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Travel Medicine and Infectious Disease 2024
Topics: Humans; Schistosomiasis haematobia; Cystoscopy; Animals; Schistosoma haematobium; Urinary Tract Infections; Recurrence; Anthelmintics; Male; Female; Praziquantel; Adult
PubMed: 38423232
DOI: 10.1016/j.tmaid.2024.102702 -
PLoS Neglected Tropical Diseases Feb 2024Schistosomiasis is a significant public health concern, especially in Sub-Saharan Africa. Conventional microscopy is the standard diagnostic method in resource-limited...
INTRODUCTION
Schistosomiasis is a significant public health concern, especially in Sub-Saharan Africa. Conventional microscopy is the standard diagnostic method in resource-limited settings, but with limitations, such as the need for expert microscopists. An automated digital microscope with artificial intelligence (Schistoscope), offers a potential solution. This field study aimed to validate the diagnostic performance of the Schistoscope for detecting and quantifying Schistosoma haematobium eggs in urine compared to conventional microscopy and to a composite reference standard (CRS) consisting of real-time PCR and the up-converting particle (UCP) lateral flow (LF) test for the detection of schistosome circulating anodic antigen (CAA).
METHODS
Based on a non-inferiority concept, the Schistoscope was evaluated in two parts: study A, consisting of 339 freshly collected urine samples and study B, consisting of 798 fresh urine samples that were also banked as slides for analysis with the Schistoscope. In both studies, the Schistoscope, conventional microscopy, real-time PCR and UCP-LF CAA were performed and samples with all the diagnostic test results were included in the analysis. All diagnostic procedures were performed in a laboratory located in a rural area of Gabon, endemic for S. haematobium.
RESULTS
In study A and B, the Schistoscope demonstrated a sensitivity of 83.1% and 96.3% compared to conventional microscopy, and 62.9% and 78.0% compared to the CRS. The sensitivity of conventional microscopy in study A and B compared to the CRS was 61.9% and 75.2%, respectively, comparable to the Schistoscope. The specificity of the Schistoscope in study A (78.8%) was significantly lower than that of conventional microscopy (96.4%) based on the CRS but comparable in study B (90.9% and 98.0%, respectively).
CONCLUSION
Overall, the performance of the Schistoscope was non-inferior to conventional microscopy with a comparable sensitivity, although the specificity varied. The Schistoscope shows promising diagnostic accuracy, particularly for samples with moderate to higher infection intensities as well as for banked sample slides, highlighting the potential for retrospective analysis in resource-limited settings.
TRIAL REGISTRATION
NCT04505046 ClinicalTrials.gov.
Topics: Artificial Intelligence; Gabon; Microscopy; Retrospective Studies; Schistosoma haematobium; Schistosomiasis haematobia; Sensitivity and Specificity; Humans
PubMed: 38394298
DOI: 10.1371/journal.pntd.0011967 -
Scientific Reports Feb 2024Schistosomiasis, a prevalent water-borne disease second only to malaria, significantly impacts impoverished rural communities, primarily in Sub-Saharan Africa where over...
Schistosomiasis, a prevalent water-borne disease second only to malaria, significantly impacts impoverished rural communities, primarily in Sub-Saharan Africa where over 90% of the severely affected population resides. The disease, majorly caused by Schistosoma mansoni and S. haematobium parasites, relies on freshwater snails, specifically Biomphalaria and Bulinus species, as crucial intermediate host (IH) snails. Targeted snail control is advisable, however, there is still limited knowledge about the community structure of the two genera especially in East Africa. Utilizing a machine learning approach, we employed random forest to identify key features influencing the distribution of both IH snails in this region. Our results reveal geography and climate as primary factors for Biomphalaria, while Bulinus occurrence is additionally influenced by soil clay content and nitrogen concentration. Favorable climate conditions indicate a high prevalence of IHs in East Africa, while the intricate connection with geography might signify either dispersal limitations or environmental filtering. Predicted probabilities demonstrate non-linear patterns, with Bulinus being more likely to occur than Biomphalaria in the region. This study provides foundational framework insights for targeted schistosomiasis prevention and control strategies in the region, assisting health workers and policymakers in their efforts.
Topics: Humans; Animals; Schistosomiasis; Biomphalaria; Snails; Bulinus; Africa, Eastern
PubMed: 38383705
DOI: 10.1038/s41598-024-54699-1 -
Pulmonary Circulation Jan 2024Whether all Schistosoma species cause pulmonary hypertension (PH) is unclear. Experimentally exposing mice to Schistosoma haematobium eggs caused PH, which was less...
Whether all Schistosoma species cause pulmonary hypertension (PH) is unclear. Experimentally exposing mice to Schistosoma haematobium eggs caused PH, which was less severe than that induced by S. mansoni exposure. These findings align with the relatively uncommon reports of pulmonary arterial hypertension associated with S. haematobium.
PubMed: 38312832
DOI: 10.1002/pul2.12336 -
Acta Parasitologica Mar 2024Trematode infections of the genus Schistosoma can induce physiological and behavioral changes in intermediate snail hosts. This is because the parasite consumes...
Impact of Schistosoma sp., Infection on Biological, Feeding, Physiological, Histological, and Genotoxicological Aspects of Biomphalaria alexandrina and Bulinus truncatus Snails.
BACKGROUND
Trematode infections of the genus Schistosoma can induce physiological and behavioral changes in intermediate snail hosts. This is because the parasite consumes essential resources necessary for the host's survival, prompting hosts to adapt their behavior to maintain some level of fitness before parasite-induced mortality occurs.
METHODS
In this study, the reproductive and biochemical parameters of Biomphalaria alexandrina and Bulinus truncatus were examined during the cercareal shedding stage of infection with Schistosoma mansoni and Schistosoma haematobium, respectively, compared with controls.
RESULTS
The study revealed an infection rate of 34.7% for S. mansoni and 30.4% for S. haematobium. In B. alexandrina infected with S. mansoni, a survival rate of 65.2% was recorded, along with a mean prepatent period of 30.3 ± 1.41 days, a mean shedding duration of 14.2 ± 0.16 days, and a mean lifespan of 44.1 ± 0.24 days. Meanwhile, in B. truncatus infected with S. haematobium, a survival rate of 56.4% was observed, with a mean prepatent period of 44.3 ± 1.41 days, a mean shedding duration of 22.6 ± 2.7 days, and a mean lifespan of 66.9 ± 1.6 days. Feeding increased in both infected species of snails, while the net reproductive rate (Ro) of the infected snails decreased. Total antioxidant (TAO) and lipid peroxidation activity increased in the two infected snail species during shedding, while Glutathione-S-transferase levels decreased. Lipid peroxidase activity and nitrogen oxide levels significantly decreased in infected B. alexandrina and increased in infected Bulinus. Steroid hormone levels were elevated in infected Biomphalaria, whereas they were reduced in infected Bulinus. Comet assay parameters showed an increase in the two infected genera after infection compared to control snails, indicating genotoxic damage and histopathological damage was observed.
CONCLUSIONS
These findings demonstrate that infection with larva species diverse biochemical, hormonal, genotoxic, and histopathological changes in the tissues responsible for fecundity and reproduction in B. alexandrina and B. truncates comparing with controls.
Topics: Animals; Biomphalaria; Schistosoma mansoni; Bulinus; Host-Parasite Interactions; Schistosoma haematobium; Feeding Behavior; Cercaria; Reproduction
PubMed: 38302641
DOI: 10.1007/s11686-023-00760-4 -
PLoS Neglected Tropical Diseases Jan 2024Malaria and schistosomiasis are two important parasitic diseases that are a particular threat to young children and pregnant women in sub-Saharan Africa. Malaria and... (Review)
Review
Malaria and schistosomiasis are two important parasitic diseases that are a particular threat to young children and pregnant women in sub-Saharan Africa. Malaria and schistosomiasis prevention and control strategies primarily focus on the distribution of long-lasting insecticidal nets and the delivery of praziquantel tablets to at-risk populations in high burden settings through mass drug administration, respectively. The objective of this scoping review was to identify previous efforts to integrate malaria and schistosomiasis prevention and control programs in the literature and to summarize the strategies and approaches used in these programs following the PRISMA-ScR guidelines. We reviewed published and grey literature using a combination of keywords and search terms following themes surrounding "malaria", "Plasmodium falciparum", "Anopheles", "schistosomiasis", "Schistosoma haematobium", "Schistosoma mansoni", and "snails". Neither a date limit nor relevant terms for prevention and control were used. Out of 6374, eight articles were included in the scoping review-three articles investigated the integration of mass drug administration for schistosomiasis with the administration of antimalarials, four articles investigated the effect of administering antimalarials on malaria, schistosomiasis, and their co-infection, and one article assessed the impact of an educational intervention on malaria and schistosomiasis knowledge and preventative behaviors. Our findings suggest that there is an opportunity to link disease control programs to increase access and coverage of interventions to improve outcomes for malaria, schistosomiasis, and their co-infection. Further research is needed on the potential benefits, feasibility, and cost-effectiveness of integrating malaria and schistosomiasis prevention and control programs.
Topics: Pregnancy; Child; Animals; Humans; Female; Child, Preschool; Antimalarials; Coinfection; Malaria; Schistosomiasis; Schistosoma haematobium
PubMed: 38265982
DOI: 10.1371/journal.pntd.0011886 -
Pathogens (Basel, Switzerland) Jan 2024Schistosomiasis is a bloodborne, and waterborne parasitic disease caused by the human species, namely and . The parasite requires an intermediate snail host, where...
Schistosomiasis is a bloodborne, and waterborne parasitic disease caused by the human species, namely and . The parasite requires an intermediate snail host, where they grow and develop, along with a human host (definitive). egg detection in feces () and urine () are the WHO-recommended confirmatory diagnostic tests. The goal of our research was to determine the efficacy of detecting single or dual Schistosome species from filtered human urine samples collected in Tanzania by amplifying species-specific cell-free repeat DNA fragments via polymerase chain reaction (PCR) and gel electrophoresis. In total, 104 filtered human urine samples were evaluated and collected from individuals residing in the village of Kayenze, Tanzania. All samples were detected with 100% accuracy and no cross-amplification was present. For a single infection of , 22 (21%) of the samples were positive, while 15 (14%) of the samples were negative via PCR. Moreover, for a single infection of , 7 (7%) of the samples were positive, while 15 (14%) of the samples were negative. Dual infections were found in a higher percentage, with 60 (58%) of the samples being positive. Thus, we have justified that PCR is more sensitive and specific by amplifying species-specific cell-free repeat DNA fragments from the same urine sample than WHO-recommended methods of processing stool and urine.
PubMed: 38251366
DOI: 10.3390/pathogens13010059 -
PLoS Neglected Tropical Diseases Jan 2024Schistosomiasis is a parasitic disease in Tanzania affecting over 50% of the population. Current control strategies involve mass drug administration (MDA) campaigns at...
Enabling targeted mass drug administration for schistosomiasis in north-western Tanzania: Exploring the use of geostatistical modeling to inform planning at sub-district level.
INTRODUCTION
Schistosomiasis is a parasitic disease in Tanzania affecting over 50% of the population. Current control strategies involve mass drug administration (MDA) campaigns at the district level, which have led to problems of over- and under-treatment in different areas. WHO guidelines have called for more targeted MDA to circumvent these problems, however a scarcity of prevalence data inhibits decision makers from prioritizing sub-district areas for MDA. This study demonstrated how geostatistics can be used to inform planning for targeted MDA.
METHODS
Geostatistical sub-district (ward-level) prevalence estimates were generated through combining a zero-inflated poisson model and kriging approach (regression kriging). To make predictions, the model used prevalence survey data collected in 2021 of 17,400 school children in six regions of Tanzania, along with several open source ecological and socio-demographic variables with known associations with schistosomiasis.
RESULTS
The model results show that regression kriging can be used to effectively predict the ward level parasite prevalence of the two species of Schistosoma endemic to the study area. Kriging was found to further improve the regression model fit, with an adjusted R-squared value of 0.51 and 0.32 for intestinal and urogenital schistosomiasis, respectively. Targeted treatment based on model predictions would represent a shift in treatment away from 193 wards estimated to be over-treated to 149 wards that would have been omitted from the district level MDA.
CONCLUSIONS
Geostatistical models can help to support NTD program efficiency and reduce disease transmission by facilitating WHO recommended targeted MDA treatment through provision of prevalence estimates where data is scarce.
Topics: Child; Animals; Humans; Tanzania; Mass Drug Administration; Schistosomiasis haematobia; Schistosoma haematobium; Prevalence
PubMed: 38227610
DOI: 10.1371/journal.pntd.0011896 -
British Medical Bulletin Mar 2024Female genital schistosomiasis (FGS) is a chronic gynaecological disease affecting girls and women in sub-Saharan Africa (SSA), caused by the parasite Schistosoma (S.)...
BACKGROUND
Female genital schistosomiasis (FGS) is a chronic gynaecological disease affecting girls and women in sub-Saharan Africa (SSA), caused by the parasite Schistosoma (S.) haematobium. FGS is associated with sexual dysfunction, reproductive tract morbidity and increased prevalence of HIV and cervical precancer lesions.
SOURCE OF DATA
Key peer-reviewed published literature.
AREAS OF AGREEMENT
FGS screening and diagnosis require costly equipment and specialized training, seldom available in resource-limited settings. FGS surveillance is not included in wider schistosomiasis control strategies. The interplay of FGS with other SRH infections is not fully understood. Integration of FGS within sexual and reproductive health (SRH) control programmes needs to be explored.
AREAS OF CONTROVERSY
There are no standardized methods for individual or population-based FGS screening and diagnosis, hindering accurate disease burden estimates and targeted resource allocation. Treatment recommendations rely on public health guidelines, without rigorous clinical evidence on efficacy.
GROWING POINTS
Integrating FGS screening with SRH programmes offers an opportunity to reach at-risk women with limited access to healthcare services. Home-based self-sampling coupled with handheld colposcopes operated by primary healthcare workers show promise for FGS diagnosis and surveillance at scale.
AREAS TIMELY FOR DEVELOPING RESEARCH
There is growing interest in decentralizing strategies for FGS screening and diagnosis. The accurate predictions on the 'cost-effectiveness' of these approaches will determine their affordability and feasibility within the overburdened health systems in SSA. Clinical trials are needed to optimize FGS treatment. Longitudinal studies can expand on the epidemiological knowledge on co-morbidities and integration within other SRH interventions.
Topics: Female; Humans; Schistosomiasis; Genitalia, Female; Genital Diseases, Female; Specimen Handling; Prevalence
PubMed: 38220571
DOI: 10.1093/bmb/ldad034 -
Proceedings. Biological Sciences Jan 2024Different populations of hosts and parasites experience distinct seasonality in environmental factors, depending on local-scale biotic and abiotic factors. This can lead...
Different populations of hosts and parasites experience distinct seasonality in environmental factors, depending on local-scale biotic and abiotic factors. This can lead to highly heterogeneous disease outcomes across host ranges. Variable seasonality characterizes urogenital schistosomiasis, a neglected tropical disease caused by parasitic trematodes (). Their intermediate hosts are aquatic snails that are highly adapted to extreme rainfall seasonality, undergoing prolonged dormancy yearly. While snails have a remarkable capacity for rebounding following dormancy, we investigated the extent to which parasite survival within snails is diminished. We conducted an investigation of seasonal snail schistosome dynamics in 109 ponds of variable ephemerality in Tanzania from August 2021 to July 2022. First, we found that ponds have two synchronized peaks of schistosome infection prevalence and observed cercariae, though of lower magnitude in the fully desiccating than non-desiccating ponds. Second, we evaluated total yearly schistosome prevalence across an ephemerality gradient, finding ponds with intermediate ephemerality to have the highest infection rates. We also investigated dynamics of non-schistosome trematodes, which lacked synonymity with schistosome patterns. We found peak schistosome transmission risk at intermediate pond ephemerality, thus the impacts of anticipated increases in landscape desiccation could result in increases or decreases in transmission risk with global change.
Topics: Animals; Ponds; Tanzania; Trematoda; Schistosoma; Spatio-Temporal Analysis; Snails
PubMed: 38196367
DOI: 10.1098/rspb.2023.1766