S146 • JID 2005:192 (Suppl 1) • Gentsch et al.
S U P P L E M E N T A R T I C L E
Serotype Diversity and Reassortment
between Human and Animal Rotavirus Strains:
Implications for Rotavirus Vaccine Programs
Jon R. Gentsch,1Ashley R. Laird,1Brittany Bielfelt,1Dixie D. Griffin,1Krisztia ´n Ba ´nyai,2Madhu Ramachandran,1
Vivek Jain,1Nigel A. Cunliffe,3Osamu Nakagomi,4Carl D. Kirkwood,5Thea K. Fischer,1Umesh D. Parashar,1
Joseph S. Bresee,1Baoming Jiang,1and Roger I. Glass1
1Respiratory and Enteric Viruses Branch, Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia;
2Regional Laboratory of Virology, Baranya County Institute of State Public Health Service, Pe ´cs, Hungary;
and Genito-Urinary Medicine, University of Liverpool, Liverpool, United Kingdom;
Sakamoto, Nagasaki, Japan;
3Department of Medical Microbiology
4Nagasaki University Graduate School of Biomedical Sciences
5Murdoch Children’s Research Institute, Royal Children’s Hospital, Victoria, Australia
The development of rotavirus vaccines that are based on heterotypic or serotype-specific immunity has
prompted many countries to establish programs to assess the disease burden associatedwithrotavirusinfection
and the distribution of rotavirus strains. Strain surveillance helps to determine whether the most prevalent
local strains are likely to be covered by the serotype antigens found in current vaccines. After introduction
of a vaccine, this surveillance could detect which strains might not be covered by the vaccine. Almost 2 decades
ago, studies demonstrated that 4 globally common rotavirus serotypes(G1–G4) represent 190%oftherotavirus
strains in circulation. Subsequently, these 4 serotypes were used in the development of reassortant vaccines
predicated on serotype-specific immunity. More recently, the application of reverse-transcription polymerase
chain reaction genotyping, nucleotide sequencing, and antigenic characterization methods has confirmed the
importance of the 4 globally common types, but a much greater strain diversity has also been identified (we
now recognize strains with at least 42 P-G combinations). These studies also identified globally (G9) or
regionally (G5, G8, and P2A) common serotype antigens not covered by the reassortant vaccines that have
undergone efficacy trials. The enormous diversity and capacity of human rotaviruses for change suggest that
rotavirus vaccines must provide good heterotypic protection to be optimally effective.
Globally, rotavirus infection is the most important
cause of severe diarrhea in children. Most deaths occur
in less-industrialized countries , and health orga-
nizations worldwide are promoting the developmentof
rotavirus vaccines to help control this disease. The cur-
rent strategy is based on the use of live, attenuated
rotavirus vaccine candidates designed to elicit immu-
nity comparable to that induced by natural rotavirus
infections by providing homotypic or heterotypic pro-
tection against severe diarrhea caused by the major ro-
Financial support: Centers for Disease Control and Prevention.
Potential conflicts of interest: none reported.
Reprints or correspondence: Dr. Jon R. Gentsch, Respiratory and Enteric Viruses
Branch, MS G-04, Centers for Disease Control and Prevention, 1600 Clifton Rd.
NE, Atlanta, GA 30333 (firstname.lastname@example.org).
The Journal of Infectious Diseases
? 2005 by the Infectious Diseases Society of America. All rights reserved.
tavirus serotypes in circulation . The earliest vaccine
candidates were individual animal rotaviruses with se-
rotypes that were usually distinct from those of com-
mon human strains. Although these candidate vaccines
provided good heterotypic protection in some vaccine
trials, in other trials, they either failed to provide pro-
tection or provided the best protection only when the
serotype of the animal strain matched that of the in-
fecting human strain . These results suggested that
serotype-specific immunity might play an important
role in protection against rotavirus gastroenteritis.This
notion prompted the development of vaccine candi-
dates based on human strains and human-animal re-
assortants containing the common serotype antigensof
human strains. Over the past 2 decades, studies of the
burden of rotavirus disease and strain surveillance in
many countries have assessed the need for rotavirus
by guest on December 28, 2014
Diversity of Rotavirus Strains • JID 2005:192 (Suppl 1) • S147
microscopic reproduction of a virion (right) show the location of major structural proteins. NSP, nonstructural protein. Reproduced with permission
from Estes .
Rotavirus structure showing protein coding assignments of 11 genome RNA segments (left). Schematic diagram (middle) and cryoelectron
vaccines and have determined the most important human ro-
tavirus (HRV) serotypes that should be targeted by candidate
In this report, we review the results of strain surveillance and
new insights gained from these studies on the potential mech-
anisms of the evolution and spread of new rotavirus strains.
Although other recently published articles have reviewed the
strain diversity and genetic and antigenic variation of rotavirus,
our aim is to provide a profile of strains that could potentially
affect rotavirus vaccine programs [4–6].
ROTAVIRUS STRUCTURE AND SEROTYPES
Rotaviruses, which comprise a genus of the Reoviridae family,
have a capsid with 3 protein layers that encase a genome with
11 segments of double-stranded RNA (dsRNA) (figure 1) .
Each segment usually codes for a single structural or nonstruc-
tural protein. The inner layer encasing dsRNA is composed of
the VP2 protein and small numbers of the VP1 and VP3 pro-
teins, which are associated with the genomic RNA. This core
is surrounded by the middle protein layer, which is composed
entirely of VP6, the antigen that defines group and subgroup
(SG) specificities. The outer capsid layer consists of the VP7
glycoprotein layer, in which VP4 spikes are embedded. The 2
outer capsid proteins carry rotavirus serotype (neutralization)–
specific antigens and are encoded by segments 4 (VP4protease-
sensitive protein and P serotype antigen) and by segments 7,
8, or 9 (VP7 glycoprotein and G serotype antigen). Because the
VP4 and VP7 proteins are encoded by separate gene segments,
rotaviruses can generate new P-G serotype antigen combina-
tions through reassortment after dual infection of single cells.
Because both serotype antigens are believed to be key in the
development of protective immunity, it is necessary to assess
their prevalence and to study genetic and antigenic variation
for both G and P serotypes. Although there is good evidence
from animal experiments that passively transferred VP7- and
VP4-specific antibodies protect separately, it is less clear which
component of the immune response is most important for
protection after natural infection or vaccination .
At least 10 G serotypes and 11 P serotypes and subtypes of
HRV have been identified. Because identification of P serotypes
is technically difficult, usually, only the corresponding VP4
ies. To distinguish strains that have been identified by geno-
typing only from those identified by P-serotyping, a dual no-
menclature is used. P genotypes are expressed as “P,” followed
by a number in brackets (e.g., P), whereas P serotypes are
designated by “P” with a serotype number, followed by the
corresponding genotype in brackets (e.g., P2A) .
Rotaviruses can also be classified according to their VP6 SG
specificity (I or II), by use of an EIA with monoclonal antibod-
ies (MAbs) or by nucleotide sequencing of a VP6 gene frag-
ment [9, 10], and according to their RNA profile (long or short
electropherotype), by use of acrylamide gels and on the basis
of the migration rate of gene 11. The short-electropherotype
phenotype results from a partial duplication in gene 11, which
by guest on December 28, 2014
S148 • JID 2005:192 (Suppl 1) • Gentsch et al.
adapted from Woods et al. ) or that used G-serotyping and P-genotyping or G- and P-genotyping (right panel). The “other” category in the chart
of P and G types refers to strains that were nontypeable (NT) for P type, G type, or P and G type, or were mixed infections of common P or G types.
Findings from typing studies conducted during 1987–1991 that used G serotype–specific monoclonal antibodies (left panel; data are
causes it to migrate more slowly than gene segment 10, whereas
the standard-sized gene 11 of long-electropherotypestrainsmi-
grates faster than segment 10 .
The most common HRV strains belong to 2 distinct genome
constellations (genogroups) that are only minimally related, as
determined by high-stringency hybridization procedures per-
formed with whole-genome probes [12, 13]. Strains of the Wa
genogroup typically have long electropherotypes and carry the
SG II antigen, whereas members of the DS-1 genogroupusually
have short electropherotypes and carry the SG I antigen.
Serotypes are defined by neutralization studies, and the im-
mune targets are usually located in the outer capsid. During
the early 1980s, the first data on the distribution of rotavirus
serotypes were obtained through cultivation of the most com-
mon isolates found in stool samples and their characterization
in cross-neutralization studies by use of antisera that were hy-
perimmune to the individual strains . These studies iden-
tified 4 common serotypes, now designated serotypes G1–G4,
protein. Studies of animal models subsequently demonstrated
that VP7 played an important role in protective immunity [15,
16]. On the basis of these pioneering studies, the 4 commonly
identified G serotypes were chosen for incorporation into early
and current reassortant vaccine candidates. The subsequentde-
velopment of EIA methods for direct typing of rotaviruses in
stool samples, by use of serotype-specific MAbs [17, 18], al-
lowed for large-scale epidemiologic studies that document-
ed the global incidence of those 4 original serotypes (reviewed
elsewhere [19, 20]) (figure 2, left panel). In those studies, se-
rotype G1 represented approximatelyhalfofthestrainsglobally,
followed by serotypes G3, G4, and G2 [19, 20]. Overall, MAb
serotyping data suggested that serotypes G1–G4 represented at
least 90% of strains circulating globally and needed to be tar-
geted by candidate vaccines. Typically, ∼30% of rotavirus-pos-
itive stool specimens cannot be typed with MAbs and are, thus,
designated as nontypeable (NT) strains . Characterization
of NT strains by cultivation and by antigenic and molecular
analysis led to the identification of several new HRV serotypes
(G8, G9, and G12). Thus, by 1990, there were 7 different HRV
G types, although types G8, G9, and G12 were considered to
be rare [22–25].
The serotypes of rotavirus needed to be reconsidered when
VP4, the other outer capsid protein, was identified as an in-
dependent serotype antigen (P serotype) by sequencing of VP4
genes from strains with different G serotypes and by neutral-
ization studies [15, 26, 27]. P serotypes were also shown to be
important for protective immunity by studies of animalmodels
in which reassortants containing HRV P serotypes and animal
rotavirus G serotypes were used . However, serotyping was
a challenge in the absence of a collection of MAbs specific for
the diversity of P serotypes. Although MAbs to severalcommon
P serotypes were identified, cross-reactivity between the types
precluded their use for routine P serotyping [29, 30].
New methods that greatly facilitated strain surveillancestud-
ies, including reverse-transcription polymerase chain reaction
(RT-PCR) genotyping and automated nucleotide sequencing,
have been widely used for this purpose since the early 1990s.
A multiplexed, seminested RT-PCR method to identify G se-
by guest on December 28, 2014
Diversity of Rotavirus Strains • JID 2005:192 (Suppl 1) • S149
Examples of regionally important strains from India () [41, 42], Malawi (n p 133 ) , and Brazil (n p 100 ) n p 130
rotypes by genotyping  permitted the detection of both the
common serotypes (G1–G4) and the rare serotypes (e.g., G8
and G9) for which EIA-based serotyping antibodies wereeither
not available or not in routine use. Finally, these multiplexed
RT-PCR methods were extended to permit genotyping of the
other major neutralization protein, the P protein (VP4) [32,
33]. As for G-genotyping, common P types (P and P)
and newly identified rare P types (P, P, and P) could
be detected. Analogous hybridization methods for genotyping
were also developed [34, 35].
In 8 countries, initial surveillance studies conducted with G-
and P-genotyping or with G-serotypingandP-genotypingagain
showed the presence of 4 common types (described in depth
elsewhere ). In agreement with earlier molecular and an-
tigenic characterization of culture-adapted prototype G1–G4
strains isolated from children with diarrhea, most G1, G3, and
G4 isolates found in stool specimens were of genotype P,
with SG II specificity and long electropherotypes, whereas G2
strains were of genotype P, with SG I specificity and short
electropherotypes. Surprisingly, these studies also detected 10
uncommon reassortants, including rare P types (P, P,
and P) and G types (G5), at a combined prevalence of ∼3%,
suggesting that earlier studies in which serotyping was used
alone underestimated strain diversity. This notion proved to be
true as expanded surveillance studies, especially those conduct-
ed in developing countries where surveys were not previously
performed, yielded many examples of unexpected G and P
REVIEW OF STUDIES
We have reviewed the global distribution of rotavirus strains
as documented by studies of rotavirus diarrhea conducted in
35 countries and involving 121,000 HRV strains. Studies were
included in our review if they were published in the English
language through January 2004 and if they reported G and P
type combinations. These studies usually used RT-PCR geno-
typing exclusively, but some used a combination of G-serotyp-
ing and RT-PCR (figure 2) [37–105]. The 4 common strains—
PG1, PG2, PG4, and PG3—represent almost 72%
of all strains, and 12% consist of 2 reassortants of the recently
emerged serotype G9 (PG9 and PG9). Strains in the
“other” category typically included mixed infections with glob-
ally common types and those that could not be typed for P or
G genotype or for both P and G genotype. Approximately 6%
of typeable strains are composed of 25 other P-G combinations
types (figure 2, right panel).
A number of studies showed striking examples of strain di-
versity that, together, demonstrated the importance of serotypes
other than G1–G4 as a cause of gastroenteritis in children.These
studies included the detection of PG5 in Brazil, PG8 and
PG8 in Malawi, and PG9 in India (figure 3). Although G5
and G8 do not appear to be globally important (figure 4), they
are clearly of major importance in Brazil and Malawi [40, 95,
106]. Serotype G8 may also be epidemiologically important in
strain was detected in India (figure 3), it was still believed to be
rare elsewhere and, thus, was considered to be only regionally
common . However, a recent compilation of surveillance
studies performed since 1995, including many not reviewedhere
because they did not report P-G genotype combinations, indi-
cated that G9 emerged as early as 1993 to become 1 of 5 im-
portant serotypes globally, with a prevalence of at least 5.8%
through the end of 2001 . When recent studies showing a
countrywide prevalenceas highas40%areincluded,theestimate
of G9 prevalence is likely to increase substantially .
To try to develop a current picture of strains that have the
highest potential to affect rotavirus vaccination programs, we
summarized the most important P-G combination types de-
tected in surveillance studies conducted since 1996 that ana-
lyzed at least 50 strains (table 1). Strain types thathadanoverall
by guest on December 28, 2014
Table 1. Summary of rotavirus P- and G-genotyping studies conducted since 1996.
Region, country, year
Uncommon and regional strains
Mixed G1G3G4 G9G2 G1 G3G1 G2G8 G9
1995–19969212000 58801200 1100 
1996–199810012040 43 1400000 10170 
1996–1998490 1121 550 145 1307002 461027 
1982–199413055790 15000100 270 16
1996–199891 13 1045 160000012 1525 
1997–1998 536335 1100000118 15
1997–1999 15740 103 152100000325 319
Chile, 1985–1987 and 1993–1995 12365040202000002291
1988–1991 and 1998–2001103413011200000015256
Total for region, no. (%) of strains1989543 (27.3)83 (4.2)93 (4.7)26 (1.3)405 (20.4) 51 (2.6)22 (1.1)25 (1.3) 4 (0.2)0 (0)12 (0.6)217 (10.9)416 (20.9)
North America, United States
1996–19991316 994311415143107004228 383[47, 48]
Total for region, no. (%) of strains14161010 (71.3)31 (2.1)15 (1.1) 15 (1.1)143 (10.142 (3.0)0 (0)7 (0.5)0 (0)0 (0)42 (3.0) 49 (3.5)45 (3.2)
Austria, 1997–1999 335248627000000009450
France, 1995–1998 7714787245284043004151
Germany, 1997–1998 740386 9 830600000052510 
Hungary, 1992–20002841338 32194500000017030
1995–1998193 1031190290000006 350
1997–1999 330 1060 37094 190000062102 
Italy, 1990–1994108411 5632201000011
Spain, 1996–1999145 623 47080000003220
by guest on December 28, 2014http://jid.oxfordjournals.org/Downloaded from
1995–1996121 59540 315000001 160 
1995–19983301215695181 61 326330200 26 75 31432 
Total for region, no. (%) of strains6328 3772 (59.6) 135 (2.1)731 (11.6) 85 (1.3)549 (8.7)63 (1.0)0 (0) 7 (0.1)3 (0) 0 (0) 26 (0.4)182 (2.9) 709 (11.2)
1998 50010010 321500433
1998–2000238310 5820 277 43684 5722 
Guinea-Bissau, 1996–1998 167 13000 1901340001873
Cuba, Kenya, Libya, 2000602813151005001051
Malawi, 1997–1999 414 11193 21000170 1103 157 46 [53, 95]
Nigeria, 1999–2000110 10000000 1012004 731 
Tunisia, 1995–199951 1200025000003245
Total for region, no. (%) of strains1147221 (19.3)96 (8.3)25 (2.2)73 (6.3)33 (2.9) 5 (0.4)61 (5.3)33 (2.9)100 (8.7)116 (10.1)12 (1.0)57 (5.0) 260 (22.7)
Bangladesh, 1988–199735136085103820530377940 16
1990–1992102 7100081100003 162 
1989–1995 133885038004202392610[41, 42]
1995–1999126151150 1614012040 571
1996–1998287440 16146200029026 35 5110
1998–2000159 3209024600100354210 
Korea, 1998–2000 555016023061007 132 
1999–2000889 51821033 100502 17200 39 18 35
Total for region, no. (%) of strains 3002975 (32.5)77 (2.6)259 (8.6)28 (0.9) 518 (17.2) 99 (3.2)16 (5.3)41 (1.4) 40 (1.4)0 (0)102 (3.4) 253 (8.4)467 (15.6)
Australia, 1993–19964634 3142 (67.8)39 (0.84)76 (1.6)0 (0)530 (11.4)0 (0)0 (0)1 (0)1 (0)0 (0) 0 (0) 0 (0.1)841 (0.3)4
Total, no. (%) of strains18,5169663 (52.2)461 (2.5) 1199 (6.5)227 (1.2)2178 (11.7) 260 (1.4)99 (0.5) 114 (0.6)148 (0.8) 116 (0.6)194 (1.1) 725 (3.9)2738 (14.8)394 (2.2)
PG8, PG10, PG1, PG3, PG4, PG6, PG1, PG9, PG4, and PG6. The total no. of these strains from each study is shown in the column labeled “No. of rare strains.” M, mixed infection; NT,
Data are no. of strains, except where noted. The following strains, which occurred at a prevalence of !0.1%–0.4%, were not listed: PG4, PG8, PG4, PG9, PG3, PG4, PG5, PG2, PG5,
by guest on December 28, 2014http://jid.oxfordjournals.org/Downloaded from
S152 • JID 2005:192 (Suppl 1) • Gentsch et al.
Reassortants of human rotavirus P and G serotypes, including uncommon and regional strains isolated from children with diarrhea
incidence of !0.5% are listed in the note to table 1. Fivestrains,
including the PG9 strain, were considered to be globallycom-
mon on the basis of overall prevalence. Although the PG9
strain was detected first, as the emergence of G9 began around
1995, more recent studies suggested that the PG9 strain may
be predominant [90, 110]. At least 6 regionally common strains,
including PG5, PG8, and PG9, with a prevalence of at
least 0.5%, are circulating among children. Of note, P strains,
which were previously identified as the third most prevalent P
type , represented 15% of the circulating strains in 30 of 47
studies reviewed (data not shown). Genotyping studies con-
ducted in 11 of 12 African countries (not reviewed here) doc-
umented a prevalence of 18%–75% for the P strain, which
suggests that the average global prevalence may prove to be
substantially higher as more surveys are completed in Africa
and Asia . Finally, strains with G types other than the
common ones (G1–G4 and G9), including G5, G6, G8, and
G10 in various combinations with P, P, P, P, and
P types, made up ∼1.2% of the total.
When overall strain incidence was compared with the inci-
dence in studies conducted in different continents, several dif-
ferences are obvious. The most striking difference is the higher
incidence of P strains in Latin America, Africa, and Asia,
compared with that in more-industrialized areas, such asEurope
and North America. In addition, the incidenceof unusualstrains
Finally, as mentioned above (figure 3), the regional importance
of some strains (e.g., PG8 in Malawi and PG9 in India) is
The introduction of molecular typing methods has enhanced
our understanding of the diversity of rotavirus strains that af-
fect both the development of rotavirus vaccines and our un-
derstanding of viral evolution. This review of 121,000 strains
from 35 countries provides several new insights.
These studies confirmed the continued importanceofserotypes
G1–G4. Globally, 190% of single fully typeable strains bearthese
by guest on December 28, 2014
Diversity of Rotavirus Strains • JID 2005:192 (Suppl 1) • S153
VP7 antigens, and only Africa had an incidence of !90% (i.e.,
86%) for these serotypes.
Increased Strain Diversity
Studies conducted before 1990 suggested that only 4 common
serotypes accounted for virtually all rotavirusstrainscirculating
among children. Since then, along with the widespread appli-
cation of RT-PCR genotyping and molecular methods, strain
surveillance and characterization studies have led to the iden-
tification of at least 42 distinct P-G type combinations among
the 10 HRV G serotypes and 11 HRV P serotypes and subtypes,
representing more than one-third of the 110 theoretically pos-
sible P-G combinations (figures 2, 3, and 4) [26, 111–129]. In
addition to the original 4 strains, at least 8 other globally or
regionally common strains have been described that, overall,
contain 4 additional serotype antigens (G5, G8, G9, and P)
and that are not included in the polyvalent rotavirus vaccine
currently in development. This number is likely to increase as
surveillance studies continue. Many of the 42 strains, including
several that are epidemiologicallyimportant,appeartohavebeen
formed by the introduction of a new serotype antigen gene into
a common HRV strain (e.g., the introduction of G8 and G12
VP7genes into DS-1genogroupstrains)[111,113].Otherstrains
may have arisen by interspecies transmission or by reassortment
between human and animal rotaviruses [130, 131]. The finding
of this enormous diversity among rotavirus strains provides in-
new challenges for rotavirus vaccine programs.
Vaccines currently in the late stages of development include
one based on a monovalent serotype P1AG1 HRV strain(Ro-
tarix; GlaxoSmithKline) and another based on a pentavalentbo-
vine-human reassortant strain containing G1–G4 and P1A
antigens (RotaTeq; Merck) [133, 134]. Rotarix is based on the
whereas RotaTeq is based on serotype-specific immunity and, in
theory, should contain the antigens of the most common HRV
strains to achieve optimal protection. Thus, one major challenge
for the RotaTeq vaccine will be to protect effectively against the
globally (G9) or regionally (G5 and G8) common G serotypes
that have been identified by strain surveillance in recent years
but that are not present in the vaccine. Although RotaTeq might
be expected to provide a measure of protection against some of
these strains (e.g., PG5 and PG9) because of shared P
serotype antigens, other strains (e.g., PG9 and PG8) share
neither serotype antigen and, thus, may offer the biggest chal-
lenge to this vaccine. On the other hand, the Rotarix vaccine
may work well against strains that have different serotypes but
many cross-reactive antigens(e.g.,strainsinthesame[Wa]geno-
group: PG9 and PG3), but the vaccine may be challenged
by short-electropherotype PG2 and PG9 strains that not
only have distinct serotype antigens but also belong to a com-
pletely unique genogroup (DS-1) from the Rotarix strain and,
thus, have fewer cross-reactive antigens. Consequently, it will be
important to determine from vaccine trials of these 2 candidates
whether they elicit immunity against strains that may challenge
their protection mechanism . In this regard, available vaccine
trial data for Rotarix show that it provides cross-protection
against PG9 strains, but it is not yet knownwhetheritprotects
against PG2 strains of the DS-1 genogroup .
Mechanisms of Rotavirus Evolution
In addition to the challenges posed for rotavirus vaccine pro-
grams, the great diversity observed in studies of rotavirus
strain surveillance and characterization provides insights into
the genetic variation and spread of rotavirus strains. Rota-
viruses evolve by point mutations, gene rearrangements of
primarily nonstructural genes, and reassortment events, all of
which have long been known [5, 136]. An intermolecular
recombination of rotavirus has been described once .
Reassortment between the common strains
detected in surveillance studies is well documented. The globally
common genotype P strains with serotype G1, G3, G4, or G9
VP7 genes belong to the same genome constellation (Wa geno-
group), as indicated by the ability of all genes, except VP7, to
cross-hybridize with other genogroup members . The fifth
globally common strain, PG2, belongs to a distinct genome
constellation (DS-1 genogroup) that does not cross-hybridize
with any gene segment from typical members of the Wa geno-
group. Nucleotide sequencing studies provided strong evidence
that reassortment occurs between circulating genotype P
strains with G1, G3, G4, or G9 specificity when it was found
that phylogenetically distinct VP4 genes of such strains can seg-
regate with VP7 genes of 11 G serotype [138, 139]. Other se-
quencing studies demonstrated that all 11 genes reassorted be-
tween typical long-electropherotype G1 and G4 strains. When
fragments of each gene of cocirculating G1 and G4 strains were
sequenced, it was found that the cognate genes from the 2 se-
rotypes could be distinguished phylogenetically. Subsequently, it
was shown that the distinct lineages of each gene could be iden-
tified in both serotypes, demonstrating that reassortment occurs
in all 11 gene segments of such strains . Together, these
studies show that reassortment is a major evolutionary mecha-
nism in common circulating rotavirus strains.
In contrast to the high level of multigenic reassortment that
is believed to occur between members of the same genogroup
(designated “intragenogroup reassortment”), independent seg-
regation of genes between the major HRV genogroups (desig-
evidence, in part, comes from early studies showing that the G
types of commonly circulating strains are usually associatedwith
a single P type, SG, and electropherotype . These data con-
by guest on December 28, 2014
S154 • JID 2005:192 (Suppl 1) • Gentsch et al.
[36, 40, 41, 97–99, 101–103, 105, 159]. BAN, Bangladesh; BRA, Brazil; IND, India; JPN, Japan; Malay, Malaysia; S. Afr, South Africa; USA, United
States of America.
Differences in the incidence of mixed infections in developed versus developing countries. Data are adapted from the followingreferences:
firmed earlier investigations conducted by use of PAGE analysis,
subgrouping, and whole-genome hybridization of partially re-
stricted exchange of gene segments between strains in the2 main
rotavirus genome constellations (Wa and DS-1 genogroups )
. However, more-complete surveillance studies have docu-
mented numerous examples of the reassortment of serotype an-
tigen genes across genogroups, and single G types have been
detected in association with a wide variety of P types. The global
incidence of these reassortants is low (!10%), but it is clear that
they can be very common in some settings; PG9 is common
among both Wa genogroup and DS-1 genogroup strains .
Numerous examples of intergenogroup reassortment in other
genes are also well documented [141–144].
The generation of new P-G genotype combinations by the
introduction of genes from novel serotypes represents another
mechanism for thegenerationofrotavirusdiversity.Sequencing
studies of the VP7 gene of emerging serotype G9 strains de-
tected around 1995 demonstrate that the VP7 gene is distinct
from the cognate gene of G9 strains first isolated in the United
States a decade previously . This result indicates that the
modern lineage is not directly descended from the original lin-
eage, and may, instead, be the result of a recent introduction
into humans through reassortment [145, 146].
In children with diarrhea, the modern G9 VP7 gene lineage
was first detected among long-electropherotype PG9 strains
during the 1994–1995 rotavirus season in Japan and among
PG9, PG9, and PG9 strains over the next several years
in other countries [62, 145–149]. Hybridizationstudiesindicate
that these strains represent 2 distinct genotypes, PG9 and
PG9, which were single-segment reassortants of typical
members of the Wa and DS-1 genogroups, respectively .
The same G9 lineage was subsequently shown to be present as
early as 1993 in Indian neonates, who excreted a long-electro-
pherotype PG9 strain in the absence of symptoms of diar-
rhea . Thus, it is plausible that these unusual neonatal
infections could have been an early source for the spread of
this gene to children with diarrhea, from which it subsequently
spread globally and reassorted to produce a variety of new
diversity involves the introduction of animal rotavirus genes
either through transmission of whole viruses or through re-
assortment. Evidence for the first of these mechanisms came
from hybridization studies that used whole-genome probes
made from HRV strains by in vitro transcription. For example,
all 11 segments of several HRVs (e.g., AU-1, P3G3, and
HCR-3 P5AG3 strains) are virtually indistinguishable from
feline and canine strains with the same serotype, suggesting
that these uncommon strains with novel P serotypes were de-
rived through interspecies transmission to humans [130, 131].
However, only a few strains have high homology to all 11 genes
of animal rotaviruses, suggestingthatinterspeciestransmissions
that result in gastroenteritis are rare.
for the introduction of animal rotavirus genes into HRVs is
through reassortment. Examples of both rare (e.g., G6, G8,
P3, and P5A) and common (e.g., G3, G4, and P1A)
P and G HRV serotypes (figure 4) that have very close genetic
and antigenic relationships with the same rotavirus serotype in
that, when some common HRV G serotypes (G3 and G4) and
P serotypes (P1A) are sequenced, they are almost indistin-
guishable from the same genes in porcine or canine rotavirus
strains, which suggests that even common HRV serotypes may
have recent animal origins . Whole-genome hybridiza-
tion experiments and nucleotide sequencing show that animal-
Another major source of HRV
A more common mechanism
by guest on December 28, 2014
Diversity of Rotavirus Strains • JID 2005:192 (Suppl 1) • S155
human reassortants may contain only a serotype antigen gene
(e.g., strain 116E) or several genes related to animal rotaviruses
[151, 152]. In the case of strain 116E, the VP4 gene is highly
related to the bovine serotype P8G10 VP4 gene, whereas
the remaining 10 genes are related to typical HRV strains of
the Wa genogroup (e.g., P1AG1, SG II, long electrophero-
type) ; strain I321 (PG10) contains 2 genes from
HRVs of the Wa genogroup, and its remaining genes are from
a bovine rotavirus . Some of the G5 strains isolated in
Brazil, such as Br1054 (PG5), contain several genes each
from human Wa genogroup strains and porcine rotaviruses re-
lated to the serotype G5 isolate, OSU . Other uncommon
strains, such as PA151 (P3G6) and PCP5 (P3G3), which
were isolated in Italy, have the same P serotype as feline ro-
taviruses and the felinelike HRV strain AU-1. Unlike AU-1,
these strains are apparent reassortants, deriving several genes
each from bovine rotaviruses and AU-1–like rotaviruses .
Strains that have the same numbers of bovine and HRV genes
or the same P and G types as PA151 and PCP5 have been
detected in the United States and Hungary [113, 155]. The
finding of such close sequence similarity in thesegeographically
and temporally diverse strains suggests that they possibly share
a common origin. These strains may have entered the human
population at least once or more and subsequently may have
acquired a G3 VP7 gene through reassortment with a human
G3 rotavirus [113, 126].
A variety of other HRVs with strong associations with ani-
mal strains have been reported. The serotype G8 strain 69M
(P4G8), which has a supershort electropherotype pattern,
G8 strains (e.g., Hal1166 and other PG8 isolates) from a
variety of settings share similar relatedness to the human DS-1
genogroup and bovine rotaviruses, but they also share a high
homology to the typically lapine VP4 gene (P), which sug-
gests that such strains could have been derived through re-
assortment events in 2 different animal species [125, 156–158].
The great degree of strain diversityamong
rotaviruses, particularly in some developing countries, suggests
that, for children, coinfections with 2 different rotavirus se-
rotypes may be a relatively frequent occurrence. In fact, mixed
infections with rotavirus strains appear to be quite common
in some settings in developing countries, on the basis of studies
showing 2 RNA profiles in the same patient specimens and on
the basis of results of RT-PCR genotyping and EIA serotyping
studies that demonstrated the presence of 11 genotype or se-
rotype in the same stool sample [36, 132, 159]. In strain prev-
alence surveys, the highest levels of detection of mixed infec-
tions are often in developing countries, where higher numbers
of different genotype combinations have been detected (figures
3 and 5) [41, 51, 99, 160]. In India, for example, multicenter
surveys identified as many as 9 P-G genotype combinations
among rotavirus specimens collected in a single city [41, 64].
In contrast, in studies conducted in developed countries, fewer
mixed infection were seen, and fewer genotype combinations
were detected per city surveyed (figure 5) . Thus, the high
levels of detection of mixed infection in children with diarrhea,
especially in developing countries, may play a major role in
generating strain diversity.
infections in neonates could be an important source of novel
rotavirus strains. It has been known since the 1970s that strains
with common G serotypes and genogroups and novel P se-
rotypes (P2A) circulated in hospital nurseries, often without
producing symptoms of diarrhea . These strains some-
times circulated continually in the same nursery for years and
thus served as an uninterrupted reservoir where mixed infec-
tions could potentially occur any time another strain was in-
troduced by staff or visitors. Although, at first, theywerethought
to be confined to neonates, P strains are relatively common
in children with diarrhea, suggesting that reassortment in neo-
nates could be one possible source for new strains. Strains un-
dergoing reassortment in neonates could explain the origin of
other HRVs as well. As noted, the VP7 gene of novel PG9
strains was first detected in infected neonates by sequenceanaly-
sis. The same VP7 gene lineage is now common in children with
The novel P2AG8 strains that are common in Malawi were
detected in neonates and children with diarrhea in Malawi at
approximately the same time [53, 162]. Two distinct P8
strains with G9 or G10 specificity were first detected in neonates
[163, 164]. The PG10 strains are now common in children
with diarrhea in some parts of India, whereas a PG4 reas-
sortant is detected infrequently in sick Indian children [42, 165].
We thank Claudia Chesley for her help in editing the paper.
1. Miller MA, McCann L. Policy analysis of the use of hepatitis B, Hae-
mophilus influenzae type B-, Streptococcus pneumoniae-conjugate,and
rotavirus vaccines, in national immunization schedules. Health Econ
2. Kapikian AZ, Hoshino Y, Chanock RM. Rotaviruses. In: Howley PM,
ed. Fields virology. 4th ed. Vol. 2. Philadelphia: Lippincott, Williams
& Wilkins, 2001:1787–833.
3. Perez-Schael I, Blanco M, Vilar M, et al. Clinical studies of a quad-
rivalent rotavirus vaccine in Venezuelan infants. J Clin Microbiol
4. Cunliffe N, Bresee J, Gentsch J, Glass R. The expanding diversity of
rotaviruses. Lancet 2002;359:640–2.
5. Desselberger U, Iturriza-Gomara M, Gray JJ. Rotavirus epidemiology
and surveillance. Novartis Found Symp 2001;238:125–47;discussion,
by guest on December 28, 2014
S156 • JID 2005:192 (Suppl 1) • Gentsch et al.
6. Palombo EA. Genetic and antigenic diversity of human rotaviruses:
7. Estes MK. Rotaviruses and their replication.In:HowleyPM,ed.Fields
virology. 4th ed. Vol. 2. Philadelphia: Lippincott, Williams & Wilkins,
8. Offit PA. Rotaviruses: immunological determinants of protection
against infection and disease. Adv Virus Res 1994;44:161–202.
9. Greenberg H, McAuliffe V, Valdesuso J, et al. Serological analysis of
the subgroup protein of rotavirus using monoclonalantibodies.Infect
10. Iturriza-Gomara M, Wong C, Blome S, Desselberger U, Gray J. Mo-
lecular characterization of VP6 genes of human rotavirus isolates:
correlation of genogroups with subgroups and evidence of indepen-
dent segregation. J Virol 2002;76:6596–601.
11. Matsui SM, Mackow ER, Matsuno S, Paul PS, Greenberg HB. Se-
quence analysis of gene 11 equivalents from “short” and “supershort”
strains of rotavirus. J Virol 1990;64:120–4.
12. Flores J, Perez I, White L, et al. Genetic relatedness among human
rotaviruses as determined by RNA hybridization. Infect Immun 1982;
13. Nakagomi O, Nakagomi T, Akatani K, Ikegami N. Identification of
rotavirus genogroups by RNA-RNA hybridization. Mol Cell Probes
14. Wyatt RG, James HD Jr, Pittmann AL, et al. Direct isolation in cell
culture of human rotaviruses and their characterization into four se-
rotypes. J Clin Microbiol 1983;18:310–7.
15. Hoshino Y, Sereno MM, Midthun K, Flores J, Kapikian AZ, Chanock
RM. Independent segregation of two antigenic specificities (VP3 and
VP7) involvedin neutralizationofrotavirusinfectivity.ProcNatlAcad
Sci USA 1985;82:8701–4.
16. Offit PA, Blavat G. Identification of two rotavirus genes determining
neutralization specificities. J Virol 1986;57:376–8.
17. Coulson B, Unicomb LE, Pitson GA, Bishop RF. Simple and specif-
ic enzyme immunoassay using monoclonal antibodies for serotyping
human rotaviruses. J Clin Microbiol 1987;25:509–15.
18. Taniguchi K, Urasawa T, Morita Y, Greenberg HB, Urasawa S. Direct
serotyping of human rotavirus in stools using serotype 1-, 2-, 3-, and
19. Woods PA, Gentsch J, Gouvea V, et al. Distribution of serotypes of
human rotavirus in different populations. J Clin Microbiol 1992;30:
20. Koshimura Y, Nakagomi T, Nakagomi O. 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. Microbiol Immunol 2000;44:499–510.
21. Coulson BS. VP4 and VP7 typing using monoclonal antibodies.Arch
Virol Suppl 1996;12:113–8.
22. Matsuno S, Hasegawa A, Mukoyama A, Inouye S. A candidate for a
new serotype of human rotavirus. J Virol 1985;54:623–4.
23. Clark HF, Hoshino Y, Bell LM, et al. Rotavirus isolate W161 repre-
senting a presumptive new human serotype. J Clin Microbiol 1987;
24. Taniguchi K, Urasawa T, Kobayashi N, Gorziglia M, Urasawa S. Nu-
cleotide sequence of VP4 and VP7 genes of human rotaviruses with
subgroup I specificity and long RNA pattern: implication for new G
serotype specificity. J Virol 1990;64:5640–4.
25. Nakagomi T, Akatani K, Ikegami N, Katsushima N, Nakagomi O.
Occurrence of changes in human rotavirus serotypes with concurrent
changes in genomic RNA electropherotypes. J Clin Microbiol 1988;
26. Gorziglia M, Green K, Nishikawa K, et al. Sequence of the fourth
gene of human rotaviruses recovered from asymptomatic or symp-
tomatic infections. J Virol 1988;62:2978–84.
27. Gorziglia M, Larralde G, Kapikian AZ, Chanock RM. Antigenic re-
lationships among human rotaviruses as determined by outer capsid
protein VP4. Proc Natl Acad Sci USA 1990;87:7155–9.
28. Offit PA, Blavat G, Greenberg HB, Clark HF. Molecular basis of ro-
tavirus virulence: role of gene segment 4. J Virol 1986;57:46–9.
29. Coulson BS. Typing of human rotavirus VP4 by an enzyme immu-
noassay using monoclonal antibodies. J Clin Microbiol 1993;31:1–8.
30. Padilla-Noriega L, Werner-Eckert R, Mackow ER, et al. Serologic
analysis of human rotavirus serotypes P1A and P2 by using mono-
clonal antibodies. J Clin Microbiol 1993;31:622–8.
31. Gouvea V, Glass RI, Woods P, et al. Polymerase chain reaction am-
plification and typing of rotavirus nucleic acid from stool specimens.
J Clin Microbiol 1990;28:276–82.
32. Gentsch JR, Glass RI, Woods P, et al. Identification of group A ro-
tavirus gene 4 types by polymerase chain reaction. J Clin Microbiol
33. Gunasena S, Nakagomi O, Isegawa Y, et al. Relative frequency of VP4
gene alleles among human rotaviruses recovered over a 10 yearperiod
(1982–1991) from Japanese children with diarrhea. J Clin Microbiol
34. Flores J, Sears J, Perez Schael I, Lanata C, Kapikian AZ. Identification
of human rotavirus serotype by hybridization to polymerase chain
reaction-generated probes derived from a hyperdivergent region of
the gene encoding outer capsid protein VP7. J Virol 1990;64:4021–4.
35. Larralde G, Flores J. Identification of gene 4 alleles among human
rotaviruses by polymerase chain reaction-derived probes. Virology
36. Gentsch JR, Woods PA, Ramachandran M, et al. Review of G and P
typing results from a global collection of strains: implications for
vaccine development. J Infect Dis 1996;174:S30–6.
37. Landaeta ME, Dove W, Vinh H, et al. Characterization of rotaviruses
causing diarrhoea in Vietnamese children. Ann Trop Med Parasitol
38. Ehlken B, Laubereau B, Karmaus W, et al. Prospective population-
based study on rotavirus disease in Germany. Acta Paediatrica 2002;
39. Buesa J, de Souza CO, Asensi M, Martinez C, Prat J, Gil MT. VP7
and VP4 genotypes among rotavirus strains recovered from children
with gastroenteritis over a 3-year period in Valencia, Spain. Eur J
40. Leite JP, Alfieri AA, Woods P, Glass RI, Gentsch JR. Rotavirus G and
P types circulating in Brazil: characterization by RT-PCR, probe hy-
bridization, and sequence analysis. Arch Virol 1996;141:2365–74.
41. Ramachandran M, Das BK, Vij A, et al. Unusual diversity of human
rotavirus G and P genotypes in India. J Clin Microbiol1996;34:436–9.
42. Das BK, Kumar RK, Bhan MK. Rotavirus gastroenteritis and vaccine
development. Indian J Pediatr 1998;65:S36–40.
43. Husain M, Seth P, Dar L, Broor S. Classification of rotavirus into G
and P types with specimens from children with acute diarrhea in New
Delhi, India. J Clin Microbiol 1996;34:1592–4.
44. O‘Ryan M, Mamani N, Avendano LF, et al. Molecular epidemiology
of human rotaviruses in Santiago, Chile. Pediatr Infect Dis J 1997;
45. Arista S, Vizzi E, Ferraro D, Cascio A, Di Stefano R. Distribution of
VP7 serotypes and VP4 genotypes among rotavirus strains recovered
from Italian children with diarrhea. Arch Virol 1997;142:2065–71.
46. Adah MI, Rohwedder A, Olaleye OD, Durojaiye OA, Werchau H.
Further characterization of field strains of rotavirus from Nigeria:
VP4 genotype P6 most frequently identified among symptomatically
infected children. J Trop Pediatr 1997;43:267–74.
47. Ramachandran M, Gentsch JR, Parashar UD, et al. Detection and
characterization of novel rotavirus strains in the United States. J Clin
48. Griffin DD, Kirkwood C, Parashar UD, et al. Surveillance of rotavirus
strains in the United States: identification of unusual strains. J Clin
49. Mascarenhas JDP, Paiva FL, Barardi CRM, Gabbay YB, Simoes CO,
Linhares AC. Rotavirus G and P types in children in Belem, Northern
Brazil, as determined by RT-PCR: occurrence of mixed P type infec-
tions. J Diarrhoeal Dis Res 1998;16:8–14.
by guest on December 28, 2014
Diversity of Rotavirus Strains • JID 2005:192 (Suppl 1) • S157
50. Wu H, Taniguchi K, Urasawa T, Urasawa S. Serological and genomic
characterization of human rotaviruses detected in China. J Med Virol
51. Unicomb LE, Podder G, Gentsch JR, et al. Evidence ofhigh-frequency
genomic reassortment of group A rotavirus strains in Bangladesh:
emergence of type G9 in 1995. J Clin Microbiol 1999;37:1885–91.
52. Iturriza-Gomara M, Green J, Brown DWG, Desselberger U, Gray JJ.
Comparison of specific and random priming in the reverse transcrip-
tion polymerase chain reaction for genotyping group A rotaviruses.
J Virol Methods 1999;78:93–103.
53. Cunliffe NA, Gondwe JS, Broadhead RL, et al. Rotavirus G and P
types in children with acute diarrhea in Blantyre, Malawi, from 1997
to 1998: predominance of novel PG8 strains. J Med Virol 1999;
54. O‘Mahony J, Foley B, Morgan S, Morgan JG, Hill C. VP4 and VP7
genotyping of rotavirus samples recovered from infected children in
Ireland over a 3-year period. J Clin Microbiol 1999;37:1699–1703.
55. Rodriguez Castillo A, Villa AV, Ramirez Gonzalez JE, et al. VP4 and
VP7 genotyping by reverse transcription-PCR of human rotavirus in
Mexican children with acute diarrhea.JClinMicrobiol2000;38:3876–8.
56. Espul C, Cuello H, Martinez N, et al. Genomicand antigenicvariation
among rotavirus strains circulating in a large city of Argentina. J Med
57. Bon F, Fromantin C, Aho S, Pothier P, Kohli E. G and P genotyping
of rotavirus strains circulating in France over a three year period:
detection of G9 and P strains at low frequencies. J Clin Microbiol
58. Cubitt WD, Steele AD, Iturriza M. Characterisation of rotaviruses
from children treated at a London hospital during 1996: emergence
of strains G9P2A and G3P2A. J Med Virol 2000;61:150–4.
59. Trabelsi A, Peenze I, Pager C, Jeddi M, Steele D. Distribution of
rotavirus VP7 serotypes and VP4 genotypes circulating in Sousse,
Tunisia, from 1995 to 1999: emergence of naturalhumanreassortants.
J Clin Microbiol 2000;38:3415–9.
60. Audu R, Omilabu SA, de Beer M, Peenze I, Steele AD. Diversity of
human rotavirus VP6, VP7, and VP4 in Lagos State, Nigeria. J Health
Popul Nutr 2002;20:59–64.
61. Arguelles MH, Villegas GA, Castello A, et al. VP7 and VP4genotyping
of human group A rotavirus in Buenos Aires, Argentina. J Clin Mi-
62. Araujo IT, Ferreira MSR, Failho AM, et al. RotavirusgenotypesPG9,
PG9, and PG9 in hospitalized children with acute gastroenteritis
in Rio de Janeiro, Brazil. J Clin Microbiol 2001;39:1999–2001.
63. Fischer TK, Steinsland H, Molbak K, et al. Genotype profile of ro-
tavirus strains from children in a suburban community in Guinea-
Bissau, West Africa. J Clin Microbiol 2000;38:264–7.
64. Jain V, Das BK, Bhan MK, Glass RI, Gentsch JR. Great diversity of
group A rotavirus strains and high prevalence of mixed rotavirus
infections in India. Indian Strain Surveillance Collaborating Labo-
ratories. J Clin Microbiol 2001;39:3524–9.
65. Bok K, Castagnaro N, Borsa A, et al. Surveillance for rotavirus in
Argentina. J Med Virol 2001;65:190–8.
66. Ananthan S, Saravanan P. Genomic diversity of group A rotavirus
RNA from children with acute diarrhoea in Chennai, south India.
Indian J Med Res 2000;111:50–6.
67. Van Man N, Van Trang N, Lien HP, et al. The epidemiologyanddisease
burden of rotavirus in Vietnam: sentinel surveillance at 6 hospitals. J
Infect Dis 2001;183:1707–12.
68. O’Halloran F, Lynch M, Cryan B, O’Shea H, Fanning S. Molecular
characterization of rotavirus in Ireland: detection of novel strains
circulating in the population. J Clin Microbiol 2000;38:3370–4.
69. Asmah RH, Green J, Armah GE, et al. Rotavirus G and P genotypes
in rural Ghana. J Clin Microbiol 2001;39:1981–4.
70. Armah GE, Pager CT, Asmah RH, et al. Prevalence of unusual human
rotavirus strains in Ghanaian children. J Med Virol 2001;63:67–71.
71. Adah MI, Wade A, Taniguchi K. Molecular epidemiology of rotavi-
ruses in Nigeria: detection of unusual strains with G2P andG8P
specificities. J Clin Microbiol 2001;39:3969–75.
72. Coluchi N, Munford V, Manzur J, et al. Detection, subgroup speci-
ficity, and genotype diversity of rotavirusstrainsinchildrenwithacute
diarrhea in Paraguay. J Clin Microbiol 2002;40:1709–14.
73. Steele AD, Kasolo FC, Bos P, Peenze I, Oshitani H, Mpabalwani E.
strains in Lusaka, Zambia. Ann Trop Paediatr 1998;18:111–6.
74. Adhikary AK, Zhou Y, Kakizawa J, et al. Distribution of rotavirus
VP4 genotype and VP7 serotype among Chinese children. Acta Pae-
diatr Jpn 1998;40:641–3.
75. Kang G, Green J, Gallimore CI, Brown DW. Molecular epidemiology
of rotaviral infection in South Indian children with acute diarrhea
from 1995–1996 to 1998–1999. J Med Virol 2002;67:101–5.
76. Araujo IT, Fialho AM, de Assis RM, et al. Rotavirus strain diversity
in Rio de Janeiro, Brazil: characterization of VP4 and VP7 genotypes
in hospitalized children. J Trop Pediatr 2002;48:214–8.
77. Santos N, Soares CC, Volotao EM, Albuquerque MC, Hoshino Y.
Surveillance of rotavirus strains in Rio de Janeiro, Brazil, from 1997
to 1999. J Clin Microbiol 2003;41:3399–402.
78. Rosa ESML, Pires De Carvalho I, Gouvea V. 1998–1999 Rotavirus
seasons in Juiz de Fora, Minas Gerais, Brazil: detection of an unusual
G3P epidemic strain. J Clin Microbiol 2002;40:2837–42.
79. Kang G, Raman T, Green J, Gallimore CI, Brown DW. Distribution
of rotavirus G and P types in north and south Indian children with
acute diarrhoea in 1998–99. Trans R Soc Trop Med Hyg 2001;95:
80. Das S, Sen A, Uma G, et al. Genomic diversity of group A rotavirus
strains infecting humans in eastern India. J Clin Microbiol 2002;40:
81. Binka FN, Anto FK, Oduro AR, et al. Incidence and risk factors of
paediatric rotavirus diarrhoea in northern Ghana. Trop Med Int Health
82. Song MO, Kim KJ, Chung SI, et al. Distribution of human group A
rotavirus VP7 and VP4 types circulating in Seoul, Koreabetween1998
and 2000. J Med Virol 2003;70:324–8.
83. Doan LT, Okitsu S, Nishio O, Pham DT, Nguyen DH, Ushijima H.
Epidemiological features of rotavirus infection among hospitalized
children with gastroenteritis in Ho Chi Minh City, Vietnam. J Med
84. Cunliffe N, Dove W, Bunn J, et al. Expanding global distribution of
rotavirus serotype G9: detection in Libya, Kenya, and Cuba. Emerg
Infect Dis 2001;7:890–2.
85. Abdel-Haq NM, Thomas RA, Asmar BI, Zacharova V, Lyman WD.
Increased prevalence of G1P genotype among children with ro-
tavirus-associated gastroenteritis in metropolitan Detroit. J Clin Mi-
86. Souza MB, Racz ML, Leite JP, et al. Molecular and serological char-
acterization of group A rotavirus isolates obtained from hospitalized
children in Goiania, Brazil, 1998–2000. Eur J Clin Microbiol Infect
87. Noppornpanth S, Theamboonlers A, Poovorawan Y. Predominant
human rotavirus genotype G1P infection in infants and children
in Bangkok, Thailand. Asian Pac J Allergy Immunol 2001;19:49–53.
88. Mascarenhas JD, Linhares AC, Gabbay YB, Leite JP. Detection and
characterization of rotavirusGandPtypesfromchildrenparticipating
in a rotavirus vaccine trial in Belem, Brazil. Mem Inst Oswaldo Cruz
89. Bishop RF, Masendycz PJ, Bugg HC, Carlin JB, Barnes GL. Epide-
miological patterns of rotaviruses causing severe gastroenteritis in
young children throughout Australia from 1993 to 1996. J Clin Mi-
90. Iturriza-Gomara M, Green J, Brown D, Tamsay M, Desselberger U,
Gray J. Molecular epidemiology of human group A rotavirus infec-
tions in the United Kingdom between 1995 and 1998.JClinMicrobiol
91. Fruhwirth M, Brosl S, Ellemunter H, Moll-Schuler I, Rohwedder A,
by guest on December 28, 2014
S158 • JID 2005:192 (Suppl 1) • Gentsch et al.
Mutz I. Distribution of rotavirus VP4 genotypes and VP7 serotypes
among nonhospitalized and hospitalized patients with gastroenteritis
and patients with nosocomially acquired gastroenteritis in Austria. J
Clin Microbiol 2000;38:1804–6.
92. Banyai K, Gentsch J, Glass R, Uj M, Mihaly I, Szucs G. Eight-year
survey of human rotavirus strainsdemonstratescirculationofunusual
G and P types in Hungary. J Clin Microbiol 2004;42:393–7.
93. Fang Z-Y, Hui Y, Qi J, et al. Diversity of rotavirus strains among
children with acute diarrhea in China: 1998–2000 surveillance study.
J Clin Microbiol 2002;40:1875–8.
94. Laird AR, Ibarra V, Ruiz-Palacios G, Guerrero ML, Glass RI, Gentsch
JR. Unexpected detection of animal VP7 genes among common ro-
95. Cunliffe N, Gondwe JS, Graham SM, et al. Rotavirus strain diversity
in Blantyre, Malawi from 1997 to 1999. J Clin Microbiol 2001;39:
96. Martella V, Terio V, Del Gaudio G, et al. Detection of the emerging
rotavirus G9 serotype at high frequency in Italy. J Clin Microbiol
97. Rasool NBG, Larralde G, Gorziglia MI. Determination of human
rotavirus VP4 using serotype-specific cDNA probes. Arch Virol 1993;
98. Kaga E, Iizuka M, Nakagomi T, Nakagomi O. The distribution of G
(VP7) and P (VP4) serotypes among human rotaviruses recovered
from Japanese children with diarrhea. Microbiol Immunol 1994;38:
99. Timenetsky Mdo C, Santos N, Gouvea V. Survey of rotavirus G and
P types associated with human gastroenteritis in Sao Paulo, Brazil,
from 1986 to 1992. J Clin Microbiol 1994;32:2622–4.
100. Fang Z-Y, Shangjin J, Shuming Q, et al. Serotypes of groupArotavirus
isolates determined by PCR in Hebei and Henan provinces, China.
Chinese J Virol 1994;10:316–20.
101. Ushijima H, Mukoyama A, Hasegawa A, Nishimura S, Konishi K, Bosu
K. Serotyping of human rotaviruses in the Tokyo area (1990–1993) by
enzyme immunoassay with monoclonal antibodies and by reversetran-
102. Wu H, Taniguchi K, Wakasugi F, et al. Survey on the distribution of
the gene 4 alleles of human rotaviruses by polymerase chain reaction.
Epidemiol Infect 1994;112:615–22.
103. Santos N, Riepenhoff-Talty M, Clark HF, Offit P, Gouvea V. VP4
genotyping of human rotavirus in the United States. J Clin Microbiol
104. Silberstein I, Shulman LM, Mendelson E, Shif I. Distribution of both
rotavirus VP4 genotypes and VP7 serotypes among hospitalized and
nonhospitalized Israeli children. J Clin Microbiol 1995;33:1421–2.
105. Steele AD, van Niekerk MC, Mphahlele MJ. Geographic distribution
of human rotavirus VP4 genotypes and VP7 serotypes in five South
African regions. J Clin Microbiol 1995;33:1516–9.
106. Gouvea V, de Castro L, Timenetsky Mdo C, Greenberg H, Santos N.
Rotavirus serotype G5 associated with diarrhea in Brazilian children.
J Clin Microbiol 1994;32:1408–9 [erratum: J Clin Microbiol 1994;
107. Steele AD, Ivanoff B. Rotavirus strains circulating in Africa during
1996–1999: emergence ofG9strainsandPstrains.Vaccine2003;21:
108. Laird AR, Gentsch JR, Nakagomi T, Nakagomi O, Glass RI. Char-
acterization of serotype G9 rotavirus strains isolated in the United
109. Kirkwood C, Bogdanovic-Sakran N, Clark R, Masendycz P, Bishop
R, Barnes G. Report of the Australian RotavirusSurveillanceProgram,
2001/2002. Commun Dis Intell 2002;26:537–40.
110. Kirkwood C, Bogdanovic-Sakran N, Palombo E, et al. Genetic and
antigenic characterization of rotavirus serotype G9 strains isolated in
Australia between 1997 and 2001. J Clin Microbiol 2003;41:3649–54.
111. Cunliffe NA, Gentsch JR, Kirkwood CD,et al.Molecularandserologic
characterization of novel serotype G8 rotavirus strains detected in
Blantyre, Malawi. Virology 2000;274:309–20.
112. Timenetsky Mdo C, Gouvea V, Santos N, Carmona RC, Hoshino Y.
A novel human rotavirus serotype with dual G5-G11 specificity. JGen
113. Griffin DD, Nakagomi T, Hoshino Y, et al. Characterization of non-
typeable rotavirus strains from the United States: identification of a
new rotavirus reassortant (P2A,G12) and rare P3 strains related
to bovine rotaviruses. Virology 2002;294:256–69.
114. Nakagomi T, Horie Y, Koshimura Y, Greenberg HB, Nakagomi O.
Isolation of human rotavirus with a super-short RNA pattern pos-
sessing a new P2 subtype. J Clin Microbiol 1999;37:1213–6.
115. Isegawa Y, Nakagomi O, Nakagomi T, Ueda S. A VP4 sequence highly
conserved in human rotavirus strain AU-1 and feline rotavirus strain
FRV-1. J Gen Virol 1992;73:1939–46.
116. Gerna G, Sarasini A, Parea M, et al. Isolation and characterization of
two distinct human rotavirus strains with G6 specificity. J Clin Mi-
117. Pongsuwanna Y, Guntapong R, Chiwakul M, et al. Detection of a
human rotavirus with G12 and P specificity in Thailand. J Clin
118. Taniguchi K, Nishikawa K, Urasawa T, et al. Complete nucleotide se-
quence of the gene encoding VP4 of a human rotavirus (strain K8)
which has unique VP4 neutralization epitopes. J Virol 1989;63:4101–6.
119. Qian Y, Green KY. Human rotavirus strain 69M has a unique VP4 as
120. Li B, Clark HF, Gouvea V. Nucleotide sequence of the VP4-encoding
gene of an unusual human rotavirus (HCR3). Virology 1993;196:
121. Gentsch J, Das BK, Jiang B, Bhan MK, Glass RI. Similarity of the
VP4 protein of human rotavirus strain 116E to that of the bovine
B223 strain. Virology 1993;194:424–30.
122. Das M, Dunn SJ, Woode GN, Greenberg HB, Rao CD. Both surface
proteins (VP4 and VP7) of an asymptomatic neonatal rotavirusstrain
(I321) have high levels of sequence identity with the homologous
proteins of a serotype 10 bovine rotavirus. Virology 1993;194:374–9.
123. GernaG, SearsJ, Hoshino Y,etal.IdentificationofanewVP4serotype
of human rotavirus. Virology 1994;200:66–71.
124. Palombo EA, Bishop RF. Genetic and antigenic characterization of a
serotype G6 human rotavirus isolated in Melbourne, Australia. J Med
125. Browning GF, Snodgrass DR, Nakagomi O, Kaga E, Sarasini A, Gerna
G. Human and bovine serotype G8 rotaviruses may be derived by
reassortment. Arch Virol 1992;125:121–8.
126. Iizuka M, Kaga E, Chiba M, Masamune O, Gerna G, Nalagomi O.
Serotype G6 human rotavirus sharing a conserved genetic constel-
lation with natural reassortants between members of the bovine and
AU-1 genogroups. Arch Virol 1994;135:427–32.
127. Urasawa T, Taniguchi K, Kobayashi N, et al. Nucleotide sequence of
VP4 and VP7 genes of a unique human rotavirus strain Mc35 with
subgroup I and serotype 10 specificity. Virology 1993;195:766–71.
128. Okada J-I, Urasawa T, Kobayashi N, et al. New P serotype of a human
rotavirus closely related to that of a porcine rotavirus. J Med Virol
129. Rahman M, De Leener K, Goegebuer T, et al. Geneticcharacterization
of a novel, naturally occurring recombinant human G6P rotavirus.
J Clin Microbiol 2003;41:2088–95.
130. Nakagomi T, Nakagomi O. Human rotavirus HCR3 possesses a ge-
nomic RNA constellation indistinguishable from that of feline and
canine rotaviruses. Arch Virol 2000;145:2403–9.
131. Nakagomi T, Nakagomi O. RNA-RNA hybridization identifies a hu-
man rotavirus that is genetically related to feline rotavirus. J Virol
132. Gouvea V, Brantly M. Is rotavirus a population ofreassortants?Trends
by guest on December 28, 2014
Diversity of Rotavirus Strains • JID 2005:192 (Suppl 1) • S159 Download full-text
133. Bernstein DI, Sack DA, Rothstein E, et al. Efficacy of live, attenuated,
human rotavirus vaccine 89–12 in infants: a randomised placebo-
controlled trial. Lancet 1999;354:287–90.
134. Clark HF, Offit PA, Ellis RW, et al. The development of multivalent
bovine rotavirus (strain WC3) reassortant vaccine for infants. J Infect
Dis 1996;174(Suppl 1):S73–80.
135. Perez-Schael I, Salinas B, Linhares AC, et al. Protective efficacy of an
oral human rotavirus (HRV) vaccine in Latin American infants [ab-
stract 02-LB-3961]. In: Programand abstractsofthe42ndInterscience
Conference on Antimicrobial Agents and Chemotherapy(SanDiego).
Washington, DC: American Society for Microbiology, 2002.
136. Ramig R, Ward R. Genomic segment reassortment in rotaviruses and
other Reoviridae. Adv Virus Res 1991;39:163–207.
137. Suzuki Y, Gojobori T, Nakagomi O. Intragenic recombinations in
rotaviruses. FEBS Lett 1998;427:183–7.
138. Maunula L, von Bonsdorff C-H. Short sequences define genetic lin-
eages: phylogenetic analysis of group A rotaviruses based on partial
sequences of genome segments 4 and 9. J Gen Virol 1998;79:321–32.
139. Iturriza-Gomara M, Isherwood B, Desselberger U, Gray J. Reassort-
ment in vivo: driving force for diversity of human rotavirus strains
isolated in the United Kingdom between 1995 and 1999. J Virol 2001;
140. Maunula L, Von Bonsdorff CH. Frequent reassortments may explain
the genetic heterogeneity of rotaviruses: analysis of Finnish rotavirus
strains. J Virol 2002;76:11793–800.
RF. Multiple-gene rotavirus reassortants responsible for an outbreak
of gastroenteritis in central and northern Australia. J Gen Virol 1996;
human rotaviruses. J Med Virol 1985;17:135–43.
143. Nakagomi O, NakagomiT. Molecularevidencefornaturallyoccurring
single VP7 gene substitution reassortant between human rotaviruses
belonging to two different genogroups. Arch Virol 1991;119:67–81.
144. Ward RL, Nakagomi O, Knowlton DR, et al. Evidence for natural
reassortants of human rotaviruses belonging to different genogroups.
J Virol 1990;64:3219–25.
145. Ramachandran M, Kirkwood CD, Unicomb L, et al. Molecular char-
acterization of serotype G9 rotavirus strains from a global collection.
146. Iturriza-Gomara M, Cubitt D, Steele D, et al. Characterisation of
rotavirus G9 strains isolated in the UK between 1995 and 1998. J Med
147. Oka T, Nakagomi T, Nakagomi O. Apparent re-emergence of serotype
G9 in 1995 among rotaviruses recovered from Japanese children hos-
148. Bok K, Palacios G, Sijvarger K, Matson D, Gomez J. Emergence of
G9 P human rotaviruses in Argentina: phylogenetic relationships
among G9 strains. J Clin Microbiol 2001;39:4020–5.
149. Santos N, Volotao EM, Soares CC, et al. Rotavirus strains bearing
genotype G9 or P recovered from Brazilian children with diarrhea
from 1997 to 1999. J Clin Microbiol 2001;39:1157–60.
150. Santos N, Lima RC, Nozawa CM, Linhares RE, Gouvea V. Detection
of porcine rotavirus type G9 and of a mixture of types G1 and G5
associated with Wa-like VP4 specificity: evidence for natural human-
porcine genetic reassortment. J Clin Microbiol 1999;37:2734–6.
151. Das BK, Gentsch JR, Hoshino Y, et al. Characterization of the G
serotype and genogroup of New Delhi newborn rotavirus strain116E.
152. Dunn SJ, Greenberg HB, Ward RC, et al. Serotypic and genotypic
characterization of human serotype10rotavirusesfromasymptomatic
neonates. J Clin Microbiol 1993;31:165–9.
153. Alfieri AA, Leite JPG, Nakagomi O, et al. Characterization of human
rotavirus genotype PG5 from Brazil by probe-hybridization and
sequence. Arch Virol 1996;141:2353–64.
154. Iizuka M, Kaga E, Chiba M, Masamune O, Gerna G, Nakagomi O.
Serotype G6 human rotavirus sharing a conserved genetic constel-
lation with natural reassortants between members of the bovine and
AU-1 genogroups. Arch Virol 1994;135:427–32.
155. Banyai K, Gentsch J, Griffin DD, Holmes JL, Glass RI, Szucs G.
Genetic variability among serotype G6 human rotaviruses: identifi-
cation of a novel lineage isolated in Hungary. J Med Virol 2003;71:
156. Ohshima A, Takagi T, Nakagomi T, Matsuno S, Nakagomi O. Mo-
lecular characterization by RNA-RNA hybridization of a serotype 8
human rotavirus with “super-short” RNA electropherotype. J Med
157. Holmes JL, Kirkwood CD, Gerna G, et al. Characterizationofunusual
G8 rotavirus strains isolated from Egyptian children. Arch Virol 1999;
158. Palombo EZ, Clark R, Bishop RF. Characterisation of a “European-
like” serotype G8 human rotavirus isolated in Australia. J Med Virol
159. Ahmed MU, Urasawa S, Taniguchi K, et al. Analysis of humanrotavirus
by the 1988 monsoon. J Clin Microbiol 1991;29:2273–9.
160. Fischer TK, Page NA, Griffin DD, et al. Characterization of incom-
pletely typed rotavirus strains from Guinea-Bissau: identification of
G8 and G9 types and a high frequency of mixed infections. Virology
161. Albert MJ, Unicomb LE, Barnes GL, Bishop RF. Cultivation and char-
acterization of rotavirus strains infecting newbornbabiesinMelbourne,
Australia from 1975 to 1979. J Clin Microbiol 1987;25:1635–40.
162. Cunliffe NA, Rogerson S, Dove W, et al. Detection and characteri-
zation of rotaviruses in hospitalized neonates in Blantyre, Malawi. J
Clin Microbiol 2002;40:1534–7.
163. Bhan MK, Lew JF, Sazawal S, Das BK, Gentsch JR, GlassRI.Protection
conferred by neonatal rotavirus infection againstsubsequentdiarrhea.
J Infect Dis 1993;168:282–7.
164. Sukumaran M, Gowda K, Maiya PP, et al. Exclusive asymptomaticneo-
natal infections by human rotavirusstrainshavingsubgroupIspecificity
and ‘long’ RNA electropherotype. Arch Virol 1992;126:239–51.
165. Iturriza Gomara M, Kang G, Mammen A, et al. Characterization of
G10P rotaviruses causing acute gastroenteritis in neonates and
infants in Vellore, India. J Clin Microbiol 2004;42:2541–7.
166. Santos N, Hoshino Y. Global distribution of rotavirus serotypes/ge-
notypes and its implication for the development and implementation
of an effective rotavirus vaccine. Rev Med Virol 2005;15:29–56
and its possible effect on rotavirus vaccines has been published .
Since this manuscript was accepted for publication, another review of the global distribution of rotavirus strains
by guest on December 28, 2014