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Comparison of influenza viruses isolated from man and from whales
Abstract:
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.
Insights
New influenza virus strains (A/USSR/77) from the USSR in 1977 showed human N1 neuraminidase. Their hemagglutinins were distinct from whale influenza A/whale/Pacific Ocean/76, which replicated better at extreme temperatures.
Area of Science:
- Virology
- Epidemiology
Background:
- Influenza outbreaks occurred in the USSR in late 1977.
- Characterization of novel influenza strains is crucial for understanding viral evolution and public health impact.
Purpose of the Study:
- To characterize the hemagglutinins and neuraminidases of newly isolated influenza virus strains (A/USSR/77) from the USSR.
- To compare these isolates with other human and animal influenza viruses, including a whale influenza virus (A/whale/Pacific Ocean/76).
Main Methods:
- Hemagglutination inhibition (HI) tests were performed using specific antisera.
- Neuraminidase inhibition tests were conducted to determine neuraminidase type.
- Comparative analysis of viral proteins (hemagglutinin and neuraminidase) was performed.
Main Results:
- A/USSR/77 isolates possessed human N1 type neuraminidase, more related to A/sw/New Jersey/76 than A/FM/1/47.
- A/USSR/77 hemagglutinins showed reactivity with A/FM/1/47 antiserum and partial reactivity with A/whale/PO/76 antiserum.
- A/whale/Pacific Ocean/76 virus exhibited an intermediate hemagglutinin (between H0 and H1) and a Nav2-like neuraminidase.
- Whale influenza virus demonstrated superior replication at low (28°C) and high (40°C) temperatures compared to tested human strains.
Conclusions:
- The 1977 USSR influenza isolates (A/USSR/77) possessed a human N1 neuraminidase.
- The hemagglutinin of A/USSR/77 differed from that of the whale influenza virus A/whale/Pacific Ocean/76.
- Whale influenza virus displayed enhanced thermotolerance, suggesting potential differences in host adaptation or replication strategies.