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Ayob N, Burger RP, Belelie MD, Nkosi NC, Havenga H, de Necker L, Cilliers DP. Modelling the historical distribution of schistosomiasis-transmitting snails in South Africa using ecological niche models. PLoS One 2023; 18:e0295149. [PMID: 38033142 PMCID: PMC10688899 DOI: 10.1371/journal.pone.0295149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 11/14/2023] [Indexed: 12/02/2023] Open
Abstract
Schistosomiasis is a vector-borne disease transmitted by freshwater snails and is prevalent in rural areas with poor sanitation and no access to tap water. Three snail species are known to transmit schistosomiasis in South Africa (SA), namely Biomphalaria pfeifferi, Bulinus globosus and Bulinus africanus. In 2003, a predicted prevalence of 70% was reported in tropical climates in SA. Temperature and rainfall variability can alter schistosomiasis-transmitting snails' development by increasing or decreasing their abundance and geographical distribution. This study aimed to map the historical distribution of schistosomiasis from 1950 to 2006 in SA. The snail sampling data were obtained from the historical National Snail Freshwater Collection (NFSC). Bioclimatic variables were extracted using ERA 5 reanalysis data provided by the Copernicus Climate Change Service. In this study, we used 19 bioclimatic and four soil variables. The temporal aggregation was the mean climatological period pre-calculated over the 40-year reference period with a spatial resolution of 0.5° x 0.5°. Multicollinearity was reduced by calculating the Variance Inflation Factor Core (VIF), and highly correlated variables (> 0.85) were excluded. To obtain an "ensemble" and avoid the integration of weak models, we averaged predictions using the True Skill Statistical (TSS) method. Results showed that the ensemble model achieved the highest Area Under the Curve (AUC) scores (0.99). For B. africanus, precipitation-related variables contributed to determining the suitability for schistosomiasis. Temperature and precipitation-related variables influenced the distribution of B. globosus in all three models. Biomphalaria pfeifferi showed that Temperature Seasonality (bio4) contributed the most (47%) in all three models. According to the models, suitable areas for transmitting schistosomiasis were in the eastern regions of South Africa. Temperature and rainfall can impact the transmission and distribution of schistosomiasis in SA. The results will enable us to develop future projections for Schistosoma in SA based on climate scenarios.
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Affiliation(s)
- Nisa Ayob
- Unit for Environmental Sciences and Management, North-West University, Mafikeng Campus, Mafikeng, South Africa
| | - Roelof P. Burger
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom Campus, Potchefstroom, South Africa
| | - Monray D. Belelie
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom Campus, Potchefstroom, South Africa
| | - Ncobile C. Nkosi
- Unit for Environmental Sciences and Management, North-West University, Mafikeng Campus, Mafikeng, South Africa
| | - Henno Havenga
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom Campus, Potchefstroom, South Africa
| | - Lizaan de Necker
- South African Institute for Aquatic Biodiversity (NRF-SAIAB), Makhanda, South Africa
- Water Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
| | - Dirk P. Cilliers
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom Campus, Potchefstroom, South Africa
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Trippler L, Knopp S, Welsche S, Webster BL, Stothard JR, Blair L, Allan F, Ame SM, Juma S, Kabole F, Ali SM, Rollinson D, Pennance T. The long road to schistosomiasis elimination in Zanzibar: A systematic review covering 100 years of research, interventions and control milestones. Adv Parasitol 2023; 122:71-191. [PMID: 37657854 DOI: 10.1016/bs.apar.2023.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/03/2023]
Abstract
Zanzibar is among the few places in sub-Saharan Africa where interruption of Schistosoma transmission seems an achievable goal. Our systematic review identifies and discusses milestones in schistosomiasis research, control and elimination efforts in Zanzibar over the past 100 years. The search in online databases, libraries, and the World Health Organization Archives revealed 153 records published between May 1928 and August 2022. The content of records was summarised to highlight the pivotal work leading towards urogenital schistosomiasis elimination and remaining research gaps. The greatest achievement following 100 years of schistosomiasis interventions and research is undoubtedly the improved health of Zanzibaris, exemplified by the reduction in Schistosoma haematobium prevalence from>50% historically down to<5% in 2020, and the absence of severe morbidities. Experiences from Zanzibar have contributed to global schistosomiasis guidelines, whilst also revealing challenges that impede progression towards elimination. Challenges include: transmission heterogeneity requiring micro-targeting of interventions, post-treatment recrudescence of infections in transmission hotspots, biological complexity of intermediate host snails, emergence of livestock Schistosoma species complicating surveillance whilst creating the risk for interspecies hybridisation, insufficient diagnostics performance for light intensity infections and female genital schistosomiasis, and a lack of acceptable sanitary alternatives to freshwater bodies. Our analysis of the past revealed that much can be achieved in the future with practical implementation of integrated interventions, alongside operational research. With continuing national and international commitments, interruption of S. haematobium transmission across both islands is within reach by 2030, signposting the future demise of urogenital schistosomiasis across other parts of sub-Saharan Africa.
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Affiliation(s)
- Lydia Trippler
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland; University of Basel, Basel, Switzerland.
| | - Stefanie Knopp
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland; University of Basel, Basel, Switzerland
| | | | - Bonnie L Webster
- Natural History Museum, London, United Kingdom; London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | | | | | - Fiona Allan
- Natural History Museum, London, United Kingdom; London Centre for Neglected Tropical Disease Research, London, United Kingdom; University of St Andrews, St Andrews, United Kingdom
| | - Shaali Makame Ame
- Neglected Diseases Programme, Zanzibar Ministry of Health, Lumumba, Unguja, United Republic of Tanzania
| | - Saleh Juma
- Neglected Diseases Programme, Zanzibar Ministry of Health, Mkoroshoni, Pemba, United Republic of Tanzania
| | - Fatma Kabole
- Neglected Diseases Programme, Zanzibar Ministry of Health, Lumumba, Unguja, United Republic of Tanzania
| | - Said Mohammed Ali
- Public Health Laboratory - Ivo de Carneri, Wawi, Chake Chake, Pemba, United Republic of Tanzania
| | - David Rollinson
- Natural History Museum, London, United Kingdom; London Centre for Neglected Tropical Disease Research, London, United Kingdom; Global Schistosomiasis Alliance, London, United Kingdom
| | - Tom Pennance
- Natural History Museum, London, United Kingdom; London Centre for Neglected Tropical Disease Research, London, United Kingdom; Western University of Health Sciences, Lebanon, OR, United States.
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Molaba GG, Molefe-Nyembe NI, Taioe OM, Mofokeng LS, Thekisoe OMM, Mtshali K. Molecular detection of Fasciola, Schistosoma and Paramphistomum species from freshwater snails occurring in Gauteng and Free State provinces, South Africa. Vet Parasitol 2023; 320:109978. [PMID: 37364501 DOI: 10.1016/j.vetpar.2023.109978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 06/28/2023]
Abstract
Trematodiases are diseases caused by snail-borne trematode parasites that infect both animals and humans. Fascioliasis, schistosomiasis and paramphistomosis are some of these diseases and they affect millions of livestock, leading to significant economic losses. The aim of the study was to document freshwater snails occurring in selected study sites in the Free State and Gauteng provinces as well as identify and detect larval trematodes that they harbour. Samples were collected from a total of five study sites within two provinces of South Africa. Morphological features were used to identify snail species and were further confirmed genetically by polymerase chain reaction (PCR), sequencing and phylogenetic analysis. The larval trematodes were also detected by PCR, PCR-Restriction Length Fragment Polymorphism (PCR-RLFP), sequencing and phylogenetic analysis. A total of 887 freshwater snails were collected from Free State (n = 343) and Gauteng (n = 544). Five different genera of snails as well as species in the Succineidae family were documented. The snails in descending order of abundance were identified as: Physa (P.) spp. (51%), Succineidae spp. (20%), Galba (G.) truncatula (12%), Pseudosuccinea (Ps.) columella (10%), Planorbella (Pl.) duryi (6%) and Bulinus (B.) truncatus (1%). Approximately 272 DNA pools were created for genetic identification of snails and detection of trematode parasites. Schistosoma species were not detected from any of the snail species. A total prevalence of 46% was obtained for Fasciola hepatica in the identified snail species across all study sites. Overall, the highest prevalence of F. hepatica was obtained in Physa species (24%), whilst the lowest was observed in B. truncatus snails (1%). Forty three percent (43%) of the snail samples were PCR positive for Paramphistomum DNA. This is the first report of P. mexicana in South Africa. Fasciola hepatica was confirmed from all obtained snail species per study site. This is the first reported detection of F. hepatica in Pl. duryi and P. mexicana snails as well as the first confirmation of natural infection from P. acuta in South Africa.
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Affiliation(s)
- Gantshe G Molaba
- Department of Biomedical Sciences, Tshwane University of Technology, Arcadia, Pretoria 0083, South Africa
| | - Nthatisi I Molefe-Nyembe
- Department of Zoology and Entomology, University of the Free State, Phuthaditjhaba 9866, South Africa
| | - Oriel M Taioe
- Agricultural Research Council, Onderstepoort Veterinary Research, Epidemiology, Parasites and Vectors Entomology, Onderstepoort 0001, South Africa; Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2531, South Africa
| | - Lehlohonolo S Mofokeng
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2531, South Africa
| | - Oriel M M Thekisoe
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2531, South Africa
| | - Khethiwe Mtshali
- Department of Biomedical Sciences, Tshwane University of Technology, Arcadia, Pretoria 0083, South Africa.
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Gaber YA, Al-Sanabani R, Annuzaili DA, Al-Danakh A, Ling LC. Research progress of health care in Yemeni children during the war: review. Prim Health Care Res Dev 2022; 23:e55. [PMID: 36093681 DOI: 10.1017/S1463423622000421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Yemen crisis, which has been going on for more than six years, represents one of the most gruesome human plights in the modern history, especially children. OBJECTIVES This research aimed to present a comprehensive view of Yemeni children's studies during the ongoing war period, to come up with a comprehensive base that concerns humanitarians, researchers, decision-makers, and general public at large about the reality of the predicament of Yemeni child. METHOD We searched databases and identified 373 articles, of which 68 were included in this review. Review of literature between 2014 and 2020 is taken from academic sources, multilateral organizations, donors, and governmental and non-governmental organizations. The data are analyzed by date and governorates. RESULTS We chose 68 articles and divided them according to the diseases and health conditions as follows: infectious diseases (15 studies), non-infectious diseases (10 studies), blood-related diseases (7 studies), oral and dental problems (12 studies), accidents and injuries (2 studies), health system (16 studies), family and community (6 studies). Moreover, the studies were divided geographically as follows: 7 studies that were almost comprehensive for all governorates; additional studies were conducted for Amanat Al Asimah (21 studies), Taiz (12 studies), Aden and Al Hudaydah (7 studies for each), Dhamar and Ibb (6 studies for each), Abyan and Lahij (2 study for each). As for Al Bayda, Marib, Sana'a, and Socotra, each of them had one study. CONCLUSION Our assessment revealed that the ongoing Yemen crisis is underrated and largely neglected. The studies conducted so far do match the ground reality both in terms of inclusiveness and numbers.
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Rey O, Webster BL, Huyse T, Rollinson D, Van den Broeck F, Kincaid-Smith J, Onyekwere A, Boissier J. Population genetics of African Schistosoma species. Infect Genet Evol 2021; 89:104727. [PMID: 33486128 DOI: 10.1016/j.meegid.2021.104727] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/09/2021] [Accepted: 01/13/2021] [Indexed: 02/06/2023]
Abstract
Blood flukes within the genus Schistosoma (schistosomes) are responsible for the major disease, schistosomiasis, in tropical and sub-tropical areas. This disease is predominantly present on the African continent with more than 85% of the human cases. Schistosomes are also parasites of veterinary importance infecting livestock and wildlife. Schistosoma population genetic structure and diversity are important characteristics that may reflect variations in selection pressures such as those induced by host (mammalian and snail) environments, habitat change, migration and also treatment/control interventions, all of which also shape speciation and evolution of the whole Schistosoma genus. Investigations into schistosome population genetic structure, diversity and evolution has been an area of important debate and research. Supported by advances in molecular techniques with capabilities for multi-locus genetic analyses for single larvae schistosome genetic investigations have greatly progressed in the last decade. This paper aims to review the genetic studies of both animal and human infecting schistosome. Population genetic structures are reviewed at different spatial scales: local, regional or continental (i.e. phylogeography). Within species genetic diversities are discussed compared and the compounding factors discussed, including the effect of mass drug administration. Finally, the ability for intra-species hybridisation questions species integrities and poses many questions in relation to the natural epidemiology of co-endemic species. Here we review molecularly confirmed hybridisation events (in relation to human disease) and discuss the possible impact for ongoing and future control and elimination.
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Affiliation(s)
- O Rey
- Univ. Montpellier, CNRS, IFREMER, UPVD, IHPE, F-66000 Perpignan, France
| | - B L Webster
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom; London Centre for Neglected Tropical Disease Research, Imperial College London School of Public Health, London W2 1PG, United Kingdom
| | - T Huyse
- Department of Biology, Royal Museum for Central Africa, Leuvensesteenweg 13, B-3080 Tervuren, Belgium; Laboratory of Biodiversity and Evolutionary Genomics, Department of Biology, KU Leuven, Ch. Deberiotstraat 32, B-3000 Leuven, Belgium
| | - D Rollinson
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom; London Centre for Neglected Tropical Disease Research, Imperial College London School of Public Health, London W2 1PG, United Kingdom
| | - F Van den Broeck
- Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, University of Leuven, Leuven, Belgium; Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - J Kincaid-Smith
- Centre for Emerging, Endemic and Exotic Diseases (CEEED), Department of Pathobiology and Population Sciences (PPS), Royal Veterinary College, University of London, Hawkshead Campus, Herts AL9 7TA, United Kingdom
| | - A Onyekwere
- Univ. Montpellier, CNRS, IFREMER, UPVD, IHPE, F-66000 Perpignan, France
| | - J Boissier
- Univ. Montpellier, CNRS, IFREMER, UPVD, IHPE, F-66000 Perpignan, France.
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El-Kady AM, El-Amir MI, Hassan MH, Allemailem KS, Almatroudi A, Ahmad AA. Genetic Diversity of Schistosoma haematobium in Qena Governorate, Upper Egypt. Infect Drug Resist 2020; 13:3601-3611. [PMID: 33116680 PMCID: PMC7575065 DOI: 10.2147/idr.s266928] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 09/15/2020] [Indexed: 11/23/2022] Open
Abstract
Introduction Schistosomiasis is an important neglected tropical disease (NTD) in several developing countries. Praziquantel is the principle and efficacious chemotherapeutic agent that has been used to treat schistosomiasis for decades. Unfortunately, emerging resistance to praziquantel with accompanying reduced efficacy is reported in some localities. Hence, genetic diversity among parasite populations is of significant interest in assessing the effects of selective pressure generated by praziquantel therapy that might result in encouraging the emergence of new genotypes that are either non-susceptible or drug-resistant. The present study aimed to investigate the genetic diversity of Schistosoma haematobium among human populations using the RAPD technique to help clarify disease epidemiology and transmission. Materials and Methods S. haematobium eggs were isolated from 50 of 134 patients from four different localities in Qena Governorate, Upper Egypt. These patients complained of terminal hematuria and burning micturition. Samples were used for molecular analysis using RAPD-PCR primers (A02, A07, A09, A10). Results Twenty S. haematobium isolates (40%) were amplified using the selected RAPD primers. Amplification patterns of these isolates showed distinct variation in the size and number of amplified fragments, indicating high genetic variation among these isolates. Conclusion To the best of our knowledge, this study is the first to characterize the genetic diversity of S. haematobium in human populations in Upper Egypt. Future studies on a larger geographic scale involving many districts in Upper Egypt should be encouraged. Information from such a study would provide better insight into clonal lineages of S. haematobium in this endemic area. In turn, understanding transmission of the parasite may have a major role in establishing control strategies for urogenital schistosomiasis in Upper Egypt.
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Affiliation(s)
- Asmaa M El-Kady
- Department of Medical Parasitology, Faculty of Medicine, South Valley University, Qena, Egypt
| | - Mostafa I El-Amir
- Department of Medical Microbiology and Immunology, Faculty of Medicine, South Valley University, Qena, Egypt
| | - Mohammed H Hassan
- Department of Medical Biochemistry, Faculty of Medicine, South Valley University, Qena, Egypt
| | - Khaled S Allemailem
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah, Saudia Arabia
| | - Ahmad Almatroudi
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah, Saudia Arabia
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Djuikwo-Teukeng FF, Kouam Simo A, Allienne JF, Rey O, Njayou Ngapagna A, Tchuem-Tchuente LA, Boissier J. Population genetic structure of Schistosoma bovis in Cameroon. Parasit Vectors 2019; 12:56. [PMID: 30678712 PMCID: PMC6346511 DOI: 10.1186/s13071-019-3307-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 01/08/2019] [Indexed: 11/24/2022] Open
Abstract
Background Schistosomiasis is neglected tropical parasitic disease affecting both humans and animals. Due to the human health impact, population genetic studies have focused on the three main human-infecting schistosome species: Schistosoma mansoni, S. haematobium and S. japonicum. Here we present novel data on the population genetic structure of Schistosoma bovis, a highly widespread and prevalent schistosome infecting ruminants, and therefore of veterinary importance. Methods Adult S. bovis were sampled in the two main abattoirs of Cameroon (Yaoundé and Douala). Twenty-two cows originating from four distinct localities were sampled and a total of 218 parasites were recovered. All parasites were genotyped using a panel of 14 microsatellite markers and a sub-sample of 91 parasites were sequenced and characterized with the mitochondrial (cox1) and nuclear (ITS) genetic markers. Results No significant difference in allelic richness, heterozygosity, nucleotide diversity and haplotype diversity was observed between the populations. Additionally, no strong genetic structure was observed at the country scale. Our data also show that S. bovis is more polymorphic than its sister species, S. haematobium, and that the haplotype diversity is similar to that of S. mansoni while the nucleotide diversity does not significantly differ from that of S. haematobium. The resulting negative Tajima’s D* and Fu and Li’s D* indices could be a signature of population demographic expansion. No S. haematobium/S. bovis hybrids were observed in our populations, thus all samples were considered as pure S. bovis. Conclusions This study provides novel insights into genetic diversity and population genetic structure of S. bovis. No strong genetic structure was observed at the country scale but some genetic indices could be associated as a signature of population demographic expansion. Electronic supplementary material The online version of this article (10.1186/s13071-019-3307-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Alain Kouam Simo
- Université des Montagnes, Faculty of Heath Science, PO Box: 208, Bangangté, Cameroon
| | - Jean-François Allienne
- Université de Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Université de Montpellier, F-66860, Perpignan, France
| | - Olivier Rey
- Université de Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Université de Montpellier, F-66860, Perpignan, France
| | | | - Louis Albert Tchuem-Tchuente
- Centre for Schistosomiasis and Parasitology, Yaoundé, Cameroon.,Laboratory of Parasitology and Ecology, Faculty of Sciences, University of Yaoundé I, Yaoundé, Cameroon
| | - Jérôme Boissier
- Université de Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Université de Montpellier, F-66860, Perpignan, France.
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