ABSTRACT
Four viruses isolated from poultry in the USSR and Poland were identified as influenza A strains. One strain was closely related to fowl plague virus, the second showed an antigenic relationship to A/chicken/Scotland/59 (Hav5N1), and two others were antigenically related to A/duck/Ukraine/1/63 (Hav7Neq2) and A/duck/England/56 (Hav3Nav1). Antibodies to different strains of influenzavirus were detected in sera collected from poultry and from wild birds in the northern area of the USSR. More of the sera collected from migratory sea birds in the autumn gave HI reactions than did those collected in the spring. HI reactions were of higher titre when recent locally isolated viruses were used than with reference strains of influenzavirus. Sera collected in the autumn of 1969 from wild sea birds (mostly herring gulls, ducks, arctic loons, and long-tailed ducks) frequently showed HI activity not only with avian influenzavirus but also with A/equine/Miami/1/63 (Heq2 Neq2) and A/Hong Kong/1/68 (H3N2). The significance of these findings is discussed.
Subject(s)
Antigens, Viral/analysis , Bird Diseases/microbiology , Orthomyxoviridae Infections/veterinary , Orthomyxoviridae/immunology , Animals , Animals, Domestic , Bird Diseases/diagnosis , Birds , Europe , Orthomyxoviridae/isolation & purification , Orthomyxoviridae Infections/diagnosis , Serologic Tests , USSRABSTRACT
The discovery in migrating birds of influenzaviruses and the demonstration of relationships between strains found in man and in birds show the importance of these investigations for influenzavirus ecology. Investigation of birds in the far-east regions of the USSR is particularly important as many of them migrate to South-East Asia and China, the regions from which human influenza pandemics seem to originate. A total of 262 bird sera from these regions were titrated by the HI method with 20 different influenzavirus antigens (5 human, 2 equine, 1 swine, and 12 avian influenzaviruses). Haemagglutination-inhibiting activity was found in 16.8% of the tested sera, most frequently in sera of Anas formosa, Gallinago gallinago, Anas falcata, and Larus crassirostris. HI activity to A/turkey/Wisconsin/66 (Hav6N2) was found in 7.3% of the sera.
Subject(s)
Antibodies, Viral/analysis , Bird Diseases/microbiology , Orthomyxoviridae Infections/veterinary , Orthomyxoviridae/immunology , Animals , Bird Diseases/diagnosis , Birds , Hemagglutination Inhibition Tests , Orthomyxoviridae Infections/diagnosis , Orthomyxoviridae Infections/microbiology , USSRABSTRACT
Influenza A and influenza B viruses were adapted to growth at 25 degrees C. When given to volunteer subjects, the viruses were attenuated but remained infective and antigenic. The minimum immunizing dose of an egg-adapted virus appeared to be 10(5.0) EID(50). Cloning by plaque selection at 25 degrees C gave seed cultures of relatively low infectivity titres. These titres were increased when necessary by passage at 33 degrees C. No reversion to virulence was observed.Viruses attenuated in the United Kingdom and the USA were compared in volunteer trials with vaccine strains that had already been used in the USSR for mass immunization. Results were broadly similar. Currently available methods of attenuation and work with temperature-sensitive mutants are reviewed.
Subject(s)
Influenza Vaccines , Orthomyxoviridae/pathogenicity , England , Hemagglutination Inhibition Tests , Humans , Influenza, Human/immunology , Orthomyxoviridae/immunology , USSR , United StatesABSTRACT
Vaccination is at present the only means of influenza control; so far, large-scale trials of live vaccine have been made mainly in the USSR. This paper discusses such a trial in persons above 12 years of age.About 40% of the population of Smolensk and about 50% of the population of the nearby town of Jarcevo were vaccinated with live influenza vaccine in the winters of 1964-65 and 1965-66, and the incidence of influenza and other acute respiratory diseases in these towns during the 1965 epidemic and the 1966 pre-epidemic period was compared with that in nearby "control" towns. Most subjects were vaccinated 2 or 3 times with divalent A2-B vaccine in 1964, but some only once; in 1965-66, most subjects were vaccinated once with monovalent B vaccine and once with divalent A2-B vaccine.Analysis of the incidence data for the towns involved, of more detailed incidence data for about 30 000 workers and 4000 schoolchildren in Smolensk and one control town, and of a controlled trial involving about 4000 persons, indicated that the large-scale vaccination led to a reduction in incidence of about 1.5- to 2-fold in 1965 and of about 2- to 3-fold in 1966. Limited serological studies in 1966 indicated that the reduction in incidence in the group studied was not 3-fold but 4-fold. The rather low protection offered by the 1964 vaccination may have been due to the low immunogenicity of the vaccine, or to the fact that the vaccine strains used did not correspond exactly to the influenza virus strains circulating in nature.
