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Results for “Nested Genes”

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PubMed2005

The use of animal models to explore amelogenin variants in amelogenesis imperfecta.

Amelogenin proteins are secreted by ameloblast cells during tooth development. Because of extensive alternative splicing of the amelogenin primary RNA transcript, and because systematic proteolysis results in many additional peptides during enamel maturation, it has been difficult to assign function to individual amelogenins. Targeted deletions and transgenic mice have been generated in order to better understand amelogenin protein function in vivo. From these murine models, we have determined that amelogenins are responsible for normal enamel thickness and structure, but not for initiation of enamel mineral formation at the dentin-enamel junction. Although it is now clear that the amelogenin (AmelX) gene exists in a nested orientation and that AmelX is expressed at a low level in various developing tissues, the significance of these findings is incompletely understood. Future studies are expected to answer remaining questions concerning structure/function relationships among these 'enamel proteins'.

Amelogenesis Imperfecta↗

PubMed2006

Cytomegalovirus gB genotype and clinical features in Chinese infants with congenital infections.

OBJECTIVE: To investigate cytomegalovirus (CMV) glycoprotein B (gB) genotypes and clinical features in Chinese infants with congenital infections. METHODS: Urine samples were obtained from 79 infants with human CMV infection confirmed by quantitative fluorescence polymerase chain reaction (PCR). A fragment of the gB gene was amplified by nested PCR. CMV gB genotyping was carried out by restriction fragment length polymorphism, and 24 samples of the amplified DNA fragments were verified by DNA sequencing. RESULTS: The levels of CMV DNA in symptomatic and asymptomatic infants were 2.95 x 10(5) and 4.5 x 10(3) copies/ml, respectively, with a significant difference (p < 0.001). In all these cases, the most prevalent genotype was gB1 (50.63%), followed by gB3 (21.52%), gB2 (17.72%), and coinfection (10.13%); gB4 was not found. Moreover, gB1 was more prevalent in infants with liver damage (22/32) than in other symptomatic infants without liver damage (8/22, p = 0.019) or asymptomatic infants (10/25, p = 0.030). The homology of CMV gB in the 24 strains amplified as compared with the sequences of prototype strains in GenBank ranged from 97.06 to 99.64%. CONCLUSIONS: The restriction fragment length polymorphism analysis of CMV gB genotypes was definite and reliable. The gB1 genotype is the most prevalent in Chinese infants with congenital CMV disease, especially in those with liver damage, followed by genotypes gB3, gB2, and gB4.

China↗

PubMed2025

The transcriptional and translational landscape of HCoV-OC43 infection.

The coronavirus HCoV-OC43 circulates continuously in the human population and is a frequent cause of the common cold. Here, we generated a high-resolution atlas of the transcriptional and translational landscape of OC43 during a time course following infection of human lung fibroblasts. Using ribosome profiling, we quantified the relative expression of the canonical open reading frames (ORFs) and identified previously unannotated ORFs. These included several potential short upstream ORFs and a putative ORF nested inside the M gene. In parallel, we analyzed the cellular response to infection. Endoplasmic reticulum (ER) stress response genes were transcriptionally and translationally induced beginning 12 and 18 hours post infection, respectively. By contrast, conventional antiviral genes mostly remained quiescent. At the same time points, we observed accumulation and increased translation of noncoding transcripts normally targeted by nonsense mediated decay (NMD), suggesting NMD is suppressed during the course of infection. This work provides resources for deeper understanding of OC43 gene expression and the cellular responses during infection.

Humans↗

PubMed2003

Myeloperoxidase promoter region polymorphism and lung cancer risk.

Historically, myeloperoxidase activity and subsequent production of hypochlorous acid has been associated with the killing of host-invading microorganisms (bacteria, viruses, and fungi). Currently, there is a wealth of evidence that the MPO polymorphism and enzyme activity is associated with a wide range of pathological and biological processes, including lung cancer carcinogenesis. Although the molecular epidemiology reports reviewed in this chapter are not in complete agreement on all aspects of their findings, it is evident that the MPO polymorphism contributes to the modulation of overall lung cancer risk. Four of the five molecular epidemiologic studies reviewed in this chapter utilized similar case-control study designs with quite different sources of populations. These studies all demonstrate that the MPO variant genotype modulates overall lung cancer risk. However, these studies are not in agreement regarding age and gender effects, and gene-environmental interactions. The nested case control study designed utilized by Misra et al. (35) is a valid and sound approach, but their results found no evidence of an association. Certainly, heterogeneity in study populations can contribute to the variability between these studies. Additionally, epidemiologic issues such as case-control matching and sources of control populations may contribute to the conflicting findings. Thus, the publication of inconsistent or null studies as well as other positive findings is certainly encouraged to elucidate the range of effects associated with the MPO polymorphism and lung cancer risk.

Genotype↗

PubMed2001

Incorporating the ABI GeneScan analysis to a RACE-based technique for mapping multiple transcription initiation sites.

Determination of transcription initiation sites has commonly been performed by primer extension and RNase protection assay using radioactively labeled oligonucleotides. Recently, a protocol based on modified 5' rapid amplification of cDNA ends (RACE) with the use of fluorescently labeled primer was developed. Here, we describe the use of RACE-based technique in conjunction with the GeneScan analysis for the determination of transcription initiation sites of genes of interest. The RACE technique is based on the ligation of an adapter to both ends of the cDNAs. The gene of interest was first amplified by PCR using a gene-specific and a 5' adapter primer. Subsequently, nested PCR was performed using an internal gene-specific primer paired with a fluorescently end-labeled adapter primer. The size of the fluorescently labeled PCR products was directly determined by the ABI PRISM 377 GeneScan Analyzer. This novel approach provides an accurate, sensitive, and convenient method for mapping transcription initiation sites, especially for genes with multiple transcription initiation sites, for genes expressed at low levels, and for splice variants that display alternative splicing farther than a few hundred nucleotides downstream from the transcription initiation site. This article describes the application of this new method in the mapping of transcription initiation sites of two splice variants of rat frizzled related protein transcripts.

Alternative Splicing↗

PubMed2006

Evaluation of polymerase chain reaction for the detection of Paracoccidioides brasiliensis DNA on serum samples from patients with paracoccidioidomycosis.

The aim of this study was to demonstrate the DNA of Paracoccidioides brasiliensis in human serum samples of patients with paracoccidioidomycosis using the polymerase chain reaction (PCR). The diagnosis of paracoccidioidomycosis (PCM) was defined by microscopic observation of the fungus on direct exam or histopathology, culture, and serological positivity. DNA from serum of 33 patients with PCM was extracted and submitted to nested-PCR using primers from the gp 43 gene. Only one sample was positive on nested-PCR. We conclude that the prevalence of fungemia in patients with different clinical forms of PCM is low, limiting the use of serum DNA detection as an alternative diagnostic tool.

Adult↗

PubMed2006

Genotyping of single Cryptosporidium oocysts isolated from sewage and river water.

The study was designed to genotype individual Cryptosporidium oocysts using an 18S rRNA gene-based semi-nested PCR and direct sequencing procedure. Positive PCR amplification was observed in all single C. parvum HNJ-1 oocyst samples tested. Semi-nested PCR and direct sequencing was applied to Cryptosporidium oocysts isolated from sewage and river water. The procedure could genotype 54% of FITC-stained single oocysts isolated from sewage and 32% from river water. The predominant genotype in both sewage and river water was C. parvum genotype 1, accounting for 33 and 25%, respectively, of all the FITC-stained intact Cryptosporidium oocysts present.

Animals↗

PubMed2005

Risk of infection with Cryptosporidium parvum and Cryptosporidium hominis in dairy cattle in the New York City watershed.

OBJECTIVE: To determine the risk posed by Cryptosporidium parvum and Cryptosporidium hominis from dairy cattle in the New York City watershed (NYCW). SAMPLE POPULATION: Samples from cattle at risk for shedding Cryptosporidium organisms on randomly selected dairy farms in the NYCW. PROCEDURE: Feces were collected for 4 years from calves at risk for infection on 37 dairies. Oocysts were detected by use of centrifugation concentration-flotation microscopy. The DNA was directly isolated from fecal samples and used to amplify fragments of the small subunit ribosomal RNA and thrombospondin-related adhesion protein C-2 genes by use of nested polymerase chain reaction assays. Small subunit ribosomal RNA fragments were restriction digested by the enzyme Vspl and thrombospondin-related adhesion protein C-2 fragments were digested by Eco91l to distinguish between C hominis (formerly known as genotype 1) and C parvum (formerly known as genotype 2). RESULTS: Of 437 fecal samples examined, 214 contained oocysts. Amplicons were generated for 200 samples. We can be certain, with 95% confidence, that cattle in the NYCW did not harbor C hominis. CONCLUSIONS AND CLINICAL RELEVANCE: Cryptosporidium infections in cattle are under examination because of the potential contamination of public waters by manure. Although cattle may be the source of zoonotic infection via C parvum, they pose little risk for C hominis (the strain commonly isolated from humans in waterborne outbreaks of disease). Other sources of oocysts should be considered when investigating outbreaks attributable to contaminated urban drinking water because cattle pose only a small risk via shedding of C hominis.

Animals↗

PubMed2001

An automated fluorescent single strand conformation polymorphism technique for high throughput mutation screening.

OBJECTIVE: To develop a high throughput mutational detection method by multiple fluorescence-labeled polymerase chain reaction (PCR) products. METHODS: A total of 27 known mutations including 22 substitutions, 3 insertions (1, 2 and 7 bp) and 2 deletions (1 and 2 bp) in the hepatocyte nuclear factor (HNF)-4 alpha, glucokinase and HNF-1 alpha genes were tested. During nested PCR, amplified fragments were labeled with three fluorescent dyes. PCR products were visualized with an ABI-377 fluorescence sequencer using 5% glycerol or 10% sucrose in non-denaturing gel conditions. RESULTS: Twenty-five of 27 variants (93%) could be detected by combining 5% glycerol and 10% sucrose gel matrix conditions. Twenty-two of 27 (82%) and 18 of 27 (67%) variants were identified using 5% glycerol and 10% sucrose conditions, respectively. CONCLUSION: This fluorescence-based PCR single strand conformation polymorphism technique represents a simple, non-hazardous, time-saving and sensitive method for high throughput mutation detection.

Basic Helix-Loop-Helix Leucine Zipper Transcriptio↗

PubMed2002

[Detection of cytomegalovirus infection with the polymerase chain reaction and antigenemia after allogenic bone marrow transplantation].

UNLABELLED: The objective of the work was to evaluate the frequency and time of incidence of cytomegaloviral (CMV) infection and disease in patients after allogeneic bone marrow transplantation (BMT). One hundred patients were followed up (70 with a related and 30 with an unrelated donor), who had transplantations during the period between XI/1996-XI/2000. METHODS USED: nested-PCR (MIE-gene) and antigenaemia (antigen pp65). Active CMV infection was proved in antigenaemia > or = 5 positive cells or in two consecutive positive PCR. The CMV syndrome was assessed in confirmed CMV infection and otherwise inexplicable febrile conditions and/or a drop of haemogram values. For the diagnosis of CMV pneumonia the clinical picture was needed, evidence of active CMV infection and on the X-ray of the lungs interstitial pneumonia. In 33 patients both methods were used, in 67 only PCR. The first positive test appeared 6-321 days after BMT (median +/- 49 days). CMV infection was proved in 44% cases, CMV syndrome in 30% and CMV pneumonia in 4%. In patients with a related donor CMV infection was found in 34.3%, CMV syndrome in 22.9%, CMV pneumonia in 1.4%. After unrelated donor BMT CMV infection was recorded in 66.7%, CMV syndrome in 46.7% and CMV pneumonia in 10% patients. Two patients died from CMV pneumonia. CMV pneumonia was diagnosed 57-115 days after BMT (median +/- 68 days. The risk of CMV infection is high in both groups of patients, in particular in patients after unrelated donor BMT (66.7%). As far as the development of CMV pneumonia was concerned, the mortality in the authors' group was 50%.

Adult↗

PubMed2003

[Determination of the lamivudine-resistant mutants of hepatitis B virus].

INTRODUCTION: In addition to interferon, lamivudine is the other widely used antiviral agent in the therapy of chronic hepatitis B. This nucleoside analogue inhibits the RNA-dependent DNA polimerase and the reverse transcription by integrating in the viral DNA, which results in the secondary suppression of viral protein synthesis and replication of HBV. It has numerous advantages such as effective viral inhibition, mild side effects and the possibility of oral administration; on the other hand it poses the problem of time-correlated appearance of lamivudine resistant mutants during therapy. AIMS: In the Virusserology Laboratory of the Department I. Internal Medicine, Szent György Hospital, Székesfehérvár, detection and type determination of the therapy resistant mutants in the C and B domains of HBV DNA polimerase gene has been carried out the for one year. In this paper, the authors review the molecular biological background of lamivudine resistance and summarise the applied test methodologies and the early results. PATIENTS: Six-month and/or 12-, 18-month samples of 18 chronic hepatitis B patients (4 women/14 men) treated in seven Hepatology Centres in Hungary were analysed. METHODOLOGY: Mutants of codons 528, 552, and 555 in the HBV polimerase gene were determined by nested polimerase chain reaction and reverse hybridisation. RESULTS: M528, V552, I552 and I555 mutants in different variations could be detected in ten out of 18 patients. CONCLUSIONS: Nowadays, drug therapy is the only treatment option used for the therapy of early and progressed chronic hepatitis B in Hungary. This new diagnostic technique was introduced to clarify the background of ineffective lamivudine therapy. Therapy resistance can occur due to the lack of reaction or the appearance of the special, therapy resistant mutants of the virus. Detection of these YMDD mutants together with the clinical picture and the biochemical and virological parameters can help in forming a decision about cessation of lamivudine therapy or application of a new drug.

Adult↗

PubMed2004

Sequence analysis of tau 3'untranslated region and saitohin gene in sporadic progressive supranuclear palsy.

BACKGROUND: The extended tau H1 haplotype has previously been described in association with progressive supranuclear palsy (PSP). Recently, a new gene called saitohin (STH), nested within an intron of tau, has been discovered. The Q7R polymorphism of STH appears to be related to late onset Alzheimer's disease. OBJECTIVES: To search for genetic changes in the 3'untranslated region (3'UTR) of tau and adjacent sequence LOC147077, and in the coding region of STH in PSP patients. METHODS: The study included 57 PSP patients and 83 healthy controls. The genetic analysis of each region was performed through sequencing. The Q7R polymorphism was studied through restriction enzyme and electrophoresis analysis. RESULTS: No mutations were found in the regions analysed. The QQ genotype of the STH polymorphism was over-represented in participants with PSP (91.5%) compared with control subjects (47%) (p< or =0.00001). This genotype co-segregated with the H1/H1 haplotype in our PSP cases. CONCLUSIONS: Our results do not support a major role for the tau 3'UTR in PSP genetics. The QQ genotype of STH confers susceptibility for PSP and is in linkage disequilibrium with the H1/H1 haplotype.

3' Untranslated Regions↗

PubMed2003

[Analysis of 21 children with acute non-lymphoid leukemia carrying AML1/ETO fusion gene].

OBJECTIVE: It was revealed that t(8; 21) (q22; q22) was one of the most common chromosomal aberrations in acute non-lymphoid leukemia. The translocation was found to be involved in the AML1 gene on the chromosome 21 and the ETO gene on the chromosome 8, and resulted in the formation of AML1/ETO fusion gene on the derivative chromosome 8. The fusion gene was a transcription factor and played a direct role in the leukemogenesis. The translocation was mainly observed in M(2), accidentally in M(4) and M(1) and rarely in MDS. Here we studied the main clinical data in children with acute non-lymphoid leukemia (ANLL) carrying the AML1/ETO fusion gene. In addition, we discussed the significance of the detection of AML1/ETO fusion gene in the diagnosis and prognosis of children with ANLL. METHODS: The authors investigated 29 patients in our hospital from December 2000 to March 2002. The patients were divided into two groups. Group A included 21 patients, 14 males and 7 females. They were 3.6 to 14 years old and the median was 9. Group B included 8 patients, 6 males and 2 females. They were 0.8 to 14 years old and the median was 6. Diagnosis was made according to FAB and MIC criteria and the expression of AML1/ETO fusion gene was detected with nested RT-PCR. The patients were treated according to DA, DAE or BFM regimen, respectively. The main clinical indexes including age, Hb, white blood count, platelet, blasts in PBC and BM, and time of arrival at complete remission (CR), were compared statistically between the two groups with t test of independent samples. RESULTS: All the 21 patients in group A were found carrying AML1/ETO, and 17 patients (81%) were classified as M(2), the other 4 cases were of M(2) developed from MDS-RAEB-T, M(4Eo), M(5) and eosinophil leukemia, respectively. Eighteen out of 20 patients whose effects could be assessed reached CR, and the CR ratio was 90%. Two patients in group B were of AML-M(1), 3 M(2), 1 M(3), 1 M(4), and 1 M(5), respectively. None of them was found carrying AML1/ETO. Seven cases reached CR and the ratio was 87.5%. There was no significant difference between the two groups in the above clinical indices. CONCLUSIONS: Between the two groups of patients there was no significant difference in the above clinical indices. RT-PCR for the detection of AML1/ETO in children with ANLL was quick, convenient and sensitive, and could be regarded as a useful method for the diagnosis and prognosis of ANLL.

Adolescent↗

PubMed2005

[Study on the molecular epidemiology of people infected with human immunodeficiency virus-1 in Shandong province].

OBJECTIVE: To study the distribution of human immunodeficiency virus-1 (HIV-1) strains subtypes in Shandong province and to study their source in order to predict the epidemic trend. METHODS: Epidemiological investigation was made and 93 DNA fragments of HIV-1 env, gag, tat gene were amplified by nested polymerase chain reaction from people infected with HIV-1, in 2002 - 2003. Their C2-V3, P17/P24, 1st exon of tat and adjacent region were sequenced. RESULTS: Sequence analysis showed that there were 7 HIV-1 strains or circulating recombinant forms (CRFs), B' (n = 71), CRF01-AE (n = 9), CRF07-BC (n = 3), CRF08-BC (n = 3), B (n = 2), C (n = 2), CRF02-AG (n = 2). B' strains was the predominant which, covered 10 cities and 4 kinds of population including blood donors, blood receivers, spouses of the infected people and clients of the sex workers. CRF07-BC, CRF08-BC strains were identified in 5 cities, mainly from injecting drug users. CRF01-AE and other strains were found distributed in developed cities, among sex workers. CONCLUSION: There were many kinds of subtypes and CRFs of HIV and their genomes which generated obvious variation in Shandong province, suggesting that they might facilitate the spread of the disease in Shandong province.

Adolescent↗

PubMed2006

[Immunophenotypic characteristics of children with acute lymphoblastic leukemia carrying TEL-AML1 fusion gene].

To investigate the immunological and other clinical characteristics in TEL/AML1+ childhood B-acute lymphoblastic leukemia (B-ALL), immunophenotyping was performed with three-color flow cytometry, and the expression of TEL-AML1 fusion gene was detected with nested RT-PCR. Diagnosis was made according to FAB and MIC criteria. The results showed that (1) among 119 children with B-ALL, 22 (18.5%) were TEL-AML1 positive and classified as L2 morphological subtype. In TEL-AML1+ group, positive rate and score of PAS, which were 65% and 121 respectively, were all higher than that of TEL-AML1- group (P < 0.05); (2) compared with TEL-AML1- group, no significant difference was found in age, gender, white cell count and blasts count in peripheral blood of TEL-AML1+; (3) in TEL-AML1+ group, 21 out of 22 (95.5%) were common ALL, as compared with TEL-AML1- group, the positive rate of CD13 was higher (59.1%, 13/22) and the positive rate of CD20 was lower (22.7%, 5/22) than that in TEL-AML1- group, respectively (P < 0.05), and the mean fluorescence index of CD10 and HLA-DR significantly increased to 92.80 and 53.61, respectively (P < 0.05). It is concluded that TEL-AML1 rearrangement is a frequent molecular abnormality in childhood ALL. Leukemic blasts with this anomaly have special immunophenotypic characteristics. These characteristics may be useful in detection of minimal residual leukemia.

Antigens, CD20↗

PubMed2004

Powdery mildew pathogens can suppress the chitinase gene expression induced in detached inner epidermis of barley coleoptile.

Two-step PCR (RT-PCR and nested PCR) was used to detect gene expression in powdery mildew pathogen-infected cells of detached inner epidermis of barley coleoptiles. Cellular contents of infected cells were microscopically suctioned with a micropipette and subjected to PCR. Triosephosphate isomerase and glyceraldehyde-3-phosphate dehydrogenase genes involved in the glycolytic pathway and a stimulus-induced endochitinase gene were targeted, and their expression was determined by detecting cDNAs derived from spliced transcripts. The two gycolysis-related genes were constantly expressed in the tissue irrespective of pathogen inoculation. In contrast, chitinase gene expression was induced in non-infected inner epidermis after detachment. After inoculation, this expression was selectively suppressed in pathogen-invaded cells, in spite of continuous expression in non-invaded cells of the same epidermis. Thus, the present method enabled us to directly analyze transcripts in individual cells at the infection site and assess the capability of the pathogen to regulate host gene expression.

Biological Assay↗

PubMed2006

Seasonal distribution and phylogenetic analysis of human metapneumovirus among children in Osaka City, Japan.

BACKGROUND: Human metapneumovirus (hMPV) is one of the etiological agents of respiratory tract infection (RTI). Because clinical symptoms of hMPV resemble those caused by respiratory syncytial virus (RSV), clinical diagnosis of hMPV infection is difficult. Moreover, hMPV isolation using cultured cells is generally difficult and not efficient compared with reverse transcription-PCR (RT-PCR). OBJECTIVES: To assess infection and seasonal distribution of hMPV associated with RTI among children in Osaka City, Japan. STUDY DESIGN: To detect the hMPV gene, we extracted viral RNA from clinical specimens of patients with RTI and performed RT-PCR or nested-PCR for the fusion (F) gene. hMPV-specific amplicons were sequenced and subjected to phylogenetic analysis. RESULTS: From June 2004 to May 2005, we detected 29 (20.1%) hMPV strains among 144 clinical specimens. Fifteen strains were detected by RT-PCR and the remaining 14 by nested-PCR. Prevalence was principally in winter and spring with incidence peaking in April. We also detected the hMPV RNA from a patient with encephalitis. Approximately 80% of the hMPV-positive patients were younger than 3 years. To analyze these isolates precisely, a phylogenetic analysis using F gene was performed and demonstrated that Osaka City isolates of hMPV consists of two major genetic lineages each comprising two sublineages. CONCLUSIONS: We found two major genetic lineages of hMPV in Osaka City, Japan. We also found that nested-PCR was an efficient method for detecting the hMPV gene in clinical specimens. Of the 28 patients presenting with hMPV infection, 1 patient had associated encephalitis suggesting that hMPV infection might play a role in inducing encephalitis.

Adolescent↗

PubMed2001

Cross-protection studies between respiratory and calf diarrhea and winter dysentery coronavirus strains in calves and RT-PCR and nested PCR for their detection.

A 1-step RT-PCR assay, targeting a 730 bp fragment of the nucleocapsid (N) gene of bovine coronavirus (BCV), and a nested PCR assay, targeting a 407 bp fragment of the N gene, were developed to detect BCV in nasal swab and fecal samples of calves experimentally exposed to BCV. Both 1-step RT-PCR and nested PCR recognized cell culture passaged isolates of 10 bovine respiratory coronavirus (BRCV), 5 calf diarrhea (CD) and 8 winter dysentery (WD) strains of BCV, but not transmissible gastroenteritis coronavirus or bovine rotavirus. The sensitivity of the 1-step RT-PCR and nested PCR was compared to that of an antigen-capture ELISA. The lowest detection limit of the 1-step RT-PCR and nested PCR as determined by using tenfold serial dilutions of the BRCV 255 and 440 strains in BCV negative nasal swab suspensions from preexposure gnotobiotic calves was 2 x 10(4) and 2 x 10(2) TCID50/0.1 ml for each strain, respectively. The lowest detection limit of the antigen-capture ELISA as determined by using the same serially diluted samples was 1 x 10(6) TCID50/0.1 ml for each strain. Therefore, the 1-step RT-PCR and nested PCR assays were 50 and 5000 times, respectively more sensitive than the antigen-capture ELISA to detect BRCV in nasal swab suspensions. To investigate in vivo cross-protection between the BRCV and CD or WD strains of BCV and to detect nasal and fecal shedding of BCV using the 1-step RT-PCR, nested PCR and antigen-capture ELISA, 6 colostrum-deprived and two gnotobiotic calves were inoculated with a BRCV, a CD or a WD strain of BCV and then challenged 3-4 weeks later with either BRCV, CD or WD strains of BCV. All calves developed diarrhea after inoculation and BCV antigen (ELISA) or RNA (RT-PCR) was detected in the diarrheic fecal samples or the corresponding nasal swab samples. In addition, low amounts of BCV were also detected only by nested PCR in the fecal and nasal swab samples before and after diarrhea. No respiratory clinical signs were observed during the entire experimental period, but elevated rectal temperatures were detected during diarrhea in the BCV-inoculated calves. All calves recovered from infection with the BRCV, CD, or WD strains of BCV were protected from BCV-associated diarrhea after challenge exposure with either a heterologous or homologous strain of BCV. However, all calves challenged with heterologous BCV strains showed subclinical BCV infection evident by detection of nasal and fecal shedding of BCV RNA detected only by nested PCR. Such results confirm field and experimental data documenting reinfection of the respiratory and enteric tracts of cattle, suggesting that, in closed herds, respiratory or enteric tract reinfections may constitute a source of BCV transmissible to cows (WD) or neonatal or feedlot calves. In addition, the present 1-step RT-PCR and nested PCR assays were highly sensitive to detect BCV in nasal swab and fecal specimens. Therefore, these assays should be useful to diagnose BCV infections in calves and adult cows.

Animals↗