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Peter U. Fischer - One of the best experts on this subject based on the ideXlab platform.

  • An internal control for the detection of Onchocerca volvulus DNA by PCR–ELISA and rapid detection of specific PCR products by DNA Detection Test StripsTM
    Tropical Medicine and International Health, 2002
    Co-Authors: S. Pischke, Dietrich W Buttner, Eva Liebau, Peter U. Fischer
    Abstract:

    We developed a polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA) for the detection of Onchocerca volvulus DNA. To standardize the PCR and to avoid false-negative results, an internal control DNA was co-amplified by the same set of primers. We differentiated the wild-type PCR product of the O-150 DNA sequence from the internal control by specific DNA probes. Detection of biotinylated PCR products by DNA probes was performed by ELISA to quantify the PCR product or by DNA Detection Test Strips as a rapid field technique. The methods were evaluated on skin biopsies from individuals living in an area endemic for O. volvulus in Uganda, but with low microfilaria densities because of ivermectin treatment. Microfilaria density was assessed by a single skin snip and a second skin snip was examined by PCR. Among 69 samples from microfilaria carriers, 47 (68%) were positive by ELISA and 55 (80%) by test strip detection of PCR products. When 39 samples of microfilaria-negative individuals from the same area were tested, 10 (27%) were positive by ELISA and 12 (31%) by test strips. None of the 19 samples obtained from persons living in an area not endemic for O. volvulus but endemic for Mansonella streptocerca was positive in either test. Although the ELISA is theoretically more sensitive than the test strips for the detection of PCR products, examination of field samples revealed that the test strip method had a higher operational sensitivity and was more convenient to perform. Thus, the DNA Detection Test Strips are a rapid and low-tech tool for identification of PCR products in laboratories of countries endemic for onchocerciasis.

  • long term suppression of Mansonella stveptocevca microfilariae after treatment with ivermectin
    The Journal of Infectious Diseases, 1999
    Co-Authors: Peter U. Fischer, Ephraim Tukesiga, Dietrich W Buttner
    Abstract:

    The long-term effect of a single oral dose of 150 microg/kg of body weight of ivermectin on Mansonella streptocerca microfilariae was studied in western Uganda. Before treatment, the geometric mean microfilaria density (mf) in 93 infected persons was 2.4 mf/mg of skin (range, 0.1-42.6). One year after treatment, 43 persons (46%) were microfilaria-negative, and the geometric mean in the remaining persons dropped significantly, to 0.7 mf/mg (range, 0.1-6.9). Thus, ivermectin is highly effective against M. streptocerca, and a single dose leads to a sustained suppression of microfilariae in skin. In Africa, ivermectin is used for mass treatment to control Onchocerca volvulus and Wuchereria bancrofti. Because these filarial parasites are often coendemic with M. streptocerca, the treated population may receive the additional benefit of suppression of M. streptocerca microfilariae.

  • detection of the filarial parasite Mansonella streptocerca in skin biopsies by a nested polymerase chain reaction based assay
    American Journal of Tropical Medicine and Hygiene, 1998
    Co-Authors: Peter U. Fischer, Jotham Bamuhiiga, Dietrich W Buttner, Steven A Williams
    Abstract:

    To differentiate the skin-dwelling filariae Mansonella streptocerca and Onchocerca volvulus, a nested polymerase chain reaction (PCR) assay was developed from small amounts of parasite material present in skin biopsies. One nonspecific and one specific pair of primers were used to amplify the 5S rDNA spacer region of M. streptocerca. Biopsies with different microfilaria densities obtained from 104 Ugandans living in an area endemic for M. streptocerca were tested using both the nested PCR assay and standard parasitologic assessment of microfilariae. All 82 samples from microfilaria carriers were positive when tested using the nested PCR assay. In addition, M. streptocerca DNA could be detected in 16 samples thought to be microfilaria negative. Furthermore, six days following ivermectin treatment, M. streptocerca DNA was found in 12 of 14 microfilaria-negative biopsies. Control skin samples from patients infected with O. volvulus were all negative in the nested PCR assay. This assay improves the diagnosis of M. streptocerca and will facilitate further epidemiologic studies.

  • Detection of the filarial parasite Mansonella streptocerca in skin biopsies by a nested polymerase chain reaction-based assay
    1998
    Co-Authors: Peter U. Fischer, Jotham Bamuhiiga, Peter Fischer, Dietrich Bu W. Ttner, Steven A Williams, A. Williams
    Abstract:

    Detection of the filarial parasite Mansonella streptocerca skin biopsies by a nested polymerase chain reaction-based assay Article in The American journal of tropical medicine and hygiene · July 199

  • treatment of human Mansonella streptocerca infection with ivermectin
    Tropical Medicine & International Health, 1997
    Co-Authors: Peter U. Fischer, Jotham Bamuhiiga, Dietrich W Buttner
    Abstract:

    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.

Dietrich W Buttner - One of the best experts on this subject based on the ideXlab platform.

  • An internal control for the detection of Onchocerca volvulus DNA by PCR–ELISA and rapid detection of specific PCR products by DNA Detection Test StripsTM
    Tropical Medicine and International Health, 2002
    Co-Authors: S. Pischke, Dietrich W Buttner, Eva Liebau, Peter U. Fischer
    Abstract:

    We developed a polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA) for the detection of Onchocerca volvulus DNA. To standardize the PCR and to avoid false-negative results, an internal control DNA was co-amplified by the same set of primers. We differentiated the wild-type PCR product of the O-150 DNA sequence from the internal control by specific DNA probes. Detection of biotinylated PCR products by DNA probes was performed by ELISA to quantify the PCR product or by DNA Detection Test Strips as a rapid field technique. The methods were evaluated on skin biopsies from individuals living in an area endemic for O. volvulus in Uganda, but with low microfilaria densities because of ivermectin treatment. Microfilaria density was assessed by a single skin snip and a second skin snip was examined by PCR. Among 69 samples from microfilaria carriers, 47 (68%) were positive by ELISA and 55 (80%) by test strip detection of PCR products. When 39 samples of microfilaria-negative individuals from the same area were tested, 10 (27%) were positive by ELISA and 12 (31%) by test strips. None of the 19 samples obtained from persons living in an area not endemic for O. volvulus but endemic for Mansonella streptocerca was positive in either test. Although the ELISA is theoretically more sensitive than the test strips for the detection of PCR products, examination of field samples revealed that the test strip method had a higher operational sensitivity and was more convenient to perform. Thus, the DNA Detection Test Strips are a rapid and low-tech tool for identification of PCR products in laboratories of countries endemic for onchocerciasis.

  • Use of the recombinant Onchocerca volvulus protein Ov20/OvS1 for the immunodiagnostic differentiation between onchocerciasis and mansonelliasis and for the characterization of hyperreactive onchocerciasis (sowda)
    Tropical Medicine and International Health, 2000
    Co-Authors: Joseph L. Mpagi, Dietrich W Buttner, F. W. Tischendorf, Klaus D. Erttmann, Norbert W. Brattig
    Abstract:

    The protein Ov20/OvS1 was used as antigen in enzyme-linked immunosorbent assay (ELISA) and Western blot in order to differentiate onchocerciasis from African mansonelliasis and to characterize the hyperreactive form of Onchocerca volvulus infection (sowda). The specificity of the immunoglobulin G4 (IgG4) Western blot was 98% for the differentiation between persons with onchocerciasis and Mansonella microfilariae (mf) carriers (125 persons with Mansonella perstans and 92 with Mansonella streptocerca) whereas the IgG4 ELISA showed a specificity of 81% in 137 M. perstans mf carriers and 85% in 94 M. streptocerca mf carriers. The sensitivity of Ov20/OvS1 in identifying onchocerciasis using the IgG4 ELISA was 75% for 103 O. volvulus mf carriers with the generalized and 89% for 44 patients with the sowda form of onchocerciasis. Immunoglobulin E antibodies against OvS1 were found in 95% of 39 patients with hyperreactive onchocerciasis but only in 15% of 47 persons with the generalized form. Thus Ov20/OvS1 appears to be a promising candidate antigen for the diagnosis of onchocerciasis and in particular for the detection of the sowda type of disease. (authors)

  • long term suppression of Mansonella stveptocevca microfilariae after treatment with ivermectin
    The Journal of Infectious Diseases, 1999
    Co-Authors: Peter U. Fischer, Ephraim Tukesiga, Dietrich W Buttner
    Abstract:

    The long-term effect of a single oral dose of 150 microg/kg of body weight of ivermectin on Mansonella streptocerca microfilariae was studied in western Uganda. Before treatment, the geometric mean microfilaria density (mf) in 93 infected persons was 2.4 mf/mg of skin (range, 0.1-42.6). One year after treatment, 43 persons (46%) were microfilaria-negative, and the geometric mean in the remaining persons dropped significantly, to 0.7 mf/mg (range, 0.1-6.9). Thus, ivermectin is highly effective against M. streptocerca, and a single dose leads to a sustained suppression of microfilariae in skin. In Africa, ivermectin is used for mass treatment to control Onchocerca volvulus and Wuchereria bancrofti. Because these filarial parasites are often coendemic with M. streptocerca, the treated population may receive the additional benefit of suppression of M. streptocerca microfilariae.

  • detection of the filarial parasite Mansonella streptocerca in skin biopsies by a nested polymerase chain reaction based assay
    American Journal of Tropical Medicine and Hygiene, 1998
    Co-Authors: Peter U. Fischer, Jotham Bamuhiiga, Dietrich W Buttner, Steven A Williams
    Abstract:

    To differentiate the skin-dwelling filariae Mansonella streptocerca and Onchocerca volvulus, a nested polymerase chain reaction (PCR) assay was developed from small amounts of parasite material present in skin biopsies. One nonspecific and one specific pair of primers were used to amplify the 5S rDNA spacer region of M. streptocerca. Biopsies with different microfilaria densities obtained from 104 Ugandans living in an area endemic for M. streptocerca were tested using both the nested PCR assay and standard parasitologic assessment of microfilariae. All 82 samples from microfilaria carriers were positive when tested using the nested PCR assay. In addition, M. streptocerca DNA could be detected in 16 samples thought to be microfilaria negative. Furthermore, six days following ivermectin treatment, M. streptocerca DNA was found in 12 of 14 microfilaria-negative biopsies. Control skin samples from patients infected with O. volvulus were all negative in the nested PCR assay. This assay improves the diagnosis of M. streptocerca and will facilitate further epidemiologic studies.

  • treatment of human Mansonella streptocerca infection with ivermectin
    Tropical Medicine & International Health, 1997
    Co-Authors: Peter U. Fischer, Jotham Bamuhiiga, Dietrich W Buttner
    Abstract:

    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.

Jotham Bamuhiiga - One of the best experts on this subject based on the ideXlab platform.

  • detection of the filarial parasite Mansonella streptocerca in skin biopsies by a nested polymerase chain reaction based assay
    American Journal of Tropical Medicine and Hygiene, 1998
    Co-Authors: Peter U. Fischer, Jotham Bamuhiiga, Dietrich W Buttner, Steven A Williams
    Abstract:

    To differentiate the skin-dwelling filariae Mansonella streptocerca and Onchocerca volvulus, a nested polymerase chain reaction (PCR) assay was developed from small amounts of parasite material present in skin biopsies. One nonspecific and one specific pair of primers were used to amplify the 5S rDNA spacer region of M. streptocerca. Biopsies with different microfilaria densities obtained from 104 Ugandans living in an area endemic for M. streptocerca were tested using both the nested PCR assay and standard parasitologic assessment of microfilariae. All 82 samples from microfilaria carriers were positive when tested using the nested PCR assay. In addition, M. streptocerca DNA could be detected in 16 samples thought to be microfilaria negative. Furthermore, six days following ivermectin treatment, M. streptocerca DNA was found in 12 of 14 microfilaria-negative biopsies. Control skin samples from patients infected with O. volvulus were all negative in the nested PCR assay. This assay improves the diagnosis of M. streptocerca and will facilitate further epidemiologic studies.

  • Detection of the filarial parasite Mansonella streptocerca in skin biopsies by a nested polymerase chain reaction-based assay
    1998
    Co-Authors: Peter Fischer, Jotham Bamuhiiga, Dietrich Bu W. Ttner, A. Williams
    Abstract:

    Abstract. To differentiate the skin-dwelling filariae Mansonella streptocerca and Onchocerca volvulus, a nested polymerase chain reaction (PCR) assay was developed from small amounts of parasite material present in skin biopsies. One nonspecific and one specific pair of primers were used to amplify the 5S rDNA spacer region of M. streptocerca. Biopsies with different microfilaria densities obtained from 104 Ugandans living in an area endemic for M. streptocerca were tested using both the nested PCR assay and standard parasitologic assessment of microfilariae. All 82 samples from microfilaria carriers were positive when tested using the nested PCR assay. In addition, M. streptocerca DNA could be detected in 16 samples thought to be microfilaria negative. Furthermore, six days follow-ing ivermectin treatment, M. streptocerca DNA was found in 12 of 14 microfilaria-negative biopsies. Control skin samples from patients infected with O. volvulus were all negative in the nested PCR assay. This assay improves the diagnosis of M. streptocerca and will facilitate further epidemiologic studies. When evaluating skin disease cases in large regions of Africa, the two skin-dwelling filarial species, Mansonella streptocerca and Onchocerca volvulus, must be considered as possible causative agents. Mansonella streptocerca infec-tion is characterized by acute and more often chronic papula

  • Detection of the filarial parasite Mansonella streptocerca in skin biopsies by a nested polymerase chain reaction-based assay
    1998
    Co-Authors: Peter U. Fischer, Jotham Bamuhiiga, Peter Fischer, Dietrich Bu W. Ttner, Steven A Williams, A. Williams
    Abstract:

    Detection of the filarial parasite Mansonella streptocerca skin biopsies by a nested polymerase chain reaction-based assay Article in The American journal of tropical medicine and hygiene · July 199

  • treatment of human Mansonella streptocerca infection with ivermectin
    Tropical Medicine & International Health, 1997
    Co-Authors: Peter U. Fischer, Jotham Bamuhiiga, Dietrich W Buttner
    Abstract:

    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.

  • occurrence and diagnosis of Mansonella streptocerca in uganda
    Acta Tropica, 1997
    Co-Authors: Peter U. Fischer, Jotham Bamuhiiga, Dietrich W Buttner
    Abstract:

    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.

Mario O Zaidenberg - One of the best experts on this subject based on the ideXlab platform.

  • Dantur Juri et al. Malaria Journal 2013, 12:248
    2014
    Co-Authors: María Dantur J Juri, Eugenia S Ortega, Guillermina B Galante, Cecilia Veggiani A Aybar, Mario O Zaidenberg
    Abstract:

    A case of co-infection with Plasmodium vivax and Mansonella ozzardi was detected in a blood sample from a person who had shown symptoms of malaria and lived in a city that was close to the Argentina/Bolivia border. The case was detected during a random revision of thick and thin smears from patients diagnosed with malaria from various towns and cities located in north-western Argentina between 1983 and 2001. Trophozoites of P. vivax were observed in the thin blood smear along with M. ozzardi microfilaria (larval form), which presented a long, slender, pointed anucleate tail and the absence of the sheath. This last characteristic is shared with Mansonella perstans, Mansonella streptocerca and Onchocerca volvulus. More rigorously controlled studies to detect other co-infection cases in the area as well as the possibility of importation from Bolivia into Argentina are currently ongoing. The relationship between the malaria parasite and microfilaria, the potential effect of malaria treatment on the development of M. ozzardi, and the possible impact of this microfilaria on the immunity of a person against P. vivax are all still unknown. This contribution constitutes a point of focus for future studies involving the interaction between the parasites and the potential risk that humans are exposed to. Background Malaria caused by Plasmodium vivax spans the greates

  • Plasmodium vivax and Mansonella ozzardi co-infection in north-western Argentina
    Malaria Journal, 2013
    Co-Authors: María J Dantur Juri, Cecilia A Veggiani Aybar, Eugenia S Ortega, Guillermina B Galante, Mario O Zaidenberg
    Abstract:

    A case of co-infection with Plasmodium vivax and Mansonella ozzardi was detected in a blood sample from a person who had shown symptoms of malaria and lived in a city that was close to the Argentina/Bolivia border. The case was detected during a random revision of thick and thin smears from patients diagnosed with malaria from various towns and cities located in north-western Argentina between 1983 and 2001. Trophozoites of P. vivax were observed in the thin blood smear along with M. ozzardi microfilaria (larval form), which presented a long, slender, pointed anucleate tail and the absence of the sheath. This last characteristic is shared with Mansonella perstans , Mansonella streptocerca and Onchocerca volvulus . More rigorously controlled studies to detect other co-infection cases in the area as well as the possibility of importation from Bolivia into Argentina are currently ongoing. The relationship between the malaria parasite and microfilaria, the potential effect of malaria treatment on the development of M. ozzardi , and the possible impact of this microfilaria on the immunity of a person against P. vivax are all still unknown. This contribution constitutes a point of focus for future studies involving the interaction between the parasites and the potential risk that humans are exposed to.

Steven A Williams - One of the best experts on this subject based on the ideXlab platform.

  • detection of the filarial parasite Mansonella streptocerca in skin biopsies by a nested polymerase chain reaction based assay
    American Journal of Tropical Medicine and Hygiene, 1998
    Co-Authors: Peter U. Fischer, Jotham Bamuhiiga, Dietrich W Buttner, Steven A Williams
    Abstract:

    To differentiate the skin-dwelling filariae Mansonella streptocerca and Onchocerca volvulus, a nested polymerase chain reaction (PCR) assay was developed from small amounts of parasite material present in skin biopsies. One nonspecific and one specific pair of primers were used to amplify the 5S rDNA spacer region of M. streptocerca. Biopsies with different microfilaria densities obtained from 104 Ugandans living in an area endemic for M. streptocerca were tested using both the nested PCR assay and standard parasitologic assessment of microfilariae. All 82 samples from microfilaria carriers were positive when tested using the nested PCR assay. In addition, M. streptocerca DNA could be detected in 16 samples thought to be microfilaria negative. Furthermore, six days following ivermectin treatment, M. streptocerca DNA was found in 12 of 14 microfilaria-negative biopsies. Control skin samples from patients infected with O. volvulus were all negative in the nested PCR assay. This assay improves the diagnosis of M. streptocerca and will facilitate further epidemiologic studies.

  • Detection of the filarial parasite Mansonella streptocerca in skin biopsies by a nested polymerase chain reaction-based assay
    1998
    Co-Authors: Peter U. Fischer, Jotham Bamuhiiga, Peter Fischer, Dietrich Bu W. Ttner, Steven A Williams, A. Williams
    Abstract:

    Detection of the filarial parasite Mansonella streptocerca skin biopsies by a nested polymerase chain reaction-based assay Article in The American journal of tropical medicine and hygiene · July 199