title: Characterization of novel intragenotype recombination events among norovirus pandemic GII.4 variants.
abstract: Recently, there has been an increase in the number of children hospitalized due to norovirus infection in Brazil. This is due both to the occurrence of more severe norovirus-related gastroenteritis cases after the introduction of the rotavirus vaccine and an increase in the tools for the detection of the disease. This pathogen is transmitted by the fecal-oral route, and the illness is characterized by diarrhea, vomiting, nausea and abdominal cramps. The genome of the virus is organized into three open reading frames showing strong mutation rates. Additionally, homologous recombination events, which can increase the virulence of the virus and lead to genotyping mistakes in molecular epidemiological studies, frequently occur. The purpose of this study was to describe two recombination events among different GII.4 variants that infected children who were hospitalized for severe acute gastroenteritis during distinct periods of time in Belém, Brazil. The recombination among the variants US95_96/Kaiso_2003 and Den Haag_2006b/Yerseke_2006a were observed in May 2003 and February 2009, respectively. In both cases, the association between the dominant variant at that point in time and another that was circulating at a low frequency in the population of Belém was demonstrated. Interestingly, the position of the breakpoint of the recombination event in the genome was the polymerase gene and was located at the nucleotide positions 4.834 and 5.002, which is an unusual location for the occurrence of recombination as other studies have previously reported the junction region as a breakpoint. In this study, both recombinant variant strains were related to severe cases of diarrhea that lead to hospitalization, demonstrating the viral evolution of GII.4 in response to selective pressures, which ultimately lead to the emergence of novel viral types in the pediatric population. The cases discussed here reinforce the need for continuous norovirus surveillance. To our knowledge, these two GII.4 variant recombinations have not yet been previously described.
authors.affiliation: Postgraduate Program in Virology, Evandro Chagas Institute, Ananindeua, Pará, Brazil. Electronic address: jones_siqueira@ymail.com.
authors.forename: Jones Anderson Monteiro
authors.initials: JAM
authors.lastname: Siqueira
authors.affiliation: Postgraduate Program in Virology, Evandro Chagas Institute, Ananindeua, Pará, Brazil. Electronic address: renatobandeira@gmail.com.
authors.forename: Renato da Silva
authors.initials: RDS
authors.lastname: Bandeira
authors.affiliation: Virology Section, Evandro Chagas Institute, Health Surveillance Secretariat, Brazilian Ministry of Health, Ananindeua, Pará, Brazil. Electronic address: mariajustino@iec.pa.gov.br.
authors.forename: Maria Cleonice Aguiar
authors.initials: MCA
authors.lastname: Justino
authors.affiliation: Virology Section, Evandro Chagas Institute, Health Surveillance Secretariat, Brazilian Ministry of Health, Ananindeua, Pará, Brazil. Electronic address: alexandrelinhares@iec.pa.gov.br.
authors.forename: Alexandre da Costa
authors.initials: ADC
authors.lastname: Linhares
authors.affiliation: Virology Section, Evandro Chagas Institute, Health Surveillance Secretariat, Brazilian Ministry of Health, Ananindeua, Pará, Brazil. Electronic address: yvonegabbay@iec.pa.gov.br.
authors.forename: Yvone Benchimol
authors.initials: YB
authors.lastname: Gabbay
mesh_terms: D001938:Brazil / Q000453:epidemiology; D017250:Caliciviridae Infections / Q000453:epidemiology / Q000821:virology*; D002675:Child, Preschool; D005243:Feces / Q000821:virology; D005759:Gastroenteritis / Q000453:epidemiology / Q000821:virology*; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D007223:Infant; D029322:Norovirus / Q000235:genetics*; D016366:Open Reading Frames; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D011995:Recombination, Genetic
chemical_list: D012367:RNA, Viral
keywords: Children; Hospital; Norovirus; Recombination event; Variants