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. The possible origin of isolated PMV-2 viruses is discussed.

Analysis of influenza A virus neuraminidase using lectin test and monoclonal antibodies.

Influenza viruses causing epidemics in the U.S.S.R. in 1968-1982 and 1983 were analysed in the lectin test (LT) using polyclonal and monoclonal antibodies with specificity against neuraminidase (NA) of N2 subtype. Heterogeneity of the U.S.S.R. virus isolates in the reaction with monoclonal and polyclonal antibodies was demonstrated, though they were coming from the same year epidemic. The LT turned out to be an appropriate method to detect the antigenic drift in influenza virus NA. The results of LT were in a good agreement with those obtained by colorimetric estimation of the inhibition of enzyme activity and by competitive solid phase radioimmunoassay (SP RIA). In the LT only low steric inhibition of the NA with antihaemagglutinin monoclonal antibodies (MoAb) reacting in haemagglutination inhibition and virus neutralization tests was detected.

Population variability of serotype 3 adenoviruses circulating in the U.S.S.R.

Composition analysis of natural populations of adenovirus serotype 3 (Ad 3) strains--based on samples selected out of 170 strains isolated in different regions of the U.S.S.R. from 1976 to 1981--has demonstrated their inhomogeneity with respect to cytopathogenicity and haemagglutination activity. The strains were classified into 3 groups: low, medium and highly cytopathic. The cytopathogenicity of the strains appeared to be a rather variable feature dependent on regional climate and on seasonal complexity. In summer low cytopathogenic viruses predominated. The epidemic activity of circulating adenoviruses (proportion of adenoviruses in the aetiology of acute respiratory disease) correlated with the level of their cytopathic activity.

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. In Czechoslovakia, 2 epidemics (in the 1980/81 and 1983/84 seasons) were due to influenza A (H1N1) virus. The epidemic in the 1981/82 season had two waves of unequal heights and a mixed type B and subtype A (H3N2) etiology; a two-wave epidemic associated with isolates of influenza A (H1N1) and influenza B viruses was also recorded in the 1983/84 season. The influenza A (H3N2) epidemic in 1983 was of explosive character. All influenza viruses circulating in the two countries between 1980 and 1985 were of the same antigenic profile, but were isolated from the epidemics that occurred in different influenza seasons. The virological surveillance revealed strains of virus closely related to drift variants detected from outbreaks in 1977-1979 and the new variants A/Chile 1/83, A/Philippines 2/82, A/Caen 1/84 and B/USSR 100/83.

Return of epidemic A1 (H1N1) influenza virus.

Limited outbreaks of influenza were reported in the far east of the U.S.S.R. early in November, 1977, and a week or two later in cities in Siberia and the European parts of the U.S.S.R. The majority of influenza-virus isolates belonged to the H1N1 subtype of influenza-A virus, though strains of the current H3N2 subtype were also isolated. A moderate epidemic of H1N1 influenza spread throughout the country in the middle of December. Mainly children over 5 years and young adults were infected.

Influenza in the USSR in 1977: recurrence of influenzavirus A subtype H1N1.

Early in November 1977, several outbreaks of influenza were reported in the far eastern region of the USSR. The epidemic spread rapidly throughout the country affecting mainly people under the age of 20 years. Most of the strains of virus isolated were found to be influenza A subtype H1N1. The serological characterization of the strains is described in this paper.

Comparison of influenza viruses isolated from man and from whales.

Four isolates of influenza virus strains from Moscow and Habarovsk that caused outbreaks of influenza in November and December 1977 in several cities of the USSR were studied and their haemagglutinins and neuraminidases were compared with those of other human and animal influenza viruses including A/whale/Pacific Ocean/76. In H1 tests these isolates, designated A/USSR/77, reacted with immune serum against A/FM/1/47 (H1N1) to the homologous titre, and with antiserum against A/whale/PO/19/76 virus to 1/8 of the homologous titre. In neuraminidase inhibition tests all A/USSR/77 isolates showed the presence of human N1 type neuraminidase, more closely related to A/sw/New Jersey/76 (Hsw1N1) than to A/FM/1/47 (H1N1) virus. The haemagglutinin of A/whale/Pacific Ocean/19/76 virus occupies an intermediate position between H0 and H1, but its neuraminidase is close to Nav2. The virus from whales multiplies better at low (28 degrees C) and at high (40 degrees C) temperatures than do the viruses of human origin that were tested.

Persistent SV5 virus infection in continuous cell cultures.

A continuous line of guinea pig kidney cells (CGPK/H) and a continuous line of mouse fibroblasts (L/H) spontaneously infected with parainfluenza virus SV5 were found. These cultures showed no enhanced cell degeneration or symplast formation, nor was haemagglutinin accumulation or infectious virus demonstrated in them. However, regular reproduction of ribonucleoprotein (RNP) characteristic of parainfluenza viruses, morphologically complete virions and antigens producing antibody to SV5 virus were found in the cells. Focal haemadsorption neutralized by antiserum to SV5 virus was also demonstrated. The infection persisted in the cell populations for over 2 years (the observation period) under standard conditions of cell dispersion and subcultivation.