Molecular and evolutionary characterization of norovirus GII.17 in the northern region of Brazil.

BACKGROUND: Currently, norovirus (NoV) is associated with one-fifth of all acute gastroenteritis (AGE) cases worldwide. The NoV GII.17_2014 variant has been associated with gastroenteritis outbreaks in several Asian countries, replacing the previously dominant Sydney 2012 variant. There is limited data about circulation of this new strain in Brazil. This study aimed to describe the phylogenetic and evolutionary characteristics of the GII.17_2014 strains in the Northern region of Brazil. METHODS: NoV was detected by enzyme immunoassay (EIA) in 645 stool samples of AGE cases that were reported in Pará and Amazonas states during 2015-2016. All positive samples were tested for NoV GI and GII by reverse transcription polymerase chain reaction (RT-PCR) and the amplicons were subjected to genome sequencing. The GII.17-positive samples were retested by PCR using different sets of designed primers, which target a highly conserved capsid gene region. Next, the amplicons were sequenced and phylogenetically analyzed using Bayesian inferences. RESULTS: Of the 645 samples tested, 208 (32.2%) tested were positive for NoV by EIA, among which 95 (45.7%) were genotyped. Among the genotyped samples, 12 (12.6%) were characterized as GII.17_2014 with the first case detected in November 2015 (1/30, 3.3%) and the others in 2016 (11/65, 16.9%). All strains found in our study were clustered in clade D (epidemic strain). The uncorrelated log-normal model estimations calculated the rate of evolution for GII-17 strains as 1.95 × 10- 3 (1.28 × 10- 3-2.63 × 10- 3). In total, 36 nucleotide changes were observed after analyzing the VP1 sequence, among which 28 occurred in the P2 region. CONCLUSIONS: These data demonstrate the evolutionary dynamics in NoV GII.17_2014 strains, which indicated high mutation rates with nucleotide substitutions and indels that are related to the elevated levels of antigenic diversity. This partly explains the increase in viral prevalence.

Enteropathogens detected in a daycare center, Southeastern Brazil: bacteria, virus, and parasite research.

INTRODUCTION: The objective of this study was to determine the prevalence and etiological profile of enteropathogens in children from a daycare center. METHODS: From October 2010 to February 2011 stool samples from 100 children enrolled in a government daycare center in the municipality of São José do Rio Preto, in the state of São Paulo, were collected and analyzed. RESULTS: A total of 246 bacteria were isolated in 99% of the fecal samples; 129 were in the diarrheal group and 117 in the non-diarrheal group. Seventy-three strains of Escherichia coli were isolated, 19 of Enterobacter, one of Alcaligenes and one of Proteus. There were 14 cases of mixed colonization with Enterobacter and E. coli. Norovirus and Astrovirus were detected in children with clinical signs suggestive of diarrhea. These viruses were detected exclusively among children residing in urban areas. All fecal samples were negative for the presence of the rotavirus species A and C. The presence of Giardia lamblia, Entamoeba coli, Endolimax nana and hookworm was observed. A significant association was found between food consumption outside home and daycare center and the presence of intestinal parasites. CONCLUSIONS: For children of this daycare center, intestinal infection due to pathogens does not seem to have contributed to the occurrence of diarrhea or other intestinal symptoms. The observed differences may be due to the wide diversity of geographical, social and economic characteristics and the climate of Brazil, all of which have been reported as critical factors in the modulation of the frequency of different enteropathogens.

Identification of two sublineages of genotype G2 rotavirus among diarrheic children in Parauapebas, Southern Pará State, Brazil.

On a world scale, group A human rotaviruses are the most common cause of severe acute gastroenteritis during infancy and childhood, including five (G1, G2, G3, G4, and G9) epidemiologically important genotypes. Among these, G2 denotes a different genogroup which appears to have a cyclic pattern of occurrence and yet little information is available about its genetic variability. The aim of this report was to characterize the emergence of G2 genotype in Paraupebas, Southern Pará State, Brazil, some of which detected after introduction of rotavirus vaccine. A total of 241 fecal specimens from young children with acute gastroenteritis were collected from the "Yutaka Takeda Hospital," a Municipality Hospital, and at the Parauapebas' Health Unit, Pará, from January to September 2006 and during March to November 2008. All samples were tested for rotavirus using immunochromatography, polyacrylamide gel electrophoresis (PAGE), and RT-PCR, yielding an overall positivity of 12.45% (30/241). Rotavirus G2P[4] was identified in 27 of 30 samples (90%), followed by G1P[8] (2/30, 6.67%) and G9P[8] (1/30, 3.33%). Phylogenetic analysis was performed in 15 of the G2 strains, all of which grouped into lineage II. Four of these strains clustered into sublineage II-a (year 2006) and 11 into one possible new sublineage named II-c (year 2008, except SAL-1920-C). The recent re-emergence of G2 genotype associated with lineage II in Brazil warrants the continuous monitoring of circulating rotavirus strains following the nationwide universal use of rotavirus vaccine.