The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Jim Todd - One of the best experts on this subject based on the ideXlab platform.
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the development and validation of dried blood spots for external quality assurance of Syphilis Serology
BMC Infectious Diseases, 2013Co-Authors: Pieter W Smit, Thomas Van Der Vlis, David Mabey, John Changalucha, Julius Mngara, Benjamin Clark, Aura Andreasen, Jim ToddAbstract:Background Syphilis causes up to 1,500,000 congenital Syphilis cases annually. These could be prevented if all pregnant women were screened, and those with Syphilis treated with a single dose of penicillin before 28 weeks gestation. In recent years, rapid point-of-care tests have allowed greater access to Syphilis screening, especially in rural or remote areas, but the lack of quality assurance of rapid testing has been a concern. We determined the feasibility of using dried blood spots (DBS) as specimens for quality assurance of Syphilis serological assays.
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the development and validation of dried blood spots for external quality assurance of Syphilis Serology
BMC Infectious Diseases, 2013Co-Authors: Pieter W Smit, Thomas Van Der Vlis, David Mabey, John Changalucha, Julius Mngara, Benjamin Clark, Aura Andreasen, Jim ToddAbstract:Syphilis causes up to 1,500,000 congenital Syphilis cases annually. These could be prevented if all pregnant women were screened, and those with Syphilis treated with a single dose of penicillin before 28 weeks gestation. In recent years, rapid point-of-care tests have allowed greater access to Syphilis screening, especially in rural or remote areas, but the lack of quality assurance of rapid testing has been a concern. We determined the feasibility of using dried blood spots (DBS) as specimens for quality assurance of Syphilis serological assays. We developed DBS extraction protocols for use with Treponema pallidum particle agglutination assay (TPPA), Treponema pallidum haemagglutination assay (TPHA) and an enzyme immunoassay (EIA) and compared the results with those using matching plasma samples from the same patient. Since DBS samples showed poor performance with TPHA and EIA (TPHA sensitivity was 50.5% (95% confidence interval: 39.9–61.2%) and EIA specificity was 50.4% (95% CI: 43.7–57.1%), only the DBS TPPA was used in the final evaluation. DBS TPPA showed an sensitivity of 95.5% (95% CI: 91.3–98.0%) and a specificity of 99.0% (95% CI: 98.1–99.5%) compared to TPPA using plasma samples as a reference. DBS samples can be recommended for use with TPPA, and may be of value for external quality assurance of point-of-care Syphilis testing.
Benjamin Clark - One of the best experts on this subject based on the ideXlab platform.
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the development and validation of dried blood spots for external quality assurance of Syphilis Serology
BMC Infectious Diseases, 2013Co-Authors: Pieter W Smit, Thomas Van Der Vlis, David Mabey, John Changalucha, Julius Mngara, Benjamin Clark, Aura Andreasen, Jim ToddAbstract:Background Syphilis causes up to 1,500,000 congenital Syphilis cases annually. These could be prevented if all pregnant women were screened, and those with Syphilis treated with a single dose of penicillin before 28 weeks gestation. In recent years, rapid point-of-care tests have allowed greater access to Syphilis screening, especially in rural or remote areas, but the lack of quality assurance of rapid testing has been a concern. We determined the feasibility of using dried blood spots (DBS) as specimens for quality assurance of Syphilis serological assays.
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the development and validation of dried blood spots for external quality assurance of Syphilis Serology
BMC Infectious Diseases, 2013Co-Authors: Pieter W Smit, Thomas Van Der Vlis, David Mabey, John Changalucha, Julius Mngara, Benjamin Clark, Aura Andreasen, Jim ToddAbstract:Syphilis causes up to 1,500,000 congenital Syphilis cases annually. These could be prevented if all pregnant women were screened, and those with Syphilis treated with a single dose of penicillin before 28 weeks gestation. In recent years, rapid point-of-care tests have allowed greater access to Syphilis screening, especially in rural or remote areas, but the lack of quality assurance of rapid testing has been a concern. We determined the feasibility of using dried blood spots (DBS) as specimens for quality assurance of Syphilis serological assays. We developed DBS extraction protocols for use with Treponema pallidum particle agglutination assay (TPPA), Treponema pallidum haemagglutination assay (TPHA) and an enzyme immunoassay (EIA) and compared the results with those using matching plasma samples from the same patient. Since DBS samples showed poor performance with TPHA and EIA (TPHA sensitivity was 50.5% (95% confidence interval: 39.9–61.2%) and EIA specificity was 50.4% (95% CI: 43.7–57.1%), only the DBS TPPA was used in the final evaluation. DBS TPPA showed an sensitivity of 95.5% (95% CI: 91.3–98.0%) and a specificity of 99.0% (95% CI: 98.1–99.5%) compared to TPPA using plasma samples as a reference. DBS samples can be recommended for use with TPPA, and may be of value for external quality assurance of point-of-care Syphilis testing.
Ronald C. Ballard - One of the best experts on this subject based on the ideXlab platform.
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comparison of clinically directed disease specific and syndromic protocols for the management of genital ulcer disease in lesotho
Sexually Transmitted Infections, 1998Co-Authors: Ye Htun, Y Dangor, G. Fehler, Stephen A Morse, David L Trees, Consuelo M Becksague, Ronald C. BallardAbstract:OBJECTIVE To evaluate two protocols for the syndromic management of genital ulcer disease (GUD) in Lesotho, southern Africa and to compare the performance of these protocols with that of a conventional disease specific approach. METHODS A cross sectional study was conducted among consecutive patients with GUD attending an STD clinic in Maseru, Lesotho. The clinical diagnoses were made by using predefined criteria at the initial visit before the performance of laboratory tests. Attempts were made to detect the specific aetiology of the genital ulcers using PCR assays and Syphilis Serology. The results of PCR assays and Syphilis Serology were used as the gold standard against which the performance of the management approaches were applied. RESULTS Of 100 patients initially recruited into the study, Haemophilus ducreyi infection was detected in 56%, herpes simplex virus in 26%, Treponema pallidum in 23%, and lymphogranuloma venereum in 7%. No pathogens were detected in 6% of patients. 17% of patients had mixed infections. Sensitivity, specificity, positive and negative predictive values of the three management protocols for GUD were compared after applying each to the study population. Theoretically, the lowest correct treatment rate would have been obtained by using the disease specific protocol (62%) compared with more than 90% in both syndromic management protocols. Considerable overtreatment for primary Syphilis would occur following application of both syndromic protocols. This would be the result of the overdiagnosis of chancroid, in particular the misdiagnosis of genital herpes as chancroid, which would receive treatment for Syphilis unnecessarily. The HIV seroprevalence among these patients was 36%. A significantly higher rate of HIV seropositivity was detected among the patients with herpes simplex virus infection when compared with those patients having other causes of genital ulcer disease (58% v 27%; odds ratio 3.73; 95% CI 1.26-11.26; p = 0.01). CONCLUSIONS Poor sensitivity, specificity, and predictive values were recorded when the disease specific protocol was applied to the study population. In contrast, the syndromic management protocols provided adequate treatment for more than 90% of patients with GUD. Protocol C, which identified a minority of cases of genital herpes, was found to have an advantage when compared with protocol B (all patients with genital ulcer disease treated for both Syphilis and chancroid) in that 29% of genital herpes cases would receive appropriate counselling.
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Syphilis Serology in patients with primary Syphilis and non treponemal sexually transmitted diseases in southern africa
Sexually Transmitted Infections, 1991Co-Authors: A Sischy, Y Dangor, F Da Lexposto, H G Fehler, F Radebe, D D Walkden, S D Miller, Ronald C. BallardAbstract:The reactivity of a non-specific reagin (RPR) test and a specific treponemal (FTA-ABS) test were determined in 21 patients with primary Syphilis, 430 patients with proven non-treponemal genital ulcerations and 719 patients with acute urethritis presenting at a clinic for sexually transmitted diseases in southern Africa. Excluding those 21 cases of primary Syphilis, 358 of 1149 tests performed (31%) were found to be reactive by at least one test. The rate of false positive RPR tests was very low (0.02%). Significantly higher rates of seropositivity were detected in patients with genital ulcerations than in patients with acute urethritis. The highest rates were detected among patients with proven lymphogranuloma venereum (34% RPR positive, FTA-ABS positive; 19% RPR negative, FTA-ABS positive). The geometric mean titres (GMT) of positive RPR tests in non-treponemal infections were found to be lower than in darkfield positive cases of genital ulcer disease.
Oriol Mitjà - One of the best experts on this subject based on the ideXlab platform.
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haemophilus ducreyi as a cause of skin ulcers in children from a yaws endemic area of papua new guinea a prospective cohort study
The Lancet Global Health, 2014Co-Authors: Oriol Mitjà, Charmie Godornes, August Kapa, Penias Moses, Sheila A. Lukehart, Gideon Pokowas, Jennifer Robson, Sarah G Cherian, Wendy HouineiAbstract:Summary Background Skin infections with ulceration are a major health problem in countries of the south Pacific region. Yaws, caused by Treponema pallidum subspecies pertenue and diagnosed by the presence of skin ulcers and a reactive Syphilis Serology, is one major cause, but this infection can be confused clinically with ulcers due to other causative agents. We investigated T pallidum pertenue and another bacterium known to cause skin infections in the Pacific islands— Haemophilus ducreyi —as causes of skin ulceration in a yaws-endemic region. Additionally, we identified specific signs and symptoms associated with these causative agents of cutaneous ulcers and compared these findings with laboratory-based diagnoses. Methods We did a prospective cohort study of five yaws-endemic villages (total population 3117 people) during a yaws elimination campaign in Papua New Guinea in April, 2013. We enrolled all consenting patients with chronic moist or exudative skin ulcers. We undertook a detailed dermatological assessment, Syphilis Serology, and PCR on lesional swabs to detect the presence of T pallidum pertenue and H ducreyi . Patients with PCR-confirmed bacterial infections were included in a comparative analysis of demographics and clinical features. Findings Full outcome data were available for 90 people with skin ulcers. Of these patients, 17 (19%) had negative results in all molecular tests and were therefore excluded from the comparative analyses. A bacterial cause was identified in 73 (81%) participants—either H ducreyi (n=42), T pallidum pertenue (yaws; n=19), or coinfection with both organisms (dual infection; n=12). The demographic characteristics of the patients infected with yaws and with H ducreyi were similar. Skin lesions in patients with yaws and in those with dual infection were larger than those in patients infected with H ducreyi (p=0·071). The lesions in patients with yaws and dual infection were more circular in shape (79% and 67%) than in those infected with H ducreyi (21%; p vs 14%; p vs 31%; p=0·0003). The prevalence of reactive combined Serology (positive T pallidum haemagglutination test and rapid plasmin reagin titre of ≥1:8) was higher in cases of yaws (63%) and dual infections (92%) than in H ducreyi infections (29%; p Interpretation In this yaws-endemic community, H ducreyi is an important and previously unrecognised cause of chronic skin ulceration. Reactive Syphilis Serology caused by latent yaws can occur in ulcers with the presence of H ducreyi alone. The introduction of PCR for ulcer surveillance could improve the accuracy of diagnosis in countries with yaws eradication campaigns. Funding Newcrest Mining Company.
Bruce W Dixon - One of the best experts on this subject based on the ideXlab platform.
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Syphilis Serology in blood donors a possible surrogate marker for human immunodeficiency virus risk
Vox Sanguinis, 1991Co-Authors: Glenn Ramsey, Frank Soltis, Rebecca Bowman, Jean Mcnamee, Linda F Hahn, Bruce W DixonAbstract:. We report a preliminary study on whether Syphilis Serology might be reactive in some blood donors at risk for human immunodeficiency virus (HIV) infection. We retrospectively analyzed voluntary blood donations with reactive Treponema pallidum antibody (TPA) tests according to the type of donation, the presence of other safety markers, confidential unit exclusion, Syphilis diagnosis, and HIV risk factors. Over 2 years (1987–1988), 1 in 8,900 regular homologous donations (n = 258,610) was TPA positive as compared with 1 in 2,200 directed donations (n = 6,685) and 1 in 300 autologous donations (n = 8,870; p < 0.05 for both). The rate in directed donations was not significantly higher than in first-time regular donors (1 in 4,800; n = 57,000). TPA-positive donations had higher rates of antibody to hepatitis B core antigen and confidential unit exclusion than TPA-negative donations. Ten TPA-positive homologous or directed donors had latent or previously treated Syphilis (1 in 26,500 such donations), and 2 of these had HIV risk factors. None of the autologous donors were determined to have active Syphilis. Syphilis Serology in blood donors bears further scrutiny as a possible surrogate marker for HIV risk.
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Syphilis Serology in blood donors a possible surrogate marker for human immunodeficiency virus risk
Vox Sanguinis, 1991Co-Authors: Glenn Ramsey, Frank Soltis, Rebecca Bowman, Jean Mcnamee, Linda F Hahn, Bruce W DixonAbstract:We report a preliminary study on whether Syphilis Serology might be reactive in some blood donors at risk for human immunodeficiency virus (HIV) infection. We retrospectively analyzed voluntary blood donations with reactive Treponema pallidum antibody (TPA) tests according to the type of donation, the presence of other safety markers, confidential unit exclusion, Syphilis diagnosis, and HIV risk factors. Over 2 years (1987-1988), 1 in 8,900 regular homologous donations (n = 258,610) was TPA positive as compared with 1 in 2,200 directed donations (n = 6,685) and 1 in 300 autologous donations (n = 8,870; p less than 0.05 for both). The rate in directed donations was not significantly higher than in first-time regular donors (1 in 4,800; n = 57,000). TPA-positive donations had higher rates of antibody to hepatitis B core antigen and confidential unit exclusion than TPA-negative donations. Ten TPA-positive homologous or directed donors had latent or previously treated Syphilis (1 in 26,500 such donations), and 2 of these had HIV risk factors. None of the autologous donors were determined to have active Syphilis. Syphilis Serology in blood donors bears further scrutiny as a possible surrogate marker for HIV risk.
