Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Quantitative PCR”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 649 records · Page 36Linked to original sources
PubMed2002

Processing of gene expression data generated by quantitative real-time RT-PCR.

Quantitative real-time PCR represents a highly sensitive and powerful technique for the quantitation of nucleic acids. It has a tremendous potential for the high-throughput analysis of gene expression in research and routine diagnostics. However, the major hurdle is not the practical performance of the experiments themselves but rather the efficient evaluation and the mathematical and statistical analysis of the enormous amount of data gained by this technology, as these functions are not included in the software provided by the manufacturers of the detection systems. In this work, we focus on the mathematical evaluation and analysis of the data generated by quantitative real-time PCR, the calculation of the final results, the propagation of experimental variation of the measured values to the final results, and the statistical analysis. We developed a Microsoft Excel-based software application coded in Visual Basic for Applications, called Q-Gene, which addresses these points. Q-Gene manages and expedites the planning, performance, and evaluation of quantitative real-time PCR experiments, as well as the mathematical and statistical analysis, storage, and graphical presentation of the data. The Q-Gene software application is a tool to cope with complex quantitative real-time PCR experiments at a high-throughput scale and considerably expedites and rationalizes the experimental setup, data analysis, and data management while ensuring highest reproducibility.

Computational Biology↗
PubMed1999

Differential priming of RNA templates during cDNA synthesis markedly affects both accuracy and reproducibility of quantitative competitive reverse-transcriptase PCR.

Quantitative competitive reverse-transcriptase PCR is the most sensitive method for studying gene expression. To investigate whether the accuracy of the calculated target mRNA copy number is affected by the cDNA priming process, we utilized primers of different lengths, concentrations and primer sequences to prime cDNA synthesis reactions. Our results show a approximately 19-fold increase in the calculated mRNA copy number from cDNA synthesis reactions primed with random hexamers (P<0.001, n=4), and a approximately 4-fold increase in copy number with a specific hexamer (P<0.001, n=4) compared with that obtained with a 22-mer-sequence-specific primer. The increase in calculated mRNA copy number obtained by priming cDNA synthesis with the shorter specific and non-specific primers could be explained largely by the synthesis of truncated standard cDNA molecules lacking a requisite binding site for amplification with PCR primers. Since these truncated standard cDNA molecules could not be amplified and standard RNA is used to quantify target mRNA copy number, this phenomenon resulted in overestimation of target mRNA copy number. In conclusion, accurate determination of target mRNA copy number is most likely if a long specific antisense primer is used to prime cDNA synthesis.

Base Sequence↗
PubMed1999

Monitoring of epstein-barr virus DNA load in peripheral blood by quantitative competitive PCR.

A competitive quantitative PCR (Q-PCR) assay combined with simple silica-based DNA extraction was developed for monitoring of Epstein-Barr virus (EBV) DNA load in unfractionated peripheral blood. The Q-PCR is based on competitive coamplification of a highly conserved 213-bp region of the EBNA-1 open reading frame with an internal standard (IS), added in a known concentration. The IS has the same amplicon length and base composition as the wild-type (WT) EBNA-1 amplicon but differs in 23 internally randomized bases. Competitive coamplification yields two PCR products that are quantified by enzyme immunoassay or by electrochemiluminescence detection, with probes specific for the 23 differing internal nucleotides. The Q-PCR has a sensitivity of 10 copies of either WT or IS plasmid DNA. The Q-PCR was validated by quantification of known amounts of plasmid containing the WT EBNA-1 target. Furthermore, we determined EBV genome copy numbers in different cell lines. For EBV quantification in clinical samples, DNA was isolated from lysed whole blood by silica-affinity purification. Forty-six percent of healthy donor peripheral blood samples were positive by Q-PCR. In most of these samples, viral load was less than 2,000 EBV copies/ml of blood. In peripheral blood samples from two AIDS-related non-Hodgkin's lymphoma patients, elevated EBV loads (up to 120,000 copies/ml) were observed, which decreased upon therapy. In Burkitt's lymphoma patients, up to 4,592,000 EBV genome copies/ml of blood were detected. In conclusion, the EBNA-1-based Q-PCR assay provides a reproducible, accurate, and easy method for studying the relationship between EBV load and clinical parameters.

Burkitt Lymphoma↗
PubMed1996

Semi-automated PCR method for quantitating MDR1 expression.

The MDR1 gene is involved in drug resistance in many hematopoietic and solid tumors. The Quantitative PCR System 5000 (QPCR-5000; Perkin-Elmer) is a new instrument system that uses electrochemiluminescence to automatically quantitate polymerase chain reaction (PCR) products. A comparative study between radioactively labeled PCR (32P-PCR) and QPCR was performed to analyze the MDR1 gene expression in the drug-resistant (Doxorubicin) cell lines Dox40, Dox6, the parental cell line 8226/S, CEM Dox1 and three acute myeloid leukemia (AML) patient samples. Using the Dox40 and Dox6 resistant cell lines, we compared the sensitivities of QPCR and 32P-PCR. A strong signal was obtained from QPCR at 20 to 25 cycles (which is in the linear range for quantitation), while a weak signal was obtained using 32P-PCR at the same cycle number. Dilution experiments gave better precision with the QPCR than with the radioactive method. AML samples were studied with the MDR1-specific MAbs MRK16 and 4E3, and the efflux function was analyzed using Rh-123 retention in the absence or presence of verapamil. The three samples showed high (D = 0.79), medium (D = 0.52) and negative (D = 0.08) p-glycoprotein (P-gp) levels and correlated with efflux function. The MDR1/beta 2-M mRNA ratios for 32P-PCR were 0.41, 0.40 and 0.12, respectively, and were 0.127, 0.097 and 0.028, respectively, for QPCR. There were significant differences between the samples with high and medium P-gp levels comparing the two methods. Very low levels of MDR1 in CEM Dox1 cells could be detected only by QPCR. In conclusion, QPCR was found to be more reproducible, accurate and sensitive than 32P-PCR.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2003

Evaluation of a PCR assay for quantitation of Rickettsia rickettsii and closely related spotted fever group rickettsiae.

A spotted fever rickettsia quantitative PCR assay (SQ-PCR) was developed for the detection and enumeration of Rickettsia rickettsii and other closely related spotted fever group rickettsiae. The assay is based on fluorescence detection of SYBR Green dye intercalation in a 154-bp fragment of the rOmpA gene during amplification by PCR. As few as 5 copies of the rOmpA gene of R. rickettsii can be detected. SQ-PCR is suitable for quantitation of R. rickettsii and 10 other genotypes of spotted fever group rickettsiae but not for R. akari, R. australis, R. bellii, or typhus group rickettsiae. The sensitivity of SQ-PCR was comparable to that of a plaque assay using centrifugation for inoculation. The SQ-PCR assay was applied successfully to the characterization of rickettsial stock cultures, the replication of rickettsiae in cell culture, the recovery of rickettsial DNA following different methods of extraction, and the quantitation of rickettsial loads in infected animal tissues, clinical samples, and ticks.

Animals↗
PubMed2003

The use of housekeeping genes (HKG) as an internal control for the detection of gene expression by quantitative real-time RT-PCR.

Quantitative real-time RT-PCR is a very useful technique for estimating gene expression at the mRNA level. The expression of a tested gene has to be compared with that of a control gene. Various housekeeping genes have been used as control genes in different systems. In our study we tested several housekeeping genes in the model of gene expression after induction of apoptosis and differentiation. The myeloid cell lines were incubated with phorbol esters, butyric acid and combination of TNFalpha and IFNgamma to induce differentiation. Camptothecin was used for induction of apoptosis. Tested control genes included beta2-microglobulin, GAPDH, 18S ribosomal RNA and abl. GAPDH was found to be the best control gene in the apoptotic system. Different control genes were suitable for different systems where differentiation or senescence was induced. Our results show that attention should be paid to the choice of an appropriate control gene of quantitative real-time RT-PCR for different experimental models and various experimental conditions.

Base Sequence↗
PubMed2003

Sensitive and rapid quantitative detection of anthrax spores isolated from soil samples by real-time PCR.

Quantitative analysis of anthrax spores from environmental samples is essential for accurate detection and risk assessment since Bacillus anthracis spores have been shown to be one of the most effective biological weapons. Using TaqMan real-time PCR, specific primers and probes were designed for the identification of pathogenic B. anthracis strains from pag gene and cap gene on two plasmids, pXO1 and pXO2, as well as a sap gene encoded on the S-layer. To select the appropriate lysis method of anthrax spore from environmental samples, several heat treatments and germination methods were evaluated with multiplex-PCR. Among them, heat treatment of samples suspended with sucrose plus non-ionic detergent was considered an effective spore disruption method because it detected up to 10(5) spores/g soil by multiplex-PCR. Serial dilutions of B. anthracis DNA and spore were detected up to a level of 0.1 ng/ microliters and 10 spores/ml, respectively, at the correlation coefficient of 0.99 by real-time PCR. Quantitative analysis of anthrax spore could be obtained from the comparison between C(T) value and serial dilutions of soil sample at the correlation coefficient of 0.99. Additionally, spores added to soil samples were detected up to 10(4) spores/g soil within 3 hr by real-time PCR. As a consequence, we established a rapid and accurate detection system for environmental anthrax spores using real-time PCR, avoiding time and labor-consuming preparation steps such as enrichment culturing and DNA preparation.

Anthrax↗
PubMed1999

Molecular genetic alterations in radiation-induced astrocytomas.

Astrocytic tumors occasionally arise in the central nervous system following radiotherapy. It is not clear if these gliomas represent a unique molecular genetic subset. We identified nine cases in which an astrocytoma arose within ports of previous radiation therapy, with total doses ranging from 2400 to 5500 cGy. Irradiated primary lesions included craniopharyngioma, pituitary adenoma, Hodgkin's lymphoma, ependymoma, pineal neoplasm, rhabdomyosarcoma, and three cases of lymphoblastic malignancies. Patients ranged from 9 to 60 years of age and developed secondary tumors 5 to 23 years after radiotherapy. The 9 postradiation neoplasms presented as either anaplastic astrocytoma (3 cases) or glioblastoma multiforme (6 cases). Two of the latter contained malignant mesenchymal components. We performed DNA sequence analysis, differential polymerase chain reaction (PCR), and quantitative PCR on DNA from formalin-fixed, paraffin-embedded tumors to evaluate possible alterations of p53, PTEN, K-ras, EGFR, MTAP, and p16 (MTS1/CDKN2) genes. By quantitative PCR, we found EGFR gene amplification in 2 of 8 tumors. One of these demonstrated strong immunoreactivity for EGFR. Quantitative PCR showed chromosome 9p deletions including p16 tumor suppressor gene (2 of 7 tumors) and MTAP gene (3 of 7). Five of 9 tumors demonstrated diffuse nuclear immunoreactivity for p53 protein. Sequencing of the p53 gene in these 9 cases revealed a mutation in only one of these cases, a G-to-A substitution in codon 285 (exon 8). Somewhat unexpectedly, no mutations were identified in PTEN, a commonly altered tumor suppressor gene in de novo glioblastoma multiformes. Unlike some radiation-induced tumors, no activating point mutations of the K-ras proto-oncogene or base pair deletions of tumor suppressor genes were noted. These radiation-induced tumors are distinctive in their high histological grade at clinical presentation. The spectrum of molecular genetic alterations appears to be similar to that described in spontaneous high grade astrocytomas, especially those of the de novo type.

Adolescent↗
PubMed1999

PCR-based quantitation of Cryptosporidium parvum in municipal water samples.

A PCR method for the quantitation of Cryptosporidium parvum oocysts in municipal drinking water samples was investigated. Quantitative PCR uses an internal standard (IS) template with unknown target numbers to compare to standards of known concentrations in a standard curve. The IS template was amplified using the same primers used to amplify a portion of a 358 bp gene fragment that encodes a repetitive oocyst wall protein in C. parvum. Municipal water samples spiked with known numbers of C. parvum oocysts were tested by quantitative PCR using the IS and the Digene SHARP Signal System Assay for PCR product detection. The absorbance readings for target DNA and IS templates versus the number of molecules of the target DNA were plotted to generate standard curves for estimating oocyst numbers. The method allowed the quantitation of oocysts from log 3 to log 5 spiked into municipal water samples.

Animals↗
PubMed1999

Significance of qualitative polymerase chain reaction combined with quantitation of viral load in the diagnosis and follow-up of cytomegalovirus infection after solid-organ transplantation.

Quantitative PCR was evaluated in the monitoring of patients with ongoing posttransplantation cytomegalovirus (CMV) infection and antiviral therapy, compared to leukoDNAemia and serology. From January 1998 until May 1999, 61 patients were followed up weekly during 3 months after transplantation by a qualitative PCR. The quantitative PCR was performed on plasma samples from 21 selected patients, of whom 12 had a primary infection and 9 a reactivation or reinfection. Analysis of the viral load differences showed that the viral loads in patients with a primary infection were significantly higher than viral loads in patients with a reactivation (p < 0.01). Based on the results of our study, we can state that qualitative PCR is a good marker for initiating preemptive therapy. In addition, viral quantitation is clinically useful for accurate diagnosis of established CMV disease, and monitoring of antiviral therapy.

Antiviral Agents↗
PubMed1993

Early detection of relapse after bone marrow transplantation in patients with chronic myelogenous leukaemia.

In patients with chronic myelogenous leukaemia (CML) treated by allogeneic bone marrow transplantation (BMT), detection of residual leukaemic cells carrying the characteristic bcr/abl rearrangement by highly sensitive techniques, such as qualitative polymerase chain reaction (PCR), is of limited value in predicting disease progression. We have therefore adapted the PCR for quantitative assessment of bcr/abl rearranged cells and applied this technique to the monitoring of residual disease in 28 CML patients during up to 106 months of follow-up after BMT. In 5 patients, quantitative PCR revealed increasing amounts of the pathological bcr/abl message, indicating the presence of a proliferating neoplastic clone, and all 5 had a subsequent relapse of disease. By contrast, the remaining 23 patients have been in maintenance-free complete remission for up to 106 months post-BMT. The monitoring by quantitative PCR of residual leukaemic cells during the post-transplant course of CML patients may allow early detection of relapse and provide a rationale for the timely initiation of treatment.

Bone Marrow Transplantation↗
PubMed2003

Congenital cytomegalovirus infection in twin pregnancies: viral load in the amniotic fluid and pregnancy outcome.

Human cytomegalovirus (CMV) is the most common cause of viral intrauterine infection and fetal damage largely attributable to maternal primary infection. Most cases of congenital CMV infection in twins reported in the literature involved only 1 twin. We assessed the validity of polymerase chain reaction (PCR) and quantitative PCR on amniotic fluid (AF), at 21 to 22 weeks' gestation and at least 6 to 8 weeks after seroconversion, to predict the outcome of newborns in twin pregnancies. Two pregnant women with twin pregnancies and 1 woman with a triple pregnancy with primary CMV infection defined by the presence of immunoglobulin (Ig) M and low IgG avidity and/or by the presence of clinical symptoms and abnormal liver enzyme values were evaluated. CMV infection was found in 6 fetuses/newborns, 3 of whom were symptomatic. In the first twin pregnancy with diamniotic-dichorionic separate placentas, CMV symptomatic infection of the female twin was demonstrated by positive virus isolation and high viral load in AF. The male fetus was not infected as demonstrated by negative CMV culture and DNA detection in AF. In the triple pregnancy, the woman had a placenta with 2 monozygotic twins (females) and a separate placenta with a heterozygotic twin (male). The quantitative PCR results were 10(3) genome equivalents (GE)/mL of females AF and 1.9 x 10(5) GE/mL of male AF. Both female twins were asymptomatic at birth, whereas the male presented petechiae, thrombocytopenia, and cerebral ventriculomegaly. In the last twin pregnancy with fused dichorionic placentas, congenital CMV infection of both twins was diagnosed at birth in contrast with prenatal diagnosis. At time of amniocentesis, the left side twin was not infected as shown by negative results of CMV culture and DNA detection in the AF. CMV infection of the right side twin was demonstrated by positive CMV DNA detection with a CMV DNA load of 4.9 x 10(4) GE/mL and positive virus isolation in the AF. The morphologic and histologic examinations of the placentas strongly supported a prenatal horizontal acquisition of CMV infection. These twin pregnancies showed a marked difference in the quantity of virus load documented by the prenatal diagnosis suggesting that twin fetuses may react differently to primary maternal infection despite being exposed to the same maternal influences. A high viral load is correlated with congenital CMV infections symptomatic at birth. In such cases, with fetal infection of only 1 twin (at amniocentesis) and fusion of placentas, fetal outcome of both twins needs to be evaluated for the possibility of viral transfer from one fetus to the other.

Amniotic Fluid↗
PubMed2007

Optimization of ribonucleic acid detection from archival Guinea pig temporal bone specimens.

HYPOTHESIS: The choice of ribonucleic acid (RNA) isolation protocol coupled with modifications to RNA extraction and detection procedures may result in a more reliable method to detect gene expression in archived temporal bones. BACKGROUND: A large number of archival temporal bones exist. Retrospective analysis of these specimens using techniques of RNA extraction will greatly enrich our understanding of the pathophysiology of specific otologic diseases. However, archival human temporal bones are aged and embedded in paraffin or celloidin, rendering isolation and manipulation of nucleic acid in preserved specimens difficult, especially as it pertains to RNA degradation. Despite some reports of moderate success in the recent past, RNA isolation and gene expression using polymerase chain reaction (PCR) analysis continues to be challenging and unreliable. Archival guinea pig temporal bone specimens were used to develop and optimize a protocol for RNA extraction and gene expression analysis using PCR and quantitative PCR methods. The genes amplified comprise housekeeping genes and genes associated with the glutamate pathway. METHODS: Archival celloidin-embedded guinea pig temporal bones were collected from the senior author's collection of experimental hydropic inner ear specimens. RNA from this tissue was extracted using the protocol described previously in 16animals and using a modified trizol extraction technique in 10 animals. Gene expression analysis was performed on the extracted RNA. Analysis included two housekeeping genes, GAPDH and 18S, as well as three mediators of the glutamate pathway, glutamate aspartate transporter, glutamate synthetase, and inducible nitric oxide synthase. RESULTS: Compared with the standard extraction protocol, the trizol-based extraction technique showed greater reliability and reproducibility of RNA detection. The housekeeping gene GAPDH or 18S was detected in 7 of 36 attempts with the standard protocol versus 9 of 9 using the modified extraction method (P < 0.001). The gene of interest, glutamate aspartate transporter, was detected in 3 of 26 attempts with the standard protocol versus 12 of 13 attempts using the modified extraction method (P < 0.001). Quantification of messenger RNA levels was then achieved using quantitative PCR methods. CONCLUSION: Improved reliability for detection of gene expression and demonstration of reproducibility were accomplished by modification of RNA extraction technique and standard reverse transcriptase PCR protocol. In addition, we also showed that gene expression from archival material can be quantified by real-time PCR.

Animals↗
PubMed1993

Molecular monitoring of the immunosuppressive effects of cyclosporine in renal transplant patients by using a quantitative polymerase chain reaction.

We have developed a rapid (24 hours) quantitative PCR assay to measure the direct effect of cyclosporine on IL-2 mRNA production by activated PBMC cultures from renal transplant patients. The PBMCs were purified from normal laboratory volunteers (group A, n = 26), CsA-treated renal transplant patients with good renal function, tested between 3 and 8 weeks (group B, n = 14) or between 2 and 8 years (group C, n = 15) after surgery, and stimulated with PHA in media supplemented with either patient serum or pooled commercially obtained AB serum. The mRNA was then isolated and, using semiquantitative PCR or quantitative PCR with a competitive inhibitor, the relative levels or exact levels of IL-2 mRNA (in attomoles) could be measured. A 3-day confirmatory lymphoproliferation assay of [3H]thymidine incorporation was also performed on the samples. Kinetic analysis of the data from group A showed that the peak level of IL-2 transcription into mRNA occurred at 6 hours after mitogen stimulation. Increasing in vitro concentrations of CsA in this group resulted in lower IL-2 mRNA levels and a shift in the peak time to 12-24 hours. In the transplant recipients, there was no correlation between individual CsA blood levels and proliferation responses. However, some correlation was found between CsA blood levels and IL-2 mRNA levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed2005

Effect of controlled ovarian hyperstimulation in IVF on endometrial gene expression profiles.

Controlled ovarian hyperstimulation (COH) used in IVF produces lower implantation rates per embryo transferred compared to natural cycles utilized in ovum donation, suggesting a suboptimal endometrial development. Endometrial receptivity has recently been investigated in natural menstrual cycles with the aid of microarray technology. The aim of this study is to investigate the impact of COH using urinary gonadotrophins with a long protocol with GnRH agonists without progesterone supplementation (similar to the natural cycle) on endometrial gene expression profiles during the window of implantation by comparing the profiles at day hCG + 7 of COH versus LH + 7 of a previous natural cycle in the same women. For this purpose we have used microarray technology by Affymetrix (GeneChip HG_U133A), which allows more than 22,000 genes to be tested simultaneously. Results were validated by semi-quantitative PCR and quantitative PCR experiments. We found that more than 200 genes showed a differential expression of more than 3-fold when COH and normal cycles were compared at hCG + 7 versus LH + 7. We simultaneously re-analysed the LH + 2 versus LH + 7 endometrial gene expression profiles in previous natural cycles in the same subject using this specific GeneChip, the results obtained were consistent with our own published results. This is the first time that gene expression profiles of the endometrium during COH are reported. The large degree of gene expression disturbance is surprising and highlights the need for further efforts to optimize COH protocols.

Embryo Implantation↗
PubMed2002

Monitoring of viral load by quantitative plasma PCR during active cytomegalovirus infection of individual liver transplant patients.

A quantitative PCR test, the Cobas Amplicor CMV Monitor, was used for the monitoring of viral load in the peripheral blood of 27 individual liver transplant patients and correlated with cytomegalovirus (CMV) pp65 antigenemia. Altogether, 243 specimens were analyzed. During the first 3 months, 20 patients showed PCR positivity which correlated with pp65 antigenemia. Of those, 13 patients developed symptomatic CMV infection 27 to 52 days after transplantation, with a significantly higher peak viral load in PCR and in pp65 assay compared with the seven asymptomatic infections (median 10,200 versus 2,240 copies/ml, P < 0.05, and median 100 versus 30 pp65-positive cells/50,000 leukocytes, P < 0.01). Five were primary infections of D+/R- cases (donor CMV seropositive and recipient seronegative) and demonstrated, except in one case, a high peak viral load (>10,000 copies/ml; range, 10,200 to 21,600 copies, and > or =50 positive cells, range, 50 to 800 cells). The peak viral loads of the six D+/R+ patients with symptomatic infection varied widely (range, 2,290 to 126,000 copies and 50 to 300 positive cells). Two D-/R+ patients developed symptomatic infection with a lower viral load (range, 1,120 to 6,510 copies and 25 to 100 positive cells). All symptomatic infections were successfully treated with ganciclovir. The asymptomatic infections all in D+/R+ patients with low copy numbers (<5,500 copies) were monitored until CMV disappeared. One of the seven PCR-negative patients had one sample with low antigenemia, but the subsequent specimens were all negative. The time-related correlation of the two methods was also good. In summary, quantitative PCR could equally well be used as the CMV pp65 assay for the monitoring of viral load in individual transplant patients.

Adult↗
PubMed2005

Use of an internal control in a quantitative RT-PCR assay for quantitation of porcine epidemic diarrhea virus shedding in pigs.

Porcine epidemic diarrhea virus (PEDV), a member of the family Coronaviridae, has caused a devastating enteric disease in the Korean swine industry. Previously, the differences between virulent field PEDV strains and a Vero cell culture adapted PEDV DR13 strain were determined using restriction fragment length polymorphism analysis (RFLP), and PEDV shedding patterns in pigs were reported. In an extension to these studies, an internal control was constructed and quantitative analysis of virus shedding after oral inoculation was established. A parent field PEDV and a cell culture adapted PEDV DR13 were inoculated orally to colostrum-deprived 1-day-old piglets, commercial 2-week-old pigs, and sows (1-5 ml dose, 10(5.8)-10(6.0) TCID(50)/0.1 ml). PEDV shedding was monitored every day and virus levels were measured using a quantitative reverse transcriptase polymerase chain reaction (RT-PCR) method. In fecal samples from experimentally-inoculated pigs, the level of virus excreted peaked at 2 days after oral inoculation and gradually decreased thereafter. In addition, PEDV from field specimens was quantified using the same RT-PCR assay to determine shedding viral load. This suggests that measurement of PEDV shedding viral load in pigs, by quantitative RT-PCR, may be a useful tool for estimating the transmission potential of PEDV in the swine population.

Animals↗