Audrey Cilli

Rare G3P(3) rotavirus strain detected in Brazil: Possible human-canine interspecies transmission

BACKGROUND An unusual strain of human rotavirus G3P[3] (R2638 strain) was detected from a 1-year-old child patient during the epidemiological survey of rotavirus in the state of São Paulo, Brazil in 2011. OBJECTIVE The aim of this study was to carry out sequence analyses of the two outer capsid proteins (VP4 and VP7) of the R2638 strain detected in order to obtain further information of the genetic relationships between human and animal rotaviruses. STUDY DESIGN Rotavirus G3P[3] was detected using a commercial immunoenzymatic assay, SDS-PAGE, and genotyped by RT-PCR. The analysis of the genetic relationship between human and animal rotaviruses was carried out by sequencing the VP7 and VP4 genes. RESULTS The VP7 gene of the R2638 strain displayed the highest nucleotide identity to the canine strains A79-10 (96.6%) and CU-1 (96.2%) isolated in USA. The VP4 sequence showed the highest nucleotide identity to P[3] canine rotavirus strain RV52/96 isolated in Italy at 94.1%. Furthermore, the VP4 genes of P[3] strains could be discriminated into two phylogentically distinct clusters. CONCLUSION The present study reinforces the hypothesis that animals rotaviruses might be able to cross the species barriers, and the lack of systematic surveillance of rotavirus infection in small animals hinders the ability to establish firm epidemiologic connections. Moreover, in 2006 rotavirus vaccine was included in the Brazilian Immunization Program, and selective vaccine pressure could increase the circulation of uncommon strains. This is the first report of G3P[3] in over 20-year period of monitoring in Brazil.

Norovirus 3rd Generation kit: an improvement for rapid diagnosis of sporadic gastroenteritis cases and valuable for outbreak detection.

The aim of this study was to evaluate the sensitivity and specificity of the Ridascreen(®) Norovirus 3rd Generation kit compared to the RT-PCR. A retrospective, descriptive study was conducted with 245 specimens from sporadic cases and outbreak surveillance samples of gastroenteritis in Brazil from 2006 to 2009. Overall, the kit showed a sensitivity of 61.8% and a specificity of 92.5%. The sensitivity for outbreaks diagnosis was 87.9% and specificity 83.8%. The Ridascreen(®) 3rd Generation could detect specimen containing genogroup (G) II with high sensitivity. However, GI and mixed infections (GI/GII) were unlikely to be detected by the kit. ELISA for Norovirus (NoV) detection provides a rapid, technically simple assay system that can be used to increase the surveillance of gastroenteritis outbreaks, especially in Public Health Laboratories with high sample throughput. This assay is useful for the detection of NoV outbreaks and is an improvement as compared to previous ELISAs; however, due to its sensitivity, RT-PCR in still required for routine NoV detection in sporadic cases investigation.

Characterization of rotavirus strains from day care centers: pre- and post-rotavirus vaccine era

OBJECTIVES In 2006 the rotavirus vaccine was included in the Brazilian Immunization Program. The aim of this study was to report the results of a 5-year surveillance study of rotavirus strains in children < 5 years with acute gastroenteritis from day care centers in the state of São Paulo, Brazil. METHODS This retrospective study was conducted with 30 day care centers from 2004 to 2008 with convenient surveillance fecal specimens, investigated by ELISA, SDS-PAGE, RT-PCR and gene sequencing to genotype characterization. RESULTS Rotavirus infection was detected in 28.3% of samples (38/134). The most frequent genotypes detected were G9P[8] and G1P[8] in 2004; G1P[8] in 2005; GNTP[NT] in 2006; G2P[4] in 2007; and there were no cases in 2008. Mixed infections were not observed. Detection rate declined from 65.7% (23/35) in 2004 to 50% (9/18) in 2007. CONCLUSIONS Genotype distribution varied according to collection year, accompanied by a reduction in detection rate. Use of rotavirus vaccine requires implementation of post-marketing surveillance to monitor rotavirus strain diversity and its efficacy against possible new emerging genotypes.

Rotavirus in adults, Brazil, 2004–2011: G2P[4] dominance and potential impact on vaccination

OBJECTIVES 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%. CONCLUSION 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.

Caracterização molecular de cepas de rotavírus e norovírus: um estudo de 6 anos (2004-2009)

OBJECTIVE To monitor rotavirus (RV) and norovirus (NoV) infections in hospitalized children ≤ 5 years with acute gastroenteritis in the state of São Paulo, Brazil, during a 6-year period (2004- 2009). METHODS This retrospective study was conducted with 61 medical centers with convenient surveillance fecal specimens, investigated by enzyme-linked immunosorbent assay, sodium dodecyl sulfate polyacrylamide gel electrophoresis, reverse polymerase chain reaction and sequencing to genotype characterization. RESULTS RV and NoV infections were detected in 29.6% (144/487) and 29.2% (26/89) of the samples, respectively. The most frequent RV genotypes detected were G9P[8] in 2004; G1P[8] in 2005; G9P[8] in 2006; and G2P[4] during 2007, 2008, and 2009. Detection rate declined from 36.3% (33/91) in 2004 to 4.2% (4/95) in 2009. NoV genogroup GII was found in 61.6% (16/26) of the samples, and GI in 11.5% (3/26). Mixed NoV-RV infections were observed in 2.2% (2/89) of the samples, involving GI+G9P[8] and GI+G2P[4] strains. CONCLUSIONS Genotype distribution varied according to collection year, accompanied by a reduction in detection rate. Use of RV vaccine requires implementation of post-marketing surveillance to monitor RV strain diversity and its efficacy against possible new emerging genotypes. NoVs have been increasingly identified as relevant etiological agents among hospitalized children and play an important role in the viral etiology of pediatric acute gastroenteritis in the state of São Paulo.

ROTAVIRUS GENOTYPES CIRCULATING IN BRAZIL, 2007-2012: IMPLICATIONS FOR THE VACCINE PROGRAM

SUMMARY Regarding public health in Brazil, a new scenario emerged with the establishment of universal rotavirus (RV) vaccination programs. Herein, the data from the five years of surveillance (2007-2012) of G- and P-type RV strains isolated from individuals with acute gastroenteritis in Brazil are reported. A total of 6,196 fecal specimens were investigated by ELISA and RT-PCR. RVs were detected in 19.1% (1,181/6,196). The peak of RV incidence moved from June-August to September. RV was detected less frequently (19.5%) among children ≤ 5 years than in older children and adolescents (6-18 years) (40.6%). Genotype distribution showed a different profile for each year: G2P[4] strains were most prevalent during 2007-2010, G9P[8] in 2011, and G12P[8] in 2012. Mixed infections (G1+G2P[4], G2+G3P[4]+P[8], G2+G12P[8]), unusual combinations (G1P[4], G2P[6]), and rare strains (G3P[3]) were also identified throughout the study period. Widespread vaccination may alter the RV seasonal pattern. The finding of RV disease affecting older children and adolescents after vaccine implementation has been reported worldwide. G2P[4] emergence most likely follows a global trend seemingly unrelated to vaccination, and G12, apparently, is emerging in the Brazilian population. The rapidly changing RV genotype patterns detected during this study illustrate a dynamic population of co-circulating wildtype RVs in Brazil.

Detection of the emerging rotavirus G12P[8] genotype at high frequency in brazil in 2014: Successive replacement of predominant strains after vaccine introduction.

The continuum characterization of rotavirus (RVA) genotypes is essential to understand how vaccine introduction could impact virus epidemiology. In the present study, an unexpected rapid changing pattern of RVA genotypes distribution in Brazilian population during three followed seasons is described. From January/2012 to December/2014, a total of 3441 fecal specimens were collected from collaborating centers across Southern, Southeastern and Midwest of Brazil. All specimens were screened for RVA using ELISA, and genotyped by RT-PCR. Differences in proportions were tested using Chi-Squares. A p-value of less than 0.05 was considered statistically significant. RVA was detected in 19.7% (677/3441). Among RVA positive cases (n=677), a total of 652 (96.3%) samples were successfully amplified by RT-PCR. G3P[8] remained prevalent in 2012 (37.6%, 69/185) and 2013 (40.1%, 74/186) (χ(2)=0.107, p=0.743), but declined markedly in 2014 (3.5%, 10/281) (χ(2)=71.770, p=0.000). G12P[8] was second highest strain in 2012 (22.7%, 42/185), decrease rapidly in 2013 (2.7%, 5/186) (χ(2)=26.224, p=0.000) and re-emerged as the predominant genotype in 2014 (86.6%, 243/281) (χ(2)=118.299, p=0.000). From July/2014, G12P[8] was the single genotype detected in all regions studied. The sudden emergence, spread and predominance of G12P[8] strain in Brazil, raised the hypothesis of a possible G12 outbreak being in progress. Nationally, the long term decline in gastroenteritis hospitalization observed in the country after RVA vaccine introduction was confirmed. Nevertheless, the sharp increase in diarrhea hospitalization prevalence from 2013 to 2014 observed in Southern and Southeastern regions is consistent with what appears to be an outbreak of G12P[8]. Continued surveillance is needed to verify the effectiveness of the RotarixTM vaccine in Brazil together with potential emergence of unusual genotypes.

Rotavirus G2P[4] and G2P[4]+[6] infections during norovirus gastroenteritis outbreak: summer season 2010, Brazil

INTRODUCTION This study aimed to monitor the seasonality of rotavirus infection, and gain insight into the variability of Brazilian strains. METHODS A total of 28 stool samples were analyzed from 698 revised cases of gastroenteritis during a norovirus outbreak in the summer of 2010 in Guarujá, Brazil. Diagnosis was performed using enzyme-linked immunosorbent assay (ELISA), reverse transcription polymerase chain reaction (RT-PCR), and sequencing. RESULTS Rotavirus infection was detected in 17.9% (5/28) of samples; 4 samples were G2P[4] genotype, and one G2P[4]+P[6] genotype. G2 and P[4] sequences showed a genetic relationship to strains from India and Russia, respectively. CONCLUSIONS The seasonal pattern of rotavirus may be a consequence of human activity apart from climate factors.

Large gastroenteritis outbreak due to norovirus GII in São Paulo, Brazil, summer 2010.

In summer 2010 (January-March 2010), the state of São Paulo (SP), located in Southern of Brazil, experienced a large gastroenteritis outbreak due to Norovirus (NoV), a common viral pathogen associated with diarrhea, with marked seasonality during spring and summer. The coast line area of the state was the most affected, probably due to the increase of population density during the summer vacations, flooding in conjunction with the waterborne and seafood components of the NoV transmission.

Rotavirus genotype G4P[8] and enteric adenovirus in HIV-positive patients with and without diarrhoea in São Paulo State, Brazil

The present study was carried out in order to identify rotavirus and enteric adenovirus in HIV-positive patients with and without diarrhoea, collected in a pre- and early highly active antiretroviral therapy era. Rotavirus was detected in 2.5% (3/118) and adenovirus in 14.4% (17/118) of the samples from patients without diarrhoea. In the patients with diarrhoea, rotavirus was identified in 1.5% (2/133) and adenovirus in 7.5% (10/133). These findings suggest no increased frequency of virus excretion in HIV-infected patients with diarrhoea. The genotype G4P[8] was characterized in all positive rotavirus samples, and this is the first report of rotavirus molecular characterization in HIV-positive patients in Brazil.