Droplet digital polymerase chain reaction (ddPCR) as a novel method for absolute quantification of major gastrointestinal nematodes in sheep

2018 ◽  
Vol 261 ◽  
pp. 1-8 ◽  
Author(s):  
Safaa T. Elmahalawy ◽  
Peter Halvarsson ◽  
Moa Skarin ◽  
Johan Höglund
Acta Tropica ◽  
2019 ◽  
Vol 200 ◽  
pp. 105175
Author(s):  
Justine Daudi Maganira ◽  
Beda John Mwang'onde ◽  
Winifrida Kidima ◽  
Chacha John Mwita ◽  
Gamba Nkwengulila ◽  
...  

2019 ◽  
Vol 56 (4) ◽  
pp. 1150-1153
Author(s):  
L M Rice ◽  
L L Robb ◽  
D A Hartman ◽  
J R Anderson ◽  
R C Kading

Abstract Hematophagous arthropod bloodmeal identification has remained a challenge in the field of vector biology, but these studies are important to understand blood feeding patterns of arthropods, spatial, and temporal patterns in arbovirus transmission cycles, and risk of human and veterinary disease. We investigated the use of an existing vertebrate primer set for use on the droplet digital polymerase chain reaction (ddPCR) platform, to explore the use of this technology in the identification and quantification of vertebrate DNA in mosquito blood meals. Host DNA was detectable 48-h post-engorgement in some mosquitoes by ddPCR, compared with 24-h post-engorgement using traditional PCR. The capability of ddPCR for absolute quantification of template DNA offers unique potential applications of this new technology to field studies on the ecology of vector-borne diseases, but currently with limited scope.


2019 ◽  
Vol 11 (27) ◽  
pp. 3410-3418 ◽  
Author(s):  
Zhenming Hu ◽  
Weibo Fang ◽  
Tong Gou ◽  
Wenshuai Wu ◽  
Jiumei Hu ◽  
...  

The flow of Mask R-CNN model for processing digital polymerase chain reaction (dPCR) fluorescence images.


Author(s):  
Jing Xu ◽  
Timothy Kirtek ◽  
Yan Xu ◽  
Hui Zheng ◽  
Huiyu Yao ◽  
...  

Abstract Objectives The Bio-Rad SARS-CoV-2 ddPCR Kit (Bio-Rad Laboratories) was the first droplet digital polymerase chain reaction (ddPCR) assay to receive Food and Drug Administration (FDA) Emergency Use Authorization approval, but it has not been evaluated clinically. We describe the performance of ddPCR—in particular, its ability to confirm weak-positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) results. Methods We clinically validated the Bio-Rad Triplex Probe ddPCR Assay. The limit of detection was determined by using serial dilutions of SARS-CoV-2 RNA in an artificial viral envelope. The ddPCR assay was performed according to the manufacturer’s specifications on specimens confirmed to be positive (n = 48) or negative (n = 30) by an FDA-validated reverse transcription–polymerase chain reaction assay on the m2000 RealTime system (Abbott). Ten borderline positive cases were also evaluated. Results The limit of detection was 50 copies/mL (19 of 20 positive). Forty-seven specimens spanning a range of quantification cycles (2.9-25.9 cycle numbers) were positive by this assay (47 of 48; 97.9% positive precent agreement), and 30 negative samples were confirmed as negative (30 of 30; 100% negative percent agreement). Nine of 10 borderline cases were positive when tested in triplicate. Conclusions The ddPCR of SARS-CoV-2 is an accurate method, with superior sensitivity for viral RNA detection. It could provide definitive evaluation of borderline positive cases or suspected false-negative cases.


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