Spatial Variation in Risk Factors of Lymphatic Filariasis in Hotspot Zones in Ghana

Abstract

Lymphatic Filariasis (LF), a parasitic nematode infection, often resulting in disability poses huge economic burden to affected countries. To meet eradication deadlines in line with the global Neglected Tropical Diseases elimination and health system strengthening goals, novel strategies are needed to complement existing approaches. LF endemicity is localized and prevalence, spatially heterogeneous. Species distribution models (SDMs) can help identify subtle differences in risk factors that influences the transmission of LF in geographically distinct regions. Thus in this contribution, presence absence records of microfilaria (m)f in Ghana were stratified into Northern and Southern Zones and used to run SDMs, whilst climate, socioeconomic and land coverage variables provided explanation information. GLM (Generalized Linear model), GBM (Generalized Boosted Model), ANN (Artificial Neural Network), SRE (Surface Range Envelope), MARS (Multivariate Adaptive Regression Splines) and RF (Random Forests) algorithms were run for both study zones and also for the entire country for the purpose of comparison. Best model quality was obtained with RF and GBM algorithms with highest AUC between 0.98 and 0.95, respectively. The models predicted high suitable environments for LF transmission in the short grass savanna areas in the northern and along the coastal southern parts of Ghana. Mainly, land cover and socioeconomic variables such as, proximity to inland waterbodies and population density uniquely influenced LF transmission in the South while poor housing was a distinctive risk factors in the North. Precipitation, temperature, slope and poverty were common risk factors but with subtle variations in response values, which was confirmed by the countrywide model. This study has demonstrated that, an understanding of the geographic distinctness in risk factors is required to inform the development of area-specific transmission control systems towards LF elimination in Ghana and internationally.

Predictive risk mapping of lymphatic filariasis residual hotspots in American Samoa using demographic and environmental factors

“…These covariates may be associated with heterogeneous exposure to mosquito bites. In areas where the parasite is transmitted predominantly by night-biting mosquitos, clustering of infection around household locations can be expected and has been demonstrated (29,32,44). The results of this study support recent evidence that the home environment may be also an important area for exposure in LF-endemic regions where W. Bancrofti is transmitted by the day-biting mosquito, Ae.…”

“…We downloaded and assembled spatial and environmental data that have been found to be associated with the geographical distribution of LF in other endemic regions (23,(29)(30)(31)(32). The boundary administrative maps and the covariate data consider for the analyses were derived from the following datasets: i) Village boundaries and buildings.…”

Cultural conceptualisations and spatial cognition in Ghanaian English

“…There were 18 pictures that showed 18 different potential scopes of use of each of the prepositions under investigation (in, on, at) on the picture description task. The pictures that were selected from the internet largely modelled the Topological Relations Picture Series (TRPS) developed by Bowerman and Pederson (1992) and adapted by Kwarteng (2020) to the Ghanaian context. The 18 selected pictures depicted a range of spatial arrangements that involve attributes of contact, support, containment and co-location of different kinds.…”

“…However, there is a paucity of literature on the ways cultural conceptualisations influence grammatical categories such as prepositions. Apart from Kwarteng (2020), who discussed spatial preposition use in the Ghanaian language from a cognitive grammar perspective, SLA research on Ghanaian English grammar has often described grammatical differences or unconventional usage in terms of errors (Owu-Ewie & Williams, 2017). This article employs the mixed-methods approach and Cultural Linguistics assumptions to examine spatial prepositional usage in Ghanaian English.…”