[The antigenic and biological properties of influenza A (H1N1) viruses isolated in the USSR and the Czechoslovak Federal Republic in 1988-1989].

A comparative study of influenza A (H1N1) virus strains isolated in one epidemic season (1988-1989) in neighbouring countries was carried out. Using polyclonal and monoclonal antibodies, some of the isolates were shown to have different antigenic and biological properties which probably determined the different intensity of the epidemic situation in the USSR and CzSFR in 1988-1989.

[Surveillance of acute respiratory diseases in the 1988/1989 season in Czechoslovakia].

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.

The source of avian paramyxoviruses isolated during an outbreak of influenza among children.

In 1986 five avian paramyxovirus (PMV) strains were isolated in embryonated chicken eggs from sick children with influenza. The strains were identified as PMV-2 serotype due to the close antigenic relationships between their HN-proteins and of the reference PMV-2 strains isolated from different birds all over the world. No seroconversion to the isolates was found in the sick children, however, HI-antibodies were detected in hen's sera, eggs of which were used for the new strains isolation.

Further evidence of the circulation of PMV-4 and influenza viruses with N2-1957 enzyme in the migratory waterfowls.

In the years 1980-1984, one paramyxovirus type 4 and 11 influenza viruses were isolated from cloacal swabs collected from migratory waterfowls in Fed. Rep. Germany.

[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].

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.

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.

Characterization of envelope antigens of influenza A (H3N2) virus isolated during 1983-1985 epidemics and from sporadic cases of infection.

Ten strains of influenza A (H3N2) virus isolated from an outbreak in 1983, and ten strains isolated in 1985 from sporadic cases of infection were included in the study. For characterization of envelope antigens were used the polyclonal and monoclonal antibodies tested in the reaction of haemagglutinin inhibition, neuraminidase inhibition, and by lectin test. The strains but slightly different in the tests with polyclonal antibodies could clearly be classified to 3-4 groups using 5 monoclonal antibodies to H antigen of A/Bangkok 1/79 and A/Philippines 2/82 strains.

Influenza activity in Czechoslovakia and the USSR, 1980-1985.

Between 1980 and 1985, Czechoslovakia had experienced 4 and the USSR 3 major influenza outbreaks. Of the 3 epidemic outbreaks in the USSR, 2 were associated with influenza B virus (in the 1980/81 and 1983/84 seasons) and 1 with influenza A virus of the H3N2 subtype. In the USSR, influenza A (H1N1) virus never predominated as a cause of epidemic during the 5 years period.

Antibodies to new variants of subtype A(H3 N2) influenza virus in pigs.

Following an explosive epidemic of A(H3N2) influenza among the human population of Czechoslovakia in 1983, haemagglutination-inhibiting antibodies (titre range 10-640) against strains A/Texas/77, A/Bangkok/79 and A/Philipines 2/83 were detected in 93% of sera collected from 135 pigs on three farms. Only 6.6% of sera were negative.

Incidence of paramyxoviruses in free-living birds in 1978-1982.

Together 41 paramyxovirus (PMV) strains (25 PMV-1, 10 PMV-4, and 6 PMV-6 serotypes) were isolated from cloacal swabs of 910 free-living birds trapped in West Slovakia from 1978 to 1982. The PMV strains were found in 9, mostly aquatic bird species. Strains belonging to the PMV-1 serotype were isolated yearly, indicating its wide distribution and circulation in nature.

Type A influenza virus strains isolated from free living ducks in Czechoslovakia during 1978-1981.

Eight influenza virus A strains were isolated from 269 cloacal swabs taken from wild ducks (Anas platyrhynchos), shot during their autumn migrations in the years 1978-1981. One strain was identified as subtype A-H3N8N6 (Hav7Neq2Nav1), the remaining seven as subtype A-H4N6 (Hav4Nav1).

Mixed infections with influenza A and B viruses.

In the course of an influenza A and B epidemic, influenza virus was isolated from 46 patients. Seven of these patients showed seroconversion against influenza virus plus another respiratory virus. In 9 patients, simultaneous antibody increase against both influenza A and B viruses was demonstrated, but only a single virus type was isolated.

Persistence in nature of influenza virus A/eq/Praha/56 (Heq1Neq1).

Equine influenza occurred in Czechoslovakia 14 years after the last epizootic in horses that had returned from abroad. Six strains A (Heq1Neq1) antigenically related to, but not identical with, strain A/eq/Praha/56 were isolated from 10 washings. Seroconversion was demonstrated with paired sera, but the antibody increase was more marked against the newly isolated strain.

A further member of the Yucaipa group isolated from the common wren (Troglodytes troglodytes).

In 1977, 477 small birds of 52 species were virologically examined. Five cloacal swabs from Troglodytes troglodytes yielded two paramyxovirus strains which were found antigenically related to, but not identical with Ch/Yucaipa/California/56 virus according to three serological tests. The ecological significance of these findings and the possibility of paramyxovirus classification into four types are discussed.

Vaccination of an adolescent group with A (H3N2) + A(HSW1N1) bivaccine before an A (H1N1) influenza epidemic.

A group of 35 adolescents aged 18--22 years were vaccinated intradermally with 0.2 ml of a mixed A (H3N2) + A (Hsw1N1) formolized vaccine and revaccinated with A (Hsw1N1) monovaccine 10 days before an A (H1N1) influenza epidemic. The vaccination had no effect on morbidity or the clinical course of disease.

A study on the role of birds in the spread of infections.

During three expeditions undertaken in March 1977 to June 1978, 797 cloacal swabs were collected from birds of 54 species. Seven salmonella strains of six serotype were isolated from Larus ridibundus (five strains), Corvus frugilegus and Acrocephalus schoenobaenus (one each). Four strains of influenza A (HAV2 NA4V) virus were isolated from Larus ridibundus.

Isolation of an influenza A virus strain from a bird embryo (Larus ridibundus) collected in Slovakia.

Avian influenza virus A/Larus 36/77 (Hav7Nav1) was isolated in 1977 from a trinket (Larus ridibundus) embryo. This result suggests the possibility of vertical transmission of influenza A virus.

Isolation of influenza virus from wild ducks (Anas platyrhynchos).

In the course of studies on influenza virus ecology, Influenzavirus A was isolated from a cloacal smear from a wild duck (Anas platyrhynchos) caught in west Slovakia. The strain was identified as A(Hav7Nav1). The results of virus isolation experiments from other species of aquatic and other small birds were negative.