Infectivity assay and neutralization test for influenza viruses in microplate cultures of a swine kidney cell line (SK-K).
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Animals↗
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A survey for arboviral antibodies in sera of humans and animals in Lombok, Republic of Indonesia.
Sera were collected from humans, cattle, horses, goats, ducks, chickens, wild birds, bats and rats in Lombok, Indonesia, and were tested by haemagglutination inhibition (HI) for antibodies to JE, ZIKA, CHIK and RR. Selected sera were tested by microneutralization tests for antibodies to the following viruses: JE, ZIKA, MVE, TMU, LGT, KUN, SEP, DEN-2, CHIK, RR, GET, SIN, BUN, BAT and BAK. Human sera had JE HI antibody in 135 (30%) of 446 tested. Neutralization tests indicated that DEN-2, ZIKA, TMU, KUN and SEP may have caused flavivirus infections. Antibodies to other arboviruses tested for were not found. HI and neutralization tests on animal sera indicated possible flavivirus infections with JE, MVE, KUN and SEP, and also that infections with BAT and BUN had occurred among domestic animals. No neutralizing antibodies were found for alphaviruses or other viruses used in the tests.
Alphavirus↗
Serologic and molecular biologic methods for SARS-associated coronavirus infection, Taiwan.
Severe acute respiratory syndrome (SARS) has raised a global alert since March 2003. After its causative agent, SARS-associated coronavirus (SARS-CoV), was confirmed, laboratory methods, including virus isolation, reverse transcriptase-polymerase chain reaction (RT-PCR), and serologic methods, have been quickly developed. In this study, we evaluated four serologic tests ( neutralization test, enzyme-linked immunosorbent assay [ELISA], immunofluorescent assay [IFA], and immunochromatographic test [ICT]) for detecting antibodies to SARS-CoV in sera of 537 probable SARS case-patients with correlation to the RT-PCR. With the neutralization test as a reference method, the sensitivity, specificity, positive predictive value, and negative predictive value were 98.2%, 98.7%, 98.7%, and 98.4% for ELISA; 99.1%, 87.8%, 88.1% and 99.1% for IFA; 33.6%, 98.2%, 95.7%, and 56.1% for ICT, respectively. We also compared the recombinant-based western blot with the whole virus-based IFA and ELISA; the data showed a high correlation between these methods, with an overall agreement of >90%. Our results provide a systematic analysis of serologic and molecular methods for evaluating SARS-CoV infection.
Antibodies, Viral↗
Candidate adenoviruses 40 and 41: fastidious adenoviruses from human infant stool.
About 200 antigenically related adenoviruses were isolated from cases of infantile diarrhoea in the Netherlands and North-West Germany. The viruses were fastidious and failed to replicate serially in human diploid fibroblasts and in primary human embryonic kidney cells. A number of strains were established in HeLa, HEp-2, Graham (293), cynomolgus monkey kidney, and Chang conjunctival cells. The viruses were mammalian adenoviruses by the usual criteria. No relationship to the 39 known human adenovirus species was found, either by neutralization tests or by haemagglutination inhibition tests. Neutralization tests showed two distinct variants, represented by strains Tak and Dugan. The variants were identical in haemagglutination inhibition tests. DNA restriction enzyme analysis showed Tak and Dugan to have considerably different genomes, indicating that these variants should be classified as different species (Wadell et al, 1983). It is proposed that the variants should be called Mastadenovirus h 40 (with reference strains Dugan and Hovi X) and Mastadenovirus h 41 (with reference strain Tak). Neutralization and haemagglutination inhibition tests demonstrated that the viruses from Glasgow and Helsinki (Hovi X) described by Johansson et al [1980] and by Kidd and Madeley [1981] belong to these two adenovirus species.
Adenoviridae Infections↗
[2 Unusual tests in tuberculosis. Neutral red test, an indirect method of evaluation of the virulence of the Koch bacillus].
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Bacillus↗
Characteristics of cell-mediated immunity after oral administration of a live influenza vaccine.
Development of immunological status of children after oral administration of a live influenza vaccine was followed using different tests of the cellular (blast transformation assay, identification of T, B and nil lymphocytes) and humoral (haemagglutination inhibition test, neuraminidase-inhibition test, neutralization test) immune response. Direct correlation was observed between the increase of neutralizing antibody and the lymphocyte stimulation indices in blast transformation assay (BTA). In vaccinated children the reactivity of lymphocytes was reduced and the amount of T lymphocytes decreased. The influenza vaccine has been shown to possess weak sensitizing properties.
Antibodies, Viral↗
Preliminary characterization of D'Aguilar virus and three Palyam group viruses new to Australia.
Between 1974 and 1980, 424 viruses were isolated at the Long Pocket Laboratories of the Division of Animal Health, CSIRO, either from insects or from the blood of sentinel cattle, and of these, 165 cross-reacted with D'Aguilar virus (an Australian Palyam group virus) in a complement fixation test. Neutralization tests were used to classify these viruses into four serotypes with the isolates D'Aguilar B8112, CSIRO 11, CSIRO 58 and CSIRO 82 as the type strains. The latter three were new to Australia. Like other orbiviruses, these four serotypes were partially sensitive to treatment with either or chloroform. Neutralizing antibodies against D'Aguilar, CSIRO 11 and CSIRO 58 viruses were detected in sera from cattle, buffalo, deer and sheep but not in sera from humans, horses, pigs or marsupials. Antibodies against CSIRO 82 virus were detected in 85% of 26 buffalo, and 0.4% of 495 cattle sera tested. The antibody distribution in Australia for D'Aguilar, CSIRO 11 and CSIRO 58 viruses fell within the distribution limits of Culicoides brevitarsis, the insect from which these viruses were most commonly recovered. The antibody distribution for CSIRO 82 virus, which was isolated from a pool containing C. schultzei and C. peregrinus, fell within the much more restricted distribution limits of these species. None of these viruses has been associated with disease.
Animals↗
[Etiology of aseptic meningitis prevalent in Xuzhou].
BACKGROUND: To find the pathogenic agents of aseptic meningitis prevalent in Xuzhou of Jiangsu province in 2001. METHODS: The enterovirus (EV) was cultured from CSF of the patients and identified with anti-serum by neutralization test. Neutralization titer of antibody in paired sera from meningitis children was determined. EV RNA was detected by RT-PCR. RESULTS: Four strains of Coxsackievirus B5, 2 strains of Coxsackievirus B3 and 1 strain of Echovirus 7 were isolated from 22 CSF specimens. The isolation rate of virus was 31.8% (7/22), 21 CSF were tested by RT-PCR, the positive rate of EV RNA was 52.4% (11/21); 57.9% (11/19) of patients paired-sera had over 4 folds antibody rise or became seroconverted. CONCLUSION: Enterovirus was the pathogenic agent of aseptic meningitis prevalent in Xuzhou of Jiangsu province, the main serotype of the virus was Coxsackievirus B5.
Antibodies, Viral↗
[Costs of influenza therapy].
The costs of outpatients with influenza. Outbreak of influenza occurs every winter in Japan and it brings a huge impacts on society and the individual. We calculated the costs of medications and medical examinations for outpatients with influenza in hospital. After we confirmed the diagnosis of influenza by rapid diagnosis system (Directigen Flu A) or hemagglutinin inhibition test, neutralization test, comparison of costs was done between influenza patients (89 cases) and non influenza patients (212 cases). Mean cost of total medication and medical examinations were 14,800 +/- 980 yen for an influenza patient and 12,420 +/- 976 yen for a non influenza patient. This data showed that treatment of the influenza patient is more expensive than non influenza patient. It must be considered that prophylaxis with influenza vaccine and treatment with antiinfluenza drugs given in the early stage of influenza are useful for reducing medical costs.
Adult↗
[A large-scale study on the safety and epidemiological efficacy of Japanese encephalitis (JE) live vaccine (SA14-14-2) in the JE endemic areas].
OBJECTIVE: To measure the safety and epidemiological efficacy of Japanese encephalitis live vaccine(SA14-14-2). METHODS: Guoyang and Mengcheng counties in Anhui Province, were chosen as observed spots where high incidence of JE was noticed in China. 1-6 years old children in two counties were inoculated with vaccine manufactured by Chengdu Biological Products Institute in the beginning of 1992. All children of 1-6 years old received one primary dose of live vaccine and the children at one or two years old were respectively given one dose for primary or booster vaccination in 1993-1996. Side effects of live vaccine had been under surveillance for five years for its safety JE cases during the epidemic season (Jun to October), were diagnosed clinically and serologically. RESULTS: Data on the safety and efficacy of the JE live vaccine(SA14-14-2) are listed as follows:1) During 1992-1996, a total number, of 335,941 children at 1-6 year old were vaccinated. No vaccine-associated encephalitis, meningitis or other serious adverse events were observed. 2) The incidence of JE case has greatly declined since the beginning of large-scale vaccination. The average JE morbidity dcreased from 11.34/100,000 in 1987-1991 to 2.74/100,000 in 1992-1996(P < 0.005). 3) The incidence of JE case in 1-6 years old in that period reduced as well. The average JE morbidity decreased from 56.24/100,000 to 13.83/100,000 in Guoyang and from 44.57/100,000 to 16.94/100,000 in Mengcheng counties respectively(P < 0.005). Most of the JE cases (94%) occurred in the unvaccinated children including all the 18 death cases. 4) Serum antibody response to immunization were measured by plaque reduction neutralization test. Neutralizing antibody seroconversion after one single vaccination were 83.87%-94.74%. CONCLUSION: The results further confirmed that JE live vaccine is safe for children and effective for prevention from JE disease in JE endemic areas.
Antibodies, Viral↗
West Nile virus: the Indian scenario.
West Nile virus (WNV) is an important arthropod borne flavivirus; usually causes a mild infection called West Nile fever (WNF) in human and horses. Mosquitoes are the principal vectors of WNV. Various Culex species are found to act as vectors in different geographical regions. The virus is maintained in a bird-mosquito cycle in nature. In India, Culex mosquitoes are tentatively incriminated as vectors of WNV. Experimental studies have shown that Culex tritaeniorhynchus, Cx. vishnui, Cx. bitaeniorhynchus and Cx. univittatus, Culex pipiens fatigans and Aedes albopictus could act as potential vectors of WNV. Transovarial transmission of WNV has been experimentally demonstrated in Culex mosquitoes. Apart from mosquitoes, the role of other arthropods is also considered in the maintenance of WNV during inter-enzootic periods. The possible role of ardeid birds in the maintenance of WNV has been described in India. Though very few clinically overt cases of human encephalitis due to WNV are observed, Japanese encephalitis virus (JEV) is found to dominate in southern India. WNF in horses has not been documented in India. JEV immunized monkeys were protected from WNV challenge and the WNV immunization was found to reduce the disease severity due to JEV. Based on the limited genome sequence analysis, the Indian isolates are grouped together under the genetic lineage-I. WNV infection is diagnosed by IgM antibody capture enzyme linked immunosorbant assay, haemagglutination inhibition test, neutralization test and reverse transcriptase-polymerase chain reaction (RT-PCR). For the effective control of Culex mosquitoes, integrated vector control strategies are recommended. Specific methods are not available for the treatment of WNV infection. However, in patients with encephalitis supportive therapy is recommended. Though a few candidate vaccines are under laboratory trial, no vaccine has been available commercially for the control of WNV infection in human and animals. In view of the global interest on WNV, this paper describes the present status of WNV in India.
Animals↗
[The prevalence of serum anti-hepatitis C virus antibodies in hemodialyzed patients].
Hepatitis C virus (HCV) is responsible for a high percentage of cases of transfusional hepatitis and is often considered the etiological agent of numerous cases of non-A, non-B hepatitis in which parenteral transmission has not been documented. Patients undergoing hemodialysis are at risk for HCV infection. We used an immunoenzymatic method and confirmatory test (neutralization test) to determine serum anti-HCV antibody positivity in order to identify the factors associated with increased risk of HCV infection. We studied 63 hemodialyzed patients from eastern Sicily and compared the mean dialytic age and transfusion case history in positive and negative groups. 17.4 percent of the patients were anti-HCV positive. Mean dialytic age was significantly higher in the anti-HCV positive group. On the contrary no significant differences regarding transfusion case history or number of units of blood transfused were seen in the two groups. Our study confirms that hemodialyzed patients are at risk for HCV infection. This risk seems to increase with dialytic age. The lack of correlation between HCV and transfusion case history suggests that it may be a hospital-acquired infection.
Age Factors↗
Search for intrafamilial transmission of hepatitis C virus in hemophilia patients.
This study was performed to determine the risk of family members of anti-hepatitis C virus (HCV)-positive hemophilia patients (index patients) for infection with HCV compared with the risk of acquiring hepatitis B virus (HBV), human immunodeficiency virus (HIV), and hepatitis A virus (HAV) infection. All index patients (n = 141) were found to be positive by first and second generation anti-HCV enzyme immunoassays (EIAs). Among their household contacts (n = 228), 224 were negative and 1 positive by both assays. Three contacts gave positive results in first generation anti-HCV EIA and negative results in second generation assay. This latter result was confirmed by further tests (neutralization test, synthetic peptides, and supplemental assay). Percent positivity for anti-HBc was about the same in non-sexual household contacts and sexual partners (13 of 109 [12%] and 7 of 54 [13%], respectively). Percent prevalence of anti-HBc was higher in contacts of index patients with chronic hepatitis B than in those of index patients who had recovered from that disease (6 of 20 [30%] and 14 of 133 [10%], respectively; P < .05). The HBV infection rate of contacts participating in controlled self-treatment was not higher than that of controls (3 of 57 [5%] and 10 of 98 [10%], respectively). Of 44 sexual partners, 5 (11%) were found to be positive for anti-HIV. Prevalence of anti-HAV matched with the age-related distribution in the German population. These findings suggest that intrafamilial transmission of HCV to family members of hemophilia patients is uncommon. In contacts of hemophilia patients, the risk of acquiring HBV infection seems to be as high in household contacts as in sexual contacts. Participation in controlled self-treatment does not appear to be an additional risk for HCV and HBV infection. There is no doubt that sexual transmission of HCV is less common than that of HBV and HIV.
Adolescent↗
Hepatitis C core antigen in Polish blood donors.
BACKGROUND: The goal of this study was to evaluate the feasibility of adopting the HCV core antigen ELISA (HCVcAg) for routine screening of Polish blood donors. STUDY DESIGN AND METHODS: A total of 133,279 donor samples were tested by ORTHO HCVcAg. All repeatedly reactive (RR) samples were tested by neutralization test for confirmation, RIBA HCV for anti-HCV, and by Cobas Amplicore for HCV RNA. All donations were tested for ALT level. RESULTS: The HCVcAg test specificity was 99.94 percent. In total, 1499 donations (1.12%) were initially reactive and 124 (0.09%) were RR. Antibodies to HCV were found in 22 out of 124 donors and HCV RNA was detected in 19 out of 22. In 10 out of the 19 HCV-RNA-positive donors, the HCVcAg neutralization test was positive. Among the 102 HCVcAg RR/anti-HCV-negative donors, there were 6 neutralization-test-positive individuals, and all were HCV RNA positive. Elevated ALT level was observed in one of them. During the follow-up studies of three HCVcAg RR/HCV-RNA-positive donors, seroconvertion was observed 5 to 7 weeks after the initial HCVcAg-positive result. In all, HCVcAg results became negative once antibodies to HCV were detected. CONCLUSION: The HCVcAg test proved to be feasible for routine screening in the Polish Blood Transfusion Service. Six HCVcAg RR/anti-HCV-negative donors were identified. The calculated residual risk in this study of donors in the preseroconversion window was 45 per million. Mandatory testing of every blood and plasma donation for HCVcAg or HCV RNA was recommended as of January 2, 2002.
Blood Donors↗
Antibody response in humans to influenza virus type B host-cell-derived variants after vaccination with standard (egg-derived) vaccine or natural infection.
Hemagglutination inhibition (HI) and neutralization tests were used to determine antibody responses to egg-derived and Madin-Darby canine kidney (MDCK)-derived influenza B virus (B/England/222/82) in paired sera from persons naturally infected with influenza B and in persons vaccinated with standard egg-derived inactivated influenza vaccine. When tested by HI, the MDCK-derived antigen gave significantly higher (8- to 12-fold) geometric mean titers (GMT) in convalescent-phase sera from persons naturally infected during community outbreaks, as well as more 4-fold titer rises, than did tests with egg-derived antigen. When tested by neutralization, however, the convalescent-phase sera GMTs were only threefold higher with the MDCK-derived antigen and an equivalent number of fourfold titer rises were detected with both antigens. With postvaccine sera, the MDCK-derived antigen gave GMTs that were threefold higher than those obtained with egg-derived antigen in both the HI and neutralization tests and both antigens detected an equivalent number of fourfold titer rises in HI and neutralization tests. Sucrose gradient-fractionated egg-derived antigen showed a single peak of hemagglutinin activity corresponding to whole virions, whereas MDCK-derived antigen contained two distinct peaks of hemagglutinin activity, one of which had a lower sedimentation rate. The overall findings indicate that the egg-derived antigen in the vaccine induced HI and neutralizing antibody to both egg- and MDCK-derived variants and suggest that titers of antibody to MDCK-derived virus may be affected by the physical form of the hemagglutinin antigen.
Animals↗
Evidence of serologic diversity within group C rotaviruses.
The Cowden strain of porcine group C rotavirus and the Shintoku strain of bovine group C rotavirus were classified as different serotypes by two-way cross-neutralization tests. Two neutralization patterns against the Cowden and Shintoku strains were observed when hyperimmune or convalescent-phase antisera to three noncultivatable porcine group C rotaviruses and a human group C rotavirus were used in one-way cross-neutralization tests. Antisera to two porcine group C rotaviruses and the human group C rotavirus neutralized the Cowden strain at high titers but did not neutralize the Shintoku strain, suggesting that these three strains are serotypically related to the Cowden strain. The remaining antisera to a porcine group C rotavirus (HF strain) reacted with the Cowden and Shintoku group C rotaviruses in cell culture immunofluorescence tests but did not neutralize either virus in one-way cross-neutralization, suggesting that the HF strain belongs to a third serotype. However, confirmation of these findings requires additional analysis by two-way cross-neutralization. Our findings support the existence of at least two distinct serotypes of group C rotaviruses, and possibly a third, among animals and humans. The serotypic similarity observed between the Cowden strain and a human group C rotavirus suggests that the cultivatable Cowden strain and antiserum to this virus may provide important reagents for the diagnosis of group C rotaviruses in humans.
Animals↗
[Detection of bovine leukemia virus antibodies using the cytotoxicity test in comparison with other serologic methods].
In ninety-five serum samples taken in a herd of five-year to seven-year cattle that was heavily infected by bovine leukosis virus, the four serological assays were used for demonstration of the antibodies to bovine leukosis virus; cytotoxic test, immunodiffusion test in agar-agar, immunoenzymatic test and serum neutralizing test. The serum neutralizing test was found to be the most sensitive: further seven positive reagents were diagnosed in comparison with immunoenzymatic test; cytotoxic and immunodiffusion tests in agar-agar have the lowest sensitivity and the results of these tests are almost identical. It was found out in forty titrated samples that serum neutralizing test was by as much as 20 times more sensitive than immunoenzymatic test, the latter being about 50 times more sensitive than cytotoxic and immunodiffusion tests.
Antibodies, Viral↗
[Possibilities and limitations of the direct radioimmunological method with double guinea-pig antibody in the detection of serum Australia antigen].
The results obtained with the direct radioimmunological method and electrosyneresis in the search for Australia antigen were compared in 3100 donor sera. In a limited number of sera, the positivity of radioimmunological examination was tested by neutralization tests with human antibody and with the serum of normal guinea-pigs. Electrosyneresis proved positive in 4% of cases, while radioimmunological examination produced a clearly positive result in 6.7% of cases and a faintly positive or doubtful result in 1.8%. The presence of doubtful results is due to the fact that the distribution of values obtained shows some overlapping between normal population and population of subjects carrying the antigen. The neutralization tests have shown a high incidence (45%) of aspecific positivity between the sera proving positive at radioimmunological examination and negative at electrosyneresis. This inconvenience should be resolved by the recent introduction of a radioimmunological method which provides for use of labelled antibody of human origin.
Animals↗