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Lima MG, Montresor LC, Pontes J, Augusto RDC, da Silva JP, Thiengo SC. Compatibility Polymorphism Based on Long-Term Host-Parasite Relationships: Cross Talking Between Biomphalaria glabrata and the Trematode Schistosoma mansoni From Endemic Areas in Brazil. Front Immunol 2019; 10:328. [PMID: 31024517 PMCID: PMC6467164 DOI: 10.3389/fimmu.2019.00328] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 02/08/2019] [Indexed: 11/13/2022] Open
Abstract
Sympatric snail populations have been kept in the laboratory since the isolation of the parasite from the field. To evaluate the influence of the intermediate host in the infectivity of S. mansoni, this allopatric strain was compared to two sympatric strains, from different geographical origins, and with different time of maintenance in the laboratory. Snail–trematode compatibility was accessed for a total of nine possible combinations (three snail populations, three schistosome strains), using different charges of parasite: 1, 5, 10, and 15 miracidia/snail. Each S. mansoni strain was characterized according to its infectivity phenotype that reflects the efficiency of their infection mechanism and all B. glabrata populations were characterized according to its (in)compatible phenotype that reflects the level of (un)susceptibility they display. For all host-parasite combinations tested the dose-response relation indicated a trend for an increase in the infectivity of S. mansoni when higher miracidial doses were used. SmRES-2 presented the highest overall infectivity rate, especially in the SmRES-2/BgRES interaction with 15 miracidia/snail. However, SmRES was more infective to BgBAR than SmRES-2, indicating that SmRES strain was more infective at the first contact with this new host than after 2 years of interaction (SmRES-2). BgBAR presented the highest susceptibility to infection. SmRES and SmRES-2 are the same parasite strains. It seems that during these 2 years of interaction, BgBAR acted like a filter and shifted the compatibility polymorphism of the strain SmRES. SmRES-2 became more infective to BgRES (sympatric) than to BgBAR (allopatric), and conversely, SmRES was more infective to BgBAR (allopatric) than to BgRES (sympatric). This interplay suggests that epigenetic mechanisms are prompting these changes. This study concerns with infection of B. glabrata snails from different Brazilian localities with S. mansoni in allopatric and sympatric associations that will partially help in understanding the natural epidemiology of schistosomiasis within natural snail populations in watercourses. This work demonstrates that there is a shift on the compatibility polymorphism profile resulting from sympatric and allopatric interactions of B. glabrata and S. mansoni that constantly change during the time of interaction.
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Affiliation(s)
- Mariana G Lima
- Curso de Pós-Graduação em Ciências Veterinárias, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil.,Laboratório de Referência Nacional em Esquistossomose-Malacologia, Instituto Oswaldo Cruz/FIOCRUZ, Rio de Janeiro, Brazil.,Área de Biofísica, Departamento de Ciências Fisiológicas, Instituto de Biologia, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil
| | - Lângia C Montresor
- Laboratório de Referência Nacional em Esquistossomose-Malacologia, Instituto Oswaldo Cruz/FIOCRUZ, Rio de Janeiro, Brazil
| | - Joana Pontes
- Laboratório de Referência Nacional em Esquistossomose-Malacologia, Instituto Oswaldo Cruz/FIOCRUZ, Rio de Janeiro, Brazil
| | - Ronaldo de C Augusto
- UMR 5244 Univ Perpignan via Domitia-CNRS-IFREMER-Univ Montpellier, Interactions Hôtes-Pathògenes-Environnements (IHPE), Université de Perpignan via Domitia, Perpignan, France
| | - Jairo Pinheiro da Silva
- Curso de Pós-Graduação em Ciências Veterinárias, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil.,Área de Biofísica, Departamento de Ciências Fisiológicas, Instituto de Biologia, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil
| | - Silvana C Thiengo
- Laboratório de Referência Nacional em Esquistossomose-Malacologia, Instituto Oswaldo Cruz/FIOCRUZ, Rio de Janeiro, Brazil
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Barbosa LM, Barros BC, de Souza Rodrigues M, Silva LK, Reis MG, Blanton RE. The effect of sample size on estimates of genetic differentiation and effective population size for Schistosoma mansoni populations. Int J Parasitol 2018; 48:1149-1154. [PMID: 30367861 PMCID: PMC6261692 DOI: 10.1016/j.ijpara.2018.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 10/04/2018] [Accepted: 10/10/2018] [Indexed: 01/28/2023]
Abstract
Eradication or local extinction of the human parasite Schistosoma mansoni is a goal for many control programs. Population genetic analyses are helping to evaluate and guide these efforts, yet what to sample, how to sample and how densely to sample is not well established. We determined the S. mansoni allele frequency profile of nearly all infected inhabitants in two small Brazilian communities and created sub-samples representing 5-50% of all detected human infections (infrapopulations). Samples were selected at random with replacement, and each size class was replicated 100 times. Mean pairwise differentiation for all infrapopulations (Di) and the variance effective population size (Ne) were calculated for each sample. Prior to community-wide treatment, the true mean Di was moderate (0.095-0.123) and Ne large (>30,000). Most samples of <50% of those infected produced estimates outside of 5% of the true value. For estimates within 10%, sample sizes of >15% of all infrapopulations were required. At the 3 year follow-up after treatment, the Di increased and Ne was reduced by >15 fold. At this time sampling of >30-45% was needed to achieve the same accuracy. Following a second treatment and 4 years from baseline, the Di further increased and Ne decreased with little change in the sampling effort required. Extensive sampling is required for accurate estimates of these important population parameters. Characteristics such as population census size, infection prevalence, the community's treatment history and the degree of infrapopulation differentiation should be taken into account. The intensity of infection was weakly correlated with the ability of a single infrapopulation to represent the component population (Dic), indicating a tendency toward random acquisition of parasite genotypes. This also suggests that targeted sampling from those most heavily infected will better represent the genetic diversity of the whole community than a random sample of infrapopulations.
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Affiliation(s)
- Lúcio M Barbosa
- Gonçalo Moniz Research Centre, Oswaldo Cruz Foundation, Rua Waldemar Falcão, 121 Brotas, Salvador, Bahia 40296-710, Brazil; Bahiana School of Medicine and Public Health, Av. Silveira Martins, n° 3386, Salvador, Bahia 41150-100, Brazil
| | - Bruna C Barros
- Bahiana School of Medicine and Public Health, Av. Silveira Martins, n° 3386, Salvador, Bahia 41150-100, Brazil
| | - Moreno de Souza Rodrigues
- Gonçalo Moniz Research Centre, Oswaldo Cruz Foundation, Rua Waldemar Falcão, 121 Brotas, Salvador, Bahia 40296-710, Brazil
| | - Luciano K Silva
- Gonçalo Moniz Research Centre, Oswaldo Cruz Foundation, Rua Waldemar Falcão, 121 Brotas, Salvador, Bahia 40296-710, Brazil
| | - Mitermayer G Reis
- Gonçalo Moniz Research Centre, Oswaldo Cruz Foundation, Rua Waldemar Falcão, 121 Brotas, Salvador, Bahia 40296-710, Brazil; Bahiana School of Medicine and Public Health, Av. Silveira Martins, n° 3386, Salvador, Bahia 41150-100, Brazil
| | - Ronald E Blanton
- Center for Global Health and Diseases, Case Western Reserve University, Biomedical Research Building, 2109 Adelbert Rd., Cleveland, OH 44106, USA.
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Ezeh C, Yin M, Li H, Zhang T, Xu B, Sacko M, Feng Z, Hu W. High genetic variability of Schistosoma haematobium in Mali and Nigeria. THE KOREAN JOURNAL OF PARASITOLOGY 2015; 53:129-34. [PMID: 25748721 PMCID: PMC4384788 DOI: 10.3347/kjp.2015.53.1.129] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 10/21/2014] [Accepted: 10/23/2014] [Indexed: 12/29/2022]
Abstract
Schistosoma haematobium is one of the most prevalent parasitic flatworms, infecting over 112 million people in Africa. However, little is known about the genetic diversity of natural S. haematobium populations from the human host because of the inaccessible location of adult worms in the host. We used 4 microsatellite loci to genotype individually pooled S. haematobium eggs directly from each patient sampled at 4 endemic locations in Africa. We found that the average allele number of individuals from Mali was significantly higher than that from Nigeria. In addition, no significant difference in allelic composition was detected among the populations within Nigeria; however, the allelic composition was significantly different between Mali and Nigeria populations. This study demonstrated a high level of genetic variability of S. haematobium in the populations from Mali and Nigeria, the 2 major African endemic countries, suggesting that geographical population differentiation may occur in the regions.
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Affiliation(s)
- Charles Ezeh
- Key Laboratory of Parasite and Vector Biology, Ministry of Public Health, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, China
| | - Mingbo Yin
- School of Life Science, Fudan University, Shanghai 200433, China
| | - Hongyan Li
- School of Life Science, Fudan University, Shanghai 200433, China
| | - Ting Zhang
- Key Laboratory of Parasite and Vector Biology, Ministry of Public Health, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, China
| | - Bin Xu
- Key Laboratory of Parasite and Vector Biology, Ministry of Public Health, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, China
| | - Moussa Sacko
- Laboratory of Parasitology, Institut National de Recherche en Sante Publique, 1771, Bamako, Mali
| | - Zheng Feng
- Key Laboratory of Parasite and Vector Biology, Ministry of Public Health, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, China
| | - Wei Hu
- Key Laboratory of Parasite and Vector Biology, Ministry of Public Health, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, China ; School of Life Science, Fudan University, Shanghai 200433, China
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Mutuku MW, Dweni CK, Mwangi M, Kinuthia JM, Mwangi IN, Maina GM, Agola LE, Zhang SM, Maranga R, Loker ES, Mkoji GM. Field-derived Schistosoma mansoni and Biomphalaria pfeifferi in Kenya: a compatible association characterized by lack of strong local adaptation, and presence of some snails able to persistently produce cercariae for over a year. Parasit Vectors 2014; 7:533. [PMID: 25425455 PMCID: PMC4253995 DOI: 10.1186/s13071-014-0533-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 11/11/2014] [Indexed: 11/29/2022] Open
Abstract
Background Schistosoma mansoni is widely distributed in sub-Saharan Africa with Biomphalaria pfeifferi being its most widespread and important snail intermediate host. Few studies have examined the compatibility of field-derived B. pfeifferi snails with S. mansoni miracidia derived from human hosts. We investigated compatibility (as defined by shedding of cercariae following exposure to miracidia) of two isolates of S. mansoni from school children from Asao (western Kenya) and Mwea (central Kenya) with B. pfeifferi collected directly from Asao stream or the Mwea rice fields. Methods We exposed snails from both regions to four different doses of miracidia (1, 5, 10 and 25) from sympatric or allopatric S. mansoni, and maintained them in a shaded, screened out-of-doors rearing facility in Kisian, in western Kenya. Both snail survival and the number of snails that became infected were monitored weekly. This was done for 25 weeks post-exposure (PE). Those infected snails which survived beyond this period were monitored until they all died. Results Although overall survival of Mwea snails maintained in western Kenya was generally low, both sympatric and allopatric combinations of parasites and snails exhibited high compatibility (approximately 50% at a dose of one miracidium per snail), with an increase in infection rates as the miracidial dose was increased (P < 0.002). Schistosomes were no more compatible with sympatric than allopatric snails, nor were snails less compatible with sympatric than allopatric schistosomes. Snail mortality increased significantly with dose of miracidia (P < 0.05). Approximately 3% of Asao snails exposed to a low dose of sympatric miracidia (1 or 5) continued to shed cercariae for as long as 58 weeks post exposure. Conclusions There were no significant local adaptation effects for either schistosomes or snails. Also, the existence of “super-survivor” snails is noteworthy for its implications for current control initiatives that mostly rely on mass drug administration (MDA). Long-term shedders could provide an ongoing source of cercariae to initiate human infections for many months, suggesting care is required in considering how human MDA treatments are timed. Future control programs should incorporate means to eliminate infected snails to complement chemotherapy interventions in controlling schistosomiasis. Electronic supplementary material The online version of this article (doi:10.1186/s13071-014-0533-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Martin W Mutuku
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), P.O Box 54840-00200, Nairobi, Kenya.
| | - Celestine K Dweni
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), P.O Box 54840-00200, Nairobi, Kenya.
| | - Moses Mwangi
- Centre for Public Health Research, KEMRI, P.O Box 20752-00200, Nairobi, Kenya.
| | - Joseph M Kinuthia
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), P.O Box 54840-00200, Nairobi, Kenya.
| | - Ibrahim N Mwangi
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), P.O Box 54840-00200, Nairobi, Kenya.
| | - Geoffrey M Maina
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), P.O Box 54840-00200, Nairobi, Kenya.
| | - Lelo E Agola
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), P.O Box 54840-00200, Nairobi, Kenya.
| | - Si-Ming Zhang
- Center for Evolutionary and Theoretical Immunology, Department of Biology, and Parasitology Division, Museum of Southwestern Biology, University of New Mexico, Albuquerque, 87131, U.S.A.
| | - Rosebella Maranga
- Department of Zoology, Jomo Kenyatta University of Agriculture and Technology, P.O Box 62000-00200, Nairobi, Kenya.
| | - Eric S Loker
- Center for Evolutionary and Theoretical Immunology, Department of Biology, and Parasitology Division, Museum of Southwestern Biology, University of New Mexico, Albuquerque, 87131, U.S.A.
| | - Gerald M Mkoji
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), P.O Box 54840-00200, Nairobi, Kenya.
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Golan R, Gower CM, Emery AM, Rollinson D, Webster JP. Isolation and characterization of the first polymorphic microsatellite markers for Schistosoma haematobium and their application in multiplex reactions of larval stages. Mol Ecol Resour 2013; 8:647-9. [PMID: 21585859 DOI: 10.1111/j.1471-8286.2007.02031.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ability of microsatellite loci to reveal genetic diversity within the trematode Schistosoma haematobium is demonstrated for the first time. Nine novel polymorphic microsatellite markers were isolated and their viability assessed on 36 S. haematobium adult worm individuals from three geographical populations. Allelic diversity and gene diversity ranged from two to seven and from 0.29 to 0.76, respectively, suggesting high variability between individuals and between unrelated populations. Three primers also amplified Schistosoma mansoni and two Schistosoma japonicum. The results suggest these primers are useful for population genetic analyses of S. haematobium.
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Affiliation(s)
- R Golan
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College, London, Norfolk Place, London W2 1PG, UK, Wolfson Wellcome Biomedical Laboratories, Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK
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Detwiler JT, Criscione CD. Testing Mendelian inheritance from field-collected parasites: Revealing duplicated loci enables correct inference of reproductive mode and mating system. Int J Parasitol 2011; 41:1185-95. [DOI: 10.1016/j.ijpara.2011.07.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 07/12/2011] [Accepted: 07/14/2011] [Indexed: 11/16/2022]
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Population genetics of Schistosoma haematobium: development of novel microsatellite markers and their application to schistosomiasis control in Mali. Parasitology 2011; 138:978-94. [PMID: 21679489 DOI: 10.1017/s0031182011000722] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The recent implementation of mass drug administration (MDA) for control of uro-genital schistosomiasis has identified an urgent need for molecular markers to both directly monitor the impact of MDA, for example to distinguish re-infections from uncleared infections, as well as understand aspects of parasite reproduction and gene flow which might predict evolutionary change, such as the development and spread of drug resistance. We report the development of a novel microsatellite tool-kit allowing, for the first time, robust genetic analysis of individual S. haematobium larvae collected directly from infected human hosts. We genotyped the parasite populations of 47 children from 2 schools in the Ségou region of Mali, the first microsatellite study of this highly neglected parasite. There was only limited evidence of population subdivision between individual children or between the two schools, suggesting that few barriers to gene flow exist in this population. Complex relationships between parasite reproductive success, infection intensity and host age and gender were identified. Older children and boys harboured more diverse infections, as measured by the number of unique adult genotypes present. Individual parasite genotypes had variable reproductive success both across hosts, a pre-requisite for evolutionary selection, and, phenotypically, in hosts of different ages and genders. These data serve as a baseline against which to measure the effect of treatment on parasite population genetics in this region of Mali, and the tools developed are suitable to further investigate this important pathogen, and its close relatives, throughout their range.
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Optimal sample storage and extraction procotols for reliable multilocus genotyping of the human parasite Schistosoma mansoni. INFECTION GENETICS AND EVOLUTION 2011; 11:1413-8. [PMID: 21605705 DOI: 10.1016/j.meegid.2011.05.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 04/05/2011] [Accepted: 05/08/2011] [Indexed: 11/21/2022]
Abstract
Genotyping individual larval stages and eggs of natural parasite populations is complicated by the difficulty of obtaining reliable genotypes from low quantity DNA template. A suitable storage and extraction protocol, together with a thorough quantification of genotyping errors are therefore crucial for molecular epidemiological studies. Here we test the robustness, handling time, ease of use, cost effectiveness and success rate of various fixation (Whatman FTA(®) Classic and Elute Cards, 70% EtOH and RNAlater(®)) and subsequent DNA extraction methods (commercial kits and proteinase K protocol). None of these methods require a cooling chain and are therefore suitable for field collection. Based on a multiplex microsatellite PCR with nine loci the success and reliability of each technique is evaluated by the proportion of samples with at least eight scored loci and the proportion of genotyping errors. If only the former is taken into account, FTA(®) Elute is recommended (83% success; 44% genotyping error; 0.2 €/sample; 1h 20 m handling time). However, when also considering the genotyping errors, handling time and ease of use, we opt for 70% EtOH with the 96-well plate technology followed by a simple proteinase K extraction (73% success; 0% genotyping error; 0.2 €/sample; 15m handling time). For eggs we suggest (1) to pool all eggs per person in 1.5 ml tubes filled with 70% EtOH for transport and (2) to identify each egg to species level prior to genotyping. To this end we extended the Rapid diagnostic PCR developed by Webster et al. (2010) with a S. mansoni-specific primer to discriminate between S. mansoni, S. haematobium and S. bovis in a single PCR reaction. The success rate of genotyping eggs was 75% (0% genotyping error). This is the first study to incorporate genotyping errors through re-amplification for the evaluation of schistosome sampling protocols and the identification of error-prone loci.
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Jones-Nelson O, Thiele EA, Minchella DJ. Transmission dynamics of two strains of Schistosoma mansoni utilizing novel intermediate and definitive hosts. Parasitol Res 2011; 109:675-87. [PMID: 21369763 DOI: 10.1007/s00436-011-2299-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 02/17/2011] [Indexed: 11/24/2022]
Abstract
The intimate host-parasite relationship mandates adaptation to the genetic and phenotypic variability of their counterparts. Here, inbred and outcrossed strains of Schistosoma mansoni were challenged with "local" and "novel" intermediate and definitive hosts to examine effects of genetic variability and novelty on infection success and dynamics. Genetically distinct lines of Biomphalaria glabrata intermediate hosts exposed to inbred and outcrossed S. mansoni larvae were assessed for differences in both snail and parasite life-history parameters. Cercariae from each parasite-snail treatment were used to infect "local" and "novel" Mus musculus definitive hosts to assess parasite infectivity and fitness. Outcrossed parasites significantly reduced snail growth, were more productive, and induced greater host mortality than inbred parasites. Mouse strain did not influence parasite infectivity or reproduction, but parasite and snail host genetic background did, affecting both sex-specific infectivity and parasite productivity. Overall, genetic background of S. mansoni and its intermediate snail host altered life history traits and transmission dynamics of the parasite throughout its life cycle.
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Affiliation(s)
- Omari Jones-Nelson
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
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Bech N, Beltran S, Portela J, Rognon A, Allienne JF, Boissier J, Théron A. Follow-up of the genetic diversity and snail infectivity of a Schistosoma mansoni strain from field to laboratory. INFECTION GENETICS AND EVOLUTION 2010; 10:1039-45. [DOI: 10.1016/j.meegid.2010.06.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 05/27/2010] [Accepted: 06/23/2010] [Indexed: 11/27/2022]
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Steinauer ML, Blouin MS, Criscione CD. Applying evolutionary genetics to schistosome epidemiology. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2010; 10:433-43. [PMID: 20176142 PMCID: PMC2861999 DOI: 10.1016/j.meegid.2010.02.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 02/09/2010] [Accepted: 02/15/2010] [Indexed: 10/19/2022]
Abstract
We review how molecular markers and evolutionary analysis have been applied to the study of schistosome parasites, important pathogens that infect over 200 million people worldwide. Topics reviewed include phylogenetics and biogeography, hybridization, infection within snails, mating systems, and genetic structure. Some interesting generalizations include that schistosome species hybridize frequently and have switched definitive hosts repeatedly in evolutionary time. We show that molecular markers can be used to infer epidemiologically relevant processes such as spatial variation in transmission, or to reveal complex patterns of mate choice. Analysis of genetic structure data shows that transmission foci can be structured by watershed boundaries, habitat types, and host species. We also discuss sampling and analytical problems that arise when using larvae to estimate genetic parameters of adult schistosome populations. Finally, we review pitfalls in methodologies such as genotyping very small individuals, statistical methods for identifying clonemates or for identifying sibling groups, and estimating allele frequencies from pooled egg samples.
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Affiliation(s)
- Michelle L Steinauer
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, Corvallis, OR 97331, United States.
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Blank WA, Reis EAG, Thiong'o FW, Braghiroli JF, Santos JM, Melo PRS, Guimarães ICS, Silva LK, Carmo TMA, Reis MG, Blanton RE. Analysis of Schistosoma mansoni population structure using total fecal egg sampling. J Parasitol 2010; 95:881-9. [PMID: 20049994 DOI: 10.1645/ge-1895.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Many parasite populations are difficult to sample because they are not uniformly distributed between several host species and are often not easily collected from the living host, thereby limiting sample size and possibly distorting the representation of the population. For the parasite Schistosoma mansoni, we investigated the use of eggs, in aggregate, from the stools of infected individuals as a simple and representative sample. Previously, we demonstrated that microsatellite allele frequencies can be accurately estimated from pooled DNA of cloned S. mansoni adults. Here, we show that genotyping of parasite populations from reproductively isolated laboratory strains can be used to identify these specific populations based on characteristic patterns of allele frequencies, as observed by polyacrylamide gel electrophoresis and automated sequencer analysis of fluorescently labeled PCR products. Microsatellites used to genotype aggregates of eggs collected from stools of infected individuals produced results consistent with the geographic distribution of the samples. Preferential amplification of smaller alleles, and stutter PCR products, had negligible effect on measurement of genetic differentiation. Direct analysis of total stool eggs can be an important approach to questions of population genetics for this parasite by increasing the sample size to thousands per infected individual and by reducing bias.
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Affiliation(s)
- Walter A Blank
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Valentim CLL, LoVerde PT, Anderson TJC, Criscione CD. Efficient genotyping of Schistosoma mansoni miracidia following whole genome amplification. Mol Biochem Parasitol 2009; 166:81-4. [PMID: 19428677 PMCID: PMC2771185 DOI: 10.1016/j.molbiopara.2009.02.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Revised: 02/12/2009] [Accepted: 02/18/2009] [Indexed: 01/25/2023]
Abstract
Small parasites and larval stages pose a problem for molecular analyses because limited amounts of DNA template are available. Isothermal methods for faithfully copying DNA have the potential to revolutionize studies of such organisms. We evaluated the fidelity of multiple displacement amplification (MDA) for amplifying DNA extracted from a single miracidium of Schistosoma mansoni. To do this we genotyped DNA extracted from 28 F1 miracidia following MDA using 56 microsatellite markers. Because these miracidia were obtained from a cross between a male and female worm of known genotypes, we were able to predict the alleles present in the progeny and quantify the genotyping error rate. We found just 8/1568 genotypes deviated from Mendelian expectations. Furthermore, because 1 of these resulted from a genuine mutation, the error rate due to MDA is 7/1568 (0.45%). We conclude that many hundreds of microsatellites or other genetic markers can be accurately genotyped from a single miracidium using this method, greatly expanding the scope of population genetic, epidemiological and evolutionary studies on this parasite.
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Affiliation(s)
- Claudia L L Valentim
- Department of Genetics, Southwest Foundation for Biomedical Research, San Antonio, TX 78245, USA
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Hanelt B, Steinauer ML, Mwangi IN, Maina GM, Agola LE, Mkoji GM, Loker ES. A new approach to characterize populations of Schistosoma mansoni from humans: development and assessment of microsatellite analysis of pooled miracidia. Trop Med Int Health 2009; 14:322-31. [PMID: 19187519 DOI: 10.1111/j.1365-3156.2009.02226.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To develop and assess a microsatellite technique to characterize populations of Schistosoma mansoni from humans. METHODS For each of five patients, we calculated the allele count and frequency at 11 loci for several pools of miracidia (50 and 100), and compared these to population values, determined by amplifying microsatellites from 186 to 200 individual miracidia per patient. RESULTS We were able to detect up to 94.5% of alleles in pools. Allele count and frequency strongly and significantly correlated between singles and pools; marginally significant differences (P < 0.05) were detected for one patient (pools of 50) for allele frequencies and for two patients (pools of 100) for allele counts. Kato-Katz egg counts and number of alleles per pool did not co-vary, indicating that further direct comparisons of the results from these two techniques are needed. CONCLUSIONS Allele counts and frequency profiles from pooling provide important information about infection intensity and complexity, beyond that obtained from traditional methods. Although we are not advocating use of pooling to replace individual genotyping studies, it can potentially be useful in certain applications as a rapid and cost effective screening method for studies of S. mansoni population genetics, or as a more informative way to quantify and characterize human worm populations.
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Affiliation(s)
- B Hanelt
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA.
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Beltran S, Galinier R, Allienne JF, Boissier J. Cheap, rapid and efficient DNA extraction method to perform multilocus microsatellite genotyping on all Schistosoma mansoni stages. Mem Inst Oswaldo Cruz 2008; 103:501-3. [DOI: 10.1590/s0074-02762008000500017] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Accepted: 07/28/2008] [Indexed: 11/21/2022] Open
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Beltran S, Boissier J. Schistosome monogamy: who, how, and why? Trends Parasitol 2008; 24:386-91. [PMID: 18674968 DOI: 10.1016/j.pt.2008.05.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 05/06/2008] [Accepted: 05/22/2008] [Indexed: 11/19/2022]
Abstract
Schistosomes represent a unique animal model for comparative analyses of monogamy. Indeed, schistosomes are classified at the lowest taxonomical level of monogamous species and lack complex social interactions, which could alter our understanding of their unusual mating system. Elements discussed here include the fact that monogamy in schistosomes could be an ancestral state between hermaphroditism and polygyny or polygynandry and the occurrence of mate changes. In addition, hypotheses are proposed to explain monogamy in schistosomes (e.g. female dispersion, the need for paternal care, oviposition site limitation or aggressiveness, and mate guarding). We also propose future experimental and analytical approaches to improve our understanding of the schistosomes' mating system.
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Affiliation(s)
- S Beltran
- UMR 5244 CNRS-EPHE-UPVD, Parasitologie Fonctionnelle et Evolutive, Laboratoire de Biologie et d'Ecologie Tropicale et Méditerranéenne, 52 Avenue Paul Alduy, 66 860 Perpignan, France
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Zavodna M, Sandland GJ, Minchella DJ. Effects of intermediate host genetic background on parasite transmission dynamics: a case study using Schistosoma mansoni. Exp Parasitol 2008; 120:57-61. [PMID: 18538767 DOI: 10.1016/j.exppara.2008.04.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Revised: 04/14/2008] [Accepted: 04/28/2008] [Indexed: 11/16/2022]
Abstract
For parasites that require multiple hosts to complete their development, genetic interplay with one host may impact parasite transmission and establishment in subsequent hosts. In this study, we used microsatellite loci to address whether the genetic background of snail intermediate hosts influences life-history traits and transmission patterns of dioecious trematode parasites in their definitive hosts. We performed experimental Schistosoma mansoni infections utilizing two allopatric populations of Biomphalaria glabrata snails and assessed intensities and sex ratios of adult parasites in mouse definitive hosts. Our results suggest that the genetic background of hosts at one point in a parasite's life cycle can influence the intensities and sex ratios of worms in subsequent hosts.
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Affiliation(s)
- Monika Zavodna
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA.
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18
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Steinauer ML, Agola LE, Mwangi IN, Mkoji GM, Loker ES. Molecular epidemiology of Schistosoma mansoni: A robust, high-throughput method to assess multiple microsatellite markers from individual miracidia. INFECTION GENETICS AND EVOLUTION 2008; 8:68-73. [DOI: 10.1016/j.meegid.2007.10.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Thiele EA, Sorensen RE, Gazzinelli A, Minchella DJ. Genetic diversity and population structuring of Schistosoma mansoni in a Brazilian village. Int J Parasitol 2007; 38:389-99. [PMID: 17825305 PMCID: PMC2476926 DOI: 10.1016/j.ijpara.2007.07.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Revised: 07/07/2007] [Accepted: 07/10/2007] [Indexed: 11/20/2022]
Abstract
The digenean trematode Schistosoma mansoni is responsible for chronic schistosomiasis worldwide, and in Brazil alone an estimated 35 million people are at risk. To evaluate epidemiological patterns among human definitive hosts, we assessed genetic diversity and population subdivision of S. mansoni infrapopulations in human hosts from the highly endemic village of Virgem das Graças in the state of Minas Gerais, Brazil. We believe this is the largest such survey to date. Genetic diversity of parasites, measured over eight polymorphic microsatellite loci, was relatively high and standard measures of inbreeding indicated that the population was panmictic. Furthermore, there was no significant isolation-by-distance of parasite infrapopulations, and measures of population subdivision indicated significant but low to moderate levels of population differentiation. We conclude that patients within this village sample from a broad range of schistosome genetic diversity and effectively act as "genetic mixing bowls" for the parasites. These results contrast with those previously observed in the Brazilian village of Melqui ades and thus provide the opportunity for comparisons of environmental and epidemiological differences that are likely to influence host-parasite coevolution and parasite transmission.
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Affiliation(s)
- E A Thiele
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA.
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Zarowiecki MZ, Huyse T, Littlewood DTJ. Making the most of mitochondrial genomes--markers for phylogeny, molecular ecology and barcodes in Schistosoma (Platyhelminthes: Digenea). Int J Parasitol 2007; 37:1401-18. [PMID: 17570370 DOI: 10.1016/j.ijpara.2007.04.014] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Revised: 04/19/2007] [Accepted: 04/24/2007] [Indexed: 11/27/2022]
Abstract
An increasing number of complete sequences of mitochondrial (mt) genomes provides the opportunity to optimise the choice of molecular markers for phylogenetic and ecological studies. This is particularly the case where mt genomes from closely related taxa have been sequenced; e.g., within Schistosoma. These blood flukes include species that are the causative agents of schistosomiasis, where there has been a need to optimise markers for species and strain recognition. For many phylogenetic and population genetic studies, the choice of nucleotide sequences depends primarily on suitable PCR primers. Complete mt genomes allow individual gene or other mt markers to be assessed relative to one another for potential information content, prior to broad-scale sampling. We assess the phylogenetic utility of individual genes and identify regions that contain the greatest interspecific variation for molecular ecological and diagnostic markers. We show that variable characters are not randomly distributed along the genome and there is a positive correlation between polymorphism and divergence. The mt genomes of African and Asian schistosomes were compared with the available intraspecific dataset of Schistosoma mansoni through sliding window analyses, in order to assess whether the observed polymorphism was at a level predicted from interspecific comparisons. We found a positive correlation except for the two genes (cox1 and nad1) adjoining the putative control region in S. mansoni. The genes nad1, nad4, nad5, cox1 and cox3 resolved phylogenies that were consistent with a benchmark phylogeny and in general, longer genes performed better in phylogenetic reconstruction. Considering the information content of entire mt genome sequences, partial cox1 would not be the ideal marker for either species identification (barcoding) or population studies with Schistosoma species. Instead, we suggest the use of cox3 and nad5 for both phylogenetic and population studies. Five primer pairs designed against Schistosoma mekongi and Schistosoma malayensis were tested successfully against Schistosoma japonicum. In combination, these fragments encompass 20-27% of the variation amongst the genomes (average total length approximately 14,000bp), thus providing an efficient means of encapsulating the greatest amount of variation within the shortest sequence. Comparative mitogenomics provides the basis of a rational approach to molecular marker selection and optimisation.
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Affiliation(s)
- M Z Zarowiecki
- Wolfson Wellcome Biomedical Laboratories, Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK
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