Serological diagnosis of parainfluenza virus infections: verification of the sensitivity and specificity of the haemagglutination-inhibition (HI), complement-fixation (CF), immunofluorescence (IFA) tests and enzyme immunoassay (ELISA).

Using four serological tests paired sera were examined of 117 patients with acute respiratory diseases, in whom parainfluenza viruses (PIV) infection was demonstrated by virus isolation, and of 41 patients with typical clinical mumps symptoms. Comparative analysis showed the high sensitivity of IFA and ELISA. A significant rise of antibodies in convalescent sera with homologous antigen of PIV was found in nearly 100 percent of cases. Only the sera of youngest children with high titres of persisting maternal antibodies remained without seroconversion. Cross heterologous antibody responses could be found by means of ELISA in 45% and by IFA in 10%, of patients who in the past experienced infection with one or more PIV or mumps virus--apart from homologous antibody reaction. HI and CF test proved to be less sensitive for detection of postinfections antibodies, especially in primoinfections with PIV types 1 and 2.

Studies of natural population variability of parainfluenza viruses during their epidemic circulation.

The population of circulating serotype 3 parainfluenza virus strains isolated in different years proved to be sufficiently polymorphic concerning its antigenic and biological features as well as their virulence for newborn hamsters. The highly virulent strain population appeared to have an antigenic pattern different from that of the prototype strain. The epidemic caused by it in groups of school and preschool children was more intensive as compared to that induced by avirulent strains population.

[Clinical diagnosis and laboratory study of acute respiratory diseases of viral origin in children]. / Klinická diagnóza a laboratorní vysetrení akutních respiracních onemocnení virového puvodu u detí.

The authors analyzed retrospectively a group of 477 children aged two months to 16 years (mean age 6 years and 5 months), hospitalized on account of acute respiratory disease and subjected to virological examination. The aetiology was revealed in 53% of the sick children. In the elucidation of the aetiology participated a number of respiratory viruses, in particular the respiratory syncytial virus. The clinical picture of the disease was very varied. It was confirmed that the clinical picture does not make it possible to express in a considerable proportion of patients suspicion of an actual infectious aetiology. A mixed aetiology of acute respiratory diseases and a varied clinical picture indicate the necessity of a rapid virological and bacteriological examination in hospital practice.

[Surveillance of acute respiratory diseases in the 1988/1989 season in Czechoslovakia]. / Surveillance akutních respiracních onemocnení v sezóne 1988/1989 v CSSR.

The authors submit an analysis of results of surveillance of acute respiratory diseases during the 1988/1989 season in the CSSR. The influenza epidemic took place between the 4th and 11th calendar week with a peak in the 7th week. During the epidemic 19.7% of the population in the CSR contracted the disease. The influenza epidemic was preceded by a high incidence of infections caused by a respiratory syncytia virus. As to the aetiology, influenza viruses subtypes A/H1N1/, A/H3N2/ and type B participated practically equally in the epidemic. The authors discuss the observed changes in the influenza epidemiology in recent years in Czechoslovakia and neighbouring countries.

Epidemiological analysis of acute respiratory disease (ARD) and characteristics of the influenza epidemic in Bohemia during the season 1986/1987.

The authors analyze the findings of epidemiological and virological surveillance of ARD in Bohemia during the season 1986/1987. In all, 57.5% of the Czech population was affected by acute respiratory disease (ARD). There were 5,950,832 cases reported, 124,444 complications (2.1% of the overall morbidity rate) and 5,374 deaths due to influenza, bronchitis, pneumonia and chronic pulmonary affection. The influenza epidemic commenced during the 48-th calendary week (CW) and lasted 5 weeks till the 52-nd CW. The epidemic was due to an influenza virus strain of the subtype A(H1N1) antigenically related to the drift variant A (Singapore) 6/86. Within an extremely short period of the epidemic, 1,094,865 influenza cases were reported and 22,313 cases of complications. 10.7% of the CSR population were affected during the epidemic in whose etiology noninfluenza respiratory viruses were significantly implicated, especially adenoviruses (41.7%) and the RS virus (26.9%). There was no excessive mortality in the course of the epidemic. The authors discuss the atypical nature of this particular influenza epidemic and the etiological role of respiratory viruses.

[A nosocomial epidemic caused by adenovirus type 3 at a clinic for children and adolescents]. / Nozokomální epidemie vyvolaná adenovirem typu 3 na klinice detí a dorostu.

The authors describe an epidemic of acute viral respiratory diseases with a nosocomial character at a clinic for children and adolescents, caused by adenovirus type 3. Of 80 exposed children 26 fell ill (attack rate 32.5%). The disease took a clinical course typical for adenovirus type 3. The authors discuss the problem of respiratory infections with a viral aetiology at paediatric departments and their possible prevention.

[Acute viral respiratory diseases as a cause of work disability in miners during an inter-epidemic period]. / Virová akutní respiracní onemocnení jako prícina pracovní neschopnosti horníku v meziepidemickém období.

During the interepidemic period between October 1 and November 20 1987 96 miners from a coal mine were examined who suffered from diseases of the upper airways which caused their work incapacity. In paired sera the rise of antibodies against M. pneumoniae and respiratory viruses were examined (adeno, influenza virus A and B, Coxsackie A21, corona 229E and OC43, parainfluenza type 1, 2 and 3, rhino type 13 and 44, RS). A viral aetiology was confirmed in 31 patients (32.3%). An evident rise of antibodies against the following viruses was found: adenoviruses 3X, Coxsackie A21 5X, coronaviruses 229E 1X and OC43 2X, parainfluenza virus type 1 1X and type 2 5X, rhinovirus type 13 11X and type 44 4X, RS virus 1X. As to the period of work incapacity and clinical manifestations, there was no difference between the diseases caused by different agents. The results of the investigation indicate that also viruses which are not used in common diagnostic practice may frequently evoke diseases which cause work incapacity.

[Virologic and morphologic study in sudden and unexpected death in children]. / Virologická a morfologická studie u náhle a neocekávane zemrelých detí.

The authors examined a group of 47 children who died at the age of 1-9 months, incl. 19 female and 28 male children. In 23 the death was described as sudden and in 24 as unexpected. From 19 dead children a virus was isolated: in 14 one or two serotypes of enterovirus were found, in two the virus of parainfluenza 3 in two adenoviruses (type 2, 7). A total of 46 viral strains were isolated. By immunofluorescence in tissues antigens of the parainfluenza virus 3 and adenovirus were detected. Immune complexes were not detected in tissues. The distribution of vaccination polioviruses in organs and tissues after a known interval following vaccination was recognized. In some of the infants a possible causal relationship between the virological and morphological findings was found and the authors discuss the possible pathogenetic role of the revealed changes in sudden death.

Occurrence and aetiology of acute respiratory diseases: results of a longterm surveillance programme.

Totals of 58,661,000 acute respiratory disease (ARD) cases, 1,376,651 bronchitis and pneumonia complications, and 93,042 deaths from influenza, bronchitis, pneumonia or chronic pulmonary affection were notified during 11 years of ARD surveillance from 1975 to 1986. All ARD seasons started with the first phase in September-December; this increase in morbidity was caused chiefly by adenoviruses, parainfluenza viruses, rhinoviruses and M. pneumoniae. Second wave of ARD morbidity occurring in January-April used to be explosive and was associated with an influenza epidemic in 9 of the 11 seasons; only in 1978/79 and 1984/85 the ARD epidemics were caused by adenoviruses and especially RSV, the share of influenza being minimal. Pneumonia and bronchitis excesses occured during epidemics caused by M. pneumoniae in 1975/76, 1980/81 and 1985/86. Particularly high mortality excesses occurred in 1976, 1977 and 1983 during epidemics elicited by a new drift variants of influenza A(H3N2). Identification of viral agent of M. pneumoniae attempted in 5474 ARD cases was successful at 37.4%. The respective contributions of parainfluenza viruses, adenoviruses, influenza A virus and RSV to overall aetiologically identified morbidity were 14.2, 13.9, 13.8, and 12.0%. Mixed infections (2-3 agents identified simultaneously) accounted for 14.6% of cases. Type B influenza virus, rhinoviruses, enteroviruses and herpes simplex virus contributed only by 5.6-7.8%. In ordinary seasons the share of M. pneumoniae in aetiologically identified ARD morbidity was 0.6-3.8%; this agent displayed predominance at 5-year cycles, when accounting for 20.5-38.9% of cases. The most frequently detected agents in individual age groups were as follows: in preschool children parainfluenza (18.6%), RSV (16.6%), and adenoviruses (17.4%); in school children M. pneumoniae (26%), influenza A and B (10.2 and 14.7% respectively), and adenoviruses (10.7%); in adolescents and young adults influenza type A (20.2%), M. pneumoniae (15.0%), and rhinoviruses (13.3%); in adults above 25 years age influenza A virus (38%), and other respiratory viruses at a frequency lower than 10% each.

[Specific and nonspecific indicators of activation of influenza viruses before an epidemic caused by influenza viruses subtype A/H3N2 and type B in Czechoslovakia in 1986]. / Specifické a nespecifické indikátory aktivizace chripkových viru pred epidemií vyvolané viry chripky subtypu A/H3N2/ a typu B v CSR v roce 1986.

The authors submit an aetiological and epidemiological analysis of the influenza epidemic which occurred in the CSR between the 4th and 14th week of 1986 and was caused by the influenza virus subtype A/H3N2/ and type B. The epidemic affected a total of 27.1% of the population, in the age group of 0-5 years 63.7%, in the age group 6-14 years 52.7% and in the age group above 15 years 17.1%. In the course of the epidemic 77,458 cases of pneumonia and bronchitis were reported and 1,412 deaths with the diagnosis influenza, bronchitis, pneumonia and chronic affection of the lungs. The authors analyze also specific indicators of the activation of influenza viruses and reach the conclusion that serological evidence of the circulation of influenza viruses in the population was detected already in the third quarter of 1985, the first isolations were made six weeks before the influenza epidemic. Activation of the influenza viruses is indicated already during the pre-epidemic period by some non-specific indicators which include the rising number of patients with acute respiratory affections in surgeries and the rising number of children absent from nurseries and nursery schools on account of these diseases. The most sensitive non-specific indicator is the rising number of patients with respiratory diseases in surgeries of the First aid medical service.

Detection of postvaccination mumps virus antibody by neutralization test, enzyme-linked immunosorbent assay and sensitive hemagglutination inhibition test.

A group of 251 children aged 2-3 years given live attenuated mumps virus vaccine PAVIVAC of Czechoslovak production were tested for antiparotitis antibody levels in pre- and postvaccination sera by neutralization test (NT), enzyme-linked immunosorbent assay (ELISA) and sensitive hemagglutination inhibition test, enhanced by heterologous antibody to human immunoglobulin G (E-HIT). The prevaccination findings were as follows: positive ELISA IgG titres, neutralization antibodies and hemagglutination inhibition antibodies were present in, respectively, 35%, 25.9% and 27.9% of the sera. Postvaccination seroconversions were evaluated in 159 susceptible vaccinees whose prevaccination sera had been negative by all three tests. The lowest seroconversion was detected by NT (74.2%), seroconversions by ELISA and E-HIT were appreciably higher (82.4% and 86.8%, respectively). The seven children showing a seroconversion by E-HIT but not by ELISA had a 4 fold increase of anti-mumps ELISA IgG antibodies as well, but the rise of antibody titres was at a level falling in the range below the positivity criterion for ELISA. The statistically evaluated detection rate for antibodies was significantly higher (significance test "t") by ELISA as compared with neutralization test. However, antibody levels (geometric mean titres) were 8-10 times lower in postvaccination sera than in convalescent sera of 30 children with mumps in all three tests.

Transplacental antibodies. Part III: Maternal antibodies against polioviruses, M. parotitidis and M. parainfluenzae.

In 1981 we examined 247 sera for the presence of antibodies against all three types of poliovirus and 253 sera for antibodies against M. parotitidis and three types of M. parainfluenzae viruses. The sera were obtained from the cord blood of mothers between 15 and 34 years of age. All mothers were divided into four age groups, each with primipara and multipara subgroups. The rate of seropositivity for type 1 and type 2 poliovirus-specific antibody was in all age groups higher than 90%, the overall seropositivity rate for type 3 poliovirus antibody was 83.6%, with 73.1% as the lowest rate for age group of youngest mothers. Significant seropositivity variations between the primipara and multipara subgroups were recorded only for type 3 antibody in the two age groups of oldest mothers (25-29 and 30-34 years). This is consistent with the assumed booster effect of Sabin vaccine strains on mothers of families with more than one child. Antibodies specific to mumps virus were present in the cord blood of 78.6% of all mothers and the rates of seropositivity were found to rise with the increasing age. Seropositivity for M. parainfluenzae type 1-specific antibody was demonstrated in 95.8%, for type 2-specific antibody in 98.9% and for type 3-specific antibody in 100% of mothers, which is suggestive of high herd immunity levels in the population.

Antibody to parainfluenza virus types 1, 2 and 3 in sera and nasal secretions of persons of different age.

Serum and secretory antibody levels against 3 types of parainfluenza virus were determined in persons ranging in age from 1 month to 74 years. With a slight decline in the group of 7 months to 2 years of children, the number of positive findings increased with age, reaching maximum in the groups of 16-24 years [types 1 and 2] and 25-74 years [type 3] old persons. Nasal secretory antibodies against parainfluenza type 3 virus were detected in all age categories, the highest number of positive findings occurred in the group of 16-24 years old persons. Secretory antibodies against type 2 virus were detected also in all age groups, but the number of positive findings was considerably lower. Secretory antibodies against type 1 virus were detectable in persons over 5 years of age, with a maximum in the age category of 16-24 years. The percentage of positive persons with antibody to type 1 virus was the lowest.

[Viral infection in acute otitis media in children (author's transl)]. / Virusinfektionen bei den akuten Mittelohrentzündungen der Kinder.

One hundred and twenty-six children with purulent otitis media were examined virologically at the Children's Otorhinolaryngological Clinic in Prague. Viral infection was established in 60, i.e. 47,8% of the patients, the evidence being isolation of virus in 25 and seroconversion in 35 children. In respect of the clinical course, the main findings were asymptomatology and nonspecificity of the cases of established viral etiology.

Haemagglutination inhibition antibodies in nasal secretions of persons after natural parainfluenza virus infection.

In 7 adults and 7 children with upper respiratory illness of parainfluenza aetiology, the virus was isolated in the acute phase from nasal washings or nasal smears in spite of high titres of haemagglutination inhibition (HI) antibodies in serum. By contrast, secretory HI antibodies were not demonstrated at the onset of illness in any of the patients, but their formation started early and the antibodies reached maximal levels about 10 days after onset of illness. The individual patients showed considerable differences in the dynamics of secretory antibody formation and especially in their persistence. In some of the patients, secretory antibodies were demonstrated as late as 12 months after the illness.