Bronchiolitis and asthma: possible common pathogenetic pathways

A discussion of possible mechanism for virus-induced wheezing in normal and asthmatic children is presented. Presently attractive theories for immune injury in viral bronchiolitis include those which depend on pathology induced by types 1, 3, and 4 of Gell and Coombs. The continuum of viral bronchiolitis with virus-induced wheezing in young children who are labeled "asthmatic" argues for some common mechanism of bronchiolar obstruction.

[Virology of acute upper respiratory tract infections (author's transl)]

The virology of acute upper respiratory tract infections is presented in a survey. The first part includes general properties of viruses (structure, replication, maturation, classification), aetiological and immunological problems of viral infections. The different respiratory viruses and their clinical picture in particular are summarized in the second part.

An investigation of the possible transmission of Rhinovirus colds through indirect contact

Rhinovirus was recovered from the fingers of 16 of 38 volunteers and others, who were swabbed during the acute stages of their colds. Very low titres of virus were also recovered from 6 of 40 objects recently handled by infected volunteers, but not from the fingers of 18 non-infected subjects whose flat-mates were shedding virus. When rhinovirus from nasal secretions was dried on skin or other surfaces during laboratory experiments, approximately 40-99% of infectivity was lost. Virus could be transferred from surface to surface by rubbing, the transfer being more efficient if it was carried out while the inoculum was still damp. Volunteers could infect themselves if a moderately heavy dose (88 TCD50) of virus was inoculated on the finger and then rubbed into the conjunctiva or nostril, especially if the inoculum was still damp. From estimates of virus titres in nasal washings and on fingers, and of amounts transferred by rubbing, it was concluded that apread of colds is unlikely to occur via objects contaminated by the hands of the virus-shedder, but that a receipient might pick up enough virus on his fingers by direct contact with heavily infected skin or secretions to constitute a risk of self-inoculation via the conjunctiva or nostril.

The Seattle virus watch. V. Epidemiologic observations of rhinovirus infections, 1965-1969, in families with young children

Rhinovirus (RV) infections in Seattle Virus Watch (VW) families (1965-1969) were monitored by screening respiratory specimens in WI-38 cell cultures and by homotypic neutralization tests on sera related to family episodes revealed by RV isolation. Temporally related illness in members not proven infected was also taken to indicate infection. RV isolates (including those from the New York VW, 1961-1965) were typed within the official 90-serotype frame. Typed isolates from New York (165 with 39 serotypes) and Seattle (456 with 59 serotypes) were compared with the Tecumseh Study to test the hypothesis that some serotypes are "common," persisting because of greater infectivity. Of 32 serotypes qualifying as "common" in at least 1 study, 4 were "common" in all 3 studies and 8 in 2 studies. The 23 "common" Seattle serotypes differed from the remaining 36 serotypes in being more infective and in their more frequent association with prolonged shedding. The New York and Seattle isolates together revealed an increase over time in the proportion not typable or of of higher numbered types, consistent with progressive shift in RV antigenic character. WI-38 isolates indicated spring peaks of RV all 4 years but a fall peak only in 1967. An even larger fall peak was seen when all specimens from September-November 1968 were re-examined in fetal tonsil diploid cells. Thus, both spring and fall peaks appear to describe RV seasonality. RV infections explained 16% of all reported respiratory illness (20% of upper respiratory), but RV-associated illness in young children, especially under 2 years, was more severe and almost twice as frequent as in adults. The age of introducers and the direct relation of family size to frequency of episodes indicate that community spread depends largely on preschool children, including infants. Within families, the secondary attack rate (SAR) was highest following paternal introduction and, for all introducers, the SAR varied inversely with age (mother excepted). RV shedding was observed most often (85% of specimens) from the day before to 6 days after illness onset but prolonged shedding was common (to 21 days in 20% and 28 days in 1.4% of infections). RV infectivity, reflected by SAR among nonimmunes, was highest for infants (78%) and, for all ages, was greater with ill than with well introducers (71% versus 27%). Immunogenicity of RV was poor (Seroresponse: 48% of shedders, 32% of nonshedding contacts) but varied greatly with serotype. Illness frequencies among non-immunes were 59% for all proven infections and 35% when infection was not shown..

Attenuation of rhinovirus type 15: relation of illness to plaque size

Rhinovirus type 15 passaged three times in WI-38 cells produced illness in only one of 35 volunteers, but infection resulted in formation of significant quantities of antibodies in the serums of 100%, and in nasal secretions of 89%, of infected volunteers. The inoculum contained large- (60%) and small- (40%) plaque variants. "Purified" large- and small-plaque inocula were prepared, and each was administered to 20 volunteers. There was a significant association of illness with the small-plaque inocula (P < 0.01) but the incidence of infection, quantitative virus shedding patterns, and mean serum and nasal secretory antibodies were not significantly different between the two groups. These findings suggest that plaque size may be an in vitro marker of attenuation of illness production by rhinoviruses.

Comparison of in vitro and cell-mediated alteration of a human Rhinovirus and its inhibition by sodium dodecyl sulfate

After human rhinovirus type 2 (HRV-2) attaches to HeLa cells, two types of subviral particles are formed which closely resemble particles produced in vitro by acid or heat. One type of particle contains RNA whereas the second sediments as an empty capsid and is RNA-deficient. Sodium dodecyl sulfate (SDS) at 10(-4) M inhibits the cell-mediated formation of these particles from HRV-2 virions and the ability of HRV-2 to form plaques, but it does not inhibit the formation of plaques by human rhinovirus 14 (HRV-14). SDS also stabilizes HRV-2 against inactivation by acid or heat to a much greater extent than it does HRV-14. In a similar manner, SDS protects against the acid inactivation of the subpopulation of HRV-2 natural top component particles which attach to virus-specific cellular receptors. This suggests that the loss of native properties of natural top component particles and of virion are related processes. The basis for this alteration and also its role in infection are discussed.

Inactivation of influenza and other viruses by a mixture of virucidal compounds

A mixture of benzalkonium chloride, Triton X100, and citric acid (Resiguard F) had a marked virucidal effect on lipid-containing deoxyribonucleic and ribonucleic acid viruses, such as vaccinia virus, herpesvirus, and influenza virus. Adenoviruses and picornaviruses were more resistant to inactivation. Electron microscopy showed that influenza particles became aggregated in the presence of Resiguard F and that the outer fringe of hemagglutinin and neuraminidase spikes seen in control virus preparations became indistinct. The mixture had no detectable antiviral activity in mice infected with influenza AO/PR/8/34 virus, and this was attributed to the reduced virucidal effect of Resiguard F in the presence of serum proteins.

Infectivity and sedimentation of rhinovirus ribonucleic acid

Ribonucleic acid extracted from the virions of two human rhinoviruses is infective and is similar in size to poliovirus ribonucleic acid.

Rhinoviraemia

Rhinoviruses have been isolated from the serum of two infants at necropsy. Failure to isolate viruses from ten other sera from infants who yielded rhinoviruses from their respiratory tracts suggests that true rhinoviraemia occurs rarely, and is infrequently associated with rhinovirus infections, both clinical and subclinical, and death. It is suggested that this is the first report of isolations of human rhinoviruses from the blood.

The rhinoviruses of man

Rhinoviruses, prominent agents of the common cold syndrome in man, are small ribonucleic acid (rna) viruses resembling enteroviruses in their physicochemical properties except for high density and lability to acid pH. Rhinoviruses are propagated in human and monkey cells. Highest titers of virus are obtained in HeLa cell cultures. Rhinoviruses produce characteristic cytopathic effect in diploid fibroblasts. A plaque assay in HeLa cells is useful for their titration. The rhinovirus group includes many serotypes. Although rhinoviruses cause predominantly upper respiratory tract symptoms, they may on occasion infect the lower respiratory tract. Volunteers with specific antibody, when challenged with homotypic rhinovirus, are protected against the common cold.

Rhinovirus infection of vervet monkeys. A model of human rhinovirus disease

Experiments are described which indicate that equine rhinovirus infection of vervet monkeys can be used as an in vivo model of human rhinovirus infection. It is, however, shown that the equine rhinovirus has properties which are not typical of human rhinoviruses.

The equine virus produced clinical signs in the monkeys and the infection could be estimated quantitatively by measuring the duration of virus excretion and the antibody response. The possible use of this rhinovirus model system for the testing of antiviral compounds is discussed.