Identification of circo-like virus-Brazil genomic sequences in raw sewage from the metropolitan area of São Paulo: evidence of circulation two and three years after the first detection.
BACKGROUND
Two novel viruses named circo-like virus-Brazil (CLV-BR) hs1 and hs2 were previously discovered in a Brazilian human fecal sample through metagenomics. CLV-BR hs1 and hs2 possess a small circular DNA genome encoding a replication initiator protein (Rep), and the two genomes exhibit 92% nucleotide identity with each other. Phylogenetic analysis based on the Rep protein showed that CLV-BRs do not cluster with circoviruses, nanoviruses, geminiviruses or cycloviruses.


OBJECTIVE
The aim of this study was to search for CLV-BR genomes in sewage and reclaimed water samples from the metropolitan area of São Paulo, Brazil, to verify whether the first detection of these viruses was an isolated finding.


METHODS
Sewage and reclaimed water samples collected concomitantly during the years 2005-2006 were purified and concentrated using methodologies designed for the study of viruses. A total of 177 treated reclaimed water samples were grouped into five pools, as were 177 treated raw sewage samples. Nucleic acid extraction, polymerase chain reaction (PCR) amplification and Sanger sequencing were then performed.e.
genomes were detected in two pools of sewage samples, p6 and p9. Approximately 28% and 51% of the CLV-BR genome was amplified from p6 and p9, respectively, including 76% of the Rep gene. The detected genomes are most likely related to CLV-BR hs1. Comparative analysis showed several synonymous substitutions within Rep-encoding sequences, suggesting purifying selection for this gene, as has been observed for other eukaryotic circular Rep-encoding single-stranded DNA (CRESS-DNA) viruses.


CONCLUSIONS
The results therefore indicated that CLV-BR has continued to circulate in Brazil two and three years after first being detected.
Instituto Adolfo Lutz, Centro de Virologia, Núcleo de Doenças Respiratórias, São Paulo, SP, Brasil.
Silvana Beres
SB
Castrignano
Instituto Adolfo Lutz, Centro de Virologia, Núcleo de Doenças Respiratórias, São Paulo, SP, Brasil.
Teresa Keico
TK
Nagasse-Sugahara
Universidade de São Paulo, Departamento de Microbiologia, São Paulo, SP, Brasil.
Patrícia
P
Garrafa
Universidade de São Paulo, Departamento de Microbiologia, São Paulo, SP, Brasil.
Telma Alves
TA
Monezi
Universidade de São Paulo, Departamento de Microbiologia, São Paulo, SP, Brasil.
Karina Medici
KM
Barrella
Universidade de São Paulo, Departamento de Microbiologia, São Paulo, SP, Brasil.
Dolores Ursula
DU
Mehnert
D017925:Circovirus / Q000235:genetics* / Q000302:isolation & purification; D002947:Cities; D004279:DNA, Viral / Q000235:genetics; D016679:Genome, Viral; D006801:Humans; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000821:virology*
D004279:DNA, Viral; D012722:Sewage