Journal of Medical Virology 80:1106–1111 (2008)

Prevalence of VP4 and VP7 Genotypes ofHuman Rotavirus in Ecuadorian ChildrenWith Acute Diarrhea

Alfredo Naranjo,1 Cecilia Cedeno,2 Enrique Teran,3* Alejandro Castello,4 and theCASERO Research Team1Hospital Metropolitano, Quito, Ecuador2Clinica Kennedy, Guayaquil, Ecuador3Merck Sharp & Dohme, Quito, Ecuador4Immunology and Virology Laboratory, Universidad Nacional de Quilmes, Buenos Aires, Argentina

The objective of the present study was todetermine rotavirus etiology and prevalence ofthe different rotavirus serotypes in Ecuadorianchildren younger than 5 years of age withgastroenteritis. Children (729) less than 5 yearsof age with acute diarrhea from either public orprivate primary health care centers in 10 differentprovinces of Ecuador, between March 2006and August 2006 were included in the study.Rotavirus infection was diagnosed using acommercial immunoenzymatic test. Rotavirusisolated from stool samples was genotyped.Rotavirus was detected in the feces of 269 of the729 children (37%) with diarrhea. The mostprevalent G genotypes were G9 (46.1%) and G2(27.2%), while the predominant P genotypes wereP[8] (57%) and P[4] (29.5%). Among the singleinfections, the predominant P/G combinationswere: P[8]G9 (56.9%) and P[4]G2 (32.6%). Thepresent countrywide survey is one of the majorstudies for one single season in Latin Americaand the first in its class in Ecuador. The valueof expanding laboratory capability throughoutLatin America in order to monitor rotavirusstrains over time, with special attention directedat those strains obtained from children whoexperience vaccine failure, is critical. Only con-tinuous monitoring of rotavirus disease burdenand genotype surveillance will provide thisinformation. J. Med. Virol. 80:1106–1111,2008. � 2008 Wiley-Liss, Inc.

KEY WORDS: rotavirus, genotype, Ecuador

INTRODUCTION

Rotavirus infection is the most common cause ofdiarrhea, gastroenteritis, and dehydration in smallchildren, both in developed and developing countries[Kapikian and Chanock, 2001]. Rotavirus infection is

responsible for acute gastroenteritis, which is charac-terized by aqueous diarrhea, fever and vomiting[Linhares et al., 1983]. Diarrhea usually is presentduring 3–8 days and is self-limited [Black et al., 1989;Bass and Greenberg, 1995]. However, diarrhea caseslasting up to 22 days have been documented [Wyattet al., 1979]. In younger children, the duration ofdiarrhea can be longer than in older children [Blacket al., 1989]. Fever and vomiting are more prominentduring the first days of the disease [Kapikian andChanock, 2001].

Almost all children will be infected with rotavirusduring early infancy. In prospective cohort studies

ET is a Merck & Co., Inc., employee. None of the other authorsreport conflicts of interest.

Characterization of Serotypes of Rotavirus in Ecuador(CASERO) Research Team (contributed equally to the study):Azuay: Patricio Barzallo (Clinica Santa Ana, Cuenca); BayronGuillen and Bolivar Mora (Hospital Santa Ines, Cuenca);Chimborazo: Orlando Echeverria (private office, Riobamba),Jaime Lopez (Hospital San Juan, Riobamba); Cotopaxi: CeciliaEstrella (Hospital Provincial, Latacunga); Esmeraldas: WalterCaicedo (Hospital Delfina Torres, Esmeraldas); Guayas: EnriqueBolona (UDIMEF, Guayaquil); Julio Lopez Campos (private office,Guayaquil); Raquel Moran (Hospital Roberto Gilbert, Guayaquil);Ivan Verduga (Clinica Alcivar, Guayaquil); Imbabura: MauricioCabascango (CEMOPLAF, Otavalo); Piedad Moya (Hospital SanVicente de Paul, Ibarra); Manabı: Syayna Pandzic (private office,Manta); Napo: Abel Barroso (Hospital Provincial, Puyo); Pastaza:Ines Fernandez (Hospital Provincial Velasco Ibarra, Tena);Pichincha: Bolivar Munoz (Hospital Baca Ortız, Quito); ElinaYanez (Centro de Salud-Hospital, Yaruqui); Netlab: Luis Narvaez;Universidad de Quilmes: Rosana Rota, Laura Esteban; MSD-Ecuador: Patricio Romero.

Grant sponsor: Merck Sharp & Dohme, Ecuador.

*Correspondence to: Enrique Teran, MD, PhD, MedicalServices, Merck Sharp & Dohme, Quito, Ecuador; Av. NNUU yRepublica de El Salvador, Edificio Citiplaza, Piso 7, Quito,Ecuador. E-mail: enrique_teran_torres@merck.com

Accepted 12 February 2008

DOI 10.1002/jmv.21181

Published online in Wiley InterScience(www.interscience.wiley.com)

� 2008 WILEY-LISS, INC.

conducted in developing countries, the incidenceof rotavirus diarrhea in small children varied from0.07 and 0.8 episodes of diarrhea/child/year and almostall children had at least one diarrhea episode due torotavirus by the age of 24 months [Kantharidis et al.,1987; Grinstein et al., 1989; Linhares et al., 1989; Reveset al., 1989]. A recent analysis demonstrated that about600,000 children die every year from rotavirus, mainlyin developing countries, and this figure represents about5% of all deaths in children younger than 5 years [Glasset al., 2006].

Previous studies suggest that natural infectionconfers mainly homotypic immunity against futureexposure, and that heterotypic immunity increases withevery exposure; the highest incidence of rotavirusdisease is in children between 3 and 24 months of age[Velazquez et al., 1996].

The classification in serotypes of rotaviruses is basedon differences of the outer capsid proteins VP7 (G types)and VP4 (P types). Serotypes G1 to G4 and G9, incombination with genotypes P[8] and P[4], make upthe majority of the human strains around the World[Gunasena et al., 1993; Mphalele and Steele, 1995;Gentsch et al., 1996]. A global survey including morethan 2,700 specimens found that genotype P[8] wasalmost invariably associated with G1, G3 or G4, andthe genotype P[4] was associated with G2 [Gentschet al., 1996]. In some developing countries, differentserotype patterns have been described. In Brazil, one-third of single infections were related to uncommonserotypes in other places, that is, P[6]G1, P[6]G3,P[6]G4, and P[3]G1 [Timenetsky et al., 1994]. P[8]G5represented 13% of all simple infections in some regionsof Brazil, being the second most frequently detectedstrain. In Bangladesh, 10% of the strains were naturalgenetic reassortants yielding uncommon combinations(P[4]G1 or P[4]G4) or non-common strains (P[6]G1)[Bern et al., 1992]. In India, P[6] strains, together withcommon G types, were responsible for 43% of all cases ofdiarrhea in children, while the next 4 most commonstrains only represented 33% [Ramachandran et al.,1996], and strains previously recognized mainly inasymptomatic neonates (P[6]G9, P[11]G9 y P[11]G10)were recovered from children with diarrhea. The P[6]strains were identified in 8% of the samples fromhospitalized cases in South Africa [Mphalele andSteele, 1995] and in 38% of samples from a survey inGuinea-Bissau [Fischer et al., 2000].

The Ministry of Public Health in Ecuador hasan Immunization Program for children under 5 yearsof age that has more than 95% of coverage, but, andeven when diarrhea is a major cause of morbidity andmortality, the immunization program does not in-clude vaccination against any gastroenteritis agent.This situation is not different in the majority ofdeveloping countries where particular informationabout rotavirus disease burden and genotype distribu-tion is now needed to rightfully introduce a rotavirusvaccine into immunization programs. Thus, the objec-tive of the present study was to determine the rotavirus

epidemiology and prevalence of the different genotypesof this agent in Ecuadorian children younger than5 years of age with gastroenteritis.

PATIENTS AND METHODS

The study included 729 children younger than 5 yearsof age with acute diarrhea with onset within 72 hr priorto study entry and no previous exposure to rotavirusvaccination. All children were enrolled from eitherpublic or private primary health care centers in10 different provinces of Ecuador: Azuay, Cotopaxi,Chimborazo, Imbabura and Pichincha (Andean region),Esmeraldas, Guayas, and Manabı (Pacific cost region),Napo, and Pastaza (Amazon region; Fig. 1). Due todata absence on rotavirus prevalence in Ecuador atthe time this study was designed, it was conducted onlyduring 6 months (from March/2006 to August/2006), asin Ecuador there are not well define seasons.

The study was approved by the Bioethics Committeeat the Biomedical Center—Central University ofEcuador and the Ecuadorian Ministry of Public Health.In addition, written consent from the parent or legalguardian of each child was obtained. Clinical informa-tion of all children was recorded, only to verify thediagnosis of gastroenteritis, in case report forms thatincluded a description of the pattern of stools 2 daysbefore the onset of diarrhea and during the diarrheicepisode. Stool samples were classified as watery, loose,or solid, with or without mucus or blood, and whether ornot fever or vomiting was observed. The data werecollected by the parent/legal guardian in conjunctionwith the consulting physician on an outpatient visit tothe health care giver. For enrollment, the World HealthOrganization (WHO) criterion of three or more looser-than-normal stools in a 24-hr period was used. Thetherapeutic plan was given on the basis of the patient’shydration level according to the WHO recommendations[WHO, 1995].

Primary rotavirus diagnosis was assessed using acommercial immunoenzymatic test (IDEIA Rotavirus,DAKO, Carpinteria, CA). Training and quality controlin its use was performed by Netlab, a referencelaboratory located in Quito, Ecuador. Rotavirus-positivestool samples were refrigerated at �48C and thenshipped, in a cooler containing dry ice, to the referencelaboratory within 2 days after collection. All sampleswere then frozen at�208C until they were shipped in dryice to the Immunology and Virology Laboratory (LIV),National University of Quilmes, Argentina, for rota-virus genotyping.

Rotavirus Genotyping

Specimens were submitted to the LIV as neat stoolsamples in individual cryotubes on dry ice. A sampleportion was suspended (10–20%) in Tris–HCl, 50 mMpH 7.5 and stored at �208C until processed. Clarifiedstool suspensions were prepared using Vertrel XF (DuPont Chemicals, Wilmington, DE) and viral RNA wasthen extracted from the aqueous phase by use of the

J. Med. Virol. DOI 10.1002/jmv

VP4 and VP7 Genotypes in Ecuador 1107

silica powder method in the presence of 4 M guanidinethiocyanate [Boom et al., 1990]. The dsRNA sampleswere subjected to multiplex semi-nested RT-PCRfor identification of G and P genotypes, as describedpreviously [Gouvea et al., 1990; Das et al., 1994;Iturriza-Gomara et al., 2000]. First, the dsRNA wassubjected to reverse transcription and initial amplifica-tion in a single tube using the QIAGEN1 OneStepReal Time—Polimerase Chain Reaction (RT-PCR)method (QIAGEN, Inc., Valencia, CA) with primersdesigned for conserved sequences of the VP7 and VP4genes. In a second PCR round, primers for the commonhuman rotavirus genotypes were used for initial screen-ing, and non-typeable strains were further investigatedusing a variety of other type-specific primers for addi-tional animal or human genotypes [Gouvea et al., 1994],including genotype G12 [Castello et al., 2006]. In thecases in which no rotavirus-specific PCR products wereobtained, the first amplification product was submittedto a generic semi-nested PCR with consensus primers[Gouvea, 1993] and a sample was considered as ‘‘non-typeable’’ (NT) when a rotavirus-specific amplicon wasvisualized following this generic reaction. When ampli-fication products could not be visualized after eitherspecific or generic PCR reactions, the sample wasconsidered ‘‘non-amplifiable’’ (NA).

RESULTS

Rotavirus Incidence and Genotyping Results

Rotavirus was detected in the feces of 269 of the729 children (37%) with diarrhea. All cases belongs to

non-hospitalized children and had a favorable clinicalcourse (no deaths were reported). Table I presents thegenotyping results obtained from these 269 samplesaccording to the G-P binary rotavirus serotype/genotypeclassification. From 260 (96.6%) and 241 (89.6%) speci-mens, amplification products were obtained for G andP typing, respectively.

Prevalence of P/G Combinations

In a total of 181 samples (67.3%), one single P/Gcombination was identified, and in 26 (9.7%) samples(9.7%), more than one G and/or P type were detected

J. Med. Virol. DOI 10.1002/jmv

TABLE I. Distribution of G and P Types of Rotavirus inDiarrheal Stools of Ecuadorian Children (March 2006 to

August 2006)

P[8] P[4] P[6] P[4þ 8] NT NA Total

G1 4 1 1 0 1 4 11G2 0 59 0 0 2 1 62G3 3 0 0 0 1 0 4G4 0 0 4 0 0 0 4G9 103 4 0 2 6 0 115G11 2 0 0 0 0 0 2G1þ 9 3 0 0 0 1 0 4G1þ 2 1 4 0 0 0 0 5G2þ 4 0 0 0 1 0 1 2G2þ 9 6 1 0 0 2 0 9G3þ 9 2 0 0 0 0 0 2G3þ 11 1 0 0 0 0 0 1G1þ 2þ 9 1 0 0 0 0 0 1NT 9 0 0 0 13 16 38NA 1 0 0 0 2 6 9TOTAL 136 69 5 3 28 28 269

Fig. 1. Geographical distribution of Ecuadorian cities from which children were recruited for the study.

1108 Naranjo et al.

(mixed infections). Among the single infections, thepredominant P/G combinations were: P[8]G9 (56.9%),P[4]G2 (32.6%), and the same percentage (2.2%) of each,P[4]G9, P[8]G1, and P[6]G4. In a low percentage ofthe single infections, the combinations P[8]G3 (1.7%)and P[8]G11 (1.1%) were identified. There were nonoticeable changes in the distribution of these combi-nations during the whole duration of the study.

Frequencies of G and P Genotypes

Taking into account the total of genotypes detectedin the amplifiable specimens and considering G andP types separately, the most prevalent G genotypes wereG9 (46.1%) and G2 (27.8%; Fig. 2). In 13.3% of theamplifiable samples, no G type could be identified withthe used set of primers (G non-typeables). On the otherhand, the predominant P genotypes were P[8] (57%) andP[4] (29.5%), with a low incidence of P[6] (2%) detectedat lower frequency and 11.5% of samples classified asP non-typeables.

DISCUSSION

In the present report, the rotavirus genotypeswere identified from strains causing diarrhea amongEcuadorian children. The most prevalent genotypesfound were P[8]G9 and P[4]G2, accounting for 89.5% ofthe single infections. Of note, the G9 genotype was theG type detected most frequently (46.1%), almost exclu-sively in combination with P[8]. Strains with this P[8]G9genotype are being increasingly identified in Brazil from1999 with high incidences recently reported in Salvador[Santos et al., 2005], Sao Paulo [Carmona et al., 2006],and Rio de Janeiro [Volotao et al., 2005]. The G9

serotype, in combination with P[8] or P[6], is nowconsidered the fourth globally important G type,representing 10.6% of all isolates between 1982 and2003 in the Americas [Santos and Hoshino, 2005].The second most frequently found G specificity in thisstudy was G2 (27.8%). The G2 serotype, in combinationwith P[4], is considered to be the second globallyimportant strain after P[8]G1, based on the most recentreview including studies published between 1989 and2004 [Santos and Hoshino, 2005]. The other commonhuman G genotypes G1, G3, and G4 were found in lowerfrequencies (7.4%, 2.5%, and 1.8%, respectively), gen-erally in the classical combination with P[8] for G1 andG3, but in non-typical combinations with P[6] in thecase of G4. In three samples (1.1%), the genotype G11was identified. It was reported for the first time inBangladesh in 2005 [Rahman et al., 2005] and veryrecently, in Nepal [Uchida et al., 2006] in a single samplein both studies. This is a typical porcine genotype[Ciarlet et al., 1994].

In the case of the P genotypes, as expected from theclassical associations with G1, G3 and the strains G9detected in this study, P[8] was the predominant (57%)type. In accordance with the frequencies of G2, P[4] wasthe second most prevalent P type (29.5%). Meanwhile,P[6] was detected (2%) in combination with G4 (foursamples) or G1 (one sample).

After more than two decades of rotavirus strainsurveillance by genotyping in five continents, the highcomplexity and diversity of rotavirus epidemiologyhas become clear [Martella et al., 2006]. Longitudinalstudies demonstrate temporal fluctuations in the pre-valence of genotypes with dominance of 1 or 2 strainsand several minor representatives of other types charac-terizing each season. These characteristics appear to bedetermined mainly by point mutations: the possibility ofreassortment among co-circulating human rotavirusstrains, and introduction of animal rotavirus alleles byco-infection of different rotavirus species and reassort-ment with human rotaviruses. Mixed infections,which represent about 15% in Latin America region[Santos and Hoshino, 2005] were detected in 9.7% of thesamples in this study and provided an opportunity forrotavirus strains to co-infect cells in the small intestine.

Natural rotavirus strains resulting from reassort-ment of animal and human strains are particularlyintriguing and could certainly explain the origin ofthe G11 strains identified in this work. Finally, theobservation that about 12% of P and G types remainuntypeable needs further study, because it is not knownwhether point mutations in the VP4 or VP7 genesprevented the primers from recognizing the strains orwhether the strains represent novel P or G genotypes.

In two recent reports on rotavirus in Ecuadorianpopulation [Eisenberg et al., 2006; Endara et al., 2007],there was found that G9 strains were the predominant,both in Quito and in 22 remote communities inEsmeraldas. Those results are in good agreement withthose described in the current study, however, this studywas conducted countrywide (in 10 of the 22 provinces of

J. Med. Virol. DOI 10.1002/jmv

Fig. 2. Frequencies of G types of rotavirus in diarrheal stools ofEcuadorian children (March 2006 to August 2006).

VP4 and VP7 Genotypes in Ecuador 1109

Ecuador), and second, all samples collected during oneseason were tested. For these reasons, this reportconstitutes one of the major studies for one single seasonin Latin America and the first in its class in Ecuador.

Two live oral rotavirus vaccines are currently licensedfor use in many countries, including Ecuador. However,the diversity of rotavirus strains poses differentchallenges for each vaccine. The Merck vaccine, Rota-Teq1, is a pentavalent product composed of five differenthuman-bovine reassortants of a parent bovine strainWC3 incorporating single VP7 genes from humanrotavirus strains of serotypes G1, G2, G3, and G4 andthe VP4 gene from strains of serotype P1A[8] (e.g.,serotype G9). This vaccine was designed to provideserotype-specific (homotypic) protection against thesecommon human rotavirus serotypes [Vesikari et al.,2006]. In the case of Rotarix1 (GlaxoSmithKline,Brussels, Belgium) previous results indicate that theP1A [8]G1 vaccine protects against diarrhea caused byG9 strains because the strains were all associated withP1A[8] [Ruiz-Palacios et al., 2006]. The results from thecurrent survey in Ecuador indicate a high prevalence ofP[4]G2 strains (24.7%), which could be a challenge forthe Rotarix1 vaccine.

These vaccines must, ideally, protect children againststrains of rotaviruses currently in circulation. In devel-oping countries, the distribution of rotavirus strainshas particular characteristics, such as high incidence ofmixed infections, unusual genotypes prevalent in somesettings, and elevated numbers of strains that areuntypeable by PCR using current primers [Castelloet al., 2004]. However, the efficacy of the earlierrotavirus vaccines tested in Latin America was lowerthan that observed in similar trials in the UnitedStates and Finland [Lanata et al., 1989, 1996; Linhareset al., 1996]. Some possible explanations for thislower efficacy are increased strain diversity, more mixedinfections, and exposure to larger inoculum. Conse-quently, it is essential to conduct strain surveillance inLatin America to characterize dominant genotypes anddetermine the prevalence of novel strains, and thushelp to reduce the risk of immunizing with a rotavirusvaccine that may not properly protect children againstthem.

It is not know if some of the non-typeable strainsare possible escape variants to these vaccines or cross-protection could improve their efficacy against unusualserotypes. These questions will only become knownwhen experience of massive vaccination campaigns arefully analyzed and strains recovered from those childrenwho fail to be protected from vaccination and developrotavirus diarrhea are characterized. Only continuousmonitoring of rotavirus disease burden and genotypesurveillance will provide this information.

REFERENCES

Bass DM, Greenberg HB. 1995. Group A rotaviruses. In: Blaser MJ,Smith PD, Ravdin JI, Greenberg HB, Guerrant RL, editors.Infections of the gastrointestinal tract. New York: Raven Press.pp 967–981.

Bern C, Unicomb L, Gentsch JR, Banul N, Yunus M, Sack RB, Glass RI.1992. Rotavirus diarrhea in Bangladeshi children: Correlation ofdisease severity with serotypes. J Clin Microbiol 30:3234–3238.

Black RE, Lopez de Romana G, Brown KH, Bravo N, Grados Bazalar O,Kanashiro HC. 1989. Incidence and etiology of infantile diarrheaand major routes of transmission in Huascar, Peru. Am J Epidemiol129:785–799.

Boom R, Sol CJ, Salimans MM, Jansen CL, Wertheim-van Dillen PM,van der Noordaa J. 1990. Rapid and simple method for purificationof nucleic acids. J Clin Microbiol 28:495–503.

Carmona RC, Timenetsky Mdo C, Morillo SG, Richtzenhain LJ. 2006.Human rotavirus serotype G9, Sao Paulo, Brazil, 1996–2003.Emerg Infect Dis 12:963–968.

Castello AA, Arvay ML, Glass RI, Gentsch J. 2004. Rotavirus strainsurveillance in Latin America: A review of the last nine years.Pediatr Infect Dis J 23:S168–S172.

Castello AA, Arguelles MH, Rota RP, Olthoff A, Jiang B, Glass RI,Gentsch JR, Glikmann G. 2006. Molecular epidemiology of group Arotavirus diarrhea among children in Buenos Aires, Argentina,from 1999 to 2003 and emergence of the infrequent genotype G12.J Clin Microbiol 44:2046–2050.

Ciarlet M, Hidalgo M, Gorziglia M, Liprandi F. 1994. Characterizationof neutralization epitopes on VP7 of serotype G11 porcinerotaviruses. J Gen Virol 75:1867–1873.

Das BK, Gentsch JR, Cicirello HG, Woods PA, Gupta A, RamachandranM, Kumar R, Bhan MK, Glass RI. 1994. Characterization ofrotavirus strains from newborns in New Delhi, India. J ClinMicrobiol 32:1820–1822.

Eisenberg JN, Cevallos W, Ponce K, Levy K, Bates SJ, Scott JC,Hubbard A, Vieira N, Endara P, Espinel M, Trueba G, Riley LW,Trostle J. 2006. Environmental change and infectious disease: Hownew roads affect the transmission of diarrheal pathogens in ruralEcuador. Proc Natl Acad Sci USA 103:19460–19465.

Endara P, Trueba G, Solberg OD, Bates SJ, Ponce K, Cevallos W,Matthijnssens J, Eisenberg JN. 2007. Symptomatic and subclinicalinfection with rotavirus P[8]G9, rural Ecuador. Emerg Infect Dis13:574–580.

Fischer TK, Steinsland H, Molbak K, Ca R, Gentsch JR, Valentiner-Branth P, Aaby P, Sommerfelt H. 2000. Genotype profiles ofrotavirus strains from children in a suburban community inGuinea-Bissau, Western Africa. J Clin Microbiol 38:264–267.

Gentsch JR, Woods PA, Ramachandran M, Das BK, Leite JP, Alfieri A,Kumar R, Bhan MK, Glass RI. 1996. Review of G and P typingresults from a global collection of strains: Implications for vaccinedevelopment. J Infect Dis 174:S30–S36.

Glass RI, Parashar UD, Bresee JS, Turcios R, Fischer TK, WiddowsonMA, Jiang B, Gentsch JR. 2006. Rotavirus vaccines: Currentprospects and future challenges. Lancet 368:323–332.

Gouvea V. 1993. PCR detection of rotavirus. In: Persing DH, Smith TF,Tenover FC, White TJ, editors. diagnostic molecular microbiology,principles and applications. Washington DC: ASM press.

Gouvea V, Glass RI, Woods P, Taniguichi K, Clark HF, Forrester B,Fang ZY. 1990. Polymerase chain reaction amplification and typingof rotavirus nucleic acid from stool specimens. J Clin Microbiol28:276–282.

Gouvea V, Santos N, Timenetsky Mdo C. 1994. VP4 typing of bovineand porcine group A rotaviruses by PCR. J Clin Microbiol 32:1333–1337.

Grinstein S, Gomez JA, Bercovich JA, Biscotti EL. 1989. Epidemiologyof rotavirus infection and gastroenteritis in prospectively mon-itored Argentine families with young children. Am J Epidemiol130:300–308.

Gunasena S, Nakagomi O, Isegawa Y, Kaga E, Nakagomi T, Steele AD,Flores J, Ueda S. 1993. Relative frequency of VP4 gene allelesamong human rotaviruses recovered over a 10 year period (1982–1991) from Japanese children with diarrhea. J Clin Microbiol31:2195–2197.

Iturriza-Gomara M, Green J, Ramsay M, Brown D, Desselberger U,Gray JJ. 2000. Molecular epidemiology of human group A rotavirusinfections in the United Kingdom between 1995 and 1998. J ClinMicrobiol 38:4394–4401.

Kantharidis P, Dyall-Smith ML, Holmes IH. 1987. Marked sequencevariation between segment 4 genes of human RV-5 and simian SA-11 rotavirus. Arch Virol 93:111–121.

Kapikian AZ, Chanock RM. 2001. Rotaviruses. In: Knipe DM, HowleyPM, editors. Fields virology, Vol. 2, 4th edition. Philadelphia:Lippincott, Williams & Wilkins Publishers. p 1787.

J. Med. Virol. DOI 10.1002/jmv

1110 Naranjo et al.

Lanata CF, Black RE, del Aguila R, Gil A, Verastegui H, Gerna G,Flores J, Kapikian AZ, Andre FE. 1989. Protection of Peruvianchildren against rotavirus diarrhea of specific serotypes by one, two,or three doses of the RIT 4237 attenuated bovine rotavirus vaccine.J Infect Dis 159:452–459.

Lanata CF, Midthun K, Black RE, Butron B, Huapaya A, Penny ME,Ventura G, Gil A, Jett-Goheen M, Davidson BL. 1996. Safety,immunogenicity, and protective efficacy of one and three doses ofthe tetravalent rhesus rotavirus vaccine in infants in Lima, Peru.J Infect Dis 174:268–275.

Linhares AC, Moncao HC, Gabbay YB, de Araujo VL, Serruya AC,Loureiro ECB. 1983. Acute diarrhea associated with rotavirusamong children in Belize, Brazil. Trans R Soc Trop Med Hyg 77:384–390.

Linhares AC, Gabbay YB, Freitas RB, da Rosa ES, Mascarenhas JD,Loureiro EC. 1989. Longitudinal study of rotavirus infectionsamong children from Belem, Brazil. Epidemiol Infect 102:129–145.

Linhares AC, Gabbay YB, Mascarenhas JDP, de Freitas RB, OliveraCS, Bellesi N, Monteiro TAF, Lins-Lainson Z, Ramos FP, ValenteSA. 1996. Immunogenicity, safety and efficacy of tetravalentrhesus-human, reassortant rotavirus vaccine Belem, Brazil. BullWHO 74:491–500.

Martella V, Ciarlet M, Banyai K, Lorusso E, Cavalli A, Corrente M, EliaG, Arista S, Camero M, Desario C, Decaro N, Lavazza A,Buonavoglia C. 2006. Identification of a novel VP4 genotype carriedby a serotype G5 porcine rotavirus strain. Virology 346:301–311.

Mphalele MJ, Steele AD. 1995. Relative frequency of human rotavirusVP4 (P) genotypes recovered over a ten-year period from SouthAfrican children with diarrhea. J Med Virol 47:1–5.

Rahman M, Matthijnssens J, Nahar S, Podder G, Sack DA, Azim T, VanRanst M. 2005. Characterization of a novel P[25], G11 human groupa rotavirus. J Clin Microbiol 43:3208–3212.

Ramachandran M, Das BK, Vij A, Kumar R, Bhambal SS, Kesari N,Rawat H, Bahl L, Thakur S, Woods PA, Glass RI, Bhan MK,Gentsch JR. 1996. Unusual diversity of human rotavirus G and Pgenotypes in India. J Clin Microbiol 34:436–439.

Reves RR, Hossain MM, Midthun K, Kapikian AZ, Naguib T, Zaki AM,DuPont HL. 1989. An observational study of naturally acquiredimmunity to rotaviral diarrhea in a cohort of 363 Egyptian children.Am J Epidemiol 130:981–988.

Ruiz-Palacios GM, Perez-Schael I, Velazquez FR, Abate H, Breuer T,Clemens SC, Cheuvart B, Espinoza F, Gillard P, Innis BL,Cervantes Y, Linhares AC, Lopez P, Macias-Parra M, Ortega-Barria E, Richardson V, Rivera-Medina DM, Rivera L, Salinas B,Pavia-Ruz N, Salmeron J, Ruttimann R, Tinoco JC, Rubio P, Nunez

E, Guerrero ML, Yarzabal JP, Damaso S, Tornieporth N, Saez-Llorens X, Vergase RF, Vesikari T, Bouckenooghe A, Clemens R,De Vos B, O’Ryan M; Human Rotavirus Vaccine Study Group. 2006.Safety and efficacy of an attenuated vaccine against severerotavirus gastroenteritis. N Engl J Med 354:11–22.

Santos N, Hoshino Y. 2005. Global distribution of rotavirus serotypes/genotypes and its implication for the development and implementa-tion of an effective rotavirus vaccine. J Med Virol 15:29–56.

Santos N, Volotao EM, Soares CC, Campos GS, Sardi SI, Hoshino Y.2005. Predominance of rotavirus genotype G9 during the 1999, and2002 seasons among hospitalized children in the city of Salvador,Bahia, Brazil: Implications for future vaccine strategies. J ClinMicrobiol 43:4064–4069.

Timenetsky Mdo C, Santos N, Gouvea V. 1994. Survey of rotavirus Gand P types associated with human gastroenteritis in Sao Paulo,Brazil, from 1986 to 1992. J Clin Microbiol 32:2622–2624.

Uchida R, Pandey BD, Sherchand JB, Ahmed K, Yokoo M, Nakagomi T,Cuevas LE, Cunliffe NA, Hart CA, Nakagomi O. 2006. Molecularepidemiology of rotavirus diarrhea among children and adults inNepal: Detection of G12 strains with P[6] or P[8] and a G11P[25]strain. J Clin Microbiol 44:3499–3505.

Velazquez FR, Matson DO, Calva JJ, Guerrero ML, Morrow AL,Carter-Campbell S, Glass RI, Estes MK, Pickering LK, Ruiz-Palacios GM. 1996. Rotavirus infection in infants as protectionagainst subsequent infections. N Engl J Med 335:1022–1028.

Vesikari T, Matson DO, Dennehy P, Van Damme P, Santosham M,Rodriguez Z, Dallas MJ, Heyse JF, Goveia MG, Black SB, ShinefieldHR, Christie CD, Ylitalo S, Itzler RF, Coia ML, Onorato MT, AdeyiBA, Marshall GS, Gothefors L, Campens D, Karvonen A, Watt JP,O’Brien KL, DiNubile MJ, Clark HF, Boslego JW, Offit PA, HeatonPM, Rotavirus Efficacy and Safety Trial (REST) Study Team. 2006.Safety and efficacy of a pentavalent human-bovine (WC3) reassor-tant rotavirus vaccine. N Engl J Med 354:23–33.

Volotao EM, Soares CC, Maranhao AG, Rocha LN, Hoshino Y, SantosN. 2005. Rotavirus surveillance in the city of Rio de Janeiro-Brazilduring 2000–2004 Detection of unusual strains with G8P[4] orG10P[9] specificities. J Med Virol 78:263–272.

World Health Organization. 1995. The Treatment of diarrhoea:A manual for physicians and other senior health workers.4th revision. WHO/CDD/SER80.2. World Health Organization,Geneva, Switzerland.

Wyatt RG, Yolken RH, Urrutia JJ, Mata L, Greenberg HB, ChanockRM, Kapikian AZ. 1979. Diarrhea associated with rotavirus in ruralGuatemala: A longitudinal study of 24 infants and young children.Am J Trop Med Hyg 28:325–328.

J. Med. Virol. DOI 10.1002/jmv

VP4 and VP7 Genotypes in Ecuador 1111