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Peter U. Fischer - One of the best experts on this subject based on the ideXlab platform.
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MARCOS AND OTHERS ATYPICAL MICROFILARIAE IN PERU Short Report: Genetic Characterization of Atypical Mansonella (Mansonella) ozzardi Microfilariae in Human Blood Samples from Northeastern Peru
2016Co-Authors: Luis A. Marcos, Nancy Arrospide, Sergio Recuenco, Cesar Cabezas, Gary J. Weil, Peter U. FischerAbstract:DNA sequence comparisons are useful for characterizing proposed new parasite species or strains. Microfilariae with an atypical arrangement of nuclei behind the cephalic space have been recently described in human blood samples from the Amazon region of Peru. Three blood specimens containing atypical microfilariae were genetically characterized using three DNA markers (5S ribosomal DNA, 12S ribosomal DNA, and cytochrome oxidase I). All atypical microfilariae were clustered into the Mansonella group and indistinguishable from M. ozzardi based on these DNA markers. The main filarial species that infect humans in Latin America are Onchocerca volvulus, Wuchereria bancrofti, and two species of Mansonella, M. ozzardi, and M. perstans. The latter are placed in different subgenera, Mansonella and Esslingeria, respectively.1 M. ozzardi is limited to Latin America, whereas the other species also occur in sub-Saharan Africa and were introduced to the new world by the slave trade.2 Atypical microfilariae (Mf) similar to M. ozzardi have been occasionally reported in Amerindian people from tropical South America. These Mf include Microfilaria bolivarensis in Venezuela,3 a microfilaria sharing characteristics with M. ozzardi and O. volvulus in Brazil,4 and an atypical Mf recently reported from Peru.5 The atypical M
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Copyright © 2012 by The American Society of Tropical Medicine and Hygiene Short Report: Genetic Characterization of AtypicalMansonella (Mansonella) ozzardi Microfilariae in Human Blood Samples from Northeastern Peru
2016Co-Authors: Luis A. Marcos, Nancy Arrospide, Sergio Recuenco, Cesar Cabezas, Gary J. Weil, Peter U. FischerAbstract:Abstract. DNA sequence comparisons are useful for characterizing proposed new parasite species or strains. Microfilariae with an atypical arrangement of nuclei behind the cephalic space have been recently described in human blood samples from the Amazon region of Peru. Three blood specimens containing atypical microfilariae were genetically characterized using three DNA markers (5S ribosomal DNA, 12S ribosomal DNA, and cytochrome oxidase I). All atypical microfilariae were clustered into the Mansonella group and indistinguishable from M. ozzardi based on these DNA markers. The main filarial species that infect humans in Latin America are Onchocerca volvulus, Wuchereria bancrofti, and two species of Mansonella, M. ozzardi, and M. perstans. The latter are placed in different subgenera, Mansonella and Esslingeria, respectively.1 M. ozzardi is limited to Latin America, whereas the other species also occur in sub-Saharan Africa and were introduced to the new world by the slave trade.2 Atypical microfilariae (Mf) similar toM. ozzardi have been occasionally reported in Amerindian people from tropica
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genetic characterization of atypical Mansonella Mansonella ozzardi microfilariae in human blood samples from northeastern peru
American Journal of Tropical Medicine and Hygiene, 2012Co-Authors: Luis Marcos, Nancy Arrospide, Sergio Recuenco, Cesar Cabezas, Gary J. Weil, Peter U. FischerAbstract:DNA sequence comparisons are useful for characterizing proposed new parasite species or strains. Microfilariae with an atypical arrangement of nuclei behind the cephalic space have been recently described in human blood samples from the Amazon region of Peru. Three blood specimens containing atypical microfilariae were genetically characterized using three DNA markers (5S ribosomal DNA, 12S ribosomal DNA, and cytochrome oxidase I). All atypical microfilariae were clustered into the Mansonella group and indistinguishable from M. ozzardi based on these DNA markers. The main filarial species that infect humans in Latin America are Onchocerca volvulus, Wuchereria bancrofti, and two species of Mansonella, M. ozzardi, and M. perstans. The latter are placed in different subgenera, Mansonella and Esslingeria, respectively. 1 M. ozzardi is limited to Latin America, whereas the other species also occur in sub-Saharan Africa and were introduced to the new world by the slave trade. 2 Atypical microfilariae (Mf) similar to M. ozzardi have been occasionally reported in Amerindian people from tropical South America. These Mf include Microfilaria bolivarensis in Venezuela, 3 a microfilaria sharing characteristics with M. ozzardi and O. volvulus in Brazil, 4 and an atypical Mf recently reported from Peru. 5 The atypical Mf reported from Brazil and Peru were morphologically similar, with two nuclei followed by a single nucleus just caudal to the cephalic space. This finding is in contrast to Mf of M. ozzardi ,w hich have a single nucleus in this position. 4,5 The geographic distance between the communities where these atypical Mf were detected is approximately 850 km, and both areas are within M. ozzardi-endemic zones. 6 Additional studies were warranted to investigate whether the atypical Mf are from a novel filarial parasite species. Therefore, the objective of this study was to use molecular markers to characterize atypical Mf found during a malaria screening (Institutional Review Board approved under Instituto Nacional de Salud and Center for Diseases Control) in Peru. Three frozen (ethylenedinitrilo)tetraacetic acid (EDTA) blood samples (two with M. ozzardi and one with atypical Mf) and three blood smears with only atypical Mf were sent to Washington University, St. Louis, MO, from the Instituto Nacional de Salud, Lima, Peru. The samples were collec- ted in La Union (7°28¢ S, 74°58¢ W), Santa Clara (3°37¢ S, 73°12¢ W), and Cahuapanas (5°14¢ S, 77°05¢ W) villages in northeast Peru (Loreto Department). M. ozzardi was identi- fied in Peru by morphological characteristics. 7 The difference
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treatment of human Mansonella streptocerca infection with ivermectin
Tropical Medicine & International Health, 1997Co-Authors: Peter U. Fischer, Jotham Bamuhiiga, Dietrich W ButtnerAbstract:We studied the short-term effects of a single dose of 150 micrograms/kg body weight ivermectin on Mansonella streptocerca in an area endemic for streptocerciasis, but not for onchocerciasis, in western Uganda. Six and 12 days after treatment no microfilaria (mf) were found in the skin of 53 out of 96 mf carriers living in 3 villages, and the geometric means of the mf densities of remaining mf carriers were only 33-40% of pretreatment levels. This reduction of mf density was highly significant (P < 0.0001). Immunohistological examination of skin biopsies showed degenerated and disintegrating mf surrounded by activated eosinophils (positive for activated cationic protein), macrophages, and neutrophils (positive for myeloperoxidase and defensin) on day 6 after treatment. Remarkable was the invasion of young, L1 protein-positive macrophages and the release of neutrophil defensin as signs of acute inflammation. We conclude that ivermectin has a strong microfilaricidal activity against M. streptocerca. Common adverse effects were increased pruritus and acute papular dermatitis in 45% of 86 mf carriers on day 6 after treatment. No serious adverse side-effects were noticed in about 700 treated persons.
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occurrence and diagnosis of Mansonella streptocerca in uganda
Acta Tropica, 1997Co-Authors: Peter U. Fischer, Jotham Bamuhiiga, Dietrich W ButtnerAbstract:During filaria surveys Mansonella streptocerca was found for the first time in Uganda, in 12 widely scattered villages in the Bundibugyo district between the Ruwenzori mountains and the Ituri forest, an area not endemic for Onchocerca volvulus. The crude prevalence in 806 examined adult persons ranged from 5 to 89% with an average of 61%. In 148 children the prevalence was 36%. The geometric mean of microfilaria (mf) densities in adult mf carriers was 1.7 mf/mg skin and the community microfilarial loads ranged from 1.0 to 13.7 mf/skin snip. In 476 persons skin snips from the shoulder contained mf in 58% and those from the buttocks in 48%. Skin snips from 68 persons digested with collagenase showed that only 30-37% of the mf emerged during 24 h incubation at 30 degrees C in isotonic salt solution. An itching acute or more often chronic papular dermatitis, predominantly on the upper parts of the body, was the typical skin lesion observed in 24% of 177 M. streptocerca mf carriers.
Jansen Fernandes Medeiros - One of the best experts on this subject based on the ideXlab platform.
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Mansonella ozzardi mitogenome and pseudogene characterisation provides new perspectives on filarial parasite systematics and CO-1 barcoding
Scientific Reports, 2018Co-Authors: James Lee Crainey, Jansen Fernandes Medeiros, Felipe Arley Costa Pessoa, Michel Abanto Marín, Túllio Romão Ribeiro Da Silva, Yago Vinícius Santos, Ana Carolina Paulo VicenteAbstract:Despite the broad distribution of M. ozzardi in Latin America and the Caribbean, there is still very little DNA sequence data available to study this neglected parasite’s epidemiology. Mitochondrial DNA (mtDNA) sequences, especially the cytochrome oxidase (CO1) gene’s barcoding region, have been targeted successfully for filarial diagnostics and for epidemiological, ecological and evolutionary studies. MtDNA-based studies can, however, be compromised by unrecognised mitochondrial pseudogenes, such as Numts. Here, we have used shot-gun Illumina-HiSeq sequencing to recover the first complete Mansonella genus mitogenome and to identify several mitochondrial-origin pseudogenes. Mitogenome phylogenetic analysis placed M. ozzardi in the Onchocercidae “ONC5” clade and suggested that Mansonella parasites are more closely related to Wuchereria and Brugia genera parasites than they are to Loa genus parasites. DNA sequence alignments, BLAST searches and conceptual translations have been used to compliment phylogenetic analysis showing that M. ozzardi from the Amazon and Caribbean regions are near-identical and that previously reported Peruvian M. ozzardi CO1 reference sequences are probably of pseudogene origin. In addition to adding a much-needed resource to the Mansonella genus’s molecular tool-kit and providing evidence that some M. ozzardi CO1 sequence deposits are pseudogenes, our results suggest that all Neotropical M. ozzardi parasites are closely related.
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molecular verification of new world Mansonella perstans parasitemias
Emerging Infectious Diseases, 2017Co-Authors: Lucyane Bastos Tavares Silva, Túllio Romão Ribeiro Da Silva, James Lee Crainey, Uziel Ferreira Suwa, Ana Carolina Paulo Vicente, Jansen Fernandes Medeiros, Felipe Arley Costa PessoaAbstract:We obtained ribosomal and mitochondrial DNA sequences from residents of Amazonas state, Brazil, with Mansonella parasitemias. Phylogenetic analysis of these sequences confirm that M. ozzardi and M. perstans parasites occur in sympatry and reveal the close relationship between M. perstans in Africa and Brazil, providing insights into the parasite’s New World origins.
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occurrence of Mansonella ozzardi diagnosed using a polycarbonate membrane in a riverside population of labrea in the western brazilian amazon
Revista Da Sociedade Brasileira De Medicina Tropical, 2016Co-Authors: Sergio De Almeida Basano, Jansen Fernandes Medeiros, Luana Janaina Souza Vera, Gilberto Fontes, Gabriel De Deus Vieira, Juliana Souza De Almeida Aranha Camargo, Ricardo De Godoi Mattos Ferreira, Luis Marcelo Aranha CamargoAbstract:INTRODUCTION Mansonella ozzardi is a widely distributed filaria worm in the Amazon region. This study aimed to determine the prevalence of M. ozzardi infection in riverine communities of Labrea municipality, Amazonas State, Brazil. METHODS A diagnostic blood filtration method in a polycarbonate membrane was used. RESULTS M. ozzardi was found in 50.3% of the sample, with the highest prevalence in farmers/fishermen (69.4%; χ 2 = -19.14, p<0.001). The prevalence was higher in longer-term residents (≥11 years; 60.2%). CONCLUSIONS M. ozzardi infection rates are high near the Purus River, much greater than those previously reported based on diagnosis using thick blood smears.
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Occurrence of Mansonella ozzardi diagnosed using a polycarbonate membrane in a riverside population of Lábrea in the Western Brazilian Amazon
Sociedade Brasileira de Medicina Tropical (SBMT), 2016Co-Authors: Sergio De Almeida Basano, Jansen Fernandes Medeiros, Luana Janaina Souza Vera, Gilberto Fontes, Gabriel De Deus Vieira, Juliana Souza De Almeida Aranha Camargo, Ricardo De Godoi Mattos Ferreira, Luis Marcelo Aranha CamargoAbstract:Abstract: INTRODUCTION Mansonella ozzardi is a widely distributed filaria worm in the Amazon region. This study aimed to determine the prevalence of M. ozzardi infection in riverine communities of Lábrea municipality, Amazonas State, Brazil. METHODS A diagnostic blood filtration method in a polycarbonate membrane was used. RESULTS M. ozzardi was found in 50.3% of the sample, with the highest prevalence in farmers/fishermen (69.4%; χ 2 = -19.14, p
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a field trial of a pcr based Mansonella ozzardi diagnosis assay detects high levels of submicroscopic m ozzardi infections in both venous blood samples and fta card dried blood spots
Parasites & Vectors, 2015Co-Authors: Jansen Fernandes Medeiros, Jose M Rubio, Lucyane Bastos Tavares Silva, James Lee Crainey, Tatiana Amaral Pires De Almeida, Felipe Arley Costa PessoaAbstract:Background Mansonella ozzardi is a poorly understood human filarial parasite with a broad distribution throughout Latin America. Most of what is known about its parasitism has come from epidemiological studies that have estimated parasite incidence using light microscopy. Light microscopy can, however, miss lighter, submicroscopic, infections. In this study we have compared M. ozzardi incidence estimates made using light microscopy, with estimates made using PCR.
Felipe Arley Costa Pessoa - One of the best experts on this subject based on the ideXlab platform.
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Mansonella ozzardi mitogenome and pseudogene characterisation provides new perspectives on filarial parasite systematics and CO-1 barcoding
Scientific Reports, 2018Co-Authors: James Lee Crainey, Jansen Fernandes Medeiros, Felipe Arley Costa Pessoa, Michel Abanto Marín, Túllio Romão Ribeiro Da Silva, Yago Vinícius Santos, Ana Carolina Paulo VicenteAbstract:Despite the broad distribution of M. ozzardi in Latin America and the Caribbean, there is still very little DNA sequence data available to study this neglected parasite’s epidemiology. Mitochondrial DNA (mtDNA) sequences, especially the cytochrome oxidase (CO1) gene’s barcoding region, have been targeted successfully for filarial diagnostics and for epidemiological, ecological and evolutionary studies. MtDNA-based studies can, however, be compromised by unrecognised mitochondrial pseudogenes, such as Numts. Here, we have used shot-gun Illumina-HiSeq sequencing to recover the first complete Mansonella genus mitogenome and to identify several mitochondrial-origin pseudogenes. Mitogenome phylogenetic analysis placed M. ozzardi in the Onchocercidae “ONC5” clade and suggested that Mansonella parasites are more closely related to Wuchereria and Brugia genera parasites than they are to Loa genus parasites. DNA sequence alignments, BLAST searches and conceptual translations have been used to compliment phylogenetic analysis showing that M. ozzardi from the Amazon and Caribbean regions are near-identical and that previously reported Peruvian M. ozzardi CO1 reference sequences are probably of pseudogene origin. In addition to adding a much-needed resource to the Mansonella genus’s molecular tool-kit and providing evidence that some M. ozzardi CO1 sequence deposits are pseudogenes, our results suggest that all Neotropical M. ozzardi parasites are closely related.
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molecular verification of new world Mansonella perstans parasitemias
Emerging Infectious Diseases, 2017Co-Authors: Lucyane Bastos Tavares Silva, Túllio Romão Ribeiro Da Silva, James Lee Crainey, Uziel Ferreira Suwa, Ana Carolina Paulo Vicente, Jansen Fernandes Medeiros, Felipe Arley Costa PessoaAbstract:We obtained ribosomal and mitochondrial DNA sequences from residents of Amazonas state, Brazil, with Mansonella parasitemias. Phylogenetic analysis of these sequences confirm that M. ozzardi and M. perstans parasites occur in sympatry and reveal the close relationship between M. perstans in Africa and Brazil, providing insights into the parasite’s New World origins.
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a field trial of a pcr based Mansonella ozzardi diagnosis assay detects high levels of submicroscopic m ozzardi infections in both venous blood samples and fta card dried blood spots
Parasites & Vectors, 2015Co-Authors: Jansen Fernandes Medeiros, Jose M Rubio, Lucyane Bastos Tavares Silva, James Lee Crainey, Tatiana Amaral Pires De Almeida, Felipe Arley Costa PessoaAbstract:Background Mansonella ozzardi is a poorly understood human filarial parasite with a broad distribution throughout Latin America. Most of what is known about its parasitism has come from epidemiological studies that have estimated parasite incidence using light microscopy. Light microscopy can, however, miss lighter, submicroscopic, infections. In this study we have compared M. ozzardi incidence estimates made using light microscopy, with estimates made using PCR.
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Mansonella ozzardi nematoda onchocercidae in the riverine population of the tefe river state of amazonia brazil
Revista Da Sociedade Brasileira De Medicina Tropical, 2014Co-Authors: Jansen Fernandes Medeiros, Cristovao Alves Da Costa, Alita Moura De Lima, Felipe Arley Costa PessoaAbstract:Introduction: This study assessed the prevalence of Mansonella ozzardi in riverine communities of the Tefe River, Amazonas, Brazil. Methods: The prevalence of M. ozzardi was estimated by microscopic examination of thick blood smears. Results: The M. ozzardi prevalence rate was 6.3% (19/300). Filarial infection was found in 8 of the 11 communities surveyed, with prevalence rates varying from 2.5% to 22.2%. Conclusions: Tefe is a region of oil and natural gas exploration, in which there is a high turnover of workers. Migration patterns may facilitate the dissemination of mansonelliasis to other regions.
Thomas Bruce Nutman - 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, Sekou F Traore, Siaka Yamoussa Coulibaly, Michel Emmanuel Coulibaly, Bourama Traore, Ibrahim Moussa Sissoko, Sibiry Samake, Ilo Dicko, Thomas Bruce 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 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, Ibrahim Moussa Sissoko, Sibiry Samake, Sekou Fantamady Traore, Ilo Dicko, 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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molecular identification of wolbachia from the filarial nematode Mansonella perstans
Molecular and Biochemical Parasitology, 2008Co-Authors: Paul B. Keiser, Joseph Kubofcik, Yacouba Coulibaly, Amy D Klion, Sekou F Traore, Abdallah A Diallo, Thomas Bruce 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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molecular identification of wolbachia from the filarial nematode Mansonella perstans
Molecular and Biochemical Parasitology, 2008Co-Authors: Paul B. Keiser, Joseph Kubofcik, Amy D Klion, Sekou F Traore, Abdallah A Diallo, Yaya I Coulibaly, Thomas Bruce 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 1393bp 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 1369bp overlapping sequence. Phylogenetic dendrograms, examining the relationship of the Mp Wolbachia to other Wolbachia 16S rDNA, showed that the Wolbachia 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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Experimental infection of humans with filariae.
Clinical Infectious Diseases, 1991Co-Authors: Thomas Bruce NutmanAbstract:: This report summarizes the findings of the 17 published studies involving humans who have been experimentally infected with filarial parasites. Over the past 60 years, 45 individuals have been deliberately infected with Wuchereria bancrofti, Brugia malayi, Brugia pahangi, Loa loa, Mansonella perstans, Mansonella ozzardi, and/or Onchocerca volvulus. The findings from these experimental infections of humans have helped define microfilarial survival and periodicity within human hosts, the prepatent period for the causative agents of lymphatic filariasis, etiologic agents for particular clinical syndromes, immunologic and hematologic consequences of filarial infection, and the role of chemotherapeutic agents in the prevention and treatment of filarial infections.
Dietrich W Buttner - One of the best experts on this subject based on the ideXlab platform.
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treatment of human Mansonella streptocerca infection with ivermectin
Tropical Medicine & International Health, 1997Co-Authors: Peter U. Fischer, Jotham Bamuhiiga, Dietrich W ButtnerAbstract:We studied the short-term effects of a single dose of 150 micrograms/kg body weight ivermectin on Mansonella streptocerca in an area endemic for streptocerciasis, but not for onchocerciasis, in western Uganda. Six and 12 days after treatment no microfilaria (mf) were found in the skin of 53 out of 96 mf carriers living in 3 villages, and the geometric means of the mf densities of remaining mf carriers were only 33-40% of pretreatment levels. This reduction of mf density was highly significant (P < 0.0001). Immunohistological examination of skin biopsies showed degenerated and disintegrating mf surrounded by activated eosinophils (positive for activated cationic protein), macrophages, and neutrophils (positive for myeloperoxidase and defensin) on day 6 after treatment. Remarkable was the invasion of young, L1 protein-positive macrophages and the release of neutrophil defensin as signs of acute inflammation. We conclude that ivermectin has a strong microfilaricidal activity against M. streptocerca. Common adverse effects were increased pruritus and acute papular dermatitis in 45% of 86 mf carriers on day 6 after treatment. No serious adverse side-effects were noticed in about 700 treated persons.
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occurrence and diagnosis of Mansonella streptocerca in uganda
Acta Tropica, 1997Co-Authors: Peter U. Fischer, Jotham Bamuhiiga, Dietrich W ButtnerAbstract:During filaria surveys Mansonella streptocerca was found for the first time in Uganda, in 12 widely scattered villages in the Bundibugyo district between the Ruwenzori mountains and the Ituri forest, an area not endemic for Onchocerca volvulus. The crude prevalence in 806 examined adult persons ranged from 5 to 89% with an average of 61%. In 148 children the prevalence was 36%. The geometric mean of microfilaria (mf) densities in adult mf carriers was 1.7 mf/mg skin and the community microfilarial loads ranged from 1.0 to 13.7 mf/skin snip. In 476 persons skin snips from the shoulder contained mf in 58% and those from the buttocks in 48%. Skin snips from 68 persons digested with collagenase showed that only 30-37% of the mf emerged during 24 h incubation at 30 degrees C in isotonic salt solution. An itching acute or more often chronic papular dermatitis, predominantly on the upper parts of the body, was the typical skin lesion observed in 24% of 177 M. streptocerca mf carriers.