The impact of mass drug administration expansion to low onchocerciasis prevalence settings in case of connected villages.
Background The existence of locations with low but stable onchocerciasis prevalence is not well understood. An often suggested yet poorly investigated explanation is that the infection spills over from neighbouring locations with higher infection densities. Methodology We adapted the stochastic indi...
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ftdoajarticles:oai:doaj.org/article:98966f87add840baac16c9af5404a3e9 2023-05-15T15:16:20+02:00 The impact of mass drug administration expansion to low onchocerciasis prevalence settings in case of connected villages. Anneke S de Vos Wilma A Stolk Luc E Coffeng Sake J de Vlas 2021-05-01T00:00:00Z https://doi.org/10.1371/journal.pntd.0009011 https://doaj.org/article/98966f87add840baac16c9af5404a3e9 EN eng Public Library of Science (PLoS) https://doi.org/10.1371/journal.pntd.0009011 https://doaj.org/toc/1935-2727 https://doaj.org/toc/1935-2735 1935-2727 1935-2735 doi:10.1371/journal.pntd.0009011 https://doaj.org/article/98966f87add840baac16c9af5404a3e9 PLoS Neglected Tropical Diseases, Vol 15, Iss 5, p e0009011 (2021) Arctic medicine. Tropical medicine RC955-962 Public aspects of medicine RA1-1270 article 2021 ftdoajarticles https://doi.org/10.1371/journal.pntd.0009011 2022-12-31T11:01:42Z Background The existence of locations with low but stable onchocerciasis prevalence is not well understood. An often suggested yet poorly investigated explanation is that the infection spills over from neighbouring locations with higher infection densities. Methodology We adapted the stochastic individual based model ONCHOSIM to enable the simulation of multiple villages, with separate blackfly (intermediate host) and human populations, which are connected through the regular movement of the villagers and/or the flies. With this model we explore the impact of the type, direction and degree of connectedness, and of the impact of localized or full-area mass drug administration (MDA) over a range of connected village settings. Principal findings In settings with annual fly biting rates (ABR) below the threshold needed for stable local transmission, persistence of onchocerciasis prevalence can well be explained by regular human traffic and/or fly movement from locations with higher ABR. Elimination of onchocerciasis will then theoretically be reached by only implementing MDA in the higher prevalence area, although lingering infection in the low prevalence location can trigger resurgence of transmission in the total region when MDA is stopped too soon. Expanding MDA implementation to the lower ABR location can therefore shorten the duration of MDA needed. For example, when prevalence spill-over is due to human traffic, and both locations have about equal populations, then the MDA duration can be shortened by up to three years. If the lower ABR location has twice as many inhabitants, the reduction can even be up to six years, but if spill-over is due to fly movement, the expected reduction is less than a year. Conclusions/significance Although MDA implementation might not always be necessary in locations with stable low onchocerciasis prevalence, in many circumstances it is recommended to accelerate achieving elimination in the wider area. Article in Journal/Newspaper Arctic Directory of Open Access Journals: DOAJ Articles Arctic PLOS Neglected Tropical Diseases 15 5 e0009011 |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
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English |
topic |
Arctic medicine. Tropical medicine RC955-962 Public aspects of medicine RA1-1270 |
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Arctic medicine. Tropical medicine RC955-962 Public aspects of medicine RA1-1270 Anneke S de Vos Wilma A Stolk Luc E Coffeng Sake J de Vlas The impact of mass drug administration expansion to low onchocerciasis prevalence settings in case of connected villages. |
topic_facet |
Arctic medicine. Tropical medicine RC955-962 Public aspects of medicine RA1-1270 |
description |
Background The existence of locations with low but stable onchocerciasis prevalence is not well understood. An often suggested yet poorly investigated explanation is that the infection spills over from neighbouring locations with higher infection densities. Methodology We adapted the stochastic individual based model ONCHOSIM to enable the simulation of multiple villages, with separate blackfly (intermediate host) and human populations, which are connected through the regular movement of the villagers and/or the flies. With this model we explore the impact of the type, direction and degree of connectedness, and of the impact of localized or full-area mass drug administration (MDA) over a range of connected village settings. Principal findings In settings with annual fly biting rates (ABR) below the threshold needed for stable local transmission, persistence of onchocerciasis prevalence can well be explained by regular human traffic and/or fly movement from locations with higher ABR. Elimination of onchocerciasis will then theoretically be reached by only implementing MDA in the higher prevalence area, although lingering infection in the low prevalence location can trigger resurgence of transmission in the total region when MDA is stopped too soon. Expanding MDA implementation to the lower ABR location can therefore shorten the duration of MDA needed. For example, when prevalence spill-over is due to human traffic, and both locations have about equal populations, then the MDA duration can be shortened by up to three years. If the lower ABR location has twice as many inhabitants, the reduction can even be up to six years, but if spill-over is due to fly movement, the expected reduction is less than a year. Conclusions/significance Although MDA implementation might not always be necessary in locations with stable low onchocerciasis prevalence, in many circumstances it is recommended to accelerate achieving elimination in the wider area. |
format |
Article in Journal/Newspaper |
author |
Anneke S de Vos Wilma A Stolk Luc E Coffeng Sake J de Vlas |
author_facet |
Anneke S de Vos Wilma A Stolk Luc E Coffeng Sake J de Vlas |
author_sort |
Anneke S de Vos |
title |
The impact of mass drug administration expansion to low onchocerciasis prevalence settings in case of connected villages. |
title_short |
The impact of mass drug administration expansion to low onchocerciasis prevalence settings in case of connected villages. |
title_full |
The impact of mass drug administration expansion to low onchocerciasis prevalence settings in case of connected villages. |
title_fullStr |
The impact of mass drug administration expansion to low onchocerciasis prevalence settings in case of connected villages. |
title_full_unstemmed |
The impact of mass drug administration expansion to low onchocerciasis prevalence settings in case of connected villages. |
title_sort |
impact of mass drug administration expansion to low onchocerciasis prevalence settings in case of connected villages. |
publisher |
Public Library of Science (PLoS) |
publishDate |
2021 |
url |
https://doi.org/10.1371/journal.pntd.0009011 https://doaj.org/article/98966f87add840baac16c9af5404a3e9 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
PLoS Neglected Tropical Diseases, Vol 15, Iss 5, p e0009011 (2021) |
op_relation |
https://doi.org/10.1371/journal.pntd.0009011 https://doaj.org/toc/1935-2727 https://doaj.org/toc/1935-2735 1935-2727 1935-2735 doi:10.1371/journal.pntd.0009011 https://doaj.org/article/98966f87add840baac16c9af5404a3e9 |
op_doi |
https://doi.org/10.1371/journal.pntd.0009011 |
container_title |
PLOS Neglected Tropical Diseases |
container_volume |
15 |
container_issue |
5 |
container_start_page |
e0009011 |
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