Mapping the Risk of Soil-Transmitted Helminthic Infections in the Philippines

Magalhães, Ricardo J. Soares; Salamat, Maria Sonia S.; Leonardo, Lydia; Gray, Darren J.; Carabin, Hélène; Halton, Kate; McManus, Donald P.; Williams, Gail M.; Rivera, Pilarita T.; Saniel, Ofelia P.; Hernandez, Leda; Yakob, Laith; McGarvey, Stephen T.; Clements, Archie C. A.

doi:10.1371/journal.pntd.0003915

Cited by 38 publications

(61 citation statements)

References 23 publications

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“…Two papers (3%) quantified the uncertainty arising due to questionnaires data, as well as the uncertainty arising due to combining age-groups in the predictions [71,101]. Regarding diagnostic techniques, two studies (3%) addressed diagnostic uncertainty by modelling sensitivity and specificity as random variables, specified as beta distributions, and quantified as posterior credible intervals [76,87]. …”

Section: Resultsmentioning

confidence: 99%

Mapping Soil Transmitted Helminths and Schistosomiasis under Uncertainty: A Systematic Review and Critical Appraisal of Evidence

et al. 2016

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BackgroundSpatial modelling of STH and schistosomiasis epidemiology is now commonplace. Spatial epidemiological studies help inform decisions regarding the number of people at risk as well as the geographic areas that need to be targeted with mass drug administration; however, limited attention has been given to propagated uncertainties, their interpretation, and consequences for the mapped values. Using currently published literature on the spatial epidemiology of helminth infections we identified: (1) the main uncertainty sources, their definition and quantification and (2) how uncertainty is informative for STH programme managers and scientists working in this domain.Methodology/Principal FindingsWe performed a systematic literature search using the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) protocol. We searched Web of Knowledge and PubMed using a combination of uncertainty, geographic and disease terms. A total of 73 papers fulfilled the inclusion criteria for the systematic review. Only 9% of the studies did not address any element of uncertainty, while 91% of studies quantified uncertainty in the predicted morbidity indicators and 23% of studies mapped it. In addition, 57% of the studies quantified uncertainty in the regression coefficients but only 7% incorporated it in the regression response variable (morbidity indicator). Fifty percent of the studies discussed uncertainty in the covariates but did not quantify it. Uncertainty was mostly defined as precision, and quantified using credible intervals by means of Bayesian approaches.Conclusion/SignificanceNone of the studies considered adequately all sources of uncertainties. We highlighted the need for uncertainty in the morbidity indicator and predictor variable to be incorporated into the modelling framework. Study design and spatial support require further attention and uncertainty associated with Earth observation data should be quantified. Finally, more attention should be given to mapping and interpreting uncertainty, since they are relevant to inform decisions regarding the number of people at risk as well as the geographic areas that need to be targeted with mass drug administration.

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Section: Resultsmentioning

confidence: 99%

Mapping Soil Transmitted Helminths and Schistosomiasis under Uncertainty: A Systematic Review and Critical Appraisal of Evidence

et al. 2016

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“…Unlike global regression approaches which have often been used in previous studies, e.g. [17,[39][40][41], the model presented in this study has the advantage of estimating spatially varying effects of risk factors. These alleviate common challenges that could lead to wrong conclusions in epidemiological research.…”

Section: Discussionmentioning

confidence: 99%

Poisson-Gamma Mixture Spatially Varying Coefficient Modeling of Small-Area Intestinal Parasites Infection<strong> </strong>

Osei¹,

Stein²,

Ofosu

2018

Preprint

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Understanding the spatially varying effects of demographic factors on the spatio-temporal variation of intestinal parasites infections is important for public health intervention and monitoring. This paper presents a hierarchical Bayesian spatially varying coefficient model to evaluate the effects demographic factors on intestinal parasites morbidities in Ghana. The modeling relied on morbidity data collected by the District Health Information Management Systems. We developed Poisson and Poisson-gamma spatially varying coefficient Models. We used the demographic factors, unsafe drinking water, unsafe toilet and unsafe liquid waste disposal as model covariates. The models were fitted using the Integrated Nested Laplace Approximations (INLA). The overall risk of intestinal parasites infection was estimated to be 10.9 per 100 people with a wide spatial variation in the district-specific posterior risk estimates. Substantial spatial variation of increasing multiplicative effects of unsafe drinking water, unsafe toilet and unsafe liquid waste disposal occurs on the variation of intestinal parasites risk. The structured residual spatial variation widely dominates the unstructured component, suggesting that the unaccounted-for risk factors are spatially continuous in nature. The study concludes that both the spatial distribution of the posterior risk and the associated exceedance probability maps are essential for monitoring and control of intestinal parasites.

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“…In soil of city outskirt areas, eggs of Taeniidae, Uncinaria and cocoons of Dipylidium caninum were found more often than in the city, and eggs of Trichocephalus were found more often in samples of soils from territories of the city. The highest concentration of eggs of helminths in the studied zones was observed in places for walking animals (Avcioglu & Balkaya, 2011;Karagiannis-Voules et al, 2014;Soares Magalhães et al, 2015). Through analysis of logistic regression, it was determined that age, environment and diet are determining risk factors of infestation of animals with the feline helminth Тoxoplasma gondii (Lopes et al, 2008).…”

Section: Introductionmentioning

confidence: 92%

Contamination of urbanized territories with eggs of helmiths of animals

et al. 2019

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The large number of species which cause parasitic infestations and the wide variety of routes and factors of their transmission give great relevance to systematic veterinary-sanitary research into environmental objects, necessarily paying attention to local natural-climatic conditions, social structure and the activities of the population. This problem is most often studied by medical researchers and ecologists, and the extent of studies on this topic from a veterinary-sanitary point of view is insufficient, which conditioned our choice of the current scientific study. Our goal was determining the level of contamination of urbanized territories with exogenous forms of helminths. The research was conducted during 2010–2018 in the territory of Kharkiv Oblast of Ukraine. During the study, we examined 41 samples of soil, extracted both in rural areas, and in urban conditions, and also 100 samples of feces of animals and birds. During the examination of soil from rural areas in Kharkiv Oblast and soil in Kharkiv and Balakleia, we found that it was contaminated with eggs of helminths of different morphotypes. It was determined that mean level of contamination of soil in rural area equaled 12.5%. At the same time, the level of contamination of soil of river banks was 15% at intensity of 52 ± 5 eggs/kg of soil and 10.0% in meadows at intensity of 54 ± 8 eggs/kg of soil. The level of contamination of the soil of park zones of urbanized territories with exogenous stages of helminths was 5–55% and that of residential zones of cities was 20.0–23.3%. In general, in the samples of soil, eggs of Strongilata, Ascaridata, Trichocephalus and Cestoda were isolated, and in the soil of rural areas also eggs of Trematoda class. It was proved that cattle and small ruminants discharge feces into the environment which have highest number of eggs of Strongylata spp. helminths (285 ± 3 eggs/g of feces). Excrement of infested birds contaminate the environment with exogenous forms of helminths of Trichocephalata (Capillaria spp.) suborder (101 ± 7 eggs/g of feces). In cities, dogs and cats, infested with helminths, discharge into the environment feces with eggs of parasites that belong to Toxocara spp. (75 ± 4 eggs/g) and Dipylidium caninum (6 ± 1 eggs/g). Droppings of infested birds contaminate the environment with exogenous forms of helminthes of Strongylata spp. (57 ± 2 eggs/g), Аscaridia spp. (19 ± 4 eggs/g) and Capillaria spp. (11 ± 2 eggs/g).

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Mapping the Risk of Soil-Transmitted Helminthic Infections in the Philippines

Cited by 38 publications

References 23 publications

Mapping Soil Transmitted Helminths and Schistosomiasis under Uncertainty: A Systematic Review and Critical Appraisal of Evidence

Mapping Soil Transmitted Helminths and Schistosomiasis under Uncertainty: A Systematic Review and Critical Appraisal of Evidence

Poisson-Gamma Mixture Spatially Varying Coefficient Modeling of Small-Area Intestinal Parasites Infection<strong> </strong>

Contamination of urbanized territories with eggs of helmiths of animals

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