Limits...
A comprehensive assessment of lymphatic filariasis inSri Lanka six years after cessation of mass drug administration.

Rao RU, Nagodavithana KC, Samarasekera SD, Wijegunawardana AD, Premakumara WD, Perera SN, Settinayake S, Miller JP, Weil GJ - PLoS Negl Trop Dis (2014)

Bottom Line: Infection rates were significantly higher in males and lower in people who denied prior treatment.Low-level persistence of LF was present in all study sites; several sites failed to meet provisional endpoint criteria for LF elimination, and follow-up testing will be needed in these areas.We recommend use of antibody and MX testing as tools to complement TAS for post-MDA surveillance.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine, Infectious Diseases Division, Washington University School of Medicine, St. Louis, Missouri, United States of America.

ABSTRACT

Background: The Sri Lankan Anti-Filariasis Campaign conducted 5 rounds of mass drug administration (MDA) with diethycarbamazine plus albendazole between 2002 and 2006. We now report results of a comprehensive surveillance program that assessed the lymphatic filariasis (LF) situation in Sri Lanka 6 years after cessation of MDA.

Methodology and principal findings: Transmission assessment surveys (TAS) were performed per WHO guidelines in primary school children in 11 evaluation units (EUs) in all 8 formerly endemic districts. All EUs easily satisfied WHO criteria for stopping MDA. Comprehensive surveillance was performed in 19 Public Health Inspector (PHI) areas (subdistrict health administrative units). The surveillance package included cross-sectional community surveys for microfilaremia (Mf) and circulating filarial antigenemia (CFA), school surveys for CFA and anti-filarial antibodies, and collection of Culex mosquitoes with gravid traps for detection of filarial DNA (molecular xenomonitoring, MX). Provisional target rates for interruption of LF transmission were community CFA <2%, antibody in school children <2%, and filarial DNA in mosquitoes <0.25%. Community Mf and CFA prevalence rates ranged from 0-0.9% and 0-3.4%, respectively. Infection rates were significantly higher in males and lower in people who denied prior treatment. Antibody rates in school children exceeded 2% in 10 study sites; the area that had the highest community and school CFA rates also had the highest school antibody rate (6.9%). Filarial DNA rates in mosquitoes exceeded 0.25% in 10 PHI areas.

Conclusions: Comprehensive surveillance is feasible for some national filariasis elimination programs. Low-level persistence of LF was present in all study sites; several sites failed to meet provisional endpoint criteria for LF elimination, and follow-up testing will be needed in these areas. TAS was not sensitive for detecting low-level persistence of filariasis in Sri Lanka. We recommend use of antibody and MX testing as tools to complement TAS for post-MDA surveillance.

No MeSH data available.


Related in: MedlinePlus

Graphic summary of comprehensive filariasis surveillance data for Public Health Inspector areas in Sri Lanka.Data shown are rates (% with 95% confidence limits as vertical lines). The dotted line in the top panel and the lower dotted lines in the two lower panels show the old provisional targets for interruption of transmission. The upper dotted lines in the two lower panels are recommended revised targets for the upper confidence limits for antibody rates in first and second grade primary school children and for filarial DNA rates in mosquitoes, respectively.
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pntd-0003281-g001: Graphic summary of comprehensive filariasis surveillance data for Public Health Inspector areas in Sri Lanka.Data shown are rates (% with 95% confidence limits as vertical lines). The dotted line in the top panel and the lower dotted lines in the two lower panels show the old provisional targets for interruption of transmission. The upper dotted lines in the two lower panels are recommended revised targets for the upper confidence limits for antibody rates in first and second grade primary school children and for filarial DNA rates in mosquitoes, respectively.

Mentions: Nineteen PHI surveys were conducted in 8 districts and in Colombo town between March 2011 and July 2013. Demographic information for survey participants is provided in Table 1, and results are summarized in Table 2 and Figure 1. Community CFA rates were <2% in 17 of 19 PHIs, but upper confidence limits for CFA were >2% in 5 of 19 PHIs. Microfilaremia rates were <1% in all PHI areas studied. Sixteen of 65 CFA-positive subjects (age range 23–70 yr) were positive for Mf (mean count 14 per 60 µl range 1–51), and 68% of Mf carriers were males. The Unawatuna PHI area in Galle district had the highest rates for several filariasis parameters (Table 2 and Figure 1).


A comprehensive assessment of lymphatic filariasis inSri Lanka six years after cessation of mass drug administration.

Rao RU, Nagodavithana KC, Samarasekera SD, Wijegunawardana AD, Premakumara WD, Perera SN, Settinayake S, Miller JP, Weil GJ - PLoS Negl Trop Dis (2014)

Graphic summary of comprehensive filariasis surveillance data for Public Health Inspector areas in Sri Lanka.Data shown are rates (% with 95% confidence limits as vertical lines). The dotted line in the top panel and the lower dotted lines in the two lower panels show the old provisional targets for interruption of transmission. The upper dotted lines in the two lower panels are recommended revised targets for the upper confidence limits for antibody rates in first and second grade primary school children and for filarial DNA rates in mosquitoes, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4230885&req=5

pntd-0003281-g001: Graphic summary of comprehensive filariasis surveillance data for Public Health Inspector areas in Sri Lanka.Data shown are rates (% with 95% confidence limits as vertical lines). The dotted line in the top panel and the lower dotted lines in the two lower panels show the old provisional targets for interruption of transmission. The upper dotted lines in the two lower panels are recommended revised targets for the upper confidence limits for antibody rates in first and second grade primary school children and for filarial DNA rates in mosquitoes, respectively.
Mentions: Nineteen PHI surveys were conducted in 8 districts and in Colombo town between March 2011 and July 2013. Demographic information for survey participants is provided in Table 1, and results are summarized in Table 2 and Figure 1. Community CFA rates were <2% in 17 of 19 PHIs, but upper confidence limits for CFA were >2% in 5 of 19 PHIs. Microfilaremia rates were <1% in all PHI areas studied. Sixteen of 65 CFA-positive subjects (age range 23–70 yr) were positive for Mf (mean count 14 per 60 µl range 1–51), and 68% of Mf carriers were males. The Unawatuna PHI area in Galle district had the highest rates for several filariasis parameters (Table 2 and Figure 1).

Bottom Line: Infection rates were significantly higher in males and lower in people who denied prior treatment.Low-level persistence of LF was present in all study sites; several sites failed to meet provisional endpoint criteria for LF elimination, and follow-up testing will be needed in these areas.We recommend use of antibody and MX testing as tools to complement TAS for post-MDA surveillance.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine, Infectious Diseases Division, Washington University School of Medicine, St. Louis, Missouri, United States of America.

ABSTRACT

Background: The Sri Lankan Anti-Filariasis Campaign conducted 5 rounds of mass drug administration (MDA) with diethycarbamazine plus albendazole between 2002 and 2006. We now report results of a comprehensive surveillance program that assessed the lymphatic filariasis (LF) situation in Sri Lanka 6 years after cessation of MDA.

Methodology and principal findings: Transmission assessment surveys (TAS) were performed per WHO guidelines in primary school children in 11 evaluation units (EUs) in all 8 formerly endemic districts. All EUs easily satisfied WHO criteria for stopping MDA. Comprehensive surveillance was performed in 19 Public Health Inspector (PHI) areas (subdistrict health administrative units). The surveillance package included cross-sectional community surveys for microfilaremia (Mf) and circulating filarial antigenemia (CFA), school surveys for CFA and anti-filarial antibodies, and collection of Culex mosquitoes with gravid traps for detection of filarial DNA (molecular xenomonitoring, MX). Provisional target rates for interruption of LF transmission were community CFA <2%, antibody in school children <2%, and filarial DNA in mosquitoes <0.25%. Community Mf and CFA prevalence rates ranged from 0-0.9% and 0-3.4%, respectively. Infection rates were significantly higher in males and lower in people who denied prior treatment. Antibody rates in school children exceeded 2% in 10 study sites; the area that had the highest community and school CFA rates also had the highest school antibody rate (6.9%). Filarial DNA rates in mosquitoes exceeded 0.25% in 10 PHI areas.

Conclusions: Comprehensive surveillance is feasible for some national filariasis elimination programs. Low-level persistence of LF was present in all study sites; several sites failed to meet provisional endpoint criteria for LF elimination, and follow-up testing will be needed in these areas. TAS was not sensitive for detecting low-level persistence of filariasis in Sri Lanka. We recommend use of antibody and MX testing as tools to complement TAS for post-MDA surveillance.

No MeSH data available.


Related in: MedlinePlus