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Manuel Ritter - One of the best experts on this subject based on the ideXlab platform.
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complete mitochondrial genome sequence of Mansonella perstans
Microbiology resource announcements, 2020Co-Authors: Matthew Chung, Jain Aluvathingal, Robin E Bromley, Suvarna Nadendla, Fanny Fri Fombad, Chi Anizette Kien, Narcisse V T Gandjui, Abdel Jelil Njouendou, Manuel Ritter, Lisa SadzewiczAbstract:ABSTRACT The 13,647-bp complete mitochondrial genome of Mansonella perstans was sequenced and is syntenic to the mitochondrial genome of Mansonella ozzardi. Phylogenetic analysis of the mitochondrial genome is consistent with the known phylogeny of ONC5 group filarial nematodes.
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dataset on in vitro maintenance of Mansonella perstans microfilariae and drug testing
Data in Brief, 2020Co-Authors: Abdel Jelil Njouendou, Fanny Fri Fombad, Chi Anizette Kien, Narcisse V T Gandjui, Manuel Ritter, Mathias E Esum, Winston Patrick Chounna Ndongmo, Flobert Njiokou, Peter Enyong, Kenneth PfarrAbstract:Abstract Endemic communities of Mansonella perstans infections have been neglected since associated pathology remains undefined. Consequently, improvements in drug therapy have also been ignored despite a large number of infected individuals in areas of Cameroon. Thus, we established an in vitro system to culture M. perstans microfilariae (Mf); the transmission stage of infection. In short, we compared the ability of two renowned culture media (Dulbecco's Modified Eagle's Medium (DMEM) and Roswell Park Memorial Institute (RPMI-1640)) to sustain Mf in culture. Media were supplemented with 10% fetal bovine serum (FBS) and monkey kidney epithelial cells (LLC-MK2) were used as feeder cells. As readout we assessed Mf survival and motility using a standardised microscopy assessment strategy. Moreover, this in vitro culture system was used to test susceptibility levels of microfilariae to different chemotherapeutic agents. Parasite motility was scored daily using a graded system and analysed using the average motility and area under the motility curve of M. perstans Mf. These datasets were analysed and discussed in detail in the related article entitled: “In vitro maintenance of Mansonella perstans microfilariae and its relevance for drug screening” [1].
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in vitro maintenance of Mansonella perstans microfilariae and its relevance for drug screening
Experimental Parasitology, 2019Co-Authors: Abdel Jelil Njouendou, Fanny Fri Fombad, Chi Anizette Kien, Narcisse V T Gandjui, Manuel Ritter, Mathias E Esum, Winston Patrick Chounna Ndongmo, Flobert Njiokou, Peter Enyong, Kenneth PfarrAbstract:Abstract Background Mansonellosis arises from infections with threadlike filarial nematodes in millions of individuals, especially in sub-Saharan Africa. Since infections present no overt clinical symptoms but attenuate immune responses that might lead to increased susceptibility and worsened disease course of concomitant infections, it is truly a neglected tropical disease. Nevertheless, only few studies focus on identifying suitable safe drugs for its control and little is known about the requirements for in vitro maintenance of the Mansonella perstans transmission stage. This study, therefore, evaluated the survival of M. perstans microfilariae (mf) using in vitro conditions that have been shown to promote survival of Loa loa, a closely related filarial nematode. Furthermore, the in vitro microfilaricidal effect of 15 agents was assessed on this helminth. Methods The ability of two basic culture media; Dulbecco's Modified Eagle's Medium (DMEM) and Roswell Park Memorial Institute (RPMI-1640) supplemented with 10% fetal bovine serum (FBS) and a monkey kidney epithelial cell line (LLC-MK2) to support the survival of M. perstans microfilariae was investigated. Subsequently, 6 anti-helminthics, 5 anti-malarials, 1 anti-microbacterial, 2 trypanocidals and 1 anti-cancer agent were tested in vitro against mf. The suitability of the culture media as well as the effect of the anti-infective agents on mf survival was assessed by scoring their motility. Results FBS supplement and additional LLC-MK2 cells significantly improved the survival of mf in DMEM and RPMI-1640 culture. In detail, RPMI-1640 supplemented with 10% FBS and LLC-MK2 cells sustained the maintenance of mf for at least 20 days (100.00 ± 0.00% survival). In co-cultures with LLC-MK2 cells without serum, M. perstans mf were maintained in DMEM and RPMI-1640 medium with a motility above 99% by day 5. Mefloquine displayed the highest microfilaricidal effect in vitro followed by artesunate. Conclusion Both RPMI and DMEM in the presence of LLC-MK2 cells are suitable for the maintenance of M. perstans mf in vitro. In absence of the feeder cells, the addition of 10% FBS to RPMI-1640 medium improved the parasite survival rate and motility. The microfilaricidal activity of mefloquine and artesunate on M. perstans mf was documented for the first time in this study and can therefore be considered as reference for further screening of agents against this parasite stage.
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Mansonella perstans microfilaremic individuals are characterized by enhanced type 2 helper t and regulatory t and b cell subsets and dampened systemic innate and adaptive immune responses
PLOS Neglected Tropical Diseases, 2018Co-Authors: Manuel Ritter, Abdel Jelil Njouendou, Winston Patrick Chounna Ndongmo, Dizzle Bita Tayong, Norman Nausch, Marc Jacobsen, Nora Nganyewo Nghochuzie, Lucy Cho Nchang, Kathrin Arndts, Samuel WanjiAbstract:: The filarial nematode Mansonella perstans is endemic throughout Africa, northern South America and the Caribbean. Interestingly, M. perstans-infected individuals present no distinct clinical picture associated with certain pathology. Due to its relatively silent nature, research on this tropical disease has been neglected, especially M. perstans-driven immune responses. A hindrance in obtaining data on M. perstans-specific responses has been the inability to obtain adult worms since their habitats in serous cavities are difficult to access. Thus, in this study, for the first time, we used Mansonella perstans worm antigen extract as stimulant to obtain filarial-specific recall and immunoglobulin responses from M. perstans microfilaremic individuals (Mp MF+) from Cameroon. Moreover, systemic immune profiles in sera and immune cell composition in peripheral blood from Mp MF+ and amicrofilaremic individuals (Mp MF-) were obtained. Our data reveal that Mp MF+ individuals showed significantly reduced cytokine (IL-4, IL-6 and IL-12p70) and chemokine levels (IL-8 and RANTES), but significantly higher MIP-1β as well as increased M. perstans-specific IgG4 levels compared to Mp MF- individuals. In contrast, upon re-stimulation with worm antigen extract, IFN-γ, IL-13, IL-10 and IL-17A secretion was enhanced in cell cultures from Mp MF+ individuals when compared to those from cultures of healthy European individuals. Moreover, analysis of immune cell composition in peripheral blood from Mp MF+ individuals revealed increased type 2 helper T (Th2), natural killer (NK), regulatory B and T cell (Breg and Treg) subsets but decreased type 1 regulatory T (Tr1) cells. In summary, this study deciphers for the first time, M. perstans-specific immune responses using worm antigen extract and shows that patent M. perstans infections have distinct Th2, Breg and Treg subsets accompanied with reduced systemic innate and adaptive immune responses and dominant filarial-specific IgG4 levels.
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successful long term maintenance of Mansonella perstans in an in vitro culture system
Parasites & Vectors, 2017Co-Authors: Abdel Jelil Njouendou, Fanny Fri Fombad, Chi Anizette Kien, Manuel Ritter, Winston Patrick Chounna Ndongmo, Kenneth Pfarr, Gandjui Tchamatchoua Victor Narcisse, Dizzle Bita Tayong, Laura E Layland, Achim HoeraufAbstract:Background Approximately 114 million people are infected with Mansonella perstans in large proportions of Africa. In contrast to other filariae that infect humans, M. perstans-infected individuals show no distinct pathology or specific clinical picture, indicating a well-tuned adaptation to the host. In addition, since M. perstans adult worms reside in serous cavities which are difficult to access, research has been hindered and there is a paucity of knowledge about the biology of M. perstans, especially the development of the different life stages as well as M. perstans-driven immune responses. Thus in this study, an in vitro culture system was developed which allows an in-depth analysis of M. perstans.
Yacouba Coulibaly - One of the best experts on this subject based on the ideXlab platform.
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A cross-sectional study of the filarial and Leishmania co-endemicity in two ecologically distinct settings in Mali
Parasites & Vectors, 2018Co-Authors: Moussa Brema Sangare, Yacouba Coulibaly, Siaka Yamoussa Coulibaly, Michel Emmanuel Coulibaly, Bourama Traore, Ilo Dicko, Ibrahim Moussa Sissoko, Sibiry Samake, Sekou Fantamady Traore, Thomas Bruce NutmanAbstract:Background Filariasis and leishmaniasis are two neglected tropical diseases in Mali. Due to distribution and associated clinical features, both diseases are of concern to public health. The goal of this study was to determine the prevalence of co-infection with filarial ( Wuchereria bancrofti and Mansonella perstans ) and Leishmania major parasites in two ecologically distinct areas of Mali, the Kolokani district (villages of Tieneguebougou and Bougoudiana) in North Sudan Savanna area, and the district of Kolondieba (village of Boundioba) in the South Sudan Savanna area. Methods The prevalence of co-infection (filarial and Leishmania ) was measured based on (i) Mansonella perstans microfilaremia count and/or filariasis immunochromatographic test (ICT) for Wuchereria bancrofti- specific circulating antigen, and (ii) the prevalence of delayed type hypersensitivity (DTH) responses to Leishmania measured by leishmanin skin test (LST). Results In this study, a total of 930 volunteers between the age of 18 and 65 were included from the two endemic areas of Kolokani and Kolondieba. In general, in both areas, filarial infection was more prevalent than Leishmania infection with an overall prevalence of 15.27% (142/930) including 8.7% (81/930) for Mansonella perstans and 8% (74/930) for Wuchereria bancrofti- specific circulating antigen. The prevalence of Leishmania major infection was 7.7% (72/930) and was significantly higher in Tieneguebougou and Bougoudiana (15.05%; 64/425) than in Boundioba (2.04%; 8/505) ( χ ^2 = 58.66, P
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A cross-sectional study of the filarial and Leishmania co-endemicity in two ecologically distinct settings in Mali.
Parasites & Vectors, 2018Co-Authors: Moussa Brema Sangare, Siaka Y Coulibaly, Yacouba Coulibaly, Sekou F Traore, Michel Emmanuel Coulibaly, Bourama Traore, Ilo Dicko, Ibrahim Moussa Sissoko, Sibiry Samake, Thomas B NutmanAbstract:Filariasis and leishmaniasis are two neglected tropical diseases in Mali. Due to distribution and associated clinical features, both diseases are of concern to public health. The goal of this study was to determine the prevalence of co-infection with filarial (Wuchereria bancrofti and Mansonella perstans) and Leishmania major parasites in two ecologically distinct areas of Mali, the Kolokani district (villages of Tieneguebougou and Bougoudiana) in North Sudan Savanna area, and the district of Kolondieba (village of Boundioba) in the South Sudan Savanna area. The prevalence of co-infection (filarial and Leishmania) was measured based on (i) Mansonella perstans microfilaremia count and/or filariasis immunochromatographic test (ICT) for Wuchereria bancrofti-specific circulating antigen, and (ii) the prevalence of delayed type hypersensitivity (DTH) responses to Leishmania measured by leishmanin skin test (LST). In this study, a total of 930 volunteers between the age of 18 and 65 were included from the two endemic areas of Kolokani and Kolondieba. In general, in both areas, filarial infection was more prevalent than Leishmania infection with an overall prevalence of 15.27% (142/930) including 8.7% (81/930) for Mansonella perstans and 8% (74/930) for Wuchereria bancrofti-specific circulating antigen. The prevalence of Leishmania major infection was 7.7% (72/930) and was significantly higher in Tieneguebougou and Bougoudiana (15.05%; 64/425) than in Boundioba (2.04%; 8/505) (χ2 = 58.66, P
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a randomized trial of doxycycline for Mansonella perstans infection
The New England Journal of Medicine, 2009Co-Authors: Yacouba Coulibaly, Benoit Dembele, Abdallah A Diallo, Ettie M Lipner, Salif S Doumbia, Siaka Y Coulibaly, Siaka Konate, Daniel Yalcouye, Dapa A. Diallo, Joseph KubofcikAbstract:Background Mansonella perstans infection is common in areas of Africa where Wuchereria bancrofti, a causative agent of lymphatic filariasis, is endemic. M. perstans is refractory to standard antifilarial therapies. The recent discovery of bacterial endosymbionts (e.g., wolbachia) in most filarial species, including M. perstans, provides new therapeutic options for reducing microfilaremia. Methods In an open-label, randomized trial, we recruited subjects with M. perstans microfilaremia, with or without concomitant W. bancrofti infection, from four villages in Mali and randomly assigned them to receive doxycycline, at a dose of 200 mg daily for 6 weeks (106 subjects), or no treatment (110). At 6 months, subjects who were coinfected with W. bancrofti underwent a second random assignment, to treatment with a single dose of albendazole (400 mg) and ivermectin (150 μg per kilogram of body weight) or no treatment. Subjects were monitored daily during the first 6-week study period for adverse events. M. perstans ...
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molecular identification of wolbachia from the filarial nematode Mansonella perstans
Molecular and Biochemical Parasitology, 2008Co-Authors: Paul B Keiser, Abdallah A Diallo, Joseph Kubofcik, Yacouba Coulibaly, Amy D Klion, Sekou F Traore, Thomas B NutmanAbstract:Wolbachiae are bacterial endosymbionts of insects and many filarial nematodes whose products trigger inflammation in filarial infections. The dependence of the parasites on their endosymbionts has also led to the use of antibiotics directed against the Wolbachiae, therapy that has been demonstrated to have a profound salutary effect on filarial infections. The identification of Wolbachiae in Mansonella species has been conclusively shown for Mansonella ozzardi (Mo), but not for Mansonella perstans (Mp) Using primers known to amplify the 16S ribosomal DNA of other filarial Wolbachiae, an identical 1393 bp band was found in all samples tested. Sequence analysis of these samples demonstrated a single consensus sequence for Mp Wolbachia 16S rDNA that was most similar to Wolbachia sequences from other filarial nematodes. When aligned with the only other Mansonella Wolbachia sequence (Mo) there were only 8 nucleotide differences in the 1369 bp overlapping sequence. Phylogenetic dendrograms, showing the relationship of the Mp Wolbachia to other Wolbachia 16S rDNA, tracked almost identically to the 5S rRNA of their parasite host. Wolbachia surface protein (WSP) was also demonstrated in protein extracted from Mp-containing whole blood. In advance of a treatment trial of Mp, a method for the quantitation of Mp Wolbachia was developed and used to demonstrate not only a relationship between microfilarial numbers and Wolbachia copy numbers, but also to demonstrate the effect of antibiotic on ridding Mp of Wolbachia.
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clinical characteristics of post treatment reactions to ivermectin albendazole for wuchereria bancrofti in a region co endemic for Mansonella perstans
American Journal of Tropical Medicine and Hygiene, 2003Co-Authors: Paul B Keiser, Abdallah A Diallo, Dapa A. Diallo, Yacouba Coulibaly, Sekou F Traore, Falaye Keita, Diakaridia Traore, Roshanak Tolouei Semnani, Ogobara K Doumbo, Amy D KlionAbstract:Post-treatment reactions to single-dose ivermectin (200 μg/kg) and albendazole (400 mg) were studied in a filarial endemic region of Mali. The prevalence of Wuchereria bancrofti in this region was 48.3% (69 of 143), and coinfection with Mansonella perstans was common (30 of 40, 75%). Microfilarial levels of M. perstans correlated positively with age (P = 0.006) and with W. bancrofti microfilarial levels (P = 0.006). Forty individuals (28 infected and 12 uninfected) were treated, with mild post-treatment reactions occurring in 35.7% (7 of 28) of the W. bancrofti-infected subjects. Reaction severity correlated with pretreatment W. bancrofti microfilarial levels (P = 0.001). There were no significant differences in the prevalence or severity of post-treatment reactions in those who were co-infected with M. perstans. It is concluded that co-infection with M. perstans does not significantly alter the post-treatment reaction profile to single-dose ivermectin/albendazole in W. bancrofti infection in this community, and that acute post-treatment reactions should not limit patient compliance in community-based programs to eliminate lymphatic filariasis.
Winston Patrick Chounna Ndongmo - One of the best experts on this subject based on the ideXlab platform.
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dataset on in vitro maintenance of Mansonella perstans microfilariae and drug testing
Data in Brief, 2020Co-Authors: Abdel Jelil Njouendou, Fanny Fri Fombad, Chi Anizette Kien, Narcisse V T Gandjui, Manuel Ritter, Mathias E Esum, Winston Patrick Chounna Ndongmo, Flobert Njiokou, Peter Enyong, Kenneth PfarrAbstract:Abstract Endemic communities of Mansonella perstans infections have been neglected since associated pathology remains undefined. Consequently, improvements in drug therapy have also been ignored despite a large number of infected individuals in areas of Cameroon. Thus, we established an in vitro system to culture M. perstans microfilariae (Mf); the transmission stage of infection. In short, we compared the ability of two renowned culture media (Dulbecco's Modified Eagle's Medium (DMEM) and Roswell Park Memorial Institute (RPMI-1640)) to sustain Mf in culture. Media were supplemented with 10% fetal bovine serum (FBS) and monkey kidney epithelial cells (LLC-MK2) were used as feeder cells. As readout we assessed Mf survival and motility using a standardised microscopy assessment strategy. Moreover, this in vitro culture system was used to test susceptibility levels of microfilariae to different chemotherapeutic agents. Parasite motility was scored daily using a graded system and analysed using the average motility and area under the motility curve of M. perstans Mf. These datasets were analysed and discussed in detail in the related article entitled: “In vitro maintenance of Mansonella perstans microfilariae and its relevance for drug screening” [1].
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in vitro maintenance of Mansonella perstans microfilariae and its relevance for drug screening
Experimental Parasitology, 2019Co-Authors: Abdel Jelil Njouendou, Fanny Fri Fombad, Chi Anizette Kien, Narcisse V T Gandjui, Manuel Ritter, Mathias E Esum, Winston Patrick Chounna Ndongmo, Flobert Njiokou, Peter Enyong, Kenneth PfarrAbstract:Abstract Background Mansonellosis arises from infections with threadlike filarial nematodes in millions of individuals, especially in sub-Saharan Africa. Since infections present no overt clinical symptoms but attenuate immune responses that might lead to increased susceptibility and worsened disease course of concomitant infections, it is truly a neglected tropical disease. Nevertheless, only few studies focus on identifying suitable safe drugs for its control and little is known about the requirements for in vitro maintenance of the Mansonella perstans transmission stage. This study, therefore, evaluated the survival of M. perstans microfilariae (mf) using in vitro conditions that have been shown to promote survival of Loa loa, a closely related filarial nematode. Furthermore, the in vitro microfilaricidal effect of 15 agents was assessed on this helminth. Methods The ability of two basic culture media; Dulbecco's Modified Eagle's Medium (DMEM) and Roswell Park Memorial Institute (RPMI-1640) supplemented with 10% fetal bovine serum (FBS) and a monkey kidney epithelial cell line (LLC-MK2) to support the survival of M. perstans microfilariae was investigated. Subsequently, 6 anti-helminthics, 5 anti-malarials, 1 anti-microbacterial, 2 trypanocidals and 1 anti-cancer agent were tested in vitro against mf. The suitability of the culture media as well as the effect of the anti-infective agents on mf survival was assessed by scoring their motility. Results FBS supplement and additional LLC-MK2 cells significantly improved the survival of mf in DMEM and RPMI-1640 culture. In detail, RPMI-1640 supplemented with 10% FBS and LLC-MK2 cells sustained the maintenance of mf for at least 20 days (100.00 ± 0.00% survival). In co-cultures with LLC-MK2 cells without serum, M. perstans mf were maintained in DMEM and RPMI-1640 medium with a motility above 99% by day 5. Mefloquine displayed the highest microfilaricidal effect in vitro followed by artesunate. Conclusion Both RPMI and DMEM in the presence of LLC-MK2 cells are suitable for the maintenance of M. perstans mf in vitro. In absence of the feeder cells, the addition of 10% FBS to RPMI-1640 medium improved the parasite survival rate and motility. The microfilaricidal activity of mefloquine and artesunate on M. perstans mf was documented for the first time in this study and can therefore be considered as reference for further screening of agents against this parasite stage.
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Mansonella perstans microfilaremic individuals are characterized by enhanced type 2 helper t and regulatory t and b cell subsets and dampened systemic innate and adaptive immune responses
PLOS Neglected Tropical Diseases, 2018Co-Authors: Manuel Ritter, Abdel Jelil Njouendou, Winston Patrick Chounna Ndongmo, Dizzle Bita Tayong, Norman Nausch, Marc Jacobsen, Nora Nganyewo Nghochuzie, Lucy Cho Nchang, Kathrin Arndts, Samuel WanjiAbstract:: The filarial nematode Mansonella perstans is endemic throughout Africa, northern South America and the Caribbean. Interestingly, M. perstans-infected individuals present no distinct clinical picture associated with certain pathology. Due to its relatively silent nature, research on this tropical disease has been neglected, especially M. perstans-driven immune responses. A hindrance in obtaining data on M. perstans-specific responses has been the inability to obtain adult worms since their habitats in serous cavities are difficult to access. Thus, in this study, for the first time, we used Mansonella perstans worm antigen extract as stimulant to obtain filarial-specific recall and immunoglobulin responses from M. perstans microfilaremic individuals (Mp MF+) from Cameroon. Moreover, systemic immune profiles in sera and immune cell composition in peripheral blood from Mp MF+ and amicrofilaremic individuals (Mp MF-) were obtained. Our data reveal that Mp MF+ individuals showed significantly reduced cytokine (IL-4, IL-6 and IL-12p70) and chemokine levels (IL-8 and RANTES), but significantly higher MIP-1β as well as increased M. perstans-specific IgG4 levels compared to Mp MF- individuals. In contrast, upon re-stimulation with worm antigen extract, IFN-γ, IL-13, IL-10 and IL-17A secretion was enhanced in cell cultures from Mp MF+ individuals when compared to those from cultures of healthy European individuals. Moreover, analysis of immune cell composition in peripheral blood from Mp MF+ individuals revealed increased type 2 helper T (Th2), natural killer (NK), regulatory B and T cell (Breg and Treg) subsets but decreased type 1 regulatory T (Tr1) cells. In summary, this study deciphers for the first time, M. perstans-specific immune responses using worm antigen extract and shows that patent M. perstans infections have distinct Th2, Breg and Treg subsets accompanied with reduced systemic innate and adaptive immune responses and dominant filarial-specific IgG4 levels.
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successful long term maintenance of Mansonella perstans in an in vitro culture system
Parasites & Vectors, 2017Co-Authors: Abdel Jelil Njouendou, Fanny Fri Fombad, Chi Anizette Kien, Manuel Ritter, Winston Patrick Chounna Ndongmo, Kenneth Pfarr, Gandjui Tchamatchoua Victor Narcisse, Dizzle Bita Tayong, Laura E Layland, Achim HoeraufAbstract:Background Approximately 114 million people are infected with Mansonella perstans in large proportions of Africa. In contrast to other filariae that infect humans, M. perstans-infected individuals show no distinct pathology or specific clinical picture, indicating a well-tuned adaptation to the host. In addition, since M. perstans adult worms reside in serous cavities which are difficult to access, research has been hindered and there is a paucity of knowledge about the biology of M. perstans, especially the development of the different life stages as well as M. perstans-driven immune responses. Thus in this study, an in vitro culture system was developed which allows an in-depth analysis of M. perstans.
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update on the distribution of Mansonella perstans in the southern part of cameroon influence of ecological factors and mass drug administration with ivermectin
Parasites & Vectors, 2016Co-Authors: Samuel Wanji, Fanny Fri Fombad, Manuel Ritter, Winston Patrick Chounna Ndongmo, Dizzle Bita Tayong, Laura E Layland, Fabrice Datchoua R Poutcheu, Jonas A Kengneouafo, Nathalie Amvongoadjia, Charity Nya NjeshiAbstract:Background Mansonellosis remains one of the most neglected of tropical diseases and its current distribution in the entire forest block of southern Cameroon is unknown. In order to address this issue, we have surveyed the distribution of Mansonella perstans in different bioecological zones and in addition, elucidated the influence of multiple rounds of ivermectin (IVM) based mass drug administration (MDA).
Fanny Fri Fombad - One of the best experts on this subject based on the ideXlab platform.
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complete mitochondrial genome sequence of Mansonella perstans
Microbiology resource announcements, 2020Co-Authors: Matthew Chung, Jain Aluvathingal, Robin E Bromley, Suvarna Nadendla, Fanny Fri Fombad, Chi Anizette Kien, Narcisse V T Gandjui, Abdel Jelil Njouendou, Manuel Ritter, Lisa SadzewiczAbstract:ABSTRACT The 13,647-bp complete mitochondrial genome of Mansonella perstans was sequenced and is syntenic to the mitochondrial genome of Mansonella ozzardi. Phylogenetic analysis of the mitochondrial genome is consistent with the known phylogeny of ONC5 group filarial nematodes.
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dataset on in vitro maintenance of Mansonella perstans microfilariae and drug testing
Data in Brief, 2020Co-Authors: Abdel Jelil Njouendou, Fanny Fri Fombad, Chi Anizette Kien, Narcisse V T Gandjui, Manuel Ritter, Mathias E Esum, Winston Patrick Chounna Ndongmo, Flobert Njiokou, Peter Enyong, Kenneth PfarrAbstract:Abstract Endemic communities of Mansonella perstans infections have been neglected since associated pathology remains undefined. Consequently, improvements in drug therapy have also been ignored despite a large number of infected individuals in areas of Cameroon. Thus, we established an in vitro system to culture M. perstans microfilariae (Mf); the transmission stage of infection. In short, we compared the ability of two renowned culture media (Dulbecco's Modified Eagle's Medium (DMEM) and Roswell Park Memorial Institute (RPMI-1640)) to sustain Mf in culture. Media were supplemented with 10% fetal bovine serum (FBS) and monkey kidney epithelial cells (LLC-MK2) were used as feeder cells. As readout we assessed Mf survival and motility using a standardised microscopy assessment strategy. Moreover, this in vitro culture system was used to test susceptibility levels of microfilariae to different chemotherapeutic agents. Parasite motility was scored daily using a graded system and analysed using the average motility and area under the motility curve of M. perstans Mf. These datasets were analysed and discussed in detail in the related article entitled: “In vitro maintenance of Mansonella perstans microfilariae and its relevance for drug screening” [1].
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in vitro maintenance of Mansonella perstans microfilariae and its relevance for drug screening
Experimental Parasitology, 2019Co-Authors: Abdel Jelil Njouendou, Fanny Fri Fombad, Chi Anizette Kien, Narcisse V T Gandjui, Manuel Ritter, Mathias E Esum, Winston Patrick Chounna Ndongmo, Flobert Njiokou, Peter Enyong, Kenneth PfarrAbstract:Abstract Background Mansonellosis arises from infections with threadlike filarial nematodes in millions of individuals, especially in sub-Saharan Africa. Since infections present no overt clinical symptoms but attenuate immune responses that might lead to increased susceptibility and worsened disease course of concomitant infections, it is truly a neglected tropical disease. Nevertheless, only few studies focus on identifying suitable safe drugs for its control and little is known about the requirements for in vitro maintenance of the Mansonella perstans transmission stage. This study, therefore, evaluated the survival of M. perstans microfilariae (mf) using in vitro conditions that have been shown to promote survival of Loa loa, a closely related filarial nematode. Furthermore, the in vitro microfilaricidal effect of 15 agents was assessed on this helminth. Methods The ability of two basic culture media; Dulbecco's Modified Eagle's Medium (DMEM) and Roswell Park Memorial Institute (RPMI-1640) supplemented with 10% fetal bovine serum (FBS) and a monkey kidney epithelial cell line (LLC-MK2) to support the survival of M. perstans microfilariae was investigated. Subsequently, 6 anti-helminthics, 5 anti-malarials, 1 anti-microbacterial, 2 trypanocidals and 1 anti-cancer agent were tested in vitro against mf. The suitability of the culture media as well as the effect of the anti-infective agents on mf survival was assessed by scoring their motility. Results FBS supplement and additional LLC-MK2 cells significantly improved the survival of mf in DMEM and RPMI-1640 culture. In detail, RPMI-1640 supplemented with 10% FBS and LLC-MK2 cells sustained the maintenance of mf for at least 20 days (100.00 ± 0.00% survival). In co-cultures with LLC-MK2 cells without serum, M. perstans mf were maintained in DMEM and RPMI-1640 medium with a motility above 99% by day 5. Mefloquine displayed the highest microfilaricidal effect in vitro followed by artesunate. Conclusion Both RPMI and DMEM in the presence of LLC-MK2 cells are suitable for the maintenance of M. perstans mf in vitro. In absence of the feeder cells, the addition of 10% FBS to RPMI-1640 medium improved the parasite survival rate and motility. The microfilaricidal activity of mefloquine and artesunate on M. perstans mf was documented for the first time in this study and can therefore be considered as reference for further screening of agents against this parasite stage.
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successful long term maintenance of Mansonella perstans in an in vitro culture system
Parasites & Vectors, 2017Co-Authors: Abdel Jelil Njouendou, Fanny Fri Fombad, Chi Anizette Kien, Manuel Ritter, Winston Patrick Chounna Ndongmo, Kenneth Pfarr, Gandjui Tchamatchoua Victor Narcisse, Dizzle Bita Tayong, Laura E Layland, Achim HoeraufAbstract:Background Approximately 114 million people are infected with Mansonella perstans in large proportions of Africa. In contrast to other filariae that infect humans, M. perstans-infected individuals show no distinct pathology or specific clinical picture, indicating a well-tuned adaptation to the host. In addition, since M. perstans adult worms reside in serous cavities which are difficult to access, research has been hindered and there is a paucity of knowledge about the biology of M. perstans, especially the development of the different life stages as well as M. perstans-driven immune responses. Thus in this study, an in vitro culture system was developed which allows an in-depth analysis of M. perstans.
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update on the distribution of Mansonella perstans in the southern part of cameroon influence of ecological factors and mass drug administration with ivermectin
Parasites & Vectors, 2016Co-Authors: Samuel Wanji, Fanny Fri Fombad, Manuel Ritter, Winston Patrick Chounna Ndongmo, Dizzle Bita Tayong, Laura E Layland, Fabrice Datchoua R Poutcheu, Jonas A Kengneouafo, Nathalie Amvongoadjia, Charity Nya NjeshiAbstract:Background Mansonellosis remains one of the most neglected of tropical diseases and its current distribution in the entire forest block of southern Cameroon is unknown. In order to address this issue, we have surveyed the distribution of Mansonella perstans in different bioecological zones and in addition, elucidated the influence of multiple rounds of ivermectin (IVM) based mass drug administration (MDA).
Abdel Jelil Njouendou - One of the best experts on this subject based on the ideXlab platform.
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complete mitochondrial genome sequence of Mansonella perstans
Microbiology resource announcements, 2020Co-Authors: Matthew Chung, Jain Aluvathingal, Robin E Bromley, Suvarna Nadendla, Fanny Fri Fombad, Chi Anizette Kien, Narcisse V T Gandjui, Abdel Jelil Njouendou, Manuel Ritter, Lisa SadzewiczAbstract:ABSTRACT The 13,647-bp complete mitochondrial genome of Mansonella perstans was sequenced and is syntenic to the mitochondrial genome of Mansonella ozzardi. Phylogenetic analysis of the mitochondrial genome is consistent with the known phylogeny of ONC5 group filarial nematodes.
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dataset on in vitro maintenance of Mansonella perstans microfilariae and drug testing
Data in Brief, 2020Co-Authors: Abdel Jelil Njouendou, Fanny Fri Fombad, Chi Anizette Kien, Narcisse V T Gandjui, Manuel Ritter, Mathias E Esum, Winston Patrick Chounna Ndongmo, Flobert Njiokou, Peter Enyong, Kenneth PfarrAbstract:Abstract Endemic communities of Mansonella perstans infections have been neglected since associated pathology remains undefined. Consequently, improvements in drug therapy have also been ignored despite a large number of infected individuals in areas of Cameroon. Thus, we established an in vitro system to culture M. perstans microfilariae (Mf); the transmission stage of infection. In short, we compared the ability of two renowned culture media (Dulbecco's Modified Eagle's Medium (DMEM) and Roswell Park Memorial Institute (RPMI-1640)) to sustain Mf in culture. Media were supplemented with 10% fetal bovine serum (FBS) and monkey kidney epithelial cells (LLC-MK2) were used as feeder cells. As readout we assessed Mf survival and motility using a standardised microscopy assessment strategy. Moreover, this in vitro culture system was used to test susceptibility levels of microfilariae to different chemotherapeutic agents. Parasite motility was scored daily using a graded system and analysed using the average motility and area under the motility curve of M. perstans Mf. These datasets were analysed and discussed in detail in the related article entitled: “In vitro maintenance of Mansonella perstans microfilariae and its relevance for drug screening” [1].
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in vitro maintenance of Mansonella perstans microfilariae and its relevance for drug screening
Experimental Parasitology, 2019Co-Authors: Abdel Jelil Njouendou, Fanny Fri Fombad, Chi Anizette Kien, Narcisse V T Gandjui, Manuel Ritter, Mathias E Esum, Winston Patrick Chounna Ndongmo, Flobert Njiokou, Peter Enyong, Kenneth PfarrAbstract:Abstract Background Mansonellosis arises from infections with threadlike filarial nematodes in millions of individuals, especially in sub-Saharan Africa. Since infections present no overt clinical symptoms but attenuate immune responses that might lead to increased susceptibility and worsened disease course of concomitant infections, it is truly a neglected tropical disease. Nevertheless, only few studies focus on identifying suitable safe drugs for its control and little is known about the requirements for in vitro maintenance of the Mansonella perstans transmission stage. This study, therefore, evaluated the survival of M. perstans microfilariae (mf) using in vitro conditions that have been shown to promote survival of Loa loa, a closely related filarial nematode. Furthermore, the in vitro microfilaricidal effect of 15 agents was assessed on this helminth. Methods The ability of two basic culture media; Dulbecco's Modified Eagle's Medium (DMEM) and Roswell Park Memorial Institute (RPMI-1640) supplemented with 10% fetal bovine serum (FBS) and a monkey kidney epithelial cell line (LLC-MK2) to support the survival of M. perstans microfilariae was investigated. Subsequently, 6 anti-helminthics, 5 anti-malarials, 1 anti-microbacterial, 2 trypanocidals and 1 anti-cancer agent were tested in vitro against mf. The suitability of the culture media as well as the effect of the anti-infective agents on mf survival was assessed by scoring their motility. Results FBS supplement and additional LLC-MK2 cells significantly improved the survival of mf in DMEM and RPMI-1640 culture. In detail, RPMI-1640 supplemented with 10% FBS and LLC-MK2 cells sustained the maintenance of mf for at least 20 days (100.00 ± 0.00% survival). In co-cultures with LLC-MK2 cells without serum, M. perstans mf were maintained in DMEM and RPMI-1640 medium with a motility above 99% by day 5. Mefloquine displayed the highest microfilaricidal effect in vitro followed by artesunate. Conclusion Both RPMI and DMEM in the presence of LLC-MK2 cells are suitable for the maintenance of M. perstans mf in vitro. In absence of the feeder cells, the addition of 10% FBS to RPMI-1640 medium improved the parasite survival rate and motility. The microfilaricidal activity of mefloquine and artesunate on M. perstans mf was documented for the first time in this study and can therefore be considered as reference for further screening of agents against this parasite stage.
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Mansonella perstans microfilaremic individuals are characterized by enhanced type 2 helper t and regulatory t and b cell subsets and dampened systemic innate and adaptive immune responses
PLOS Neglected Tropical Diseases, 2018Co-Authors: Manuel Ritter, Abdel Jelil Njouendou, Winston Patrick Chounna Ndongmo, Dizzle Bita Tayong, Norman Nausch, Marc Jacobsen, Nora Nganyewo Nghochuzie, Lucy Cho Nchang, Kathrin Arndts, Samuel WanjiAbstract:: The filarial nematode Mansonella perstans is endemic throughout Africa, northern South America and the Caribbean. Interestingly, M. perstans-infected individuals present no distinct clinical picture associated with certain pathology. Due to its relatively silent nature, research on this tropical disease has been neglected, especially M. perstans-driven immune responses. A hindrance in obtaining data on M. perstans-specific responses has been the inability to obtain adult worms since their habitats in serous cavities are difficult to access. Thus, in this study, for the first time, we used Mansonella perstans worm antigen extract as stimulant to obtain filarial-specific recall and immunoglobulin responses from M. perstans microfilaremic individuals (Mp MF+) from Cameroon. Moreover, systemic immune profiles in sera and immune cell composition in peripheral blood from Mp MF+ and amicrofilaremic individuals (Mp MF-) were obtained. Our data reveal that Mp MF+ individuals showed significantly reduced cytokine (IL-4, IL-6 and IL-12p70) and chemokine levels (IL-8 and RANTES), but significantly higher MIP-1β as well as increased M. perstans-specific IgG4 levels compared to Mp MF- individuals. In contrast, upon re-stimulation with worm antigen extract, IFN-γ, IL-13, IL-10 and IL-17A secretion was enhanced in cell cultures from Mp MF+ individuals when compared to those from cultures of healthy European individuals. Moreover, analysis of immune cell composition in peripheral blood from Mp MF+ individuals revealed increased type 2 helper T (Th2), natural killer (NK), regulatory B and T cell (Breg and Treg) subsets but decreased type 1 regulatory T (Tr1) cells. In summary, this study deciphers for the first time, M. perstans-specific immune responses using worm antigen extract and shows that patent M. perstans infections have distinct Th2, Breg and Treg subsets accompanied with reduced systemic innate and adaptive immune responses and dominant filarial-specific IgG4 levels.
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successful long term maintenance of Mansonella perstans in an in vitro culture system
Parasites & Vectors, 2017Co-Authors: Abdel Jelil Njouendou, Fanny Fri Fombad, Chi Anizette Kien, Manuel Ritter, Winston Patrick Chounna Ndongmo, Kenneth Pfarr, Gandjui Tchamatchoua Victor Narcisse, Dizzle Bita Tayong, Laura E Layland, Achim HoeraufAbstract:Background Approximately 114 million people are infected with Mansonella perstans in large proportions of Africa. In contrast to other filariae that infect humans, M. perstans-infected individuals show no distinct pathology or specific clinical picture, indicating a well-tuned adaptation to the host. In addition, since M. perstans adult worms reside in serous cavities which are difficult to access, research has been hindered and there is a paucity of knowledge about the biology of M. perstans, especially the development of the different life stages as well as M. perstans-driven immune responses. Thus in this study, an in vitro culture system was developed which allows an in-depth analysis of M. perstans.