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.

[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.

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.

Use of indirect immunofluorescence method for detection of rhinovirus-specific antibodies.

Neutralization test and the method of indirect immunofluorescence were used to study the titre of specific antibodies in 32 paired serum samples taken from subjects naturally infected by varying RV serotypes [1A, 1B, 9, 12, 15, 16, 19, 23, 26, 29, 30, 31, 41, 47]. The IF method was positive in all the examined sera, the increase in the titre of rhinovirus-specific antibodies was mostly low and in 10 cases was the titre in both serum samples identical. The neutralization test turned out to be less sensitive in detecting specific antibodies. In serum samples from 13 examined subjects it failed to detect antibody presence in either of the two serum samples, in 15 subjects was recorded an increase in the titre of antibodies, but in some of them was only small, and the identical antibody titre in both serum samples was detected in 4 subjects.

Haemagglutination-inhibiting and neutralizing antibodies to type 3 and 5 rhinoviruses in human sera and nasal washings.

Presence of antibodies to RV 3 and RV 5 was tested by HIT and NT in 60 human sera. Antibodies to RV 3 were detected in 23 sera by HIT in a titre range of 1:4--1:64 and in 19 sera by NT in a titre range of 1:4--1:256. Antibodies to RV 5 were detected in 31 sera by HIT in titres of 1:4--1:268 and 27 sera by NT in the same titre range. In a group of 22 persons with unequivocal serum antibodies nasal secretory antibodies were found in 11 subjects in titres of 1:4--1:32. In a group of 16 persons without detectable serum antibodies, presence of secretory antibodies (titre 1:4) was only found in four cases.

The spread of rhinoviruses in the Soviet Union (USSR) and in Czechoslovakia (CSSR) and the role of their pathology.

Virological, serological and immunofluorescence studies revealed circulation of rhinoviruses of the strains 1A, 1B, 2, 3, 7, 9, 10, 12, 13, 14, 16-23, 27, 29-33, 42, 48, 53, 56, 60 and 69 on the territory of Czechoslovakia and the Soviet Union. According to virological results, type 48 predominated and was followed in frequency of occurrence by types 27, 14 and 16 in the USSR and 30, 1A and 31 in the CSSR. RV infection in adults with ARD diseases was the aetiology in 28.5% of cases. Among the causative agents of acute rhinitis, rhinosinusitis and otitis, rhinovirus infection makes up a large proportion. Interrelation has been found between rhinovirus infection and chronic inflammation of the mucosa of the nose, the accessory sinuses and the ears. Prolonged course of rhinovirus infection and isolation of the virus in the late stages of disease (1-4 months after its onset) support the presumption that rhinoviruses promote chronicity of inflammation. RV was isolated from patients with chronic pneumonia from the lower respiratory passages (bronchial secretion). Rhinoviraemia was found in a child who died of ARD.

Influenza and other actue respiratory diseases in the Czech Socialist Republic, 1969-1974.

Since 1969, the incidence of acute respiratory diseases (ARD) in the Czech Socialist Republic of Czechoslovakia has been monitored by a special programme based on reports from 85 district epidemiological centres. In this paper, the incidence of ARD in three age groups, together with the incidence of complications and death rates, are presented for each season during the period 1969-1974. The significance of epidemiological observations and laboratory investigations relating to influenza and other ARD agents, such as parainfluenza viruses, adenoviruses, rhinoviruses, RS virus, coronaviruses, and Mycoplasma pneumoniae, is discussed.