The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Domenico Otranto - One of the best experts on this subject based on the ideXlab platform.
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a duplex real time polymerase chain reaction assay for the detection of and differentiation between dirofilaria immitis and dirofilaria repens in dogs and mosquitoes
Veterinary Parasitology, 2012Co-Authors: Maria Stefania Latrofa, Marco Genchi, Giada Annoscia, Donato Traversa, Filipe Dantastorres, Domenico OtrantoAbstract:Abstract This study describes a duplex real-time polymerase chain reaction (PCR) assay for the detection and differentiation between Dirofilaria immitis and Dirofilaria repens in dog blood and mosquitoes. Regions of a cytochrome oxidase 1 (cox1) mitochondrial DNA fragment and the second internal transcribed spacer (ITS-2) of nuclear ribosomal DNA were amplified from Microfilariae and adult worm samples, using a sensitive SsoFast™ EvaGreen® based real-time PCR method coupled with melting-curve analysis. The limit of the real-time PCR in detecting Microfilaria and adult worm DNA was also tested both in dog blood and in artificially infected Microfilarial. Two peaks at different melting temperatures (Tm) for D. immitis (mean ± SD = 75.7 ± 0.3 °C) and D. repens (mean ± SD = 70 ± 0.7 °C), respectively, were obtained for Microfilarial and adult positive controls of both species when examined separately and together. The real-time PCR protocol was also efficient in detecting Microfilarial and adult DNA of both species when tested in samples spiked with DNA from Aedes albopictus, in Aedes aegypti experimentally infected by D. repens and in Culex pipiens naturally infected by D. repens and D. immitis. The high sensitivity of real-time PCR confirmed its reliability in detecting small amounts of genomic DNA either in dog blood or mosquitoes (2.5 pg/μl and 3 × 10−1 pg/μl for D. immitis and D. repens, respectively). This assay is proposed as a tool for the epidemiological surveillance of the two most important Dirofilaria species in areas where they are endemic and sympatric.
Paul T. Cantey - One of the best experts on this subject based on the ideXlab platform.
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Detection of onchocerca volvulus in skin snips by microscopy and real-time polymerase chain reaction: Implications for monitoring and evaluation activities
American Journal of Tropical Medicine and Hygiene, 2016Co-Authors: Elizabeth A. Thiele, Vitaliano A. Cama, Thomson Lakwo, Sindeaw Mekasha, Francisca Abanyie, Markos Sleshi, Amha Kebede, Paul T. CanteyAbstract:Microscopic evaluation of skin biopsies is the monitoring and evaluation (M and E) method currently used by multiple onchocerciasis elimination programs in Africa. However, as repeated mass drug administration suppresses Microfilarial loads, the sensitivity and programmatic utility of skin snip microscopy is expected to decrease. Using a pan-filarial real-time polymerase chain reaction with melt curve analysis (qPCR-MCA), we evaluated 1) the use of a single-step molecular assay for detecting and identifying Onchocerca volvulus Microfilariae in residual skin snips and 2) the sensitivity of skin snip microscopy relative to qPCR-MCA. Skin snips were collected and examined with routine microscopy in hyperendemic regions of Uganda and Ethiopia (N = 500 each) and "residual" skin snips (tissue remaining after induced Microfilarial emergence) were tested with qPCR-MCA. qPCR-MCA detected Onchocerca DNA in 223 residual snips: 139 of 147 microscopy(+) and 84 among microscopy(-) snips, suggesting overall sensitivity of microscopy was 62.3% (139/223) relative to qPCR-MCA (75.6% in Uganda and 28.6% in Ethiopia). These findings demonstrate the insufficient sensitivity of skin snip microscopy for reliable programmatic monitoring. Molecular tools such as qPCR-MCA can augment sensitivity and provide diagnostic confirmation of skin biopsies and will be useful for evaluation or validation of new onchocerciasis M and E tools.
M. Boussinesq - One of the best experts on this subject based on the ideXlab platform.
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Point-of-care quantification of blood-borne filarial parasites with a mobile phone microscope
Science Translational Medicine, 2015Co-Authors: Michael V. D'ambrosio, Matthew Bakalar, Sasisekhar Bennuru, Clay Reber, Arunan Skandarajah, Lina Nilsson, Neil Switz, Joseph Kamgno, Sébastien Pion, M. BoussinesqAbstract:Parasitic helminths cause debilitating diseases that affect millions of people in primarily low-resource settings. Efforts to eliminate onchocerciasis and lymphatic filariasis in Central Africa through mass drug administration have been suspended because of ivermectin-associated serious adverse events, including death, in patients infected with the filarial parasite Loa loa. To safely administer ivermectin for onchocerciasis or lymphatic filariasis in regions co-endemic with L. loa, a strategy termed "test and (not) treat" has been proposed whereby those with high levels of L. loa Microfilariae (>30,000/ml) that put them at risk for life-threatening serious adverse events are identified and excluded from mass drug administration. To enable this, we developed a mobile phone-based video microscope that automatically quantifies L. loa Microfilariae in whole blood loaded directly into a small glass capillary from a fingerprick without the need for conventional sample preparation or staining. This point-of-care device automatically captures and analyzes videos of Microfilarial motion in whole blood using motorized sample scanning and onboard motion detection, minimizing input from health care workers and providing a quantification of Microfilariae per milliliter of whole blood in under 2 min. To validate performance and usability of the mobile phone microscope, we tested 33 potentially Loa-infected patients in Cameroon and confirmed that automated counts correlated with manual thick smear counts (94% specificity; 100% sensitivity). Use of this technology to exclude patients from ivermectin-based treatment at the point of care in Loa-endemic regions would allow resumption/expansion of mass drug administration programs for onchocerciasis and lymphatic filariasis in Central Africa.
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Co-infection with Onchocerca volvulus and Loa loa Microfilariae in central Cameroon: Are these two species interacting?
Parasitology, 2006Co-Authors: Sébastien Pion, J. A.n. Filipe, J. Gardon, Joseph Kamgno, P Clarke, María-gloria Basáñez, M. BoussinesqAbstract:Ivermectin treatment may induce severe adverse reactions in some individuals heavily infected with Loa loa. This hampers the implementation of mass ivermectin treatment against onchocerciasis in areas where Onchocerca volvulus and L. loa are co-endemic. In order to identify factors, including co-infections, which may explain the presence of high L. loa microfilaraemia in some individuals, we analysed data collected in 19 villages of central Cameroon. Two standardized skin snips and 30 mul of blood were obtained from each of 3190 participants and the Microfilarial (mf) loads of both O. volvulus and L. loa were quantified. The data were analysed using multivariate hierarchical models. Individual-level variables were: age, sex, mf presence, and mf load; village-related variables included the endemicity levels for each infection. The two species show a certain degree of ecological separation in the study area. However, for a given individual host, the presence of Microfilariae of one species was positively associated with the presence of Microfilariae of the other (OR=1.79, 95% CI [1.43-2.24]). Among individuals harbouring Loa Microfilariae, there was a slight positive relationship between the L. loa and O. volvulus mf loads which corresponded to an 11% increase in L. loa mf load per 100 O. volvulus Microfilariae. Co-infection with O. volvulus is not sufficient to explain the very high L. loa mf loads harboured by some individuals.
Maria Stefania Latrofa - One of the best experts on this subject based on the ideXlab platform.
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a duplex real time polymerase chain reaction assay for the detection of and differentiation between dirofilaria immitis and dirofilaria repens in dogs and mosquitoes
Veterinary Parasitology, 2012Co-Authors: Maria Stefania Latrofa, Marco Genchi, Giada Annoscia, Donato Traversa, Filipe Dantastorres, Domenico OtrantoAbstract:Abstract This study describes a duplex real-time polymerase chain reaction (PCR) assay for the detection and differentiation between Dirofilaria immitis and Dirofilaria repens in dog blood and mosquitoes. Regions of a cytochrome oxidase 1 (cox1) mitochondrial DNA fragment and the second internal transcribed spacer (ITS-2) of nuclear ribosomal DNA were amplified from Microfilariae and adult worm samples, using a sensitive SsoFast™ EvaGreen® based real-time PCR method coupled with melting-curve analysis. The limit of the real-time PCR in detecting Microfilaria and adult worm DNA was also tested both in dog blood and in artificially infected Microfilarial. Two peaks at different melting temperatures (Tm) for D. immitis (mean ± SD = 75.7 ± 0.3 °C) and D. repens (mean ± SD = 70 ± 0.7 °C), respectively, were obtained for Microfilarial and adult positive controls of both species when examined separately and together. The real-time PCR protocol was also efficient in detecting Microfilarial and adult DNA of both species when tested in samples spiked with DNA from Aedes albopictus, in Aedes aegypti experimentally infected by D. repens and in Culex pipiens naturally infected by D. repens and D. immitis. The high sensitivity of real-time PCR confirmed its reliability in detecting small amounts of genomic DNA either in dog blood or mosquitoes (2.5 pg/μl and 3 × 10−1 pg/μl for D. immitis and D. repens, respectively). This assay is proposed as a tool for the epidemiological surveillance of the two most important Dirofilaria species in areas where they are endemic and sympatric.
Elizabeth A. Thiele - One of the best experts on this subject based on the ideXlab platform.
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Detection of onchocerca volvulus in skin snips by microscopy and real-time polymerase chain reaction: Implications for monitoring and evaluation activities
American Journal of Tropical Medicine and Hygiene, 2016Co-Authors: Elizabeth A. Thiele, Vitaliano A. Cama, Thomson Lakwo, Sindeaw Mekasha, Francisca Abanyie, Markos Sleshi, Amha Kebede, Paul T. CanteyAbstract:Microscopic evaluation of skin biopsies is the monitoring and evaluation (M and E) method currently used by multiple onchocerciasis elimination programs in Africa. However, as repeated mass drug administration suppresses Microfilarial loads, the sensitivity and programmatic utility of skin snip microscopy is expected to decrease. Using a pan-filarial real-time polymerase chain reaction with melt curve analysis (qPCR-MCA), we evaluated 1) the use of a single-step molecular assay for detecting and identifying Onchocerca volvulus Microfilariae in residual skin snips and 2) the sensitivity of skin snip microscopy relative to qPCR-MCA. Skin snips were collected and examined with routine microscopy in hyperendemic regions of Uganda and Ethiopia (N = 500 each) and "residual" skin snips (tissue remaining after induced Microfilarial emergence) were tested with qPCR-MCA. qPCR-MCA detected Onchocerca DNA in 223 residual snips: 139 of 147 microscopy(+) and 84 among microscopy(-) snips, suggesting overall sensitivity of microscopy was 62.3% (139/223) relative to qPCR-MCA (75.6% in Uganda and 28.6% in Ethiopia). These findings demonstrate the insufficient sensitivity of skin snip microscopy for reliable programmatic monitoring. Molecular tools such as qPCR-MCA can augment sensitivity and provide diagnostic confirmation of skin biopsies and will be useful for evaluation or validation of new onchocerciasis M and E tools.
