Limits...
Hypo-endemic onchocerciasis hotspots: defining areas of high risk through micro-mapping and environmental delineation.

Kelly-Hope LA, Unnasch TR, Stanton MC, Molyneux DH - Infect Dis Poverty (2015)

Bottom Line: Second we show that integrated micro-mapping of prevalence data, and the use of environmental data to delineate riverine and forest risk factors associated with Simulium spp. and Chrysops spp. vector habitats can further help to define target intervention areas i.e. secondary hotspots within hotspots, to help avoid the risk of SAEs.These mapping examples demonstrate the value of bringing prevalence, entomological and ecological information together to develop maps for planned implementation and targeted strategies.This is critical as better mapping may the reduce costs and lower the L. loa associated risks, especially if there are extensive areas of low endemicity that may require treatment with ivermectin or alternative strategies.

View Article: PubMed Central - PubMed

Affiliation: Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA UK.

ABSTRACT

Background: Onchocerciasis (river blindness) caused by the parasite Onchocercavolvulus and transmitted by riverine Simulium spp. (Black flies) is targeted for elimination in Africa. This is a significant change in strategy from the 'control' of meso- and hyper-endemic areas through mass drug administration (MDA) with Mectizan® (ivermectin), to the 'elimination' in all endemic areas where a range of interventions may be required. The most significant challenges of elimination in low transmission or hypo-endemic areas are two-fold. First, there are vast remote areas where the focality of low transmission is relatively undefined. Second, the treatment with ivermectin increases the risk of serious adverse events (SAEs) in individuals with high parasitaemias of Loa loa, a filarial parasite widespread in Central and West Africa, which causes Tropical eye worm and transmitted by Chrysops spp. (Deer flies).

Discussion: We therefore propose novel mapping approaches using remote sensing satellite and modelled environmental data to be used in combination with rapid field surveys to help resolve the problems of targeting the expansion of onchocerciasis elimination activities in L. loa co-endemic areas. First, we demonstrate that micro-stratification overlap mapping (MOM) of available onchocerciasis and loiasis prevalence maps can be used to identify 12 key high risk areas, where low O. volvulusand high L. loa transmission overlap, which we define as "hypo-endemic hotspots". Second we show that integrated micro-mapping of prevalence data, and the use of environmental data to delineate riverine and forest risk factors associated with Simulium spp. and Chrysops spp. vector habitats can further help to define target intervention areas i.e. secondary hotspots within hotspots, to help avoid the risk of SAEs.

Summary: These mapping examples demonstrate the value of bringing prevalence, entomological and ecological information together to develop maps for planned implementation and targeted strategies. This is critical as better mapping may the reduce costs and lower the L. loa associated risks, especially if there are extensive areas of low endemicity that may require treatment with ivermectin or alternative strategies. Novel cost-effective approaches are necessary if elimination of O.volvulus transmission in Africa is to be achieved in an efficient and safe way by the goal of 2025.

No MeSH data available.


Related in: MedlinePlus

An example of micro-mapping and environmental delineation in Bas Congo, Democratic Republic of Congo
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4537576&req=5

Fig2: An example of micro-mapping and environmental delineation in Bas Congo, Democratic Republic of Congo

Mentions: The specific steps we have undertaken to develop these new strategies for ‘hypo-endemic hotspots’ in Central and West Africa are outlined below in bullet form in relation to Figs. 1 and 2, which were developed using GIS software ArcGIS 10 (ESRI, Redlands, CA).Fig. 1


Hypo-endemic onchocerciasis hotspots: defining areas of high risk through micro-mapping and environmental delineation.

Kelly-Hope LA, Unnasch TR, Stanton MC, Molyneux DH - Infect Dis Poverty (2015)

An example of micro-mapping and environmental delineation in Bas Congo, Democratic Republic of Congo
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4537576&req=5

Fig2: An example of micro-mapping and environmental delineation in Bas Congo, Democratic Republic of Congo
Mentions: The specific steps we have undertaken to develop these new strategies for ‘hypo-endemic hotspots’ in Central and West Africa are outlined below in bullet form in relation to Figs. 1 and 2, which were developed using GIS software ArcGIS 10 (ESRI, Redlands, CA).Fig. 1

Bottom Line: Second we show that integrated micro-mapping of prevalence data, and the use of environmental data to delineate riverine and forest risk factors associated with Simulium spp. and Chrysops spp. vector habitats can further help to define target intervention areas i.e. secondary hotspots within hotspots, to help avoid the risk of SAEs.These mapping examples demonstrate the value of bringing prevalence, entomological and ecological information together to develop maps for planned implementation and targeted strategies.This is critical as better mapping may the reduce costs and lower the L. loa associated risks, especially if there are extensive areas of low endemicity that may require treatment with ivermectin or alternative strategies.

View Article: PubMed Central - PubMed

Affiliation: Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA UK.

ABSTRACT

Background: Onchocerciasis (river blindness) caused by the parasite Onchocercavolvulus and transmitted by riverine Simulium spp. (Black flies) is targeted for elimination in Africa. This is a significant change in strategy from the 'control' of meso- and hyper-endemic areas through mass drug administration (MDA) with Mectizan® (ivermectin), to the 'elimination' in all endemic areas where a range of interventions may be required. The most significant challenges of elimination in low transmission or hypo-endemic areas are two-fold. First, there are vast remote areas where the focality of low transmission is relatively undefined. Second, the treatment with ivermectin increases the risk of serious adverse events (SAEs) in individuals with high parasitaemias of Loa loa, a filarial parasite widespread in Central and West Africa, which causes Tropical eye worm and transmitted by Chrysops spp. (Deer flies).

Discussion: We therefore propose novel mapping approaches using remote sensing satellite and modelled environmental data to be used in combination with rapid field surveys to help resolve the problems of targeting the expansion of onchocerciasis elimination activities in L. loa co-endemic areas. First, we demonstrate that micro-stratification overlap mapping (MOM) of available onchocerciasis and loiasis prevalence maps can be used to identify 12 key high risk areas, where low O. volvulusand high L. loa transmission overlap, which we define as "hypo-endemic hotspots". Second we show that integrated micro-mapping of prevalence data, and the use of environmental data to delineate riverine and forest risk factors associated with Simulium spp. and Chrysops spp. vector habitats can further help to define target intervention areas i.e. secondary hotspots within hotspots, to help avoid the risk of SAEs.

Summary: These mapping examples demonstrate the value of bringing prevalence, entomological and ecological information together to develop maps for planned implementation and targeted strategies. This is critical as better mapping may the reduce costs and lower the L. loa associated risks, especially if there are extensive areas of low endemicity that may require treatment with ivermectin or alternative strategies. Novel cost-effective approaches are necessary if elimination of O.volvulus transmission in Africa is to be achieved in an efficient and safe way by the goal of 2025.

No MeSH data available.


Related in: MedlinePlus