Pub Date : 2022-10-27DOI: 10.3389/fpara.2022.1033485
Gilbert Munsaka, K. Hayashida, Benjtamin Mubemba, E. Simulundu, N. Mulunda, Ruth Pule, S. Sianongo, Marina Makuluni, Walter Muleya, Katendi Changula, S. Chitanga, M. Mutengo
Background Blastocystis sp. is a common enteric eukaryote of humans whose pathogenicity is still debatable. However, a number of reported Blastocystis colonization associated with enteric disease exist. In Zambia, presence of the pathogen has previously been reported in children. However, the molecular epidemiology of Blastocystis colonization remains unclarified in Zambia. Methods and results Archived stool samples submitted for routine parasitological diagnosis at Zambia’s largest tertiary referral hospital positive for Blastocystis sp. by microscopic examination were selected for the study. Subtyping of the Blastocystis was done based on polymerase chain reactions (PCR) amplification, sequencing and subsequent phylogenetic analysis of the 18S small subunit (SSU) rDNA gene. Four subtypes, ST1 (allele 4), ST2 (allele 12), ST3 (allele 34, 36, 37, 38, 39) and ST6 (allele 122), were identified by molecular procedures in the study, with some Zambian sequences showing close relationships with those detected in non-human primates and common rats. Conclusions The study revealed the circulation of multiple Blastocystis subtypes ST1, 20% (9/45), ST2, 15% (7/45), ST3 24.4% (11/45), and ST6, 2.2% (1/45) in the study population. The close clustering of some Zambian sequences with those detected from animals suggests the possibility of the presence of both anthroponotic and zoonotic transmission cycles in the country. Further studies in animal populations are recommended for a better understanding of the epidemiology of Blastocystis and for implementation of effective evidence-based control strategies.
{"title":"Molecular subtyping of Blastocystis sp. detected in patients at a large tertiary referral hospital in Lusaka, Zambia","authors":"Gilbert Munsaka, K. Hayashida, Benjtamin Mubemba, E. Simulundu, N. Mulunda, Ruth Pule, S. Sianongo, Marina Makuluni, Walter Muleya, Katendi Changula, S. Chitanga, M. Mutengo","doi":"10.3389/fpara.2022.1033485","DOIUrl":"https://doi.org/10.3389/fpara.2022.1033485","url":null,"abstract":"Background Blastocystis sp. is a common enteric eukaryote of humans whose pathogenicity is still debatable. However, a number of reported Blastocystis colonization associated with enteric disease exist. In Zambia, presence of the pathogen has previously been reported in children. However, the molecular epidemiology of Blastocystis colonization remains unclarified in Zambia. Methods and results Archived stool samples submitted for routine parasitological diagnosis at Zambia’s largest tertiary referral hospital positive for Blastocystis sp. by microscopic examination were selected for the study. Subtyping of the Blastocystis was done based on polymerase chain reactions (PCR) amplification, sequencing and subsequent phylogenetic analysis of the 18S small subunit (SSU) rDNA gene. Four subtypes, ST1 (allele 4), ST2 (allele 12), ST3 (allele 34, 36, 37, 38, 39) and ST6 (allele 122), were identified by molecular procedures in the study, with some Zambian sequences showing close relationships with those detected in non-human primates and common rats. Conclusions The study revealed the circulation of multiple Blastocystis subtypes ST1, 20% (9/45), ST2, 15% (7/45), ST3 24.4% (11/45), and ST6, 2.2% (1/45) in the study population. The close clustering of some Zambian sequences with those detected from animals suggests the possibility of the presence of both anthroponotic and zoonotic transmission cycles in the country. Further studies in animal populations are recommended for a better understanding of the epidemiology of Blastocystis and for implementation of effective evidence-based control strategies.","PeriodicalId":73098,"journal":{"name":"Frontiers in parasitology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43119657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.3389/fpara.2022.1000673
A. Troccoli, G. d’Errico, T. D’Addabbo, N. Sasanelli, A. Bosco, M. P. Maurelli, L. Rinaldi, G. Cringoli
FLOTAC Techniques have been widely acknowledged as an effective method for the extraction of human and animal parasites. The present study is the first application of FLOTAC basic technique (FBT) for the extraction of phytoparasitic nematodes from soil and infested plant roots. Eggs and second stage juveniles (J2) of the root-knot nematode Meloidogyne incognita were extracted from infested soil and tomato roots either by FBT and conventional nematode extraction methods, such as centrifugal flotation and root maceration techniques, respectively. The number of M. incognita J2 and eggs extracted from soil by FBT was always significantly higher compared to the extraction with the centrifugal flotation method, averaging 277 vs 35 eggs and J2 mL-1 soil. Conversely, no significant differences were observed between FBT and the root maceration technique in the extraction of eggs and J2 from tomato roots. Results demonstrated that FBT can be highly effective also for the extraction of phytoparasitic nematodes. Due to its accuracy and sensitivity, FBT seems particularly suitable for nematode surveys in wide geographical areas, where an accurate and rapid detection of present phytoparasitic nematofauna is required.
{"title":"The FLOTAC basic technique as a new extraction method for root-knot nematodes (Meloidogyne spp.) from soil and roots","authors":"A. Troccoli, G. d’Errico, T. D’Addabbo, N. Sasanelli, A. Bosco, M. P. Maurelli, L. Rinaldi, G. Cringoli","doi":"10.3389/fpara.2022.1000673","DOIUrl":"https://doi.org/10.3389/fpara.2022.1000673","url":null,"abstract":"FLOTAC Techniques have been widely acknowledged as an effective method for the extraction of human and animal parasites. The present study is the first application of FLOTAC basic technique (FBT) for the extraction of phytoparasitic nematodes from soil and infested plant roots. Eggs and second stage juveniles (J2) of the root-knot nematode Meloidogyne incognita were extracted from infested soil and tomato roots either by FBT and conventional nematode extraction methods, such as centrifugal flotation and root maceration techniques, respectively. The number of M. incognita J2 and eggs extracted from soil by FBT was always significantly higher compared to the extraction with the centrifugal flotation method, averaging 277 vs 35 eggs and J2 mL-1 soil. Conversely, no significant differences were observed between FBT and the root maceration technique in the extraction of eggs and J2 from tomato roots. Results demonstrated that FBT can be highly effective also for the extraction of phytoparasitic nematodes. Due to its accuracy and sensitivity, FBT seems particularly suitable for nematode surveys in wide geographical areas, where an accurate and rapid detection of present phytoparasitic nematofauna is required.","PeriodicalId":73098,"journal":{"name":"Frontiers in parasitology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47478182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-09DOI: 10.3389/fpara.2022.984152
Karma Yeshi, R. Ruscher, A. Loukas, P. Wangchuk
Parasitic helminths secrete and excrete a vast array of molecules known to help skew or suppress the host’s immune response, thereby establishing a niche for sustained parasite maintenance. Indeed, the immunomodulatory potency of helminths is attributed mainly to excretory/secretory products (ESPs). The ESPs of helminths and the identified small molecules (SM) are reported to have diverse biological and pharmacological properties. The available literature reports only limited metabolites, and the identity of many metabolites remains unknown due to limitations in the identification protocols and helminth-specific compound libraries. Many metabolites are known to be involved in host-parasite interactions and pathogenicity. For example, fatty acids (e.g., stearic acid) detected in the infective stages of helminths are known to have a role in host interaction through facilitating successful penetration and migration inside the host. Moreover, excreted/secreted SM detected in helminth species are found to possess various biological properties, including anti-inflammatory activities, suggesting their potential in developing immunomodulatory drugs. For example, helminths-derived somatic tissue extracts and whole crude ESPs showed anti-inflammatory properties by inhibiting the secretion of proinflammatory cytokines from human peripheral blood mononuclear cells and suppressing the pathology in chemically-induced experimental mice model of colitis. Unlike bigger molecules like proteins, SM are ideal candidates for drug development since they are small structures, malleable, and lack immunogenicity. Future studies should strive toward identifying unknown SM and isolating the under-explored niche of helminth metabolites using the latest metabolomics technologies and associated software, which hold potential keys for finding new diagnostics and novel therapeutics.
{"title":"Immunomodulatory and biological properties of helminth-derived small molecules: Potential applications in diagnostics and therapeutics","authors":"Karma Yeshi, R. Ruscher, A. Loukas, P. Wangchuk","doi":"10.3389/fpara.2022.984152","DOIUrl":"https://doi.org/10.3389/fpara.2022.984152","url":null,"abstract":"Parasitic helminths secrete and excrete a vast array of molecules known to help skew or suppress the host’s immune response, thereby establishing a niche for sustained parasite maintenance. Indeed, the immunomodulatory potency of helminths is attributed mainly to excretory/secretory products (ESPs). The ESPs of helminths and the identified small molecules (SM) are reported to have diverse biological and pharmacological properties. The available literature reports only limited metabolites, and the identity of many metabolites remains unknown due to limitations in the identification protocols and helminth-specific compound libraries. Many metabolites are known to be involved in host-parasite interactions and pathogenicity. For example, fatty acids (e.g., stearic acid) detected in the infective stages of helminths are known to have a role in host interaction through facilitating successful penetration and migration inside the host. Moreover, excreted/secreted SM detected in helminth species are found to possess various biological properties, including anti-inflammatory activities, suggesting their potential in developing immunomodulatory drugs. For example, helminths-derived somatic tissue extracts and whole crude ESPs showed anti-inflammatory properties by inhibiting the secretion of proinflammatory cytokines from human peripheral blood mononuclear cells and suppressing the pathology in chemically-induced experimental mice model of colitis. Unlike bigger molecules like proteins, SM are ideal candidates for drug development since they are small structures, malleable, and lack immunogenicity. Future studies should strive toward identifying unknown SM and isolating the under-explored niche of helminth metabolites using the latest metabolomics technologies and associated software, which hold potential keys for finding new diagnostics and novel therapeutics.","PeriodicalId":73098,"journal":{"name":"Frontiers in parasitology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47821984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-07DOI: 10.3389/fpara.2022.963515
Mark C. Field
Our civilization faces unprecedented challenges, many the result of past inaction (Broecker, 1975). The COVID-19 pandemic drives on in much of the world, there is new war in Europe, continuing conflicts and military persecution of civilians elsewhere and climate change may be close to an irreversible threat to food supply and security, as well as leading to a collapse in biodiversity (Outhwaite and McCann P, 2022). Political extremism and corruption have risen on both the left and the right of the spectrum, carbon-based fuel prices have risen and remain volatile and there is a continual and increasing refugee crisis.We are already witnessing the impacts from these economic, environmental and social challenges toward health, economic prosperity and well-being, with the correlated peril that poverty and disease are intertwined. Altered impacts from diseases caused by eukaryotic pathogens, parasites, are no exception (Figure 1). Some of these events have direct effects on host and vector ranges. Migrations due to armed conflict, economic and societal concerns and climate change are potentially bringing parasitic infections into naive populations or increasing their prevalence significantly. Other movements, not necessarily classed as migration, can bring parasites directly into an otherwise unaffected population, as has been suggested for Trypanosoma cruzi into Europe (Antinori et al., 2017). These events represent challenges to healthcare and the expertise of practitioners now facing new diagnostic challenges. The news is, however, not all grim. A combination of new or improved technology, innovation and co-operation between NGOs, governments, fundraisers and granting agencies promises much, as evidenced by the London declaration of 2012 (Hotez et al., 2017). Rapid sequencing, diagnostics and cheap computing has put enormously powerful tools into our hands going forward, both for development of therapeutics against parasites and for increasing knowledge of their fundamental biology. I submit that basic biological knowledge is always of huge importance, but when coupled with an understanding of translational potential, can have a direct impact on disease. This is where molecular cellular parasitology has questions, answers and opinions to offer, and I will propose several Grand Challenges which will be complemented by a research topic article collection charging people within the field to discuss those advances and questions that, for them, are themost pressing (Box 1).
{"title":"Molecular Cellular Parasitology: The Decades and Challenges Ahead","authors":"Mark C. Field","doi":"10.3389/fpara.2022.963515","DOIUrl":"https://doi.org/10.3389/fpara.2022.963515","url":null,"abstract":"Our civilization faces unprecedented challenges, many the result of past inaction (Broecker, 1975). The COVID-19 pandemic drives on in much of the world, there is new war in Europe, continuing conflicts and military persecution of civilians elsewhere and climate change may be close to an irreversible threat to food supply and security, as well as leading to a collapse in biodiversity (Outhwaite and McCann P, 2022). Political extremism and corruption have risen on both the left and the right of the spectrum, carbon-based fuel prices have risen and remain volatile and there is a continual and increasing refugee crisis.We are already witnessing the impacts from these economic, environmental and social challenges toward health, economic prosperity and well-being, with the correlated peril that poverty and disease are intertwined. Altered impacts from diseases caused by eukaryotic pathogens, parasites, are no exception (Figure 1). Some of these events have direct effects on host and vector ranges. Migrations due to armed conflict, economic and societal concerns and climate change are potentially bringing parasitic infections into naive populations or increasing their prevalence significantly. Other movements, not necessarily classed as migration, can bring parasites directly into an otherwise unaffected population, as has been suggested for Trypanosoma cruzi into Europe (Antinori et al., 2017). These events represent challenges to healthcare and the expertise of practitioners now facing new diagnostic challenges. The news is, however, not all grim. A combination of new or improved technology, innovation and co-operation between NGOs, governments, fundraisers and granting agencies promises much, as evidenced by the London declaration of 2012 (Hotez et al., 2017). Rapid sequencing, diagnostics and cheap computing has put enormously powerful tools into our hands going forward, both for development of therapeutics against parasites and for increasing knowledge of their fundamental biology. I submit that basic biological knowledge is always of huge importance, but when coupled with an understanding of translational potential, can have a direct impact on disease. This is where molecular cellular parasitology has questions, answers and opinions to offer, and I will propose several Grand Challenges which will be complemented by a research topic article collection charging people within the field to discuss those advances and questions that, for them, are themost pressing (Box 1).","PeriodicalId":73098,"journal":{"name":"Frontiers in parasitology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46313571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-01Epub Date: 2022-07-04DOI: 10.3389/fpara.2022.963671
Richard J Martin
{"title":"Therapeutic and Diagnostic Innovation for Parasitology: Grand Challenges.","authors":"Richard J Martin","doi":"10.3389/fpara.2022.963671","DOIUrl":"10.3389/fpara.2022.963671","url":null,"abstract":"","PeriodicalId":73098,"journal":{"name":"Frontiers in parasitology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10249670/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9707062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-28DOI: 10.3389/fpara.2022.902098
A. Loukas
Parasites are themost prevalent group of eukaryotic organisms on the planet. Humans harbor more than 300 species of helminths and 70 species of protozoans (Cox, 2002). Some of these parasites are rare or accidental passengers, but at least 90 parasites are relatively common inhabitants of the human body. If the other 65,000 species of known vertebrates house a similar number of different parasites, then we are talking about almost 6 million different types of parasites in vertebrate hosts alone. Admittedly, some parasites infect multiple different hosts, but nonetheless, their diversity is impressive. Then consider the 1.3 million known invertebrate animals, most of which also harbor multicellular and unicellular parasites, and then the more than 300,000 plants and their parasites, and the concept becomes slightly overwhelming. Sadly, despite the prevalence and importance of parasites to human and animal health, there are very few examples of commercially available vaccines against parasitic diseases. In this COVID pandemic era as we witnessed anti-viral vaccines go from bench to bedside in a matter of months, it is all the more remarkable that we have so few anti-parasite vaccines despite knowing of their importance for thousands of years.
{"title":"Frontiers in Parasitology Grand Challenge","authors":"A. Loukas","doi":"10.3389/fpara.2022.902098","DOIUrl":"https://doi.org/10.3389/fpara.2022.902098","url":null,"abstract":"Parasites are themost prevalent group of eukaryotic organisms on the planet. Humans harbor more than 300 species of helminths and 70 species of protozoans (Cox, 2002). Some of these parasites are rare or accidental passengers, but at least 90 parasites are relatively common inhabitants of the human body. If the other 65,000 species of known vertebrates house a similar number of different parasites, then we are talking about almost 6 million different types of parasites in vertebrate hosts alone. Admittedly, some parasites infect multiple different hosts, but nonetheless, their diversity is impressive. Then consider the 1.3 million known invertebrate animals, most of which also harbor multicellular and unicellular parasites, and then the more than 300,000 plants and their parasites, and the concept becomes slightly overwhelming. Sadly, despite the prevalence and importance of parasites to human and animal health, there are very few examples of commercially available vaccines against parasitic diseases. In this COVID pandemic era as we witnessed anti-viral vaccines go from bench to bedside in a matter of months, it is all the more remarkable that we have so few anti-parasite vaccines despite knowing of their importance for thousands of years.","PeriodicalId":73098,"journal":{"name":"Frontiers in parasitology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46844110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-27DOI: 10.3389/fpara.2023.1076759
S. Sene, M. Pouye, R. M. Martins, F. Diallo, K. Mangou, A. Bei, Aliou Barry, O. Faye, Oumar Ndiaye, O. Faye, A. Sall, Jose-Juan Lopez-Rubio, A. Mbengue
The emergence of artemisinin partial resistance (ART-r) in Plasmodium falciparum malaria parasites has substantially compromised the efficacy of antimalarial treatments across southeast Asia (SE Asia). The spread of ART-r within the African continent could jeopardize past progress made in reducing worldwide malaria burden. A clinical index malaria case was identified in Kaolack, Senegal with persistent fever after complete artesunate-amodiaquine (ASAQ) treatment. Fifteen malaria-infected blood samples were collected by Institut Pasteur Dakar’s Senegalese sentinel surveillance system, from different healthcare centers surrounding the index case. We have identified one Plasmodium falciparum clinical isolate carrying R515K mutation in the artemisinin resistance gene PfKelch13. CRISPR-Cas9 genome editing was carried out and transgenic Pf3D7Pfkelch13R515K was tested for in vitro standard Ring-stage Survival Assay (RSA 0-3hpi). Gene editing has confirmed that PfKelch13R515K drove increased in vitro RSA0-3hpi value. In this article, we report the functional significance of PfKelch13R515K mutation in an African context.
{"title":"Identification of an in vitro artemisinin-resistant Plasmodium falciparum kelch13 R515K mutant parasite in Senegal","authors":"S. Sene, M. Pouye, R. M. Martins, F. Diallo, K. Mangou, A. Bei, Aliou Barry, O. Faye, Oumar Ndiaye, O. Faye, A. Sall, Jose-Juan Lopez-Rubio, A. Mbengue","doi":"10.3389/fpara.2023.1076759","DOIUrl":"https://doi.org/10.3389/fpara.2023.1076759","url":null,"abstract":"The emergence of artemisinin partial resistance (ART-r) in Plasmodium falciparum malaria parasites has substantially compromised the efficacy of antimalarial treatments across southeast Asia (SE Asia). The spread of ART-r within the African continent could jeopardize past progress made in reducing worldwide malaria burden. A clinical index malaria case was identified in Kaolack, Senegal with persistent fever after complete artesunate-amodiaquine (ASAQ) treatment. Fifteen malaria-infected blood samples were collected by Institut Pasteur Dakar’s Senegalese sentinel surveillance system, from different healthcare centers surrounding the index case. We have identified one Plasmodium falciparum clinical isolate carrying R515K mutation in the artemisinin resistance gene PfKelch13. CRISPR-Cas9 genome editing was carried out and transgenic Pf3D7Pfkelch13R515K was tested for in vitro standard Ring-stage Survival Assay (RSA 0-3hpi). Gene editing has confirmed that PfKelch13R515K drove increased in vitro RSA0-3hpi value. In this article, we report the functional significance of PfKelch13R515K mutation in an African context.","PeriodicalId":73098,"journal":{"name":"Frontiers in parasitology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41684281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01Epub Date: 2023-01-09DOI: 10.3389/fpara.2022.1006341
Mun Hua Tan, Heejung Shim, Yao-Ban Chan, Karen P Day
The enormous diversity and complexity of var genes that diversify rapidly by recombination has led to the exclusion of assembly of these genes from major genome initiatives (e.g., Pf6). A scalable solution in epidemiological surveillance of var genes is to use a small 'tag' region encoding the immunogenic DBLα domain as a marker to estimate var diversity. As var genes diversify by recombination, it is not clear the extent to which the same tag can appear in multiple var genes. This relationship between marker and gene has not been investigated in natural populations. Analyses of in vitro recombination within and between var genes have suggested that this relationship would not be exclusive. Using a dataset of publicly-available assembled var sequences, we test this hypothesis by studying DBLα-var relationships for four study sites in four countries: Pursat (Cambodia) and Mae Sot (Thailand), representing low malaria transmission, and Navrongo (Ghana) and Chikwawa (Malawi), representing high malaria transmission. In all study sites, DBLα-var relationships were shown to be predominantly 1-to-1, followed by a second largest proportion of 1-to-2 DBLα-var relationships. This finding indicates that DBLα tags can be used to estimate not just DBLα diversity but var gene diversity when applied in a local endemic area. Epidemiological applications of this result are discussed.
{"title":"Unravelling <i>var</i> complexity: Relationship between DBLα types and <i>var</i> genes in <i>Plasmodium falciparum</i>.","authors":"Mun Hua Tan, Heejung Shim, Yao-Ban Chan, Karen P Day","doi":"10.3389/fpara.2022.1006341","DOIUrl":"10.3389/fpara.2022.1006341","url":null,"abstract":"<p><p>The enormous diversity and complexity of <i>var</i> genes that diversify rapidly by recombination has led to the exclusion of assembly of these genes from major genome initiatives (e.g., Pf6). A scalable solution in epidemiological surveillance of <i>var</i> genes is to use a small 'tag' region encoding the immunogenic DBLα domain as a marker to estimate <i>var</i> diversity. As <i>var</i> genes diversify by recombination, it is not clear the extent to which the same tag can appear in multiple <i>var</i> genes. This relationship between marker and gene has not been investigated in natural populations. Analyses of <i>in vitro</i> recombination within and between <i>var</i> genes have suggested that this relationship would not be exclusive. Using a dataset of publicly-available assembled <i>var</i> sequences, we test this hypothesis by studying DBLα-<i>var</i> relationships for four study sites in four countries: Pursat (Cambodia) and Mae Sot (Thailand), representing low malaria transmission, and Navrongo (Ghana) and Chikwawa (Malawi), representing high malaria transmission. In all study sites, DBLα-<i>var</i> relationships were shown to be predominantly 1-to-1, followed by a second largest proportion of 1-to-2 DBLα-<i>var</i> relationships. This finding indicates that DBLα tags can be used to estimate not just DBLα diversity but <i>var</i> gene diversity when applied in a local endemic area. Epidemiological applications of this result are discussed.</p>","PeriodicalId":73098,"journal":{"name":"Frontiers in parasitology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10060044/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9288204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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