra Leone.

Koroma, Joseph, Sesay, Santigie, Sonnie, Mustapha, Hodges, Mary H, Sahr, Foday, Zhang, Yaobi and Bockarie, Moses (2013) 'Impact of three rounds of mass drug administration on lymphatic filariasis in areas previously treated for onchocerciasis in Sierra Leone.'. PLoS Neglected Tropical Diseases, Vol 7, Issue 6, e2273.

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1974-2005 studies across Sierra Leone showed onchocerciasis endemicity in 12 of 14 health districts (HDs) and baseline studies 2005-2008 showed lymphatic filariasis (LF) endemicity in all 14 HDs. Three integrated annual mass drug administration (MDA) were conducted in the 12 co-endemic districts 2008-2010 with good geographic, programme and drug coverage. Midterm assessment was conducted 2011 to determine impact of these MDAs on LF in these districts.


The mf prevalence and intensity in the 12 districts were determined using the thick blood film method and results compared with baseline data from 2007-2008. Overall mf prevalence fell from 2.6% (95% CI: 2.3%-3.0%) to 0.3% (95% CI: 0.19%-0.47%), a decrease of 88.5% (p = 0.000); prevalence was 0.0% (100.0% decrease) in four districts: Bo, Moyamba, Kenema and Kono (p = 0.001, 0.025, 0.085 and 0.000 respectively); and seven districts had reductions in mf prevalence of between 70.0% and 95.0% (p = 0.000, 0.060, 0.001, 0.014, 0.000, 0.000 and 0.002 for Bombali, Bonthe, Kailahun, Kambia, Koinadugu, Port Loko and Tonkolili districts respectively). Pujehun had baseline mf prevalence of 0.0%, which was maintained. Only Bombali still had an mf prevalence ≥1.0% (1.58%, 95% CI: 0.80%-3.09%)), and this is the district that had the highest baseline mf prevalence: 6.9% (95% CI: 5.3%-8.8%). Overall arithmetic mean mf density after three MDAs was 17.59 mf/ml (95% CI: 15.64 mf/ml-19.55 mf/ml) among mf positive individuals (65.4% decrease from baseline of 50.9 mf/ml (95% CI: 40.25 mf/ml-61.62 mf/ml; p = 0.001) and 0.05 mf/ml (95% CI: 0.03 mf/ml-0.08 mf/ml) for the entire population examined (96.2% decrease from baseline of 1.32 mf/ml (95% CI: 1.00 mf/ml-1.65 mf/ml; p = 0.000)).


The results show that mf prevalence decreased to <1.0% in all but one of the 12 districts after three MDAs. Overall mf density reduced by 65.0% among mf-positive individuals, and 95.8% for the entire population.

Item Type: Article
Subjects: WA Public Health > Preventive Medicine > WA 108 Preventive health services. Preventive medicine. Travel Medicine.
WA Public Health > Preventive Medicine > WA 110 Prevention and control of communicable diseases. Transmission of infectious diseases
WA Public Health > Health Problems of Special Population Groups > WA 395 Health in developing countries
WC Communicable Diseases > Tropical and Parasitic Diseases > WC 880 Filariasis and related conditions (General)
WC Communicable Diseases > Tropical and Parasitic Diseases > WC 885 Onchocerciasis
Faculty: Department: Biological Sciences > Department of Tropical Disease Biology
Digital Object Identifer (DOI):
Depositing User: Mary Creegan
Date Deposited: 25 Nov 2014 10:08
Last Modified: 06 Feb 2018 13:07


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