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"Monospecific" antisera to the "fragile" hemaglutinnis of H0N1 (PR8) and H1N1 (FM1) influenza viruses detected an asymmetrical cross-reaction between these two strains that could not be explained by a common neuraminidase.
In four cases of progressive multifocal leukoencephalopathy (PML), we compared biotin-labeled DNA:DNA in situ hybridization with peroxidase immunohistochemistry for the detection of JC virus (JCV). The localization of JCV DNA and JCV capsid protein was compared in formalin-fixed, paraffin-embedded brain tissues. Infected oligodendrocytes showed both JCV DNA and JCV protein. However, bizarre astrocytes demonstrated JCV capsid protein less often than JCV DNA. In situ hybridization with a biotinylated probe was as sensitive and specific as immunohistochemistry for diagnosis on formalin-fixed tissue. The presence of both JCV DNA and viral capsid protein in bizarre astrocytes suggests that these cells are neither truly transformed nor permissively infected, but are distinctively altered by JCV.
An apparatus has been developed, constructed, and tested for conditioning unlimited quantities of finished waters for enteric virus detection.
A rapid and effective RNA release procedure (RNA-RP) for detection of the Apple stem pitting virus (ASPV) and the Apple stem grooving virus (ASGV) in woody plants by reverse transcription-polymerase chain reaction (RT-PCR) was developed. RNA-RP released RNA into crude homogenate. RNA-RP was compared with classical phenol/chlorophorm extraction of RNA. The RT-PCR detection of ASPV and ASGV was shown to be similar by both the RNA preparation procedures. RNA-RP in contrast to the classical phenol/chloroform procedure represents a reliable and easy-to hand protocol convenient for routine virus detection. Leaf tissues, especially dormant bud leaves and leaves during blossom, were shown to be the most optimal material for detection of these viruses, irrespective of the used RNA preparation procedure.
A part of the 5'-noncoding region of echovirus type 9 isolates was sequenced, and an attempt was made for rapid virus detection in clinical samples obtained from 22 subjects hospitalized with aseptic meningitis. The sequence identity of 440-bp products amplified from the region by RT-PCR was 87.7% between the standard echovirus type 9(Hill strain) and the isolates. Specific IgM antibodies to Hill strain were positive in 45.5% by immunofluorescent antibody staining of virus-infected cells. A high detection rate of PCR products was observed in cerebrospinal fluids (CSFs; 54.5%) at admission, and in peripheral mononuclear cells (PMCs; 72.7%) at the end of hospitalization. Viral genomes were detectable for 2 days in serum samples, and for 6 days in PMC samples after onset of disease. When specific IgM antibody titers were less than 1:40, the amplification rate of viral genome from serum samples was 50.0%. These results indicate that the combination of specific IgM determination and viral genome amplification from CSFs will be a rapid and reliable method for early diagnosis.
An Enzyme linked-immunosorbent assay (ELISA) was recently established for the detection of sandfly Naples and Sicilian viruses (SFN and SFS) from laboratory infected as well as wild caught sandflies in Egypt. Optimal dilutions of the reactants including the coating antibodies (Rabbit antiserum), detecting antibodies (Mouse antiserum), conjugate and the time used for incubation of the substrate (ABTS) were determined for both SFN and SFS viruses. The ELISA test showed to be highly specific and sensitive except for the SFN virus which cross reacted with Toscana virus. A total of 1582 sandflies, forming 54 pools (each consisted of 2-109 flies) were collected from different governorates in Egypt (North Sinai, South Sinai, Alexandria, Giza, Qualubyia, Sharkiya and Aswan) in the years 1986-1987 and 1988, and tested for virus detection by the SFN-ELISA and SFS-ELISA. Only one pool (from Giza governorate) revirus was detected. Tests were repeated two times and confirmed by the complement fixation and plaque neutralization tests. The established ELISA technique hold great promise as a routine surveillance tool, permitting rapid, simple, sensitive, specific and inexpensive assay for the detection of the sandfly fever viruses.
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Five murine monoclonal antibodies (MAbs) against the NADL strain of bovine viral diarrhea (BVD) virus were developed, identified, and characterized. Four of the MAbs were directed against a 53-kilodalton (kDa) viral protein, and one was specific to a 47-kDa polypeptide. Competitive radioimmunoassay showed that two MAbs were specific to related epitopes of the 53-kDa protein, and the other three MAbs were each specific to a different epitope. The MAbs were used to study heterogeneity among BVD virus strains. Various degrees of reactivity of cytopathic and noncytopathic virus isolates were detected by virus neutralization and immunofluorescence assays. The virus isolates were divided into six groups based on the neutralization test. The results indicated that the 53-kDa glycoprotein of BVD virus is the major protein involved in virus neutralization and that only a few epitopes of the protein contribute to the neutralization. None of the MAbs neutralized all the BVD virus isolates tested in this study, suggesting antigenic variations among BVD virus isolates.
Human cytomegalovirus (HCMV) is the most common cause of viral intrauterine infection and fetal damage largely due to maternal primary infection. Virological procedures which are able to detect HCMV fetal infection were evaluated. HCMV IgG antibodies were detected in 62.5% of the pregnant women and 1.47% had a primary infection. From March, 1992 to August, 1995, 29 seroconversions were observed, and in 64 other cases. HCMV IgM antibodies were detected in the first serological test. The mean IgG antibody avidity test (AI) was 31% for the 11 seroconversions tested and 74% in 32 cases where IgG and IgM HCMV antibodies were detected in the first serum. In the 29 HCMV seroconversions, 19 amniocentesis were carried out and 12 fetuses (41.4%) were infected in utero. In four amniotic fluids positive in culture and PCR, the fetus or newborns were infected and in one out of the two cordocentesis undertaken, hepatitis, anemia, and thrombocytopenia were noted. In four other cases, investigations seeking HCMV in amniotic fluid were negative whereas infants were infected at birth. Among the 64 cases with positive HCMV IgM and IgG antibodies detected in the first serological test, three fetuses were infected in utero, but no amniotic fluid was available in these cases. Amniotic fluids were studied in 39 cases, and HCMV detection by culture and PCR-hybridization was negative. HCMV DNA was detected in the maternal sera of five out of 21 pairs of seroconversions and in two cases on the first negative serum. The assay was also carried out on 50 of the 64 HCMV IgM positive sera. Two had detectable HCMV DNA.
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The detection of the bluetongue virus (BTV) by conventional methods is especially difficult and labour-intensive. Molecular diagnosis is also complex because of the high genetic diversity between and within the 24 serotypes of BTV. In the present study, two laboratories joined forces to develop and validate two new RT-qPCRs detecting and amplifying BTV segments 1 and 5. The 2 assays detect strains from all 24 serotypes. They both have a detection limit of 0.01 ECE50 and all 114 samples from BTV-free goats, sheep and cattle were negative. The two assays resulted in similar C(t) values when testing biological samples collected in sheep infected experimentally with a field strain of BTV from the Mediterranean basin. On average, the C(t) values obtained with the 2 methods applied to the 24 serotypes were not significantly different from each other, but some moderate to high differences were seen with a few strains. Therefore these two methods are complementary and could be used in parallel to confirm the diagnosis of a possible new introduction of BTV. An RT-qPCR amplifying a fragment of the beta-actin mRNA was also developed and validated as internal control for the bluetongue specific assays. The three assays described allow a reliable and rapid detection of BTV.
In this study we have compared the use of PCR and conventional tissue culture methods to detect Epstein-Barr virus (EBV) in peripheral blood mononuclear cells and throat wash samples. The study population included 29 healthy adult and 20 immunocompromised EBV-seropositive donors. The results show significantly higher EBV detection rates by PCR than the tissue culture methods in throat wash samples from both donor groups (P < 0.01 in healthy donors and P < 0.009 in the immunocompromised donors) and in peripheral blood from the immunocompromised but not from the healthy donors (P < 0.008). Furthermore, when EBV DNA detection rates in throat wash cell pellet and supernatant fluid were compared, a higher positive result was obtained with the cell pellets which reached statistical significance in the immunocompromised group (P < 0.02). No correlation was found between positivity in throat wash and peripheral blood from the same donors.
An in situ hybridization protocol for detecting the herpes-like virus which infects French Pacific oysters, Crassostrea gigas, was developed. Two DNA probes were synthesized by incorporation of digoxigenin 11-dUTP during PCR. Two oyster herpes-like virus specific primer pairs, A5/A6 and C1/C6, were used. Both DIG-labelled probes were able to detect 50 pg of herpes-like virus PCR amplified DNA in Southern blot hybridizations. The probes hybridized with viral DNA in paraffin sections of infected C. gigas spat. No non-specific binding was observed. The ability of the defined in situ hybridization technique to diagnose herpes-like virus infections in oysters was compared with light and transmission electron microscopy techniques in infected and non-infected spat. In situ hybridization assays were also conducted on paraffin sections to determine virus distribution within the host and to study the pathogenesis infection. In situ hybridization confirmed that the expression pattern of the herpes-like virus was restricted to connective tissues as described previously by light and transmission electron microscopy. However, this technique also allowed the detection of viral DNA in the oyster nervous system. Some labelled cells were observed in the visceral ganglion of infected oyster spat.
To evaluate reliable methods for detection of hepatitis C virus (HCV) infection in routinely processed liver biopsies we analyzed formaldehyde-fixed and paraffin-embedded liver specimens of 10 patients with serological confirmed HCV infection. We compared (1) conventional histology; (2) indirect immunofluorescence using the mAb TORDJI-22 (Clonatec, Paris, France); (3) RT-PCR using total RNA and Southern blotting with chemiluminescent detection; (4) non-radioactive in-situ hybridization (ISH) with digoxigenin-labeled oligo- and cRNA probes; (5) direct in-situ RT-PCR with incorporation of labeled nucleotides into PCR-products, and (6) indirect in-situ RT-PCR using subsequent ISH for the visualization of intracellular PCR-products. Our results indicate that: (1) using the histological criteria described by Lefkowitch et al. [Gastroenerology 1993;104:595] together with clinical data, most chronic HCV infections can be diagnosed by conventional histology, if liver biopsies specimens are adequate; (2) the commercially available mAb TORDJI-22 appears to crossreact with non-HCV epitopes, resulting in false positives; (3) molecular methods performed on routinely fixed and processed liver biopsies frequently yield false negative results due to sampling problems, low viral copy number and RNA degradation in infected cells; (4) analysis of HCV-RNA by RT-PCR of extracted total RNA is more sensitive than indirect in-situ RT-PCR or ISH; and (5) direct in-situ RT-PCR is not reliable despite the use of modifications such as DNase pretreatment and hot-start procedures. It is concluded, that several molecular methods for HCV detection must await further improvements of protocols to be suitable for routine diagnostics on paraffin-embedded liver biopsies.
Multiple group-specific (gs) components of the avian leukosis-sarcoma viruses were detected by immunodiffusion (Ouchterlony) tests with sera from hamsters bearing tumors induced by sarcoma viruses and with sera from adult chickens immunized with avian sarcoma or leukosis viruses. Immune hamster sera detected up to four components, whereas chicken sera detected at least one. The hamster and chicken sera identified a similar antigen, as indicated by reactions of identity. Relatively few chicken sera containing neutralizing antibody to avian sarcoma or leukosis viruses reacted in immunodiffusion with the gs antigen. The gs components were released from the virion by various means of disruption, including freezing and thawing. Tests with tissues from normal chickens and from chickens with Marek's disease failed to demonstrate any reactions with hamster or chicken gs antiserum.
Serum samples from eight pregnant women and their offspring were studied by nested polymerase chain reaction (PCR) for detection of hepatitis C virus (HCV) RNA to evaluate mother-to-child transmission of this virus. The mothers were all infected with human immunodeficiency virus (HIV); none showed symptoms of HCV infection. Anti-HCV antibodies were tested for by recombinant immunoblot assay. HCV viral sequences were found in five of the mothers and four of eight children, three of them at birth. Viremia was persistent in one infant who had chronic transaminase elevation and persistently remained anti-HCV-positive. The other three babies had intermittent viremia; all were asymptomatic and lost anti-HCV antibodies during follow-up. This loss of antibodies was also observed in PCR-negative infants. Thus, these results demonstrate transmission of HCV from mother to child by women coinfected with HCV and HIV. They indicate the usefulness of PCR for direct and early detection of HCV viremia in neonates.
Polymerase chain reaction (PCR), virus culture (V), antigen detection (Ag), and in vitro antibody production (IVAP) assays may be useful for the early detection of vertically transmitted HIV-1 infection in infants under 18 months of age, when a diagnosis cannot be based on seropositivity because of maternal antibody persistence. To assess the reliability of these procedures and to correlate diagnostic results with infection status, 101 children born to HIV-1-seropositive mothers were evaluated by all these techniques within the first 6 months of life. The children were then followed up to the age of at least 18 months, when diagnosis was made on the basis of AIDS or AIDS-related complex (ARC) onset or persistence of HIV-1 seropositivity. Out of 27 children classified as infected according to the above criteria, 25 (92.5%) were repeatedly positive in IVAP test, 22 (81.5%) in the first PCR analysis, and only 19 (70.3%) in the initial V assay. On further testing, a total of 24 children (88.9%) were found positive in PCR assay, and 23 (85.2%) in V test. All these assays were found to be more sensitive than antigen detection for HIV-1 infection diagnosis, but the antigenaemia was shown to be a useful prognostic marker of disease onset. We also found that both Ag and IVAP assays could give false-positive results in the first 2 months of life, which severely limits their diagnostic value during this period of time. False-positive results in PCR assay could occur at any time of the tested period and were unrelated to the child's age.(ABSTRACT TRUNCATED AT 250 WORDS)
Assay for the antibody to the c100 protein (anti-c100) lacks sensitivity in terms of detection of hepatitis C virus (HCV) in all samples. The author used anti-c100 and antibody to the GOR epitope (anti-GOR) by the enzyme-linked immunosorbent assay to examine 524 patients with chronic liver disease and 682 volunteer blood donors in Fukuoka, Japan. The prevalence of HCV infection, as revealed by the presence of anti-c100 and/or anti-GOR, was 3.9% in 540 volunteer blood donors, 12.7% in 142 volunteers with abnormal liver function, 7.4% in 135 patients with HBsAg-positive liver disease and 89.5% in 389 patients with non-A, non-B (NANB) liver disease. These results show a higher prevalence than demonstrated only by the anti-c100 in NANB liver disease patients (82.5%, P < 0.01). The concurrence of anti-c100 and anti-GOR in subjects with HCV infection was 23.8% in 21 volunteer blood donors, 44.4% in 18 volunteers with abnormal liver function and 61.2% in 348 NANB liver disease patients. The concurrence seems to increase with deterioration of liver function. We concluded that combination assay for anti-c100 and anti-GOR demonstrated a more accurate prevalence of HCV infection than single assay for anti-c100 among NANB liver disease patients, and that the presence of anti-GOR plays a role in liver disease in anti-HCV-positive subjects.