Status of Onchocerciasis transmission after more than a decade of mass drug administration for onchocerciasis and lymphatic filariasis elimination in central Nigeria: challenges in coordinating the stop MDA decision.
This study was undertaken in five onchocerciasis/lymphatic filariasis (LF) co-endemic local government areas (LGAs) in Plateau and Nasarawa, Nigeria. Annual MDA with ivermectin had been given for 17 years, 8 of which were in combination with albendazole. In 2008, assessments indicated that LF transm...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2014-09-01
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| Series: | PLoS Neglected Tropical Diseases |
| Online Access: | http://europepmc.org/articles/PMC4169246?pdf=render |
| _version_ | 1811192114024808448 |
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| author | Darin S Evans Kal Alphonsus Jon Umaru Abel Eigege Emmanuel Miri Hayward Mafuyai Carlos Gonzales-Peralta William Adamani Elias Pede Christopher Umbugadu Yisa Saka Bridget Okoeguale Frank O Richards |
| author_facet | Darin S Evans Kal Alphonsus Jon Umaru Abel Eigege Emmanuel Miri Hayward Mafuyai Carlos Gonzales-Peralta William Adamani Elias Pede Christopher Umbugadu Yisa Saka Bridget Okoeguale Frank O Richards |
| author_sort | Darin S Evans |
| collection | DOAJ |
| description | This study was undertaken in five onchocerciasis/lymphatic filariasis (LF) co-endemic local government areas (LGAs) in Plateau and Nasarawa, Nigeria. Annual MDA with ivermectin had been given for 17 years, 8 of which were in combination with albendazole. In 2008, assessments indicated that LF transmission was interrupted, but that the MDA had to continue due to the uncertain status of onchocerciasis transmission. Accordingly, assessments to determine if ivermectin MDA for onchocerciasis could be stopped were conducted in 2009.We evaluated nodule, microfilarial (mf) skin snip, and antibody (IgG4 response to OV16) prevalence in adults and children in six sentinel sites where baseline data from the 1990s were available. We applied the 2001 WHO criteria for elimination of onchocerciasis that defined transmission interruption as an infection rate of <0.1% in children (using both skin snip and OV16 antibody) and a rate of infective (L3) blackflies of <0.05%.Among adult residents in sentinel sites, mean mf prevalence decreased by 99.37% from the 1991-1993 baseline of 42.95% (64/149) to 0.27% (2/739) in 2009 (p<0.001). The OV16 seropositivity of 3.52% (26/739) among this same group was over ten times the mf rate. No mf or nodules were detected in 4,451 children in sentinel sites and 'spot check' villages, allowing the exclusion of 0.1% infection rate with 95% confidence. Seven OV16 seropositives were detected, yielding a seroprevalence of 0.16% (0.32% upper 95%CI). No infections were detected in PCR testing of 1,568 Simulium damnosum s.l. flies obtained from capture sites around the six sentinel sites.Interruption of transmission of onchocerciasis in these five LGAs is highly likely, although the number of flies caught was insufficient to exclude 0.05% with 95% confidence (upper CI 0.23%). We suggest that ivermectin MDA could be stopped in these LGAs if similar results are seen in neighboring districts. |
| first_indexed | 2024-04-11T23:46:21Z |
| format | Article |
| id | doaj.art-2dab0611976240dbba16c0f537f44ef0 |
| institution | Directory Open Access Journal |
| issn | 1935-2727 1935-2735 |
| language | English |
| last_indexed | 2024-04-11T23:46:21Z |
| publishDate | 2014-09-01 |
| publisher | Public Library of Science (PLoS) |
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| series | PLoS Neglected Tropical Diseases |
| spelling | doaj.art-2dab0611976240dbba16c0f537f44ef02022-12-22T03:56:37ZengPublic Library of Science (PLoS)PLoS Neglected Tropical Diseases1935-27271935-27352014-09-0189e311310.1371/journal.pntd.0003113Status of Onchocerciasis transmission after more than a decade of mass drug administration for onchocerciasis and lymphatic filariasis elimination in central Nigeria: challenges in coordinating the stop MDA decision.Darin S EvansKal AlphonsusJon UmaruAbel EigegeEmmanuel MiriHayward MafuyaiCarlos Gonzales-PeraltaWilliam AdamaniElias PedeChristopher UmbugaduYisa SakaBridget OkoegualeFrank O RichardsThis study was undertaken in five onchocerciasis/lymphatic filariasis (LF) co-endemic local government areas (LGAs) in Plateau and Nasarawa, Nigeria. Annual MDA with ivermectin had been given for 17 years, 8 of which were in combination with albendazole. In 2008, assessments indicated that LF transmission was interrupted, but that the MDA had to continue due to the uncertain status of onchocerciasis transmission. Accordingly, assessments to determine if ivermectin MDA for onchocerciasis could be stopped were conducted in 2009.We evaluated nodule, microfilarial (mf) skin snip, and antibody (IgG4 response to OV16) prevalence in adults and children in six sentinel sites where baseline data from the 1990s were available. We applied the 2001 WHO criteria for elimination of onchocerciasis that defined transmission interruption as an infection rate of <0.1% in children (using both skin snip and OV16 antibody) and a rate of infective (L3) blackflies of <0.05%.Among adult residents in sentinel sites, mean mf prevalence decreased by 99.37% from the 1991-1993 baseline of 42.95% (64/149) to 0.27% (2/739) in 2009 (p<0.001). The OV16 seropositivity of 3.52% (26/739) among this same group was over ten times the mf rate. No mf or nodules were detected in 4,451 children in sentinel sites and 'spot check' villages, allowing the exclusion of 0.1% infection rate with 95% confidence. Seven OV16 seropositives were detected, yielding a seroprevalence of 0.16% (0.32% upper 95%CI). No infections were detected in PCR testing of 1,568 Simulium damnosum s.l. flies obtained from capture sites around the six sentinel sites.Interruption of transmission of onchocerciasis in these five LGAs is highly likely, although the number of flies caught was insufficient to exclude 0.05% with 95% confidence (upper CI 0.23%). We suggest that ivermectin MDA could be stopped in these LGAs if similar results are seen in neighboring districts.http://europepmc.org/articles/PMC4169246?pdf=render |
| spellingShingle | Darin S Evans Kal Alphonsus Jon Umaru Abel Eigege Emmanuel Miri Hayward Mafuyai Carlos Gonzales-Peralta William Adamani Elias Pede Christopher Umbugadu Yisa Saka Bridget Okoeguale Frank O Richards Status of Onchocerciasis transmission after more than a decade of mass drug administration for onchocerciasis and lymphatic filariasis elimination in central Nigeria: challenges in coordinating the stop MDA decision. PLoS Neglected Tropical Diseases |
| title | Status of Onchocerciasis transmission after more than a decade of mass drug administration for onchocerciasis and lymphatic filariasis elimination in central Nigeria: challenges in coordinating the stop MDA decision. |
| title_full | Status of Onchocerciasis transmission after more than a decade of mass drug administration for onchocerciasis and lymphatic filariasis elimination in central Nigeria: challenges in coordinating the stop MDA decision. |
| title_fullStr | Status of Onchocerciasis transmission after more than a decade of mass drug administration for onchocerciasis and lymphatic filariasis elimination in central Nigeria: challenges in coordinating the stop MDA decision. |
| title_full_unstemmed | Status of Onchocerciasis transmission after more than a decade of mass drug administration for onchocerciasis and lymphatic filariasis elimination in central Nigeria: challenges in coordinating the stop MDA decision. |
| title_short | Status of Onchocerciasis transmission after more than a decade of mass drug administration for onchocerciasis and lymphatic filariasis elimination in central Nigeria: challenges in coordinating the stop MDA decision. |
| title_sort | status of onchocerciasis transmission after more than a decade of mass drug administration for onchocerciasis and lymphatic filariasis elimination in central nigeria challenges in coordinating the stop mda decision |
| url | http://europepmc.org/articles/PMC4169246?pdf=render |
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