Epidemiological analysis of acute respiratory diseases (ARD) of viral etiology in the Czech Socialist Republic (CSR] and German Democratic Republic (GDR) over the period 1979 to 1984

An analysis is made of the ARD reported in CSR and the GDR over the period July 1st, 1979 to June 30th, 1984. During that time, there were 27,810,000 cases reported in CSR in the framework of ARD epidemiological surveillance, representing 2.67 cases per one inhabitant, whereas in the GDR, the total number of reported ARD was 28,900,000 yielding 1.73 cases per person. However, the GDR reported higher morbidity per one child of preschool age. The authors believe that the differences in the reported incidence of ARD between the two countries are due to differences in the reporting systems and medical officers' activity during an epidemic and in the interim period. Approximately one third of ARD reported annually in the two countries falls to the period of influenza epidemics. The authors also analyze the etiology of the influenza epidemics which affected the two countries in 1980, 1981, 1982, 1983 and 1984. In most seasons, the causative agents and morbidity excesses were different in the two countries. The drift variant B/USSR/100/83, which caused a major epidemy in CSR in 1984, has not to date been implicated in the DGR in the etiology of ARD. The cyclic epidemic due to Mycoplasma pneumoniae occurred in the GDR already in 1979-80, while CSR experienced it a year later. There was a temporal and territorial correlation between the course of A(H1N1) influenza epidemic in the two countries in 1984.     

The use of influenza vaccines and remantadine for protection against influenza in industrial enterprises

The effectiveness of inactivated and live influenza vaccines and remantidin was studied in persons with different annual morbidity rate in influenza and acute respiratory diseases (ARD). After three and more years of immunization with the inactivated vaccine the number of seroconversions to viruses A (H1N1) and A (H3N2) in vaccinees decreased, respectively, from 75.0 to 26.0% and from 79.3 to 38.8%, and after an interval of two years or the alternation of inactivated and live vaccines the number of seroconversions increased to 57.9-64.0%. The significant decrease of morbidity rate in influenza and ARD were observed only in persons, having had frequent ARD in their medical history and immunized with live and inactivated vaccines simultaneously or separately with the alternation of these vaccines every year (the effectiveness index being equal to 1.7-1.8). At the period of epidemic the controlled administration of remantadin to persons with contraindications to immunization ensured the decrease of morbidity rate in influenza 1.5-1.8 times; in vaccinees, highly susceptible to ARD, the administration of remantadin decreased morbidity rate 2.3 times.     

The reactogenicity and safety of a multicomponent vaccine (VP-4) in the prevention of acute respiratory diseases in preschoolers

The reactogenicity and safety of poly-component vaccine (VP-4), prepared from the antigens of opportunistic bacteria, in the prophylaxis of acute respiratory diseases (ARD) in children aged 2.6-6 years. The vaccine was administered intranasally in 3 administrations and orally in 6-8 administrations at intervals of 3-4 days for a period of 24 +/- 4 days. The prophylaxis of ARD with the use of VP-4 was carried out in 168 children in 4 children's preschool institutions. The control group was made up of 120 children, attending the same institutions. The study revealed that VP-4 had low reactogenicity and induced short-time systemic and local reactions (common cold, cough). The administration of VP-4 at a period of the epidemic rise on influenza and ARD morbidity did not lead to an increase in the frequency and duration of ARD in the vaccinees, as well as to the exacerbation of chronic infection and the allergization of the body.     

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.     

Studies on prophylactic efficacy of N-2-hydroxyethyl palmitamide (Impulsin) in acute respiratory infections. Serologically controlled field trials.

The results of three serologically controlled double blind field trials in army units are presented. The evaluation of results according to morbidity, regardless of aetiology, showed a significant reduction in acute respiratory diseases (ARD) after administration of Impulsin. In the 1973 trial (901 volunteers), 22.7% of ARD cases were found in the Impulsin group contrary to 34.4% in the placebo group (P less than 0.0002). The relevant values in the 1974 trial (610 volunteers) were 19.7% and 40.7% (P less than 0.002) and in the 1975 trial (353 volunteers) 10.6% and 28.8% (P less than 0.004). The study of the immunological background in representative sets of volunteers allowed determination of the aetiology, the proportion of asymptomatic infections and possible deformation of results due to preexisting protective antibodies. Manifestation rate (MR) expressing the proportion of sick persons out of all sensitive subjects with serologically proved infection was found useful. This indicator is relatively independent of randomization and is more sensitive as compared to the incidence rate. In the 1973 trial, influenza A 2 England was prevalent, the MR of infection being 15.4% in the Impulsin group and 44.9% in the placebo group (P less than 0.0002). After elimination of persons with preinfection antibodies greater than or equal to 1:256 the corresponding values of MR were 17.6% and 46.6% (P less than 0.005), reflecting the "relatively clean effect" of Impulsin. In the 1974 trial, where influenza B Hong-Kong was prevalent, MR was 14.3% and 57.1%, respectively (P less than 0.001). Preinfection antibodies were negligible. The preliminary prophylactic index of the drug seemed to be 4.3 for combined adenoviral infections (trials 1973 and 1974 taken together). In the 1975 trial, the results of serological examination were unsatisfactory. Antibodies vs. influenza A Port Chalmers were found in 24.5% of ARD only. The differnce is aetiologically unclarified ARD was statistically significant. Although displaying a significant limitation of clinical infections, the administration of Impulsin did not seem to have any influence on the formation of antibodies.     

Live enteroviral vaccines for the emergency nonspecific prevention of mass respiratory diseases during fall-winter epidemics of influenza and acute respiratory diseases]

The results of the 3-year controlled trials of a new method of nonspecific urgent prophylaxis of influenza and acute respiratory diseases (ADR) by immunization of healthy adults with standard live enterovirus oral vaccines, introduced in 2-3 administrations at intervals of 7-10 days, at the initial stages of autumn and winter epidemics are presented. Observations, carried out in three republics, covered more than 150,000 persons immunized with enterovirus interferonogenic vaccines. A considerable decrease in morbidity rate among the vaccinees was achieved (on the average, by 3.2 times) in comparison to that among nonimmunized subjects. The method of nonspecific prophylaxis with live enterovirus interferonogenic vaccines is recommended during outbreaks of diseases induced simultaneously by several causative agents of influenza and ARD, as well as by pathogenic enterovirus strains.     

Effect of a complex system of controlling influenza on a citywide scale on the etiological structure of acute respiratory diseases

Materials on the etiological structure of acute respiratory diseases (ARD) and the spread of respiratory virus infection among the population of the city under the conditions of mass vaccinal prophylaxis and chemoprophylaxis are presented. These materials indicate that the proportion of influenza A virus in the etiological structure of ARD decreased by half as the result of introducing the complex system of influenza control in the city. The proportion of other causative agents of ARD before and after introducing the complex system of influenza control irregularly varied among different age groups of the population without statistical significance. The indices characterizing the spread of influenza A virus infection among the population of the whole city were found to be significantly decreased during the second period of observation.     

Immunoprophylaxis of acute respiratory diseases with bacterial multicomponent vaccine VP-4 in children at preschool institutions

The prophylactic action of polycomponent vaccine B[symbol: see text]-4, prepared from the antigens of opportunistic bacteria, on morbidity rate in acute respiratory diseases (ARD) of bacterial and mixed (bacterial and viral) etiology in 121 children aged 2-5 years, attending pre-school institutions was evaluated. For comparison, a group of 118 children of the same age from the same institutions was formed. The vaccine was introduced after the schedule consisting of 3 intranasal and 6-9 oral administrations made at intervals of 3-4 days. The duration of the course of immunization was 26 +/- 4 days. The prophylactic effect of B[symbol: see text]-4 on ARD morbidity was evaluated by the number of ARD cases and their duration per child. The prophylactic effect of B[symbol: see text]-4 on ARD morbidity lasted 14 months (the term of observation) after immunization and was manifested by a decrease in the number and duration of ARD cases after administration of the preparation, also in a group of highly susceptible children.     

The epidemic process of an acute streptococcal respiratory infection in large organized collectives of children

The study of the specific features of the development of the epidemic process of scarlet fever, tonsillitis, and acute respiratory diseases (ARD) in two large organized groups of children revealed the presence of some differences which depended on the character of prophylactic measures taken in these groups. Thus, in the absence of prophylaxis with bicillin a pronounced increase in the level of carriership, accompanied by an increase in the infective capacity of carriers, was noted. This resulted in a high level and unfavorable dynamics of morbidity in scarlet fever, tonsillitis, and ARD. On the contrary, the use of prophylaxis with bicillin ensured the stability of the level of carriership, while the infective capacity of carriers was not pronounced. At the same time a rise in ARD morbidity was insignificant, and morbidity in scarlet fever and tonsillitis was reduced to nil.     

Control of adenovirus acute respiratory disease in U.S. Army trainees.

Although limited almost exclusively to military trainees, acute respiratory disease (ARD) caused by adenovirus types 4 and 7 had been the leading cause of hospitalization in U.S. Army personnel. This decrease which resembles influenza in clinical manifestations led to hospitalization of as many as 50% of military trainees in midwinter and imposed a heavy burden on military hospitals and training programs. In studies undertaken from 1965 to 1970, live adenovirus type 4 and subsequently type 7 vaccines were found to be safe and immunogenic and to confer protection against type specific adenovirus ARD. For the past 5 yr. military trainees have been immunized with both adenovirus vaccines during periods of expected adenovirus disease. Since 1966, use of adenovirus vaccines has been monitored through the adenovirus surveillance program which yields weekly data on incidence and etiology of ARD in basic combat trainees. Since 1973, stable adenovirus vaccines have resulted in excellent control of adenovirus ARD. Potential problems with this immunization program are discussed.     

Bacterial lysate (I.R.S. 19) applied intranasally in the prevention of acute respiratory diseases in children: a randomized double-blind study

A controlled trial was undertaken to test I.R.S. 19 (a commercial intranasal spray) versus placebo in the prevention of acute respiratory diseases (ARD) in 825 maternity-school children in three cities; another control group of 327 children received neither I.R.S. 19 nor placebo. The spraying was done twice a day for a total of 20 spraying days in each child; sprayings were interrupted on weekends and during absence, the mean spraying period being 34 calendar days. During the 6-month study (1 November to 30 April) the children were monitored for ARD morbidity causing absence from school. A total of 1,585 such ARD cases occurred; their etiology was not investigated. The indices evaluated were: total duration of ARD-associated absence, ARD incidence, and mean duration of one illness. With the administration schedule used, I.R.S. 19 did not, in an overall evaluation, surpass placebo in any of these indices in either normal children or a subgroup of children with presumed enhanced ARD susceptibility.     

The effect of immunotherapy with the VP-4 multicomponent vaccine in children with frequent acute respiratory diseases and obstructive bronchitis

The results of prolonged observations on children with frequent acute respiratory diseases (ARD), subject to immunoprophylaxis with the use of polycomponent vaccine (VP-4), prepared from the antigens of opportunistic microorganisms, are presented. The vaccine was introduced to 30 children in 3 intranasal administrations and 6-8 oral administrations. The morbidity rate of the children was registered and their clinical status was evaluated for a year after the introduction of vaccine VP-4. As revealed in these observations, the frequency of ARD cases among the immunized children decreased 3 times or more in comparison with that among the same children, registered during a year prior to the introduction of the vaccine. In addition to a decrease in the frequency of ARD cases, a decrease in their duration and in the number of antibiotic administrations, as well as in the necessity of hospitalization, were also registered.     

The efficacy of exogenous and endogenous interferonization in preventing influenza]

In this work the results of using interferon (IFN), Dibasol and the combination of these preparations for the urgent prophylaxis of influenza and acute respiratory diseases (ARD) among the employees of the Gamaleia Research Institute of Epidemiology and Microbiology (USSR Acad. Med. Sci.) are summarized. Reaferon and Dibasol decrease ARD morbidity 2 times and leukocytic IFN decreases it 1.4 times, while the combined administration of Dibasol and IFN has proved to be ineffective. Reaferon is mainly a prophylactic remedy; it has been found to bring about almost no decrease in the number of patients at the peak of morbidity, while pronouncedly decreasing it in two weeks after the administration of the preparation. Dibasol has a curative effect, sharply interrupting the beginning rise of morbidity. Reaferon normalizes the characteristics of the IFN status, decreasing the amount of circulating IFN and enhancing the capacity of leukocytes for producing alpha-IFN and gamma-IFN. For the prophylaxis of respiratory infections the use of Reaferon is advisable 3-4 weeks prior to the beginning of the epidemic and then, when the first cases of infection are registered, the course of prophylaxis with Dibasol should be carried out.     

Production of lipopolysaccharide-induced tumour necrosis factor during influenza virus infection in mice coincides with viral replication and respiratory oxidative burst

Increased morbidity and mortality occur regularly during influenza epidemics. The exact mechanisms involved are not well defined but bacterial superinfection of influenza virus infected patients is considered to play an important role. In the present study, the effect of influenza virus infection on in vivo production of turnout necrosis factor (TNF) in response to bacterial stimuli was investigated. Release of TNF in mice infected by an aerosol of influenza virus was significant after administration of bacterial lipopolysaccharide (LPS) at 72 h, whereas administration of homologous influenza virus produced only modest amounts of TNF at 96 h. Significant production of TNF was observed 48 h after intravenous administration of infectious influenza in response to LPS but not with the homologous virus. TNF induced after influenza virus infection could be blocked by a specific murine anti-TNF monoclonal antibody. Higher TNF production following aerosol influenza infection correlated with peak titres of influenza virus in the lungs of infected mice and with enhanced generation of luminoldependent chemiluminscence.     

Etiological structure of acute respiratory viral infections in children hospitalized in 1981-1999

The role of influenza and parainfluenza viruses, respiratory syncytial viruses and adenoviruses in the etiological structure of morbidity in acute respiratory virus infections (ARVI) in children hospitalized during the 19 year period is analyzed. As the result of examination of 56,287 patients by direct immunofluorescent test, respiratory viruses were detected in 21% of cases. The seasonal character, periodicity and level of ARVI morbidity were established. According to medical records, in the 1990s ARVI took a more severe course in children than that observed in the 1980s. In addition, the data on morbidity among children regarding rotavirus infection and ARVI were found to be similar.     

TT virus in the nasal secretions of children with acute respiratory diseases: relations to viremia and disease severity

The natural history and pathogenic potential of the recently identified TT virus (TTV) are currently a matter of intensive investigation. In an attempt to shed some light on these issues, nasal and blood specimens of 1- to 24-month-old children hospitalized with a clinical diagnosis of acute respiratory disease (ARD) were examined for the presence, load, and genetic characteristics of TTV. The results have indicated that at least in young children, the respiratory tract not only represents a route by which abundant TTV can be shed into the environment but also may be a site of primary infection and continual replication. Although we found no compelling evidence that TTV was the direct cause of ARD in some of the children studied, the average loads of TTV were considerably higher in patients with bronchopneumonia (BP) than in those with milder ARD, raising interesting questions about the pathophysiological significance of TTV at this site. Furthermore, group 4 TTV was detected almost exclusively in children with BP.     

Etiology of influenza according to the data of serological diagnostics in hospital patients in St. Petersburg at the period of 1968 - 2000

The specific features of the etiology of influenza in children and adults at the period of the simultaneous circulation of two subtypes of influenza virus A, according to the results in the hemagglutination-inhibition reaction in 261,490 influenza and ARD patients hospitalized in St. Petersburg in the course of 32 years, were analyzed. The results of serological diagnostics was shown to correspond to the data of the identification of influenza viruses in Russia and all over the world. At the period of epidemics diseases caused by the main infective agents of the epidemics were detected in 11.0% - 51.0% of cases and by concomitant infective agents, in 0.6% - 12.4% of cases. After the reappearance of influenza virus A(H1N1) in circulation higher frequency of mixed forms of infection and the presence of competition between the subtypes of influenza virus A was noted. In young children a decrease in differences in the proportion of influenza cases, caused by the main and concomitant infective agents, as well as between the detection of influenza in epidemic and in summer periods, was registered.     

Outbreak of acute respiratory disease caused by human adenovirus type 7 in a military training camp in Shaanxi,China

Outbreaks of ARD associated with HAdV have been reported in military populations in many countries. Here, we report an ARD outbreak caused by HAdV‐7 in a military training camp in Shaanxi Province, China, from February to March of 2012. Epidemic data and samples from the patients were collected, and viral nucleotides from samples and viral isolations were detected and sequenced. IgG and IgA antibodies against HAdV, and the neutralization antibodies against the viral strain isolated in this outbreak, were detected. Epidemiological study showed that all personnel affected were males with an average age of 19.1 years. Two peaks appeared on the epicurve and there was an 8‐day interval between peaks. Laboratory results of viral nucleotide detection carried out with clinical specimens were positive for HAdV (83.33%, 15/18). Further study through serum antibody assay, virus isolation and phylogenetic analysis showed that HAdV‐7 was the etiological agent responsible for the outbreak. IgA antibody began to appear on the 4th day after the onset and showed 100% positivity on the 8th day. The virus strain in the present outbreak was highly similar to the virus isolated in Hanzhong Shaanxi in 2009. We conclude that HAdV‐7 was the pathogen corresponding to the outbreak, and this is the first report of an ARD outbreak caused by HAdV‐7 in military persons in China. Vaccine development, as well as enhanced epidemiological and virological surveillance of HAdV infections in China should be emphasized.     

Significance of Legionella pneumophila in human respiratory pathology

The etiological structure of acute pneumonia and acute respiratory diseases was studied with a view to establishing the proportion of L. pneumophila among other causative agents of such diseases. A total of 299 patients were examined over time. The etiological diagnosis based on the data of serological examination was made in 70.6% of the patients with acute pneumonia and in 65% of the patients with acute respiratory viral infections and influenza. In the etiology of pneumonia, the leading role was found to belong to influenza A (H3N2) and B viruses, as well as to adenovirus, while in the etiology of acute respiratory viral infections and influenza, to influenza B virus, adenovirus and Mycoplasma pneumoniae. The importance of L. pneumophila in the etiology of acute pneumonia and acute respiratory diseases was shown. The proportion of L. pneumophila proved to be, on the average, 9.9% in acute pneumonia and 9.8% in acute respiratory diseases. L. pneumophila occurred most frequently in mixed infections in combination with adenovirus and influenza B virus. Diseases of Legionella etiology were found to have a seasonal character, occurring mostly in winter and spring.