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PubMed2000

Characterization of a virus obtained from snakeheads Ophicephalus striatus with epizootic ulcerative syndrome (EUS) in the Philippines.

This is the first report of the isolation and characterization of a fish virus from the Philippines. The virus was isolated using snakehead spleen cells (SHS) from severely lesioned epizootic ulcerative syndrome (EUS)-affected snakehead Ophicephalus striatus from Laguna de Bay, in January 1991. The virus induced cytopathic effects (CPE) in SHS cells yielding a titer of 3.02 x 10(6) TCID50 ml(-1) at 25 degrees C within 2 to 3 d. Other susceptible cell lines included bluegill fry (BF-2), catfish spleen (CFS) and channel catfish ovary (CCO) cells. Replication in chinook salmon embryo cells (CHSE-214) was minimal while Epithelioma papulosum cyprini cells (EPC) and rainbow trout gonad cells (RTG-2) were refractory. Temperatures of 15 to 25 degrees C were optimum for virus replication but the virus did not replicate at 37 degrees C. The virus can be stored at -10 and 8 degrees C for 30 and 10 d, respectively, without significant loss of infectivity. Viral replication was logarithmic with a 2 h lag phase; viral assembly in the host cells occurred in 4 h and release of virus occurred 8 h after viral infection. A 1-log difference in TCID50 titer between the cell-free virus and the total virus was noted. Freezing and thawing the virus caused a half-log drop in titer. Viral exposure to chloroform or heating to 56 degrees C for 30 min inactivated the virus. Exposure to pH 3 medium for 30 min resulted in a more than 100-fold loss of viral infectivity. The 5-iododeoxyuridine (IUdR) did not affect virus replication, indicating a RNA genome. Neutralization tests using the Philippine virus, the ulcerative disease rhabdovirus (UDRV) and the infectious hematopoietic necrosis virus (IHNV) polyvalent antisera showed slight cross-reaction between the Philippine virus antiserum and UDRV but established no serological relationship with SHRV and IHN virus. Transmission electron microscopy (TEM) of SHS cells infected with the virus showed virus particles with typical bullet morphology and an estimated size of 65 x 175 nm. The Philippine virus was therefore a rhabdovirus, but the present study did not establish its role in the epizootiology of EUS.

Animals↗
PubMed1990

Enzyme-linked immunosorbent assay for detection of IgG antibody to human herpesvirus 6.

A lysate of human herpesvirus 6 (HHV-6)-infected cord blood mononuclear cells was used as antigen for enzyme-linked immunosorbent assay for the detection of IgG antibody to HHV-6. Antibody responses after exanthem subitum were well correlated with clinical recovery from the disease and the level of antibody activities was well correlated with indirect immunofluorescence assay and the neutralization test. Seroconversion to other human herpesvirus, including cytomegalovirus, was not observed in infants with exanthem subitum. All of the infants had by the age of 1 month antibodies to HHV-6, which decreased with age to the lowest level at the age of 3 to 6 months and then increased and reached the maximum level by 1 to 2 years of age. After 3 years of age, the prevalence was almost stable.

Adolescent↗
PubMed1999

Dobrava virus infection: serological diagnosis and cross-reactions to other hantaviruses.

Recent data have shown that Dobrava (DOB) hantavirus is the cause of severe haemorrhagic fever with renal syndrome (HFRS) in central and eastern Europe. To determine whether serological assays need to be based on the homologous viral antigen rather than on closely related hantavirus antigens, acute and convalescent sera from patients with HFRS collected in former Yugoslavia were examined for IgM and IgG to three hantavirus antigens; DOB, Hantaan (HTN) and Puumala (PUU). Focus reduction neutralization test was included for comparison and confirmation of the enzyme-linked immunosorbent assay (ELISA) results. Although the results showed that the cross-reactivity was high between these three antigens during the acute phase of the disease, one of 155 patients serum samples reacted only in the DOB antigen-based IgM assay. The evaluation of IgG reactivities revealed that a DOB antigen-based IgG ELISA has to be used in sero-epidemiological studies; 7.1% (11/155) of the acute phase/early convalescent sera and 12.5% (2/16) of the late convalescent sera, respectively, reacted only with the homologous DOB antigen.

Convalescence↗
PubMed2002

Serological divergence of Dobrava and Saaremaa hantaviruses: evidence for two distinct serotypes.

In order to investigate the serological relationship of Dobrava hantavirus (DOBV, originating from Slovenia) and the Dobrava-like Saaremaa virus (SAAV, recently discovered in Estonia) we analysed 37 human serum samples, 24 from Estonia and 13 from the Balkans, by focus reduction neutralization test (FRNT). Most of the Estonian sera (19), including all sera from Saaremaa island (12), reacted with higher FRNT end-point titres to the local SAAV; the majority of them (15 and 11, respectively), with at least fourfold or higher titres to SAAV than to DOBV. In contrast, out of the 13 sera collected in Slovenia, Bosnia-Herzegovina and Greece, only one reacted more strongly with SAAV (with a twofold higher titre), while 10 of these sera reacted more strongly with the local DOBV (9/10 with fourfold or higher titres). These results indicate that DOBV and SAAV define unique hantavirus serotypes.

Bosnia and Herzegovina↗
PubMed1976

Radiculomyelitis following acute haemorrhagic conjunctivitis.

The clinical manifestations and natural history of radiculomyelitis following a newly reported disease--acute haemorrhagic conjunctivitis (AHC)--have been studied in 33 patients in Taiwan, and the following observations made: All the patients in this series were adults at ages ranging from 21 to 55 years; the salient initial neurological manifestations were radicular pains and acute flaccid paralysis which developed from five to thirty-seven days after the onset of AHC. In some patients, signs and symptoms indicating involvement of the meninges, cranial nerves and the white matter of the cord were observed; motor paralysis was the most striking feature during the whole clinical course; it consisted of flaccid asymmetrical weakness in one or more limbs, usually being more severe in the lower limbs than in the upper, and often more proximal than distal. Atrophy in the severely affected muscles usually became apparent in the second or third week of the weakness; the prognosis regarding the return of function in the affected muscles was dependent on the severity of the involvement. Permanent incapacitation due to paralysis and muscular atrophy in the affected proximal muscles of lower limbs was the main sequel in severe cases. The pattern and prognosis of flaccid motor paralysis were reminiscent of acute poliomyelitis in which the anterior horn cells of the spinal cord are mainly involved. Pleocytosis ranging from 11 to 270 per mm3 was noted in the majority of the patients when the cerebrospinal fluid was examined within the first three weeks from the onset of neurological symptoms; the total protein level was raised invariably from the second week onwards in all specimens, and remained so throughout the subsequent course as long as the seventh week or later. Tissue culture neutralization tests were performed on the sera from 9 patients; significant rises in the antibody titres (greater than or equal to 1:16) to AHC virus antigens were found in 8 cases, and in 2 of them a fourfold rise in the paired sera was noted. The differentiation of this syndrome from poliomyelitis and from Guillain-Barré syndrome, the relative freedom of children from neurological complications of AHC and the aetiological relationship of AHC virus to the syndrome have been discussed. It is concluded that this unusual neurological syndrome is caused by the neurovirulent properties of the AHC virus.

Adenoviruses, Human↗
PubMed2002

PCR-RFLP based molecular typing of enteroviruses isolated from patients with aseptic meningitis in Korea.

We have evaluated PCR-RFLP as a practical method for rapid typing of enteroviruses causing aseptic meningitis in Korea. Through blind examination of 80 clinical isolates from patients with aseptic meningitis, we have compared the results of conventional serotyping with PCR-RFLP based genotyping, which was developed for this study. Among the 80 case isolates, which had been previously typed by routine neutralization test, only 42 cases (52.5%) were matched with typing by PCR-RFLP. The result clearly demonstrated that the enterovirus serotype does not coincide with the genotype. Therefore, the classification of enteroviruses by genotyping with PCR-RFLP, although rapid and simple, may be complicated by regional or seasonal differences. However, the PCR-RFLP method developed in this study is applicable to the epidemiological study of enteroviruses when regional or seasonal differences exist, and is useful in identifying the source of an infection.

Enterovirus↗
PubMed1999

Protective immune response to 16 kDa immunoreactive recombinant protein encoding the C-terminal VP1 portion of Foot and Mouth Disease Virus type Asia 1.

Recombinant protein of Foot and Mouth Disease Virus (FMDV) type Asia 1 corresponding to the C-terminal half of VP1 was expressed in Escherichia coli. As an alternative to the synthetic peptide, this selected C-terminal region was used as a protein vaccine in guinea pigs in order to study the immune response with various adjuvant formulations: immune stimulatory complexes (ISCOMs), Montanide ISA 206, Freund's incomplete adjuvant (FIA), lipopolysaccharide (LPS) and cytokine mixture. A primary dose of 40 microg/animal followed by a booster of the same dose was injected after a 21-day interval. The sera were collected at intervals of 21, 42 and 63 days after the booster. The humoral response to vaccine was monitored by sandwich enzyme-linked immunosorbent assay (ELISA) and a serum neutralization test (SNT). The guinea pig sera showed high titers both in ELISA and SNT, which could be protective. Further, irrespective of the adjuvant preparation used, the vaccine conferred protection against the challenge virus 105 days post-vaccination in 13 of 15 animals (86%). The results indicated that a combination of recombinant protein ISCOMs and Montanide ISA 206 would be a better choice for achieving early protective titers and longer lasting immunity and that the C-terminal half of the VP1 protein may be tried as a safe vaccine for secondary immunization.

Animals↗
PubMed1978

[Aujeszky's disease. Studies on the possibility of differentiating between contaminated pig-breeding farms and farms on which the pigs have been inoculated with the Bartha vaccine (author's transl)].

The serological studies reported in the present paper were done on forty-one pig-breeding farms contaminated with Aujeszky's disease and four farms that were free from this disease and on which fifty per cent of the animals had been inoculated with the Bartha vaccine. The serological studies were based on the serum neutralization test (SN test). On contaminated farms, the majority of the animals present at the time of outbreak of the disease were serologically positive. Comparison of the serological findings on farms on which there had been outbreaks of the disease from two to seven and from seven to twelve months previously, showed that there was hardly any difference in titre levels between the two groups. Of twenty-eight breeding boars used for service at the time of the outbreak, twenty-one per cent were serologically negative. Serological studies in breeding gilts showed that virulent virus was only transmitted up to two months after the outbreak of the disease.

Animals↗
PubMed1978

Secretory antibody responses in cattle infected with foot-and-mouth disease virus.

Antibody responses in serum, saliva, nasal secretions, or esophageal-pharyngeal fluid of foot-and-mouth disease virus-infected steers were examined by single radial immunodiffusion and mouse-neutralization tests. In steers infected with type O foot-and-mouth disease virus, high serum antibody titers were detected within 10 days after infection. Antibody was first detected in saliva at 30 days and gradually increased to a plateau at about 90 days. Small amounts of antibody continued to be secreted in saliva and in nasal secretions for at least 6 months. Antibody was not detected in esophageal-pharyngeal fluid. The major antibody activity in secretions was due to secretory immunoglobulin A as revealed by radioimmunoelectrophoresis.

Animals↗
PubMed2003

Seroprevalence of neutralizing antibodies to measles virus in a vaccinated population in Iran, 1998.

Measles is an acute highly infectious viral disease. Although live attenuated vaccine is used throughout the world, outbreaks of disease still occur in many countries including Iran. In this cross-sectional study, by implementing a viral neutralization test and cell culture techniques, the seroprevalence of neutralizing anti-measles antibodies was assessed. Three hundred and fifty-four blood samples were collected and random-cluster classified from healthy subjects 6 months to 16 years old, residing in the town of Khodabandeh and its rural areas. Of the total subjects, 174 (49.2%) were girls and 180 (50.8%) were boys. From 354 subjects studied, 310 (87.6%) had neutralizing anti-measles antibody titer of 1:8 or higher and were considered to be immune and 44 (12.4%) had lower antibody titers. At the time of specimen collection, information with regards to age, sex, history of vaccination and place of residence were collected. Chi2 statistical test demonstrated a significant association between immune status and grouped age at the time of first vaccination (p < 0.009). The proportion test indicated significant differences in rate of seropositivity in paired age groups (3-8 vs. 9-11 and 9-11 vs. 12-64 months) (p < 0.02). The use of reliable techniques for assessing success of vaccination programs and performing seroepidemiological studies in order to organize national programs of control and eradication of measles are necessary.

Antibodies, Viral↗
PubMed1987

Detection of serum antibody responses to RIT 4237 rotavirus vaccine by ELISA and neutralization assays.

Immunoglobulin class-specific determination by ELISA and a virus neutralization test (NT) were compared for the detection of the serum antibody responses after vaccination of infants with the RIT 4237 rotavirus vaccine (of bovine origin). A capture method was applied for specific IgM determination by ELISA because of its greater sensitivity and reproducibility over the conventional ELISA-IgM test. NT was improved through the use of an enzyme-labelled antibody for the detection of non-neutralized virus. In 6-12-month-old children, the most sensitive single test to detect an antibody response was the ELISA-IgM capture method, but the combination of ELISA-IgM and IgG tests or ELISA-IgM and NT detected the highest seroconversion rate of 79%. In newborn infants high levels of maternal antibody made the ELISA-IgG test unsuitable. ELISA-IgM gave a response rate of 31%, but NT with homologous virus was the most sensitive indicator of a serological response to the vaccine in this age group, yielding a 45% response rate.

Antibodies, Viral↗
PubMed2004

Longitudinal studies of West Nile virus infection in avians, Yucatán State, México.

Following the introduction of West Nile virus (WNV) into North America in 1999, surveillance for evidence of infection with this virus in migratory and resident birds was established in Yucatán State, México in March 2000. Overall, 8611 birds representing 182 species and 14 orders were captured and assayed for antibodies to WNV. Of these, 5066 (59%) birds were residents and 3545 (41%) birds were migrants. Twenty-one (0.24%) birds exhibited evidence of flavivirus infection. Of these, 8 birds had antibodies to WNV by epitope-blocking enzyme-linked immunosorbent assay. Five (0.06%) birds (gray catbird, brown-crested flycatcher, rose-breasted grosbeak, blue bunting and indigo bunting) were confirmed to have WNV infections by plaque reduction neutralization test. The WNV-infected birds were sampled in December 2002 and January 2003. The brown-crested flycatcher and blue bunting presumably were resident birds; the other WNV seropositive birds were migrants. These data provide evidence of WNV transmission among birds in the Yucatán Peninsula.

Animal Migration↗
PubMedDate not supplied

Identification and analysis of the Georgia 98 serotype, a new serotype of infectious bronchitis virus.

Twenty-five field infectious bronchitis viruses (IBVs) similar to, but genetically distinct from, the DE072 serotype were isolated from several states in the United States from 1990 through 1999 and were examined molecularly and antigenically. A 421-bp sequence in the hypervariable region of the S1 gene was examined, and phylogenetic analysis on that region indicated that these viruses are closely related but fall into unique groups. Cross-virus neutralization testing and entire S1 sequence analysis on selected isolates further confirmed that fact, and we divided the viruses into the DE072 serotype and two other unique groups. In a vaccine protection trial, the commercially available DE072 vaccine showed less than 50% protection against viruses in one of the groups. The majority of the recent isolates belong to that group and share very low antigenic relatedness to the DE072 strain as well as other serotypes of IBV. Consequently, we designated this group as a new serotype, Georgia 98. We developed a restriction fragment length polymorphism analysis that can differentiate this new serotype from all other serotypes of IBV.

Animals↗
PubMed2006

Measles-virus-neutralizing antibodies in intravenous immunoglobulins.

Measles infection induces lifelong immunity; however, wild-type infection stimulates higher levels of measles-virus-neutralizing antibodies (mnAbs) than does vaccination. Because the proportion of the donor population with vaccine-induced measles immunity is increasing, this study was conducted to determine whether this shift in demographic characteristics affects mnAb levels in contemporary lots of Immune Globulin Intravenous (Human) (IGIV). When 166 lots of 7 IGIV products manufactured between 1998 and 2003 were assayed by plaque-reduction neutralization test, there was a progressive decrease in geometric mean titers in lots manufactured between 1999 and 2002. IGIV products manufactured from recovered plasma had significantly higher titers than did those manufactured from Source Plasma, which could reflect a change in donor demographic characteristics, because Source Plasma donors tend to be much younger. A reduction in mnAbs also correlated with the loss of either IgG1 and IgG3, possibly because of certain manufacturing procedures, or bivalent antibodies (i.e., intact IgG and F(ab')2), because of fragmentation.

Antibodies, Viral↗
PubMed1986

Bovine herpesvirus 1: molecular and antigenic characteristics of variant viruses isolated from calves with neurological disease.

This report presents data showing that several virus isolates recovered in Argentina, mainly from calves with non-purulent meningo-encephalitis, represent a hitherto unrecognized antigenic variant of BHV-1. The following experimental approaches have been adopted to demonstrate both the unique features among and the relatedness with BHV-1 of these isolates: i) crossed serum neutralization test with rabbit immune sera, ii) analysis by SDS-polyacrylamide gel electrophoresis of radio-labeled virus induced polypeptides and glycoproteins, iii) discriminating reactivity of a panel of monoclonal antibodies which recognize known virus types, and iv) restriction endonuclease analysis of viral DNA. Another strain of BHV-1, which exhibits a specific neuropathogenic potential [Hall et al., Austral. Vet. J. 42, 229-237 (1966)] shares all major features with the viral strains originating from Argentina. Our results imply that antigenic variants of BHV-1 exist and that they can be accurately and easily identified and differentiated by the available methods.

Animals↗
PubMed1996

Khabarovsk virus: a phylogenetically and serologically distinct hantavirus isolated from Microtus fortis trapped in far-east Russia.

Two hantavirus strains, MF43 and MF113, isolated from Microtus fortis trapped in the Khabarovsk region of far-eastern Russia, were analysed by direct nucleotide sequencing of PCR generated fragments of the M and S segments, by immunofluorescence and by focus reduction neutralization tests (FRNT). The nucleotide sequences revealed that the two isolates were closely related to each other but distinct from all other hantaviruses. Phylogenetic analysis of the M and S segments showed that the MF strains form a separate branch in the Hantavirus tree, positioned between the branches of Prospect Hill and Puumala viruses. The strains were shown to be serologically distinct from the other hantavirus serotypes by FRNT using immune rabbit sera. Puumala virus was the closest relative, both genetically and serologically. We propose that this new hantavirus serotype should be named Khabarovsk (KBR).

Animals↗
PubMed2001

[Detection of Arcanobacterium haemolyticum phospholipase D neutralizing antibodies in patients with acute tonsillitis].

Neutralization test carried on a non-nutrient blood agar prepared from sheep erythrocytes sensibilized with equi factor of Rhodococcus equi was used for the detection of antibodies against phospholipase D (PLD) of Arcanobacterium haemolyticum. Altogether, 433 sera from 404 patients aged 1 to 25 years with the signs of acute tonsillitis were examined. Antibodies against PLD were found in 28 patients (6.9%). In 116 sera from persons without the signs of tonsillitis the antibodies against PLD were detected in one case (0.9%). The titres reached the values from 4 to 64. Out of 84 paired sera, the significant change of the titre, i.e. at least the four-fold one, was observed five times: three times as the seroconversions, twice as the declines of the titre. The antibodies were found most often in children aged 11 to 15 years, 10 times out of 97 (10.3%). In 253 patients with the tonsillitis, the result of the parallel bacteriologic examinations of throat swabs was at the disposal. A. haemolyticum was successfully isolated in 3 cases, but only owing to the inhibition of staphylococcal hemolysis around its colonies. All three cases were also serologically positive. Consequently, our results show that neutralizing antibodies against PLD of A. haemolyticum can be detected in patients with tonsillitis.

Actinomycetales↗
PubMed1984

Ockelbo disease in Sweden: epidemiological, clinical, and virological data from the 1982 outbreak.

An outbreak of Ockelbo disease, a syndrome with rash, arthralgia and moderate fever reactions, which occurred in Sweden 1982 is described. A virus, designated Edsbyn 5/82, isolated from mosquitoes and closely related to Sindbis virus (Togaviridae: Alphavirus) is the probable etiologic agent. Sixty-five patients with typical clinical manifestations of the disease became ill in August 1982 and exhibited antibody titer rises against both Edsbyn 5/82 and Sindbis viruses by indirect immunofluorescence and the mixed hemadsorption technique. With the latter method, but not by the neutralization tests, antibody titers were significantly higher against Edsbyn 5/82 virus than against Sindbis virus. Most cases occurred in central Sweden between the 60th and 63rd parallels. The frequency of antibody in healthy individuals (blood donors) within the endemic area was 2-3% and in foci with high incidence, antibody positivity reached 8%. Antibody frequencies continuously decreased south and north of this area. Antibody decline was followed in a group of 12 patients who had Ockelbo disease in 1981. Mixed hemadsorption titers were 4-6 times higher against Edsbyn 5/82 than against Sindbis virus. A 2- to 4-fold antibody decline took place from early convalescence to 20 months after onset.

Adolescent↗