Evidence for natural reassortants of human rotaviruses belonging to different genogroups

Abstract

Of 335 rotavirus isolates associated with diarrheal disease in Bangladesh that were culture adapted and subsequently characterized for electropherotype, subgroup, and serotype, 9 had properties that suggested they may be natural reassortants between human rotaviruses belonging to different "genogroups." Two of these were examined in greater detail by RNA-RNA hybridization with prototype strains representative of each of the three proposed human rotavirus genogroups. One subgroup II isolate, 248, with a "long" electrophoretic pattern was neutralized by hyperimmune antisera to both serotype 2 and 4 strains. Consistent with these results, seven RNA segments of this isolate formed hybrids with human strains belonging to the Wa genogroup and four segments hybridized with strains belonging to the DS-1 genogroup. The second isolate examined, 456, belonged to subgroup II and had a long electrophoretic pattern but was found to be a serotype 2 strain. This isolate also appeared to be an intergenogroup reassortant because three of its segments formed hybrids with strains belonging to the Wa genogroup and eight hybridized with viruses of the DS-1 genogroup. On the basis of the relative migration rates of these RNA-RNA hybrids during gel electrophoresis, a suggested origin for each gene segment was proposed which was consistent with the results expected from electrophoretic, subgroup, and serotypic analyses.

The Relative Frequencies of G Serotypes of Rotaviruses Recovered from Hospitalized Children with Diarrhea: A 10‐Year Survey (1987–1996) in Japan with a Review of Globally Collected Data

“…Eighteen studies reported that none of the rotavirus specimens possessed an unusual combination of serotype and electropherotype. However, several studies reported strains having an unusual combination of serotype and electropherotype (4,6,16,55,57,64,72,74). The frequency of the isolation of these rotaviruses varied from nil (0/605 in New England) (7) to 2.7% (9/335 in Bangladesh) (72).…”

“…1) and G2. Serotype G2 strains possessing long RNA patterns have thus far been reported in six studies (1,6,31,43,65,72), and some were demonstrated by RNA-RNA hybridization to be reassortants between members of the Wa and DS-1 genogroups (35,72).…”

Typing of human group A rotavirus with alkaline phosphatase‐labeled oligonucleotide probes or a monoclonal enzyme immunoassay in unfrozen stools of children with diarrhea in Bangkok

“…The experience of determining G types in Australia [Coulson et al, 1988;Unicomb et al, 19881, England [Noel et al, 19911, and Japan [Taniguchi et al, 19871 where most rotavirus G types are similar to the reference strains and types 1 and 2 are predominant, is different than i n Bangladesh where genetic reassortment of the viral genome occurs frequently [Ward et al, 1990;Ahmed et al, 19911 and the predominant G types change within a few months [Ward et al, 19911. Little is known about the distribution and seasonal variation of rotavirus G types in children in developing…”

Classical and molecular techniques for the diagnosis of viral gastroenteritis

“…So far, 14 G types and more than 20 P types have been differentiated indicating extensive genomic diversity within group A rotaviruses (Estes, 1996). As these proteins are coded for by different RNA segments and as rotaviruses reassort readily in doubly infected cells both in vitro (Garbarg-Chenon et al, 1984) and in vivo (Gombold and Ramig, 1986;Ward et al, 1990), the observed diversity due to various combinations of VP7 and VP4 types becomes very large.…”