Distribution of schistosomiasis intermediate snail in Lore Lindu National Park, Central Sulawesi

Schistosomiasis in Indonesia is only found in three locations, namely the Napu Highland and the Bada Highland in Poso District and the Lindu Highland in Sigi District, Central Sulawesi Province. The disease is caused by Schistosoma japonicum with snail Oncomelania hupensis lindoensis as its intermediate host. The previous study found that almost all of this host snail foci area were distributed in the seepage water near the Lore Lindu National Park area. Unfortunately, there was no evidence whether O. h. lindoensis exists in the Lore Lindu National Park Area. The study aimed to map the focus areas of schistosomiasis intermediate host snails in the Lore Lindu National Park. The survey was conducted in February 2018, covering 12 villages belong to Napu Highland, Bada Highland, and Lindu Highland. Data collection included surveys on the snail habitat and the snail density. In both activities, geographic coordinates were determined using Global Positioning System (GPS). The results showed 14 foci areas of O. h. lindoensis were found in the buffer zone of Lore Lindu National Park.

High Prevalence of Urinary Schistosomiasis in a Desert Population: Results from an Exploratory Study Around the Ounianga Lakes in Chad

Background: Researching a water-borne disease in the middle of the Sahara desert might not seem the most relevant concern. However, nomadic Sahelian pastoralist’s health concerns regarding their livestock and anecdotal reports about trematode infections of Fasciola spp and Schistosoma spp in desert-raised animals justified an exploratory study focusing on the lakes of Ounianga in Northern Chad. The aim was to test whether trematode parasites such as Schistosoma spp occur in human populations living around the Sahara desert lakes of Ounianga Kebir and Ounianga Saker in northern Chad. Methods: The study comprised of three components. First, a cross sectional survey based on a random sample drawn from the population to detect infections with S. haematobium and S. mansoni ; second, focus group discussions exploring disease priorities, access to health and health seeking behaviour; and third, searching water contact sites for intermediate host snails. Samples of trematode parasites and snails were confirmed on species level by molecular genetics methods. Results: Among 258 participants, the overall S. haematobium prevalence using urine filtration was 39.1% (95% CI 33.2% – 45.1%), with 51.5% of the infected suffering from heavy infection. The intermediate host snail of S. haematobium ( Bulinus truncatus ) occurred at water sites near both study villages, revealing the potential for local transmission. Although a positive S. mansoni POC-CCA test result was obtained from 15.2% (10.6%-19.7%) of the samples no intermediate host snails of S. mansoni were found, and the relevance of S. mansoni remains uncertain. Qualitative findings underline the importance of morbidity caused by urinary schistosomiasis, and the lack of access to diagnostics and treatment as a major health concern. Conclusion: This research revealed a high prevalence of urinary schistosomiasis in the population living around the lakes of Ounianga in the Sahara, a UNESCO world heritage site in Chad. Despite the high public health importance of the associated morbidity expressed by the population there is no access to diagnostics and treatment. Further research is needed to develop and test a context adapted intervention.

Schistosome infection in Senegal is associated with different spatial extents of risk and ecological drivers for Schistosoma haematobium and S. mansoni

Schistosome parasites infect more than 200 million people annually, mostly in sub-Saharan Africa, where people may be co-infected with more than one species of the parasite. Infection risk for any single species is determined, in part, by the distribution of its obligate intermediate host snail. As the World Health Organization reprioritizes snail control to reduce the global burden of schistosomiasis, there is renewed importance in knowing when and where to target those efforts, which could vary by schistosome species. This study estimates factors associated with schistosomiasis risk in 16 villages located in the Senegal River Basin, a region hyperendemic for Schistosoma haematobium and S. mansoni. We first analyzed the spatial distributions of the two schistosomes’ intermediate host snails (Bulinus spp. and Biomphalaria pfeifferi, respectively) at village water access sites. Then, we separately evaluated the relationships between human S. haematobium and S. mansoni infections and (i) the area of remotely-sensed snail habitat across spatial extents ranging from 1 to 120 m from shorelines, and (ii) water access site size and shape characteristics. We compared the influence of snail habitat across spatial extents because, while snail sampling is traditionally done near shorelines, we hypothesized that snails further from shore also contribute to infection risk. We found that, controlling for demographic variables, human risk for S. haematobium infection was positively correlated with snail habitat when snail habitat was measured over a much greater radius from shore (45 m to 120 m) than usual. S. haematobium risk was also associated with large, open water access sites. However, S. mansoni infection risk was associated with small, sheltered water access sites, and was not positively correlated with snail habitat at any spatial sampling radius. Our findings highlight the need to consider different ecological and environmental factors driving the transmission of each schistosome species in co-endemic landscapes.

Risk factors of schistosomiasis and the health effect among patients attending Alkalakla Health Centre - Khartoum State-Sudan (2018)

Schistosomiasis (Bilharziasis) is the most prevalent parasitic disease after malaria in terms of socioeconomic and public health importance in the developing world and is listed as a Neglected Tropical disease (NTD). Objectives of the study are to identify the risk factors of schistosomiasis and its health effect among patients attending Algubba Health Center and Algalaa health Center in Al kalakla area (September 2017 to January 2018) to set recommendations according to the results. Methods and Material: - 150 patients were selected for the study by cross-sectional descriptive convenience study. Questionnaire is the main source of obtaining data & information. Data were entered and analyzed statistically using Statistical Package for Social Science (SPSS). Results: - The age group of the participants between (5 to 14) years old 64%, most of them are males 92%, educational level is secondary 80%, live in bricks houses 72. 7%, , the monthly income is medium (1000 to 2000 SD)41.3%, the family head are self-employed represents 54%, respondents have access to the house electricity constitute98%, about 32.7% of the study group live near to the river, regularly swim in the river constitute 93.3%, activities of respondents near the river for the swimming 49.3%. Most of the study population the symptoms appeared before one month 59.3%, suffer from urinary schistosomiasis 86.7%, the proportion of those who have negative health impacts due to schistosomiasis 45.3%, suffer from loss of weight.40% of population study are not agree that schistosomiasis associated with other diseases,96%of respondents have the knowledge about schistosomiasis, and 64% of them received the information from the health education program. In conclusions, it is clear that swimming, house near to the river, age sex (male), and loss of body weight is the most common health effects due to schistosomiasis. The researcher recommended: to the health authority that health education programs should be conducted for the community about sanitation practices (no urination and defecation in water sources), the school health programs should be activated in schools as risk group for adolescent boys, making an especial program for detection and treatment of sick people, and repeating & regular chemotherapy to those at risk of infection, control of the intermediate host snail should be continuing.

Fasciola hepatica larval development within the intermediate host.

This book chapter focuses on host snail species and larval behavior forms in snails, and features of parasitic infections in naturally or experimentally infected snails, or in coinfected snails.

Can Potamopyrgus antipodarum (Gastropoda) affect the prevalence of Trichobilharzia szidati in Lymnaea stagnalis populations?

Swimmer's itch is an emerging disease caused by bird schistosomes affecting people all over the world. Lymnaeidae − main host snails in Europe − are the source of harmful cercariae of these zoonotic parasites. The aim of this work was to determine whether Polish lakes, inhabited by Potamopyrgus antipodarum (Gray, 1843), result in a lower potential risk of swimmer's itch compared to lakes uninhabited by this non-native snail species. As a result of the dilution effect created by increasing the diversity of co-occurring non-host targets for miracidia, the risk of this zoonosis may be reduced. We studied the prevalence of digenean trematodes in Lymnaea stagnalis (Linnaeus, 1758) populations from 30 water bodies partly inhabited by P. antipodarum. The bird schistosome infection in snail hosts was found in five lakes inhabited and 11 lakes uninhabited by the non-native snails. The prevalence of these parasitesin host snail populations in the lakes uninhabited was significantly higher than in lakes inhabited by P. antipodarum. We conclude that P. antipodarum seems to be a good potential target for reducing the risk of swimmer's itch via the dilution effect. We expect from our point of view to stimulate a discussion on the use of this species to protect bathing areas against the threat of swimmer's itch.

Next-Generation Sequencing Reveals that Oxidative Phosphoryla-tion Might Be a Key Pathway Differently Expressed in the Third and Fourth Stages Larvae of Angiostrongylus cantonensis

Background: When Angiostrongylus cantonensis develops from the third and fourth stage, it needs to change its host from the middle host, snail to the final host, rat. However, the mechanism involved in this change remains unclear. Methods: The transcriptome differences of the third and fourth stages of A. cantonensis were explored by next-generation Illumina Hiseq/Miseq sequencing in China, in 2018. Results: Overall, 137 956 488 clean reads and 20 406 213 373 clean bases of the two stages larvae were produced. Based on the queries against the Gene Ontology (GO), NCBI non-redundant protein sequences (Nr), Swissprot, and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, 14 204 differentially expressed genes (DEGs) were predicted. GO enrichment analysis revealed 5660 DEGs with the top s categories as followings: biological process (GO:0008150, related to 5345 DEGs), cellular component (GO:0005575, related to 5297 DEGs), molecular function (GO:0003674, related to 5290 DEGs). In KEGG enrichment analysis, 116 genes were related to oxidative phosphorylation and 49 genes involved in the glycolytic process. Conclusion: Metabolism changes, especially oxidative phosphorylation and glycolysis, might play a key role in A. cantonensis infection of its final rat host. Many other pathways might also contribute to the transcriptome changes between these two life stages. Overall, additional studies are needed for further details.