Persistence of Q strain of H2N2 influenza virus in avian species: antigenic, biological and genetic analysis of avian and human H2N2 viruses.

The characteristics of an avian influenza virus were compared in detail with those of human Asian (H2N2) influenza viruses. Antigenic analysis by different antisera against H2N2 viruses and monoclonal antibodies to both the hemagglutinin and neuraminidase antigens showed that an avian isolate, A/duck/München/9/79 contained hemagglutinin and neuraminidase subunits closely related to those of the early human H2N2 viruses which had been prevalent in 1957. However, this avian virus gave low HI titers with absorbed and non-absorbed antisera to different human H2N2 viruses isolated in 1957. Like human Q phase variant, such as A/RI/5-/57 (H2N2), hemagglutination of the above avian strain was not inhibited by the purified non-specific gamma-inhibitor from guinea pig serum. Growth behavior at restrictive temperature (42 degrees C) clearly differentiate the avian H2N2 virus from human influenza viruses, showing that the former virus grew well in MDCK cells at 42 degrees C but not the latters. Genomic analysis of these viruses revealed that the oligonucleotide map of H2N2 virus isolated from a duck was quite different from those of human H2N2 viruses from 1957 to 1967. The oligonucleotide mapping also indicated that different H2N2 influenza virus variants had co-circulated in humans in 1957.

Human influenza A viruses in pigs: isolation of a H3N2 strain antigenically related to A/England/42/72 and evidence for continuous circulation of human viruses in the pig population.

An influenza virus strain isolated in Northern Italy in 1977 was identified as belonging to the H3N2 subtype (A/swine/Italy/1850/77). A close antigenic relationship to the human strain A/England/42/72 was demonstrated. Serologic surveys of 548 pig sera from 53 farms in two provinces in Northern Italy demonstrated the existence of antibodies to the swine/Italy/1850/77 strain and to A/Hong Kong/1/68, A/Victoria/3/75 and H 1 N 1 (Hsw 1 N 1) strains in the pig population.

Evidence for the natural transmission of influenza A virus from wild ducts to swine and its potential importance for man.

In 1979, epidemics of influenza occurred in pigs in Belgium from which were isolated strains of influenza A (Hsw1N1) virus antigenically closely related to Hsw1N1 strains previously isolated from ducks in North America and the Federal Republic of Germany. This finding is considered as the first supportive evidence that an influenza A virus in an avian species might have been transmitted to mammals.

[Sensitiveness of viruses fo gamma radiation (author's transl)]. / Empfindlichkeit von Viren gegen Gammastrahlen.

The sensitiveness of viruses to gamma rays was compared using eight viruses suspended with low concentration in drinking water, and four viruses present in high concentrations in tissue culture medium. The results show that the following factors are responsible for the resistance of viruses to gamma rays: 1. type of virus: the specific radiation resistance varied considerably; in general, there was a closer correlation with the general resistance of the virus to chemico-physical influences than with the type of nucleic acid of the virus examined; 2. medium of suspension and state of aggregation: high protein content and lyophilisation increased the resistance to gamma rays widely; 3. virus concentration: the virus reduction by a factor of 10 in suspensions with high virus concentration needed a higher radiation dose compared with suspensions of low virus content. All the results demonstrate the kinetics of inactivation to be a 1st order reaction. The increase of temperature to 41 degrees C did not show any significant influence.

Occurrence of Hsw 1 N 1 subtype influenza A viruses in wild ducks in Europe.

Two identical strains of influenza A viruses antigenically related to swine influenza (Hsw 1 N 1) have been isolated from adult mallard ducks (Anas platyrhynchos) in Southern Germany. They were designated A/Duck/Bavaria/1/77 and A/Duck/Bavaria/2/77. Serologic tests revealed a close antigenic relationship to the strain A/Duck/Alberta/35/76. Experimental infections of piglets with strain A/Duck/Bavaria/1/77 demonstrated the susceptibility of swine to this virus strain. The virus was isolated from nasal swabs of infected piglets up to 8 days p. inf. and from contact animals up to 9 days. No seroconversion was detected during an observation period of 30 days.

[Stability in drinking and surface water of nine virus species from different genera (author's transl)]. / Stabilität von neun Virusarten unterschiedlicher Genera in Trinkund Oberflächenwasser

The stability of nine viruses, Aujeszky, Sindbis, Vesicular Stomatitis, Newcastle Disease, Vaccinia, FMD, HCC, Reo and Teschen virus in drinking and surface water was investigated comparatively at temperatures of 9 and 15 degrees C as well as the influence of water factors like seasonal difference in temperature, pH value, hardness and sort of water. The results can be summarized as follows: 1. At temperatures of 9 to 15 degrees C the majority of the viruses remained stabil in natural water for an astonishing long time. 2. Starting with virus concentration of about 10(4) infectious units per ml Teschen, Vaccinia, Reo, HCC and ND virus could mostly be demonstrated in water longer than 200 days and FMD, Aujeszky, Vesicular Stomatitis and Sindbis virus for 20 to 50 days on average at 9 degrees C. The stability of the viruses investigated decreased in water in the named turn. 3. Based on these results it can be assumed that under natural conditions with very low virus content of some particles the labile viruses such as Toga, Herpes, Rhabdo and pH labile Picorna remain infectious in water for some days. They should not have any importance as water contaminants. More resistant viruses like Paramyxo may keep infectious for weeks and very stabile viruses such as Entero, Reo, Adeno and Pox viruses several weeks to months. 4. As to factors temperature, pH, hardness and sort of water-within the naturally differing range-only the temperature and only in the case of less resistant viruses showed significant influence on the virus stability in water.