Showing papers on "Influenza A virus published in 1975"

Plaque assay and primary isolation of influenza A viruses in an established line of canine kidney cells (MDCK) in the presence of trypsin.

Abstract: A wide variety of influenza A viruses, comprising human, equine, porcine, and avian strains, grew productively in an established line of canine kidney cells (MDCK) under an overlay medium containing trypsin, and formed well-defined plaques regardless of their prior passage history. Plaquing efficiency was comparable to the efficiency of infection in fertile eggs via allantoic route. MDCK cells have also been successfully employed for the primary isolation of influenza A virus from throat washings of patients. Parallel titration of several clinical specimens showed that the inoculation into MDCK cells followed by incubation in the presence of trypsin was an isolation procedure as sensitive as the amniotic inoculation into fertile eggs.

Clinically Useful Method for the Isolation of Respiratory Syncytial Virus

Abstract: A simple method for the isolation of respiratory syncytial virus (RSV) is reported; it is relatively rapid and results in a high frequency of recovery of virus. A nasal secretion specimen with high titers of virus is inoculated at the bedside onto susceptible cell lines to avoid loss of viral infectivity due to liability of the virus. During an outbreak of RSV, viral specimens were obtained by this method from all young children admitted to the hospital with lower respiratory tract disease. RSV or influenza A virus was recovered from 89% of these 45 children. RSV was isolated from 87% of those with pneumonia. RSV was recovered 60% less often from specimens obtained simultaneously by conventional nasopharyngeal swabs. Identification of RSV cytopathic effect was more rapid with use of the bedside nasal wash method and was accomplished in an average of four days. Hence, this information was available to the clinicician when it was still useful in the management of the patient's illness.

Nosocomial influenza infection as a cause of intercurrent fevers in infants.

Abstract: All patients on an infants9 ward manifesting intercurrent fevers were studied for viral and bacterial etiology during a community outbreak of influenza A During a one-month period, of 29 infants admitted to the ward, 17 were hospitalized for seven or more days Intercurrent fever complicated the course of 13 (76%) of these 17 infants Nosocomially acquired influenza A infection was found in 12 (92%) of the 13 infants Two of these also contracted a dual infection with influenza B The fever lasted an average of 27 days with a peak of 382 to 398 C Initial white blood cell counts tended to be high and Shifted to the left These infants appeared to be at high risk for developing lower respiratory tract disease Seven of the 12 had infiltrates on chest X-ray, and five subsequently developed a secondrly bacterial pneumonia These infants tended to be young, five were under 6 months, and all but one had underlying cardiorespiratory disease They also appeared to have prolonged shedding of influenza virus from their nasal secretions Six of seven shed the virus for 7 to 21 days

Inhibition of the replication of influenza A and B viruses by a nucleoside analogue (ribavirin).

Abstract: Summary A synthetic nucleoside analogue 1-β-d-ribofuranosyl-1,2,4-triazole-3-carboxamide (ribavirin or RTCA) inhibits the replication in tissue culture of influenza B virus and also a wide range of influenza A viruses of human, animal and avian origin. The synthesis of influenza virus-induced antigens and also structural and non-structural polypeptides is inhibited by RTCA as detected by immunofluorescence and by pulse labelling experiments with [35S]-methionine. The inhibitory effects of RTCA on influenza A virus replication in tissue culture is reversed by a molar excess of guanosine or xanthosine which suggests that the compound acts at an early stage of virus RNA synthesis prior to the utilisation of the latter nucleosides. A possible inhibitory effect of RTCA on cellular DNA replication is not excluded.

Characterization of the mRNA of influenza virus.

Abstract: The kinetics of the appearance of influenza mRNA, the distribution of mRNA between free and membrane-associated polyribosomes, its poly(A) content, and the extent to which the genome was transcribed into mRNA early in infection were determined. Polyribosomes were prepared from influenza virus-infected cells labeled for 30-min periods at various times after infection with [3H]uridine. Most of the 3H-labeled RNA extracted from these polyribosomes sedimented as a heterogeneous 8S to 20S peak in sucrose gradients, and it was largely complementary to virion RNA. By the following criteria, the complementary RNA had properties normally ascribed to mRNA: (i) it labeled rapidly with [3H]uridine; (ii) after glutaraldelyde treatment, it banded with polyribosomes in CsCl density gradients; and (iii) it contained poly(A). In chick cells at 37 C, virus mRNA was first detectable at 45 min postinfection and reached its maximal rate of appearance at 2 to 2.5 h postinfection. The free and membrane-bound polyribosomes of infected cells were separated and were found to contain the same classes of mRNA. There was no absolute segregation of mRNA sequences into either polyribosome class although each probably contained distinct ratios of the different mRNA's. From 45 min postinfection onwards, both membrane-bound and free polysomal poly(A)-containing RNA contained sequences complementary to at least 80% of the genome RNA, whereas poly(A)-minus RNA contained sequences complementary to 90 to 100% of the genome. There was no evidence for the temporal control of transcription of influenza mRNA. At 31 C, when virus development was slowed relative to 37 C,complementary RNA first appeared at 1 h postinfection. At this time, total polysomal RNA contained sequences complementary to the whole genome.

The sudden infant death syndrome and epidemic viral disease

Abstract: A study was done to investigate the relationship between the sudden infant death syndrome (SIDS) and epidemic respiratory viral disease among hospitalized children under 18 months of age. During the 42 month-period of this study, there were 778 sudden infant deaths in Chicago and 3244 hospital admissions of children under 18 months for respiratory disease. Four outbreaks of respiratory syncytial (RS) virus infections, three outbreaks of influenza A virus infections, and several small clusters of parainfluenza virus infections occurred during the course of this study. Influenza A was the only virus infection found to have a statistically significant association with SIDS. Although environmental temperature was also significantly correlated with SIDS, the association with influenza A virus infection was independent of this temperature effect and neither association was strong.

Failure of attenuated temperature-sensitive influenza A (H3N2) virus to induce heterologous interference in humans to parainfluenza type 1 virus.

Abstract: The present investigation was undertaken to determine if a candidate live vaccine virus, influenza A/Hong Kong/68-ts-1 [E] (H3N2), induced heterologous interference against an interferon-sensitive, wild-type, parainfluenza type 1 challenge virus. The parainfluenza virus was administered 7 days after Hong Kong/68-ts-1 [E] virus infection. The clinical response, daily quantitative virus shedding, interferon production, and serum and nasal wash antibody responses were determined in an experimental group (influenza A virus followed by parainfluenza virus) and 10 volunteers in a control group (parainfluenza virus only). The volunteers were selected on the basis of susceptibility to the two viruses, i.e. serum hemagglutination-inhibition antibody titer of is less than or greater to 1:8 for influenza virus and low nasal wash antibody titer (is less than or greater to 1:8) for parainfluenza virus. Despite a 100% infection rate in the Hong Kong/68-ts-1 [E] vaccinees, no heterologous interference was induced against the parainfluenza type 1 virus challenge.

Demonstration of Antibodies to Both Hemagglutinin and Neuraminidase Antigens of H3N2 Influenza A Virus in Domestic Dogs

Abstract: Serologic evidence of infection with human (H3N2) influenza viruses of 6 of 79 dogs sampled in New York City in March-April 1973 was obtained through the use of four different methods for measurement

Inhalatory infection of mice with influenza A0/PR8 virus. II. Detection of the virus in the blood and extrapulmonary organs.

Abstract: In the course of experimental aerosol infection of mice with influenza A virus, the latter was regularly detected in the blood, liver, salivary glands, spleen, pancreas, kidneys, heart and irregularly in cervical and mediastinal lymph nodes. The findings of extrapulmonary virus were in direct quantitative relationship to the rate of lung involvement.

Antibody levels to parainfluenza, rubella, measles, and influenza A virus in children with polymyositis.

Abstract: The CF and HI antibody titers to rubella and measles viruses, the CF titers to influenxa A, and the HI titers to parainfluenza 1, 2, and 3 were carried out on the sera of 20 patients with childhood polymyositis and their matched controls. The titers for measles, parainfluenxa 1, and influenza A were slightly higher for patients than for controls. The control group had antibody titers to rubella and parainfluenza 2 and 3 higher than or similar to those of patients. Strong patterns or significant differences for a given virus or virus group were not encountered.

Clinical Trials with Alice Strain, Live, Attenuated, Serum Inhibitor-Resistant Intranasal Influenza A Vaccine

Abstract: Two clinical trials with Alice strain intranasal influenza vaccine were performed. In study no. 1 (utilizing random selection and double-blind control), 50 subjects received a bivalent inactivated influenza vaccine intramuscularly, 99 subjects received Alice strain vaccine intranasally, and 50 subjects received a placebo intranasally. No symptomatology could be attributed to the intranasal route of immunization. Convalescent-phase geometric mean titers of hemagglutination inhibition antibody were higher after intramuscular vaccination; seroconversion occurred in 16 or 17 recipients of the Alice strain, with initial titers of less than 1:8. Clinical and virologic surveillance for 20 weeks after vaccination revealed no influenza A illnesses in participants of the study. In study no. 2, 75% of the subjects with initial nasal antibody titers of less than 1:3 developed measurable nasal antibody after receiving Alice strain vaccine.

Live attenuated influenza virus vaccine trial in children.

Abstract: Thirty-four children received intranasally a live attenuated influenza A virus vaccine, and were then followed for six months to evaluate the vaccine safety, immunogenicity, and efficacy. All but one of the 31 children with hemagglutination inhibition (HI) titers less than 64 before inoculation responded with at least a four-fold rise in antibody titer to a single dose of vaccine. One child required two doses. Seven (21%) of the vaccinees also responded with production of nasal neutralizing antibody. The vaccine was well tolerated with few clinical reactions. Two vaccinees developed fever possibly attributable to the vaccine. No transmission of the vaccine virus to any of the 25 unvaccinated contact children was demonstrable. Five months after this vaccine trial an influenza epidemic due to a heterologous influenza A strain occurred in the community. During this outbreak acute febrile and/or respiratory illness occurred in 12 or 52% of the contact controls, and in six or 19% of the vaccinees. In two of these six vaccinees, influenza A infection was confirmed by at least a four-fold increase in HI titer. This study suggests this study suggests that this vaccine is safe, easily administered, highly immunogenic in children, and is protective against a heterologous strain epidemic in the community.

Epidemiology of herpesvirus and respiratory virus infections. Part 1. Serologic findings.

Abstract: The majority of the population group studied had complement-fixation antibodies toward the following viruses: influenza type A, respiratory syncytial, cytomegalovirus, and Epstein-Barr. The herpesvirus infections (cytomegalovirus and Epstein-Barr virus) seemed to be prevalent. Only low incidences of antibodies were found toward adenovirus, influenza type B, influenza type C, and parainfluenza type II. A total of 70 aucte virus infections (increases of antibody titer) were diagnosed in 49 patients. Besides cytomegalovirus, no particular virus infection occurred in a large number. Only 11 of the 70 acute virus infections diagnosed serologically were accompanied by clinical signs of disease

Antigenic relationship between the surface antigens of avian and equine influenze viruses.

Abstract: Influenza virus Equine 1 (A/equine/Prague/56) has a hemagglutinin which is antigenically related to the hemagglutinin of fowl plague virus strain Rostock (FPV) and a neuraminidase which cross-reacts with the enzyme of virus N (A/chick/Germany/49). After a single injection of chickens with Equine 1 virus no hemagglutination inhibiting (HI) and neutralizing antibodies against FPV can be demonstrated, although the birds are fully protected against a lethal dose of FPV. HI and neutralizing antibodies against FPV appear after a second injection of Equine 1 virus several weeks after the first one. Liberation of newly sunthesized FPV from the host cell is ingibited by antibodies cross-reacting with any antigen of virus surface.

Cellular RNA and Influenza-Virion RNA are Synthesized from Different Pyrimidine-Nucleoside-Triphosphate Pools in Chick-Embryo Cells

Abstract: Chick embryo cells infected with an influenza A (fowl plague) virus have been labelled with (3H)-uridine for different lengths of time. Virion RNA and cellular RNA have been separated by specific hybridization with a surplus of unlabelled viral complementary RNA and RNase digestion. The ratio of the specific radioacticity in the UMP and CMP moieties of both types of RNA has been determined. Since the rate of approach to equilibrium of CMP to UMP labelling of both types of RNA is completely different it is concluded that cellular and virion RNA are synthesized using different pyrimidine nucleoside triphosphate pools.

Respiratory virus disease in Malaysian children: a serological study.

Abstract: Paired sera from 101 Malaysian children aged up to 10 years and suffering from respiratory illnesses were examined serologically for evidence of respiratory viral infections. Of these children, 32.6% showed rising antibody titres for one or more of the test agents. Respiratory syncytial virus appeared to be the main respiratory pathogen involved, followed by Mycoplasma pneumoniae, parainfluenza viruses, adenoviruses, and influenza A virus. These findings are generally similar to those reported by others in temperate and tropical countries.

Abortive infection of L cells by influenza virus: absence of virion RNA synthesis.

Abstract: Influenza virus multiplies productively in chick cells and abortively in L cells. The infecting influenza virus RNA genomes are less stable in infected L cells than in infected chick cells. However, transcription of the virus genome in L cells, while reduced in rate, is not decreased in extent. There is no detectable synthesis of virion RNA in L cells, and this is the most likely cause of the abortive infection.

Assessment of resistance to influenza virus infection in animal models.

Abstract: The antibody response and immunity to challenge infection were determined in ferrets immunized with inactivated influenza vaccine in saline or adjuvant. Adjuvanated vaccines induced variable titres of serum antibody, and the degree of immunity to challenge infection was directly related to the titre of serum HI antibody induced by these vaccines. Conventional doses of saline vaccine did not induce serum HI antibody, and the ferrets were completely susceptible to challenge infection. Infection with live virus produced a more solid immunity to challenge infection than immunization with a adjuvant vaccines, even though immunization induced higher titres of serum HI antibody. Ferrets previously infected with a heterotypic influenza A virus, but not other viruses, produced serum HI antibody in response to subsequent immunization with inactivated influenza vaccine. Similar results were obtained in hamsters and mice. Thus, the failure of animals to produce antibody in response to immunization with saline inactivated vaccines was due to the absence of a previous priming infection; this prior experience would be a feature of most volunteers. Live virus infection produced nasal antibody in ferrets, but inactivated vaccines only induced serum antibody. This may explain the more solid immunity observed following infection; however, at the time of challenge infection, no nasal wash antibody could be detected. Immunization with inactivated vaccine in Freund's complete adjuvant and influenza virus infection both produced a cell-mediated immune response; thus, the difference in the degree of immunity induced by these two immunization procedures are probably not due to differences in the cell-mediated immune response. However, cell-mediated immunity was measured by skin tests and by macrophage migration inhibition tests with spleen cells; the reaction of cells from the respiratory tract may be more important, but was not measured in these studies.

Live attenuated influenza virus vaccines in patients with chronic broncho-pulmonary diseases. Clinical and immunological evaluation.

Abstract: The safety and potency of two live attenuated influenza A virus vaccines, administered intranasally, were tested in outpatients suffering from chronic obstructive lung disease, during two successive trials performed between 1972 and 1974. The vaccine strains were representative of the prevalent influenza A virus types; the Ann strain was derived from a classical H3N2 (A/Hong-Kong/878/69) isolated and the Alice strain from a recent H3N2 drift (A/England/42/72). The serum and nasal antibody responses were studied in a total of 40 vaccinees. When a sufficient virus dose was administered, the hemagglutination-inhibition (HI) seroconversion rate was, respectively, 86 and 73% for each vaccine trial in patients with low (less than or equal to 32) prevaccination antibody titers. A booster effect was also observed in some subjects with higher prevaccination titers. In the two trials, clear-cut rises in local antibody activity, as tested in nasal washings' samples were found in, respectively, 92 and 75% of the patients devoid of initial titer before vaccination and in 40 and 37%, respectively, of the subjects having low prevaccination titers. Clinical symptoms were observed in 29% of the cases; they were, however, mild and transient and their occurrence was not necessarily related to the vaccination. Two administrations of intranasal attenuated virus appear therefore to be safe and to lead to a satisfactory antibody response in this "high risk" group of patients.

Demonstration of avian influenza-A virus in Iran by immunodiffusion technique.

Abstract: A total of 1000 chicken serum samples (CSS) and 235 turkey serum samples (TSS) were tested by an immunodiffusion procedure against soluble antigen (S-antigen) prepared from avian influenza-A virus (AIAV), T/Calif/5142/66. None of the CSS tested developed any precipitin line, whereas 8.9% of the TSS tested developed well-defined precipitin lines against S-antigen. This observation confirmed the presence of AIAV in Iran.

An immunoprecipitin study of the incidence of influenza A antibodies in animal sera in the Ottawa area.

Abstract: A survey of over 600 'normal' sera from 14 animal species by immunoprecipitin tests in cellulose acetate using viron antigens revealed a high incidence of precipitating activity against a broad range of influenza A virus strains, particularly A2hHong Kong/1/68 and /PR8. However, serum treatments trypsin-heat-periodate, NaIO4, V. cholerae receptor-destroying enzyme (RDE), or kaolin eliminated most precipitating activity, which suggests that it was due to "non-specific" inhibitors of influenze viruses. A resistant minority could not be identified as inhibitor or antibody on this basis. Precipitation of the influenza A major type-specific antigen in virus-soluble antigens by human 7S gamma globulin antibody (IgG), demonstrated to be specific for influenza virus, was established as a reference reaction to identify similar immunoprecipitin reactions occurring between virus-soluble antigens and normal or immune sera. Complement fixation tests provided supplementary evidence for the presence of influenza A antibodies in these sera. Influenza A antibodies were found in only a few sera of six animal species: cat, dog, rabbit, goat, chipmunk, and sheep. Thus the animal species examined in the Ottawa area have not revealed an unequivocal reservoir for human influenza A viruses.

Isolation of influenza A virus in Reye's syndrome.

Abstract: Reye's syndrome, or encephalopathy with fatty degeneration of the viscera, is an acute and often fatal childhood illness in which signs of brain swelling and liver enlargement develop rapidly (Olson et at., 1970). The course of the disease is characteristic, and, once unconsciousness has developed, it can be diagnosed without difficulty. This is a common disorder in north-eastern Thailand and probably affects hundreds of children· annually (Olson et at., 1970; 1971). Sporadic cases are also found in the other parts of the country (Visudhiphan, unpublished data).