A comparative virological study of children in hospital with respiratory and diarrhoeal illnesses

Mixed viral infections: detection and management

An analysis was done of the incidence and nature of mixed virus infections diagnosed in the same clinical specimen from immunocompetent patients; respiratory viruses were emphasized. Few studies have addressed mixed viral infections in any systematic fashion. The relevant studies reviewed focused on clinical relationships or diagnostic methods. Data relating to multiple infections were usually derived incidentally to the purpose of the investigations. Sixty-three percent of the reports with data on mixed infections identified them in < 5% of the total number of viral infections. Respiratory syncytial virus was the most common coinfecting virus, and respiratory syncytial virus and influenza virus were the most common virus pair identified. In considering rapid diagnostic techniques, in 87% of the reports with available data a virus was diagnosed in > 10% of specimens that were negative for the virus targeted by one method. There was no indication that mixed infections were associated with increased disease in immunocompetent patients or in certain immunocompromised patients. Immunocompromised patients, however, appeared to have a greater incidence of multiple infections. Mixed infections of single cells also occur and may have important clinical implications relative to reactivation of latent viruses and enhanced disease. The requirement for a comprehensive strategy for viral diagnosis involving multiple techniques was indicated by these findings.

Epidemiological features of type 22 echovirus infection

During a 25-year observation period, isolates of type 22 echovirus were obtained from 109 patients. 92% of the patients were < 2 years old. Echovirus type 22 was isolated with peaks both during late summer and autumn, as enterovirus infections, and during the winter months and early spring, as respiratory viruses. Diarrhea was the most common symptom, followed by obstructive bronchitis and, less often, CNS symptoms. Nosocomial infections were common. In a noticeable number of the children, maternal neutralizing antibodies were most probably present at the time of infection. The epidemiologic features of type 22 echovirus infections with regard to age and seasonal distribution, contagiousness and a relative lack of protection by neutralizing antibodies differed from most enterovirus infections.

A year's experience of the rotavirus syndrome and its association with respiratory illness

In a hospital study rotavirus was identified in 51% of 152 children with diarrhoea. These patients showed a clinical pattern that was distinct from patients in whom the diarrhoea was associated with bacteria, other viruses, or no pathogens. A respiratory illness was described in 66% of rotavirus patients and usually preceded the gastrointestinal symptoms. Vomiting lasted between one and 3 days and was curtailed by substituting the normal diet with clear fluids. Watery diarrhoes continued for 4 or 5 days, even when rehydration was by the intravenous rather than the oral route. Prolonged diarrhoea was rare. Most children infected with rotavirus were under 2 years of age, but dehydration was most severe in infants aged between 12 and 18 months. A clinician can thus recognise the rotavirus syndrome and expect spontaneous recovery if adequate rehydration is maintained for a critical few days.

Stool viruses in babies in Glasgow. I. Hospital admissions with diarrhoea

Stools from 183 babies under 2 years of age admitted to Ruchill Hospital with diarrhoea were examined by electron microscopy, virus culture, bacterial culture and light microscopy. As far as possible, several stools were examined from each patient and the results showed rotaviruses, astroviruses and other viruses in association with symptoms, as well as the expected bacterial pathogens. Examination of several stools from the same patient also showed that in this age group the viral flora of the gut changes rapidly and that the viruses seen by electron microscopy were only rarely grown in cell culture and vice versa. This phenomenon was particularly noted with adenoviruses. In 30% of cases no microbial pathogen was identified and in the remainder the presence of the infecting organism did not always coincide with the symptoms. It is concluded that, with viruses at least, presence of the organism does not constitute proof of causation.

Significance of respiratory virus isolations. A study in primary schoolchildren

This study was undertaken in a primary school to determine how frequently viruses, Mycoplasma pneumoniae, and pathogenic bacteria could be isolated from children in whom there was no evidence of acute respiratory infection. The clinical status was firmly established before the virological and bacteriological results were recorded. Respiratory illness was found during 79 out of 224 interviews (35%). Specimens were taken at 112 of these interviews and children were re-examined 6 days later to ensure that no symptoms had developed during the intervening period. Viruses were isolated from 2 out of 65 (3%) of the investigations performed in asymptomatic children, compared with 11 out of 47 (23%) in those who had episodes of mild respiratory illnesses. Haemophilus influenzae and Streptococcus pneumoniae were more commonly isolated in the 47 children with symptoms than in those without. There was a close correlation between the virological findings of this study and those in children attending a nearby general practice, where the isolation rate in episodes of respiratory illness was 23% during the same period.

Antigenic relationships amongst coronaviruses

Several serological interrelationships between various members of the corona-virus group have been revealed in neutralization, complement fixation, and gel-diffusion tests, using human and hyperimmune animal sera. Several members of this group of human and animal pathogens are shown to cross-react in one or more type of test, but one member, avian infectious bronchitis virus, was shown to be unrelated. Mouse hepatitis virus (MHV₃) was found to be antigenically related to a number of human types of coronavirus. Difficulties were encountered in the investigation of paired human sera in demonstrating the specificity of antibody rises, placing doubt on the values of some serological studies. The significance of these interrelationships is discussed in the light of other investigations.

A comparative study of methods for the diagnosis of respiratory virus infections in childhood

Nasopharyngeal secretions and cough/nasal swabs were taken from 111 children admitted to hospital in Newcastle upon Tyne with acute lower respiratory disease. A comparison was made between nasopharyngeal secretions and cough/nasal swabs as material for isolation of viruses in tissue culture. These results were, in turn, compared with those obtained by applying a fluorescent antibody technique to the exfoliated cells in the nasopharyngeal secretions for the rapid diagnosis of respiratory syncytial virus infection.

More viruses were isolated in tissue culture from nasopharyngeal secretion than from cough/nasal swabs. Further evidence for the superiority of nasopharyngeal secretions was obtained by comparing the virus isolations in the laboratory in 1967 with those in 1968. Respiratory syncytial virus was not only isolated more often but more quickly in tissue culture inoculated with nasopharyngeal secretions.

The fluorescent antibody technique not only provided a diagnosis on the patient's day of admission in 95% of those infected with respiratory syncytial virus but also proved to be as sensitive as the culture of nasopharyngeal secretions and considerably more sensitive than the culture of cough/nasal swabs for the diagnosis of respiratory syncytial virus infection.

We wish to acknowledge the invaluable help given us by consultants, medical officers, ward sisters and their staff in the paediatric wards of the Child Health Department. We also wish to thank the technical staff in the Department of Virology for their aid.

Virus infections and respiratory disease of childhood

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