Molecular epidemiology of adenoviruses isolated in Iceland during 1988-1990.

All human adenoviruses isolated in Iceland during 1988-1990 have been subjected to restriction endonuclease analysis. Of 55 isolates altogether, subgenus C (Ad1, Ad2, and Ad5) predominated with 42 isolates followed by subgenus B (Ad3 and Ad7) with 12. Analysis of the 9 Ad1 isolates revealed 6 DNA-variants. Among these the established DNA-variants D4, D7, and D10 were recognized. The remaining 3 DNA-variants were primarily found in Iceland. Among the 22 Ad2 isolates, 7 DNA-variants could be distinguished. D2 predominated with 15 isolates whereas the prototype was isolated only once. The novel 5 DNA-variants of Ad2 were all closely related to D2. Analysis of the 11 Ad5 isolates revealed 6 DNA-variants, 2 of which (D2 and D5) were already established. Ice2 and D3 were the most common occurring DNA-variants of Ad5. Ad5 showed the highest degree of genomic variability within subgenus C, both in terms of the low degree of pair-wise comigration of restriction fragments and the number of principal variants of RE-patterns. Analysis of the 9 Ad3 isolates revealed 3 DNA-variants: D3, D10, and Ice1 (a novel DNA-variant that resembles D10). The DNA-variants D3 and D10 were each represented by 4 isolates. The three Ad7 isolates belonged all to the DNA-variant D5.

Characterization of two divergent adenovirus 31 strains.

Two divergent strains of adenovirus type 31 were analyzed by neutralization test and restriction endonuclease (RE) patterns in an effort to find the basis for their genetic variability. One strain, isolated from the throat of a child in Maryland during an upper respiratory illness in 1968, was partially neutralized by Ad 31 antisera (to 16-fold lower than homologous titer) while its own antiserum fully neutralized prototype Ad 31 virus, but shared only 9% of comigrating RE fragments with Ad 31 prototype (vs. 30% with Ad 18 prototype); however, PCR tests specific for the inverted terminal repeat (ITR) sequence of Ads 12 and 18 were negative. The other strain, recovered from a stool sample from an infant with diarrhea in Georgia in 1979, was inhibited by Ad 31 antiserum to within 4-fold homologous titer, but shared only 15% of comigrating fragments with Ad 31 prototype (vs. 91% with Ad 18 prototype); ITR-specific PCR tests with this virus were positive for Ad 12/Ad 18. These data suggest that both strains are from separate evolutionary lines of Ad 31 unrelated to all other isolates studied to date by RE analysis, and that the partial neutralization by prototype Ad 31 antisera might represent small mutations in the hexon gene.