Rotavirus in adults, Brazil, 2004-2011: G2P[4] dominance and potential impact on vaccination.
OBJECTIVE
The aim of this study was to monitor rotavirus (RV) infections in adults >18 years with acute gastroenteritis during 2004-2011 national Brazilian RV surveillance. In addition, to characterize the RV group A (RVA) strains in order to gain insight into the supposed vaccine selective pressure imposed to Brazilian children population.


METHODS
A total of 2102 convenient fecal specimens were investigated by ELISA, PAGE, and RT-PCR.


RESULTS
RV was detected in 203 (9.6%) of 2102 specimens, and showed a marked peak of detection in September. RVA infection was detected in 9.4% (197/2102) and RV group C (RVC) in 0.3% (6/2102). The most frequent genotypes detected in 2004 and 2005 were G9P[8] (38.5%; 5/13) and G1P[8] (54.5%; 6/11), respectively. The dominant genotype identified from 2006 to 2011 was G2P[4] (64.4%; 116/180). Detection rate varied during the 8-year period of the study from 0.7% to 12.9%.


CONCLUSIONS
The high detection rate of G2P[4] in adults provides further evidence that its dominance reflects the seasonality of RVA strains instead of the supposed selective advantage created by vaccination program. It also can be suggested that adult infections may serve as a reservoir to maintain RVA strains in childhood gastroenteritis. Considering the detection rate, the evident reduction of RVA frequency observed in children after vaccine introduction was not present in adults.
Adolfo Lutz Institute, Virology Center, Enteric Disease Laboratory, Av. Dr. Arnaldo, 355, São Paulo, SP, Brazil. Electronic address: driluchs@gmail.com.
Adriana
A
Luchs
Adolfo Lutz Institute, Virology Center, Enteric Disease Laboratory, Av. Dr. Arnaldo, 355, São Paulo, SP, Brazil.
Audrey
A
Cilli
Adolfo Lutz Institute, Virology Center, Enteric Disease Laboratory, Av. Dr. Arnaldo, 355, São Paulo, SP, Brazil.
Simone Guadagnucci
SG
Morillo
Adolfo Lutz Institute, Virology Center, Enteric Disease Laboratory, Av. Dr. Arnaldo, 355, São Paulo, SP, Brazil.
Rita
R
de Cassia Compagnoli Carmona
Adolfo Lutz Institute, Virology Center, Enteric Disease Laboratory, Av. Dr. Arnaldo, 355, São Paulo, SP, Brazil.
Maria
M
do Carmo Sampaio Tavares Timenetsky
D000293:Adolescent; D000328:Adult; D001938:Brazil / Q000453:epidemiology; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000821:virology*; D005759:Gastroenteritis / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D005838:Genotype; D006801:Humans; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012401:Rotavirus / Q000235:genetics / Q000276:immunology; D012400:Rotavirus Infections / Q000453:epidemiology* / Q000517:prevention & control; D022243:Rotavirus Vaccines / Q000276:immunology*; D012621:Seasons
D022243:Rotavirus Vaccines
Adults; Brazil; Rotavirus group A; Rotavirus group C; Vaccination