Identification of Risk Areas for Intestinal Schistosomiasis, Based on Malacological and Environmental Data and on Reported Human Cases

Coelho, Paulo Ricardo Silva; Ker, Fabrício T. O; Araújo, Amanda Domingues de; Guimarães, Ricardo José de Paula Souza e; Negrão-Corrêa, Déborah; Caldeira, Roberta Lima; Geiger, Stefan Michael

doi:10.3389/fmed.2021.642348

Cited by 7 publications

(8 citation statements)

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“…(Ampullaridae); 767 omphalaria (Planorbidae). In the latter case, more detailed data were previously pub [37], with the following species identified: Biomphalaria glabrata (Say, 1818), Biomp tenagophila (d'Orbigny, 1835), Biomphalaria straminea (Dunker, 1848), Biomphalaria ku (Clessin, 1883), and Biomphalaria cousini (Paraense, 1966) (Figures 1 and 2). (Moricand, 1839) (Planorbidae); 44 as Omalonyx d'Orbigny, 1837 (Succinidae); 16 as Pseudosuccinea columella (Say, 1817) (Lymnaeidae); 8 as Pomacea sp.…”

Section: Resultsmentioning

confidence: 94%

Survey on Limnic Gastropods: Relationships between Human Health and Conservation

et al. 2022

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The present work aimed to study ecological aspects related to the distribution pattern of medically important and native freshwater mollusks, found in a rural municipality in the state of Minas Gerais, Brazil. Malacological captures were carried out in aquatic environments (lentic and lotic) from 46 locations between October 2018 and September 2019. The collected specimens were subjected to taxonomic identification and evaluation for infection with trematode larvae. Qualitative data were used to analyze the similarity and the odds ratios between the environmental variables. In total, 1125 specimens were sampled, belonging to the following species: Biomphalaria glabrata, B. tenagophila, B. straminea, B. kuhniana, B. cousini, Biomphalaria sp., and Drepanotrema cimex (Planorbidae), Stenophysa marmorata (Physidae), Omalonyx sp. (Succineidae), Pseudosuccinea columella (Lymnaeidae), and Pomacea sp. (Ampullaridae). Echinostome, strigeocercaria, and xiphidiocercaria types of larval trematodes were detected in S. marmorata and D. cimex. Of note was the similarity in the distribution of S. marmorata, a supposedly endangered species, with that of the medically important Biomphalaria species, with the two sharing environments. This complex scenario led us to reflect on and discuss the need for the control of important intermediate hosts, as well as the conservation of endangered species. This relevant issue has not yet been discussed in detail, in Brazil or in other countries that recommend snail control.

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Section: Resultsmentioning

confidence: 94%

Survey on Limnic Gastropods: Relationships between Human Health and Conservation

et al. 2022

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“…Nevertheless, echinostome cercariae were not found among 767 specimens of Biomphalaria spp. (including B. glabrata) collected in Alvorada de Minas (Coelho et al, 2021), the type locality of E. maldonadoi n. sp., which may suggest that E. paraensei and E. maldonadoi n. sp.…”

Section: Discussionmentioning

confidence: 99%

“…Details of malacological techniques and preliminary evaluation of infection with larval trematodes are as described in Coelho et al . ( 2021 , 2022 ). The infected snail was sent to the laboratory for further parasite identification.…”

Section: Methodsmentioning

confidence: 99%

“…The isolate of the parasite evaluated in this study was obtained from a specimen of S. marmorata collected in the municipality of Alvorada de Minas, Minas Gerais, Brazil, in February 2019 during a malacological survey focused on the epidemiology of schistosomiasis. Details of malacological techniques and preliminary evaluation of infection with larval trematodes are as described in Coelho et al (2021Coelho et al ( , 2022. The infected snail was sent to the laboratory for further parasite identification.…”

Section: Sampling and Experimental Infectionmentioning

confidence: 99%

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A new cryptic species of Echinostoma (Trematoda: Echinostomatidae) closely related to Echinostoma paraensei found in Brazil

et al. 2023

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Echinostoma paraensei, described in Brazil at the end of the 1960s and used as a biological model for a range of studies, belongs to the ‘revolutum’ complex of Echinostoma comprising species with 37 collar spines. However, molecular data are available only for a few isolates maintained under laboratory conditions, with molecular prospecting based on specimens originating from naturally infected hosts virtually lacking. The present study describes Echinostoma maldonadoi Valadão, Alves & Pinto n. sp., a species cryptically related to E. paraensei found in Brazil. Larval stages (cercariae, metacercariae and rediae) of the new species were found in the physid snail Stenophysa marmorata in the State of Minas Gerais, Brazil, the same geographical area where E. paraensei was originally described. Adult parasites obtained experimentally in Meriones unguiculatus were used for morphological (optical microscopy) and molecular [28S, internal transcribed spacer (ITS), nad1 and cox1] characterization. The morphology of larval and adult parasites (most notable the small-sized dorsal spines in the head collar), associated with low (0–0.1%) molecular divergence for 28S gene or ITS region, and only moderate divergence for the mitochondrial cox1 gene (3.83%), might suggest that the newly collected specimens should be assigned to E. paraensei. However, higher genetic divergence (6.16–6.39%) was found in the mitochondrial nad1, revealing that it is a genetically distinct, cryptic lineage. In the most informative phylogenetic reconstruction, based on nad1, E. maldonadoi n. sp. exhibited a strongly supported sister relationship with E. paraensei, which may indicate a very recent speciation event giving rise to these 2 species.

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“…Malacological surveys for the presence of the intermediate snail host and schistosomiasis infections in snails are a common schistosomiasis surveillance tool used in endemic countries worldwide [5][6][7][8][9][10][11][12]. Schistosomiasis transmission is highly influenced by environmental conditions, as the presence of an infected intermediate snail host is a necessary precondition for transmission to humans and other vertebrate hosts [13].…”

Section: Introductionmentioning

confidence: 99%

Open-source environmental data as an alternative to snail surveys to assess schistosomiasis risk in areas approaching elimination

et al. 2023

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Background Although the presence of intermediate snails is a necessary condition for local schistosomiasis transmission to occur, using them as surveillance targets in areas approaching elimination is challenging because the patchy and dynamic quality of snail host habitats makes collecting and testing snails labor-intensive. Meanwhile, geospatial analyses that rely on remotely sensed data are becoming popular tools for identifying environmental conditions that contribute to pathogen emergence and persistence. Methods In this study, we assessed whether open-source environmental data can be used to predict the presence of human Schistosoma japonicum infections among households with a similar or improved degree of accuracy compared to prediction models developed using data from comprehensive snail surveys. To do this, we used infection data collected from rural communities in Southwestern China in 2016 to develop and compare the predictive performance of two Random Forest machine learning models: one built using snail survey data, and one using open-source environmental data. Results The environmental data models outperformed the snail data models in predicting household S. japonicum infection with an estimated accuracy and Cohen’s kappa value of 0.89 and 0.49, respectively, in the environmental model, compared to an accuracy and kappa of 0.86 and 0.37 for the snail model. The Normalized Difference in Water Index (an indicator of surface water presence) within half to one kilometer of the home and the distance from the home to the nearest road were among the top performing predictors in our final model. Homes were more likely to have infected residents if they were further from roads, or nearer to waterways. Conclusion Our results suggest that in low-transmission environments, leveraging open-source environmental data can yield more accurate identification of pockets of human infection than using snail surveys. Furthermore, the variable importance measures from our models point to aspects of the local environment that may indicate increased risk of schistosomiasis. For example, households were more likely to have infected residents if they were further from roads or were surrounded by more surface water, highlighting areas to target in future surveillance and control efforts.

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Identification of Risk Areas for Intestinal Schistosomiasis, Based on Malacological and Environmental Data and on Reported Human Cases

Cited by 7 publications

References 48 publications

Survey on Limnic Gastropods: Relationships between Human Health and Conservation

Survey on Limnic Gastropods: Relationships between Human Health and Conservation

A new cryptic species of Echinostoma (Trematoda: Echinostomatidae) closely related to Echinostoma paraensei found in Brazil

Open-source environmental data as an alternative to snail surveys to assess schistosomiasis risk in areas approaching elimination

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