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Anne Geiger - One of the best experts on this subject based on the ideXlab platform.
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The composition and abundance of bacterial communities residing in the gut of Glossina palpalis palpalis captured in two sites of southern Cameroon
Parasites & Vectors, 2019Co-Authors: Jean Marc Tsagmo Ngoune, Trésor T. Melachio, Guilhem Sempere, Majoline T. Tchioffo, Julie Reveillaud, Flobert Njiokou, Luc Abate, Anne GeigerAbstract:BackgroundA number of reports have demonstrated the role of insect bacterial flora on their host’s physiology and metabolism. The tsetse host and vector of trypanosomes responsible for human sleeping sickness (human African Trypanosomiasis, HAT) and nagana in Animals (African Animal Trypanosomiasis, AAT) carry bacteria that influence its diet and immune processes. However, the mechanisms involved in these processes remain poorly documented. This underscores the need for increased research into the bacterial flora composition and structure of tsetse flies. The aim of this study was to identify the diversity and relative abundance of bacterial genera in Glossina palpalis palpalis flies collected in two Trypanosomiasis foci in Cameroon.MethodsSamples of G. p. palpalis which were either negative or naturally trypanosome-positive were collected in two foci located in southern Cameroon (Campo and Bipindi). Using the V3V4 and V4 variable regions of the small subunit of the 16S ribosomal RNA gene, we analyzed the respective bacteriome of the flies’ midguts.ResultsWe identified ten bacterial genera. In addition, we observed that the relative abundance of the obligate endosymbiont Wigglesworthia was highly prominent (around 99%), regardless of the analyzed region. The remaining genera represented approximately 1% of the bacterial flora, and were composed of Salmonella, Spiroplasma, Sphingomonas, Methylobacterium, Acidibacter, Tsukamurella, Serratia, Kluyvera and an unidentified bacterium. The genus Sodalis was present but with a very low abundance. Globally, no statistically significant difference was found between the bacterial compositions of flies from the two foci, and between positive and trypanosome-negative flies. However, Salmonella and Serratia were only described in trypanosome-negative flies, suggesting a potential role for these two bacteria in fly refractoriness to trypanosome infection. In addition, our study showed the V4 region of the small subunit of the 16S ribosomal RNA gene was more efficient than the V3V4 region at describing the totality of the bacterial diversity.ConclusionsA very large diversity of bacteria was identified with the discovering of species reported to secrete anti-parasitic compounds or to modulate vector competence in other insects. For future studies, the analyses should be enlarged with larger sampling including foci from several countries.
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the composition and abundance of bacterial communities residing in the gut of glossina palpalis palpalis captured in two sites of southern cameroon
Parasites & Vectors, 2019Co-Authors: Trésor T. Melachio, Guilhem Sempere, Majoline T. Tchioffo, Anne Geiger, Julie Reveillaud, Flobert Njiokou, Luc Abate, Jean NgouneAbstract:A number of reports have demonstrated the role of insect bacterial flora on their host’s physiology and metabolism. The tsetse host and vector of trypanosomes responsible for human sleeping sickness (human African Trypanosomiasis, HAT) and nagana in Animals (African Animal Trypanosomiasis, AAT) carry bacteria that influence its diet and immune processes. However, the mechanisms involved in these processes remain poorly documented. This underscores the need for increased research into the bacterial flora composition and structure of tsetse flies. The aim of this study was to identify the diversity and relative abundance of bacterial genera in Glossina palpalis palpalis flies collected in two Trypanosomiasis foci in Cameroon. Samples of G. p. palpalis which were either negative or naturally trypanosome-positive were collected in two foci located in southern Cameroon (Campo and Bipindi). Using the V3V4 and V4 variable regions of the small subunit of the 16S ribosomal RNA gene, we analyzed the respective bacteriome of the flies’ midguts. We identified ten bacterial genera. In addition, we observed that the relative abundance of the obligate endosymbiont Wigglesworthia was highly prominent (around 99%), regardless of the analyzed region. The remaining genera represented approximately 1% of the bacterial flora, and were composed of Salmonella, Spiroplasma, Sphingomonas, Methylobacterium, Acidibacter, Tsukamurella, Serratia, Kluyvera and an unidentified bacterium. The genus Sodalis was present but with a very low abundance. Globally, no statistically significant difference was found between the bacterial compositions of flies from the two foci, and between positive and trypanosome-negative flies. However, Salmonella and Serratia were only described in trypanosome-negative flies, suggesting a potential role for these two bacteria in fly refractoriness to trypanosome infection. In addition, our study showed the V4 region of the small subunit of the 16S ribosomal RNA gene was more efficient than the V3V4 region at describing the totality of the bacterial diversity. A very large diversity of bacteria was identified with the discovering of species reported to secrete anti-parasitic compounds or to modulate vector competence in other insects. For future studies, the analyses should be enlarged with larger sampling including foci from several countries.
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transcriptional profiling of midguts prepared from trypanosoma t congolense positive glossina palpalis palpalis collected from two distinct cameroonian foci coordinated signatures of the midguts remodeling as t congolense supportive niches
Frontiers in Immunology, 2017Co-Authors: Jean Ngoune, Flobert Njiokou, Beatrice Loriod, Ginette Kamengasse, Nicolas Fernandeznunez, Claire Rioualen, Jacques Van Helden, Anne GeigerAbstract:Our previous transcriptomic analysis of Glossina palpalis gambiensis experimentally infected or not with Trypanosoma brucei gambiense aimed to detect differentially expressed genes associated with infection. Specifically, we selected candidate genes governing tsetse fly vector competence that could be used in the context of an anti-vector strategy, to control human and/or Animal Trypanosomiasis. The present study aimed to verify whether gene expression in field tsetse flies (G. p. palpalis) is modified in response to natural infection by trypanosomes (Trypanosoma congolense), as reported when insectary-raised flies (G. p. gambiensis) are experimentally infected with T. b. gambiense. This was achieved using the RNA-seq approach, which identified 524 differentially expressed genes (DEGs) in infected versus non-infected tsetse flies, including 285 down-regulated genes and 239 up-regulated genes (identified using DESeq2). Several of these genes were highly differentially expressed, with log2 fold change values in the vicinity of either +40 or -40. Down-regulated genes were primarily involved in transcription/translation processes, whereas encoded up-regulated genes governed amino acid and nucleotide biosynthesis pathways. The BioCyc metabolic pathways associated with infection also revealed that down-regulated genes were mainly involved in fly immunity processes. Importantly, our study demonstrates that data on the molecular cross-talk between the host and the parasite (as well as the always present fly microbiome) recorded from an experimental biological model has a counterpart in field flies, which in turn validates the use of experimental host/parasite couples.
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Transcriptional profiling of midguts prepared from Trypanosoma/T. congolense-positive Glossina palpalis palpalis collected from two distinct Cameroonian foci : coordinated signatures of the midguts’ remodeling as T. congolense-supportive niches
Frontiers in Immunology, 2017Co-Authors: Jean Marc Tsagmo Ngoune, Flobert Njiokou, Beatrice Loriod, Claire Rioualen, Jacques Van Helden, Ginette Kame-ngasse, Nicolas Fernandez-nunez, Anne GeigerAbstract:Our previous transcriptomic analysis of Glossina palpalis gambiensis experimentally infected or not with Trypanosoma brucei gambiense aimed to detect differentially expressed genes (DEGs) associated with infection. Specifically, we selected candidate genes governing tsetse fly vector competence that could be used in the context of an anti-vector strategy, to control human and/or Animal Trypanosomiasis. The present study aimed to verify whether gene expression in field tsetse flies (G. p. palpalis) is modified in response to natural infection by trypanosomes (T. congolense), as reported when insectary-raised flies (G. p. gambiensis) are experimentally infected with T. b. gambiense. This was achieved using the RNA-seq approach, which identified 524 DEGs in infected vs. non-infected tsetse flies, including 285 downregulated genes and 239 upregulated genes (identified using DESeq2). Several of these genes were highly differentially expressed, with log2 fold change values in the vicinity of either +40 or −40. Downregulated genes were primarily involved in transcription/translation processes, whereas encoded upregulated genes governed amino acid and nucleotide biosynthesis pathways. The BioCyc metabolic pathways associated with infection also revealed that downregulated genes were mainly involved in fly immunity processes. Importantly, our study demonstrates that data on the molecular cross-talk between the host and the parasite (as well as the always present fly microbiome) recorded from an experimental biological model has a counterpart in field flies, which in turn validates the use of experimental host/parasite couples.
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Population dynamics of Glossina palpalis gambiensis symbionts, Sodalis glossinidius, and Wigglesworthia glossinidia, throughout host-fly development.
Infection genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases, 2012Co-Authors: Illiassou Hamidou Soumana, Gérard Cuny, David Berthier, Bernadette Tchicaya, Sophie Thevenon, Anne GeigerAbstract:The tsetse fly (Diptera: Glossinidae), the vector of trypanosomes causing human and Animal Trypanosomiasis, harbors symbiotic microorganisms including the primary symbiont Wigglesworthia glossinidia, involved in the fly’s nutrition and fertility, and the secondary symbiont Sodalis glossinidius, involved in the trypanosome establishment in the fly’s midgut. Both symbionts are maternally transmitted to the intrauterine progeny through the fly’s milk gland secretions. In this study, we investigated the population dynamics of these symbionts during fly development. Wigglesworthia and Sodalis densities were estimated using quantitative PCR performed on Glossina palpalis gambiensis at different developmental stages. The results showed that the density of the primary Wigglesworthia symbiont was higher than that of Sodalis for all host developmental stages. Sodalis densities remained constant in pupae, but increased significantly in adult flies. The opposite situation was observed for Wigglesworthia, whose density increased in pupae and remained constant during the female adult stage. Moreover, Wigglesworthia density increased significantly during the transition from the pupal to the teneral stage, while mating had a contradictory effect depending on the age of the fly. Finally, tsetse fly colonization by both symbionts appears as a continuous and adaptive process throughout the insect’s development. Last, the study demonstrated both symbionts of G. p. gambiensis, the vector of the chronic form of human African Trypanosomiasis, to be permanent inhabitants of the colony flies throughout their life span. This was expected for the primary symbiont, Wigglesworthia, but not necessarily for the secondary symbiont, S. glossinidius, whose permanent presence is not required for the fly’s survival. This result is of importance as Sodalis could be involved in the tsetse fly vector competence and may constitute a target in the frame of sleeping sickness fighting strategies.
Sue Christina Welburn - One of the best experts on this subject based on the ideXlab platform.
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Suspected resistance of Trypanosoma species to diminazene aceturate on a cattle farm in Nigeria.
Tropical Animal Health and Production, 2019Co-Authors: Paul Olalekan Odeniran, Ewan T. Macleod, Isaiah Oluwafemi Ademola, Sue Christina WelburnAbstract:African Animal Trypanosomiasis is a major cause of mortality and economic losses for the livestock industry in Nigeria. Chemotherapy has been the most reliable option for cattle herders, and the most commonly found drug on the market is diminazene aceturate. To ascertain the long-term efficacy of this compound, we sampled a cattle herd in Ogun State, Nigeria, 2 months after they were treated with diminazene aceturate. The ITS-PCR results revealed 19 positives for trypanosome DNA out of the 79 samples tested (24.1%, 95% CI 16.0–34.5). Seventeen out of the total 19 positives were Trypanosoma congolense (21.5%, 95% CI 13.9–31.8). Mixed infections were also observed. Therefore, the persistence of bovine Trypanosomiasis at this Nigerian cattle farm despite treatment could be due to diminazene aceturate resistant trypanosomes being present in the herd.
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Molecular identification of bloodmeal sources and trypanosomes in Glossina spp., Tabanus spp. and Stomoxys spp. trapped on cattle farm settlements in southwest Nigeria.
Medical and veterinary entomology, 2019Co-Authors: Paul Olalekan Odeniran, Ewan T. Macleod, Isaiah Oluwafemi Ademola, Sue Christina WelburnAbstract:The interactions of host, vector and parasite in bovine Trypanosomiasis transmission cycles in southwest Nigeria are not yet well understood. Trypanosoma (Trypanosomatida: Trypanosomatidae) species infection prevalences and bloodmeal sources were determined in transmitting vectors of the genera Glossina (Diptera: Glossinidae), Tabanus (Diptera: Tabanidae) and Stomoxys (Diptera: Muscidae) collected using Nzi traps in cattle settlements in southwest Nigeria. Sequenced cytochrome B mitochondrial DNA segments obtained from vector digestive tracts identified bloodmeal sources from eight host species, namely human, cattle, hippopotamus, giraffe, gazelle, spotted hyena, long-tailed rat and one unidentified species. Overall, 71.1% [95% confidence interval (CI) 63.0-78.1], 33.3% (95% CI 21.9-47.0) and 22.2% (95% CI 16.2-29.9), respectively, of Glossina, Tabanus and Stomoxys flies were positive for trypanosomes. The observed trypanosome species were Trypanosoma vivax, Trypanosoma congolense, Trypanosoma brucei, Trypanosoma evansi, Trypanosoma simiae and Trypanosoma godfreyi. Trypanosome DNA was more prevalent in tsetse (34.8% Tr. vivax, 51.1% Tr. b. brucei, 5.2% Tr. congolense, 4.4% Tr. simiae and 24.4% mixed infections) than in other flies and the main determinants in all flies were seasonal factors and host availability. To the best of the present group's knowledge, this is the first report of Trypanosoma species in Tabanus and Stomoxys flies in Nigeria. It indicates that vector control programmes should always consider biting flies along with tsetse flies in the control of human and Animal Trypanosomiasis.
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bovine and small ruminant african Animal Trypanosomiasis in nigeria a review
Veterinary Parasitology: Regional Studies and Reports, 2018Co-Authors: Paul Olalekan Odeniran, Ewan T. Macleod, Isaiah Oluwafemi Ademola, Sue Christina WelburnAbstract:Abstract Despite extensive attempts over many decades to control African Animal Trypanosomiasis (AAT) across the tsetse fly belt of Nigeria, AAT persists as major Animal health problem causing severe morbidity and mortality in livestock. The large agricultural losses in turn have severe adverse impacts on sustainable agricultural development. Despite this, in the past 50 years there have been no significant national control programs against AAT. This review explores the history of AAT control in Nigeria, examining the successes and failures in measures adopted in Nigeria to control AAT and the changing disease epidemiology.
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the burden and spatial distribution of bovine african trypanosomes in small holder crop livestock production systems in tororo district south eastern uganda
Parasites & Vectors, 2014Co-Authors: Kim Picozzi, Michael Thrusfield, Dennis Muhanguzi, Jan Hattendorf, Charles Waiswa, John David Kabasa, Sue Christina WelburnAbstract:Background: African Animal Trypanosomiasis (AAT) is considered to be one of the greatest constraints to livestock production and livestock-crop integration in most African countries. South-eastern Uganda has suffered for more than two decades from outbreaks of zoonotic Human African Trypanosomiasis (HAT), adding to the burden faced by communities from AAT. There is insufficient AAT and HAT data available (in the Animal reservoir) to guide and prioritize AAT control programs that has been generated using contemporary, sensitive and specific molecular techniques. This study was undertaken to evaluate the burden that AAT presents to the small-scale cattle production systems in south-eastern Uganda. Methods: Randomised cluster sampling was used to select 14% (57/401) of all cattle containing villages across Tororo District. Blood samples were taken from all cattle in the selected villages between September-December 2011; preserved on FTA cards and analysed for different trypanosomes using a suite of molecular techniques. Generalized estimating equation and Rogen-Gladen estimator models were used to calculate apparent and true prevalences of different trypanosomes while intra cluster correlations were estimated using a 1-way mixed effect analysis of variance (ANOVA) in R statistical software version 3.0.2. Results: The prevalence of all trypanosome species in cattle was15.3% (95% CI; 12.2-19.1) while herd level trypanosome species prevalence varied greatly between 0-43%. Trypanosoma vivax (17.4%, 95% CI; 10.6-16.8) and Trypanosoma brucei rhodesiense (0.03%) were respectively, the most, and least prevalent trypanosome species identified. Conclusions: The prevalence of bovine trypanosomes in this study indicates that AAT remains a significant constraint to livestock health and livestock production. There is need to implement tsetse and Trypanosomiasis control efforts across Tororo District by employing effective, cheap and sustainable tsetse and Trypanosomiasis control methods that could be integrated in the control of other endemic vector borne diseases like tick-borne diseases.
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the dispersal ecology of rhodesian sleeping sickness following its introduction to a new area
PLOS Neglected Tropical Diseases, 2013Co-Authors: Nicola A Wardrop, Eric M Fevre, Peter M Atkinson, Sue Christina WelburnAbstract:Tsetse-transmitted human and Animal Trypanosomiasis are constraints to both human and Animal health in sub-Saharan Africa, and although these diseases have been known for over a century, there is little recent evidence demonstrating how the parasites circulate in natural hosts and ecosystems. The spread of Rhodesian sleeping sickness (caused by Trypanosoma brucei rhodesiense) within Uganda over the past 15 years has been linked to the movement of infected, untreated livestock (the predominant reservoir) from endemic areas. However, despite an understanding of the environmental dependencies of sleeping sickness, little research has focused on the environmental factors controlling transmission establishment or the spatially heterogeneous dispersal of disease following a new introduction. In the current study, an annually stratified case-control study of Rhodesian sleeping sickness cases from Serere District, Uganda was used to allow the temporal assessment of correlations between the spatial distribution of sleeping sickness and landscape factors. Significant relationships were detected between Rhodesian sleeping sickness and selected factors, including elevation and the proportion of land which was “seasonally flooding grassland” or “woodlands and dense savannah.” Temporal trends in these relationships were detected, illustrating the dispersal of Rhodesian sleeping sickness into more ‘suitable’ areas over time, with diminishing dependence on the point of introduction in concurrence with an increasing dependence on environmental and landscape factors. These results provide a novel insight into the ecology of Rhodesian sleeping sickness dispersal and may contribute towards the implementation of evidence-based control measures to prevent its further spread.
Jean Ngoune - One of the best experts on this subject based on the ideXlab platform.
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the composition and abundance of bacterial communities residing in the gut of glossina palpalis palpalis captured in two sites of southern cameroon
Parasites & Vectors, 2019Co-Authors: Trésor T. Melachio, Guilhem Sempere, Majoline T. Tchioffo, Anne Geiger, Julie Reveillaud, Flobert Njiokou, Luc Abate, Jean NgouneAbstract:A number of reports have demonstrated the role of insect bacterial flora on their host’s physiology and metabolism. The tsetse host and vector of trypanosomes responsible for human sleeping sickness (human African Trypanosomiasis, HAT) and nagana in Animals (African Animal Trypanosomiasis, AAT) carry bacteria that influence its diet and immune processes. However, the mechanisms involved in these processes remain poorly documented. This underscores the need for increased research into the bacterial flora composition and structure of tsetse flies. The aim of this study was to identify the diversity and relative abundance of bacterial genera in Glossina palpalis palpalis flies collected in two Trypanosomiasis foci in Cameroon. Samples of G. p. palpalis which were either negative or naturally trypanosome-positive were collected in two foci located in southern Cameroon (Campo and Bipindi). Using the V3V4 and V4 variable regions of the small subunit of the 16S ribosomal RNA gene, we analyzed the respective bacteriome of the flies’ midguts. We identified ten bacterial genera. In addition, we observed that the relative abundance of the obligate endosymbiont Wigglesworthia was highly prominent (around 99%), regardless of the analyzed region. The remaining genera represented approximately 1% of the bacterial flora, and were composed of Salmonella, Spiroplasma, Sphingomonas, Methylobacterium, Acidibacter, Tsukamurella, Serratia, Kluyvera and an unidentified bacterium. The genus Sodalis was present but with a very low abundance. Globally, no statistically significant difference was found between the bacterial compositions of flies from the two foci, and between positive and trypanosome-negative flies. However, Salmonella and Serratia were only described in trypanosome-negative flies, suggesting a potential role for these two bacteria in fly refractoriness to trypanosome infection. In addition, our study showed the V4 region of the small subunit of the 16S ribosomal RNA gene was more efficient than the V3V4 region at describing the totality of the bacterial diversity. A very large diversity of bacteria was identified with the discovering of species reported to secrete anti-parasitic compounds or to modulate vector competence in other insects. For future studies, the analyses should be enlarged with larger sampling including foci from several countries.
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transcriptional profiling of midguts prepared from trypanosoma t congolense positive glossina palpalis palpalis collected from two distinct cameroonian foci coordinated signatures of the midguts remodeling as t congolense supportive niches
Frontiers in Immunology, 2017Co-Authors: Jean Ngoune, Flobert Njiokou, Beatrice Loriod, Ginette Kamengasse, Nicolas Fernandeznunez, Claire Rioualen, Jacques Van Helden, Anne GeigerAbstract:Our previous transcriptomic analysis of Glossina palpalis gambiensis experimentally infected or not with Trypanosoma brucei gambiense aimed to detect differentially expressed genes associated with infection. Specifically, we selected candidate genes governing tsetse fly vector competence that could be used in the context of an anti-vector strategy, to control human and/or Animal Trypanosomiasis. The present study aimed to verify whether gene expression in field tsetse flies (G. p. palpalis) is modified in response to natural infection by trypanosomes (Trypanosoma congolense), as reported when insectary-raised flies (G. p. gambiensis) are experimentally infected with T. b. gambiense. This was achieved using the RNA-seq approach, which identified 524 differentially expressed genes (DEGs) in infected versus non-infected tsetse flies, including 285 down-regulated genes and 239 up-regulated genes (identified using DESeq2). Several of these genes were highly differentially expressed, with log2 fold change values in the vicinity of either +40 or -40. Down-regulated genes were primarily involved in transcription/translation processes, whereas encoded up-regulated genes governed amino acid and nucleotide biosynthesis pathways. The BioCyc metabolic pathways associated with infection also revealed that down-regulated genes were mainly involved in fly immunity processes. Importantly, our study demonstrates that data on the molecular cross-talk between the host and the parasite (as well as the always present fly microbiome) recorded from an experimental biological model has a counterpart in field flies, which in turn validates the use of experimental host/parasite couples.
Flobert Njiokou - One of the best experts on this subject based on the ideXlab platform.
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The composition and abundance of bacterial communities residing in the gut of Glossina palpalis palpalis captured in two sites of southern Cameroon
Parasites & Vectors, 2019Co-Authors: Jean Marc Tsagmo Ngoune, Trésor T. Melachio, Guilhem Sempere, Majoline T. Tchioffo, Julie Reveillaud, Flobert Njiokou, Luc Abate, Anne GeigerAbstract:BackgroundA number of reports have demonstrated the role of insect bacterial flora on their host’s physiology and metabolism. The tsetse host and vector of trypanosomes responsible for human sleeping sickness (human African Trypanosomiasis, HAT) and nagana in Animals (African Animal Trypanosomiasis, AAT) carry bacteria that influence its diet and immune processes. However, the mechanisms involved in these processes remain poorly documented. This underscores the need for increased research into the bacterial flora composition and structure of tsetse flies. The aim of this study was to identify the diversity and relative abundance of bacterial genera in Glossina palpalis palpalis flies collected in two Trypanosomiasis foci in Cameroon.MethodsSamples of G. p. palpalis which were either negative or naturally trypanosome-positive were collected in two foci located in southern Cameroon (Campo and Bipindi). Using the V3V4 and V4 variable regions of the small subunit of the 16S ribosomal RNA gene, we analyzed the respective bacteriome of the flies’ midguts.ResultsWe identified ten bacterial genera. In addition, we observed that the relative abundance of the obligate endosymbiont Wigglesworthia was highly prominent (around 99%), regardless of the analyzed region. The remaining genera represented approximately 1% of the bacterial flora, and were composed of Salmonella, Spiroplasma, Sphingomonas, Methylobacterium, Acidibacter, Tsukamurella, Serratia, Kluyvera and an unidentified bacterium. The genus Sodalis was present but with a very low abundance. Globally, no statistically significant difference was found between the bacterial compositions of flies from the two foci, and between positive and trypanosome-negative flies. However, Salmonella and Serratia were only described in trypanosome-negative flies, suggesting a potential role for these two bacteria in fly refractoriness to trypanosome infection. In addition, our study showed the V4 region of the small subunit of the 16S ribosomal RNA gene was more efficient than the V3V4 region at describing the totality of the bacterial diversity.ConclusionsA very large diversity of bacteria was identified with the discovering of species reported to secrete anti-parasitic compounds or to modulate vector competence in other insects. For future studies, the analyses should be enlarged with larger sampling including foci from several countries.
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the composition and abundance of bacterial communities residing in the gut of glossina palpalis palpalis captured in two sites of southern cameroon
Parasites & Vectors, 2019Co-Authors: Trésor T. Melachio, Guilhem Sempere, Majoline T. Tchioffo, Anne Geiger, Julie Reveillaud, Flobert Njiokou, Luc Abate, Jean NgouneAbstract:A number of reports have demonstrated the role of insect bacterial flora on their host’s physiology and metabolism. The tsetse host and vector of trypanosomes responsible for human sleeping sickness (human African Trypanosomiasis, HAT) and nagana in Animals (African Animal Trypanosomiasis, AAT) carry bacteria that influence its diet and immune processes. However, the mechanisms involved in these processes remain poorly documented. This underscores the need for increased research into the bacterial flora composition and structure of tsetse flies. The aim of this study was to identify the diversity and relative abundance of bacterial genera in Glossina palpalis palpalis flies collected in two Trypanosomiasis foci in Cameroon. Samples of G. p. palpalis which were either negative or naturally trypanosome-positive were collected in two foci located in southern Cameroon (Campo and Bipindi). Using the V3V4 and V4 variable regions of the small subunit of the 16S ribosomal RNA gene, we analyzed the respective bacteriome of the flies’ midguts. We identified ten bacterial genera. In addition, we observed that the relative abundance of the obligate endosymbiont Wigglesworthia was highly prominent (around 99%), regardless of the analyzed region. The remaining genera represented approximately 1% of the bacterial flora, and were composed of Salmonella, Spiroplasma, Sphingomonas, Methylobacterium, Acidibacter, Tsukamurella, Serratia, Kluyvera and an unidentified bacterium. The genus Sodalis was present but with a very low abundance. Globally, no statistically significant difference was found between the bacterial compositions of flies from the two foci, and between positive and trypanosome-negative flies. However, Salmonella and Serratia were only described in trypanosome-negative flies, suggesting a potential role for these two bacteria in fly refractoriness to trypanosome infection. In addition, our study showed the V4 region of the small subunit of the 16S ribosomal RNA gene was more efficient than the V3V4 region at describing the totality of the bacterial diversity. A very large diversity of bacteria was identified with the discovering of species reported to secrete anti-parasitic compounds or to modulate vector competence in other insects. For future studies, the analyses should be enlarged with larger sampling including foci from several countries.
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transcriptional profiling of midguts prepared from trypanosoma t congolense positive glossina palpalis palpalis collected from two distinct cameroonian foci coordinated signatures of the midguts remodeling as t congolense supportive niches
Frontiers in Immunology, 2017Co-Authors: Jean Ngoune, Flobert Njiokou, Beatrice Loriod, Ginette Kamengasse, Nicolas Fernandeznunez, Claire Rioualen, Jacques Van Helden, Anne GeigerAbstract:Our previous transcriptomic analysis of Glossina palpalis gambiensis experimentally infected or not with Trypanosoma brucei gambiense aimed to detect differentially expressed genes associated with infection. Specifically, we selected candidate genes governing tsetse fly vector competence that could be used in the context of an anti-vector strategy, to control human and/or Animal Trypanosomiasis. The present study aimed to verify whether gene expression in field tsetse flies (G. p. palpalis) is modified in response to natural infection by trypanosomes (Trypanosoma congolense), as reported when insectary-raised flies (G. p. gambiensis) are experimentally infected with T. b. gambiense. This was achieved using the RNA-seq approach, which identified 524 differentially expressed genes (DEGs) in infected versus non-infected tsetse flies, including 285 down-regulated genes and 239 up-regulated genes (identified using DESeq2). Several of these genes were highly differentially expressed, with log2 fold change values in the vicinity of either +40 or -40. Down-regulated genes were primarily involved in transcription/translation processes, whereas encoded up-regulated genes governed amino acid and nucleotide biosynthesis pathways. The BioCyc metabolic pathways associated with infection also revealed that down-regulated genes were mainly involved in fly immunity processes. Importantly, our study demonstrates that data on the molecular cross-talk between the host and the parasite (as well as the always present fly microbiome) recorded from an experimental biological model has a counterpart in field flies, which in turn validates the use of experimental host/parasite couples.
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Transcriptional profiling of midguts prepared from Trypanosoma/T. congolense-positive Glossina palpalis palpalis collected from two distinct Cameroonian foci : coordinated signatures of the midguts’ remodeling as T. congolense-supportive niches
Frontiers in Immunology, 2017Co-Authors: Jean Marc Tsagmo Ngoune, Flobert Njiokou, Beatrice Loriod, Claire Rioualen, Jacques Van Helden, Ginette Kame-ngasse, Nicolas Fernandez-nunez, Anne GeigerAbstract:Our previous transcriptomic analysis of Glossina palpalis gambiensis experimentally infected or not with Trypanosoma brucei gambiense aimed to detect differentially expressed genes (DEGs) associated with infection. Specifically, we selected candidate genes governing tsetse fly vector competence that could be used in the context of an anti-vector strategy, to control human and/or Animal Trypanosomiasis. The present study aimed to verify whether gene expression in field tsetse flies (G. p. palpalis) is modified in response to natural infection by trypanosomes (T. congolense), as reported when insectary-raised flies (G. p. gambiensis) are experimentally infected with T. b. gambiense. This was achieved using the RNA-seq approach, which identified 524 DEGs in infected vs. non-infected tsetse flies, including 285 downregulated genes and 239 upregulated genes (identified using DESeq2). Several of these genes were highly differentially expressed, with log2 fold change values in the vicinity of either +40 or −40. Downregulated genes were primarily involved in transcription/translation processes, whereas encoded upregulated genes governed amino acid and nucleotide biosynthesis pathways. The BioCyc metabolic pathways associated with infection also revealed that downregulated genes were mainly involved in fly immunity processes. Importantly, our study demonstrates that data on the molecular cross-talk between the host and the parasite (as well as the always present fly microbiome) recorded from an experimental biological model has a counterpart in field flies, which in turn validates the use of experimental host/parasite couples.
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trypanosoma vivax t congolense forest type and t simiae prevalence in domestic Animals of sleeping sickness foci of cameroon
Parasite, 2011Co-Authors: H Nimpaye, Flobert Njiokou, Guy Roger Njitchouang, Stephane Herder, T Njine, Tazoacha AsonganyiAbstract:Summary: In order to better understand the epidemiology of Human and Animal Trypanosomiasis that occur together in sleeping sickness foci, a study of prevalences of Animal parasites (Trypanosoma vivax, T. congolense “forest type”, and T. simiae) infections was conducted on domestic Animals to complete the previous work carried on T. brucei gambiense prevalence using the same Animal sample. 875 domestic Animals, including 307 pigs, 264 goats, 267 sheep and 37 dogs were sampled in the sleeping sickness foci of Bipindi, Campo, Doume and Fontem in Cameroon. The polymerase chain reaction (PCR) based method was used to identify these trypanosome species. A total of 237 (27.08 %) domestic Animals were infected by at least one trypanosome species. The prevalence of T. vivax, T. congolense “forest type“ and T. simiae were 20.91 %, 11.42 % and 0.34 % respectively. The prevalences of T. vivax and T. congolense “forest type” differed significantly between the Animal species and between the foci (p < 0.0001); however, these two trypanosomes were found in all Animal species as well as in all the foci subjected to the study. The high prevalences of T. vivax and T. congolense “forest type” in Bipindi and Fontem-Center indicate their intense transmission in these foci.
Jean Marc Tsagmo Ngoune - One of the best experts on this subject based on the ideXlab platform.
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The composition and abundance of bacterial communities residing in the gut of Glossina palpalis palpalis captured in two sites of southern Cameroon
Parasites & Vectors, 2019Co-Authors: Jean Marc Tsagmo Ngoune, Trésor T. Melachio, Guilhem Sempere, Majoline T. Tchioffo, Julie Reveillaud, Flobert Njiokou, Luc Abate, Anne GeigerAbstract:BackgroundA number of reports have demonstrated the role of insect bacterial flora on their host’s physiology and metabolism. The tsetse host and vector of trypanosomes responsible for human sleeping sickness (human African Trypanosomiasis, HAT) and nagana in Animals (African Animal Trypanosomiasis, AAT) carry bacteria that influence its diet and immune processes. However, the mechanisms involved in these processes remain poorly documented. This underscores the need for increased research into the bacterial flora composition and structure of tsetse flies. The aim of this study was to identify the diversity and relative abundance of bacterial genera in Glossina palpalis palpalis flies collected in two Trypanosomiasis foci in Cameroon.MethodsSamples of G. p. palpalis which were either negative or naturally trypanosome-positive were collected in two foci located in southern Cameroon (Campo and Bipindi). Using the V3V4 and V4 variable regions of the small subunit of the 16S ribosomal RNA gene, we analyzed the respective bacteriome of the flies’ midguts.ResultsWe identified ten bacterial genera. In addition, we observed that the relative abundance of the obligate endosymbiont Wigglesworthia was highly prominent (around 99%), regardless of the analyzed region. The remaining genera represented approximately 1% of the bacterial flora, and were composed of Salmonella, Spiroplasma, Sphingomonas, Methylobacterium, Acidibacter, Tsukamurella, Serratia, Kluyvera and an unidentified bacterium. The genus Sodalis was present but with a very low abundance. Globally, no statistically significant difference was found between the bacterial compositions of flies from the two foci, and between positive and trypanosome-negative flies. However, Salmonella and Serratia were only described in trypanosome-negative flies, suggesting a potential role for these two bacteria in fly refractoriness to trypanosome infection. In addition, our study showed the V4 region of the small subunit of the 16S ribosomal RNA gene was more efficient than the V3V4 region at describing the totality of the bacterial diversity.ConclusionsA very large diversity of bacteria was identified with the discovering of species reported to secrete anti-parasitic compounds or to modulate vector competence in other insects. For future studies, the analyses should be enlarged with larger sampling including foci from several countries.
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Transcriptional profiling of midguts prepared from Trypanosoma/T. congolense-positive Glossina palpalis palpalis collected from two distinct Cameroonian foci : coordinated signatures of the midguts’ remodeling as T. congolense-supportive niches
Frontiers in Immunology, 2017Co-Authors: Jean Marc Tsagmo Ngoune, Flobert Njiokou, Beatrice Loriod, Claire Rioualen, Jacques Van Helden, Ginette Kame-ngasse, Nicolas Fernandez-nunez, Anne GeigerAbstract:Our previous transcriptomic analysis of Glossina palpalis gambiensis experimentally infected or not with Trypanosoma brucei gambiense aimed to detect differentially expressed genes (DEGs) associated with infection. Specifically, we selected candidate genes governing tsetse fly vector competence that could be used in the context of an anti-vector strategy, to control human and/or Animal Trypanosomiasis. The present study aimed to verify whether gene expression in field tsetse flies (G. p. palpalis) is modified in response to natural infection by trypanosomes (T. congolense), as reported when insectary-raised flies (G. p. gambiensis) are experimentally infected with T. b. gambiense. This was achieved using the RNA-seq approach, which identified 524 DEGs in infected vs. non-infected tsetse flies, including 285 downregulated genes and 239 upregulated genes (identified using DESeq2). Several of these genes were highly differentially expressed, with log2 fold change values in the vicinity of either +40 or −40. Downregulated genes were primarily involved in transcription/translation processes, whereas encoded upregulated genes governed amino acid and nucleotide biosynthesis pathways. The BioCyc metabolic pathways associated with infection also revealed that downregulated genes were mainly involved in fly immunity processes. Importantly, our study demonstrates that data on the molecular cross-talk between the host and the parasite (as well as the always present fly microbiome) recorded from an experimental biological model has a counterpart in field flies, which in turn validates the use of experimental host/parasite couples.