Diversity of enteric and non-enteric human adenovirus strains in Brazil, 2006-2011.

During 2006-2011, 5035 fecal samples were tested by PCR for human adenovirus (HAdV) and sequenced. HAdV was detected in 198 cases (3.9%), with the highest rate in children ≤ 5 years. Enteric HAdVs were the most prevalent genotypes (78%; 146/187): HAdV-F41 (63.6%; 119/187), HAdV-F40 (12.3%; 23/187), HAdV-A12 (1.6%; 3/187) and HAdV-A31 (0.5%; 1/187). Non-enteric HAdVs were detected in 22% (41/187): HAdV-C1 (8.0%; 15/187), HAdV-C2 (6.9%; 13/187), HAdV-C5 (4.3%; 8/187), HAdV-D8 (1.3%; 2/187), HAdV-B21 (0.5%; 1/187), HAdV-B3 (0.5%; 1/187) and HAdV-C6 (0.5%; 1/187). This 6-year retrospective study points out a high diversity of HAdV types circulating in Brazil and highlights the need to carry out molecular epidemiological studies of HAdV among patients with acute diarrheal infection on a regular basis.

Coxsackievirus A6 strains causing an outbreak of hand-foot-and-mouth disease in Northeastern Brazil in 2018.

Hand-foot-and-mouth disease (HFMD) is a highly contagious viral disease commonly associated to Enteroviruses (EV). During 2018, Brazil faced massive HFMD outbreaks spread across the country. This study aimed to characterize the EV responsible for the HFMD outbreak that occurred in Paraiba State, Brazilian Northeastern region, in 2018, followed by a phylogenetic analysis to detail information on its genetic diversity. A total of 49 serum samples (one from each patient) collected from children ≤ 15 years old, clinically diagnosed with HFMD were tested for EV using conventional RT-PCR and RT-qPCR. EV infection was confirmed in 71.4% (35/49) of samples. The mean and median ages were 1.83 years and one year old, respectively. Twenty-two EV-positive samples were successfully sequenced and classified as EV-A species; 13 samples were also identified with the CV-A6 genotype. The phylogenetic analysis (VP1 region) of three samples revealed that the detected CV-A6 strains belonged to sub-lineage D3. The CV-A6 strains detected here clustered with strains from South America, Europe and West Asia strains that were also involved in HFMD cases during the 2017-2018 seasons, in addition to the previously detected Brazilian CV-A6 strains from 2012 to 2017, suggesting a global co-circulation of a set of different CV-A6 strains introduced in the country at different times. The growing circulation of the emerging CV-A6 associated with HFMD, together with the detection of more severe cases worldwide, suggests the need for a more intense surveillance system of HFMD in Brazil. In addition, this investigation was performed exclusively on serum samples, and the analysis of whole blood samples should be considered and could have shown advantages when employed in the diagnosis of enteroviral HFMD outbreaks.

Enteric adenovirus epidemiology from historical fecal samples in Brazil (1998-2005): Pre-rotavirus vaccine era.

Human adenovirus (HAdV) is recognized as frequent cause of acute gastroenteritis and enteric viruses can be preserved in frozen stored feces for long periods of times. The purpose of the present study was to investigate enteric HAdV genotypic diversity in archival fecal specimens stored from 1998 to 2005 in order to understand the natural history of HAdV in diarrheal patients in Brazil before rotavirus vaccine introduction. A total of 3346 specimens were tested for HAdV using conventional PCR. Genotypes were identified by sequencing. HAdV was detected in 6.8% (228/3346). Positivity was higher in children ≤ 5 years and males (p < 0.05). HAdV was most frequently observed during winter and spring seasons (p < 0.05). HAdV-F41 was the most prevalent genotype (59.2%;135/228), followed by HAdV-F40 (16.2%;37/228), HAdV-C1 (5.2%;12/228), HAdV-C2 (5.2%;12/228), HAdV-C5 (3.1%;7/228), HAdV-A12 (1.3%;3/228), HAdV-E4 (0.9%;2/228), HAdV-B3 (0.9%;2/228) and HAdV-B21 (0.4%;1/228). In 7.6% (17/228) only species D could be defined. HAdV-E4 strains were phylogenetic analyzed and classified as lineage (a)-like PG II. HAdV prevalence remained stable in Brazilian population, regardless rotavirus vaccine introduction. The predominant HAdV genotypes detected did not change over time, highlighting a high diversity of circulating strains in the country throughout decades. Due to the historical lack of HAdV genotyping surveillance in Brazil, HAdV-E4 epidemiology is virtually unknown in the country. The present study contributed significantly to the understanding of the natural history of HAdV in diarrheal patients in Brazil. The acquired data are important for clinical diagnosis, particularly for studies investigating enteric viruses' prevalence and molecular epidemiology of archival clinical specimens.

Coxsackievirus A6 strains causing an outbreak of hand-foot-and-mouth disease in Northeastern Brazil in 2018

ABSTRACT Hand-foot-and-mouth disease (HFMD) is a highly contagious viral disease commonly associated to Enteroviruses (EV). During 2018, Brazil faced massive HFMD outbreaks spread across the country. This study aimed to characterize the EV responsible for the HFMD outbreak that occurred in Paraiba State, Brazilian Northeastern region, in 2018, followed by a phylogenetic analysis to detail information on its genetic diversity. A total of 49 serum samples (one from each patient) collected from children ≤ 15 years old, clinically diagnosed with HFMD were tested for EV using conventional RT-PCR and RT-qPCR. EV infection was confirmed in 71.4% (35/49) of samples. The mean and median ages were 1.83 years and one year old, respectively. Twenty-two EV-positive samples were successfully sequenced and classified as EV-A species; 13 samples were also identified with the CV-A6 genotype. The phylogenetic analysis (VP1 region) of three samples revealed that the detected CV-A6 strains belonged to sub-lineage D3. The CV-A6 strains detected here clustered with strains from South America, Europe and West Asia strains that were also involved in HFMD cases during the 2017-2018 seasons, in addition to the previously detected Brazilian CV-A6 strains from 2012 to 2017, suggesting a global co-circulation of a set of different CV-A6 strains introduced in the country at different times. The growing circulation of the emerging CV-A6 associated with HFMD, together with the detection of more severe cases worldwide, suggests the need for a more intense surveillance system of HFMD in Brazil. In addition, this investigation was performed exclusively on serum samples, and the analysis of whole blood samples should be considered and could have shown advantages when employed in the diagnosis of enteroviral HFMD outbreaks.

Epidemiologia dos bocavirus humano em amostras fecais históricas no Brasil (1998-2005) / Epidemiology of human bocavirus in historical fecal samples in Brazil (1998-2005)

O bocavírus humano (HBoV) foi descrito pela primeira vez em 2005 e desde então associado como agente etiológico causador de doenças respiratórias e diarreia em todo mundo. Há 4 genótipos de HBoV identificados até o momento. HBoV-1 é comumente associado as infecções respiratórias, enquanto o HBoV-2, HBoV-3 e HBoV-4 são frequentemente detectados em amostras fecais. Coinfecções envolvendo o HBoV e outros agentes virais entéricos são frequentes. Vírus entéricos podem ser preservados em fezes congeladas por longos períodos. O objetivo do presente estudo foi investigar a frequência e a diversidade genotípica dos HBoV em amostras fecais históricas armazenadas e coletadas antes de 2005, a fim de compreender a história natural dos HBoV em pacientes com diarreia nas regiões Centro Oeste, Sul e Sudeste do Brasil. A associação do HBoV com outros vírus gastroentéricos de importância epidemiológica na doença diarreica também foi explorada. Um total de 3347 amostras foram selecionadas e testadas para HBoV por qPCR. As amostras positivas foram genotipadas por PCR convencional seguido de sequenciamento Sanger. As amostras positivas para HBoV por qPCR também foram testadas para a presença de Norovírus (NoV) por RT-qPCR e para Adenovirus Humano (HAdV) por PCR convencional e sequenciamento. HBoV foi detectado em 5,8% (195/3347). Coinfecção com NoV foi encontrada em 25,6% (50/195), HAdV 8,2% (16/195) e a tripla-infecção em 1% (2/195), totalizando 34,9% (68/195) de casos de coinfecções. Esses achados indicam que o HBoV pode ter um papel epidemiológico importante como único agente causador de doença diarreica em pacientes (65,2% de monoinfecções). A taxa de detecção variou significativamente de acordo com os anos de 2000-2001, 2002-2003 e 2003-2004 (p<0,05).

The human bocavirus (HBoV) was first described in 2005 and has since been associated as an etiological agent causing respiratory diseases and diarrhea worldwide. There are four genotypes of HBoV identified so far. HBoV-1 is commonly associated with respiratory infections, while HBoV-2, HBoV-3, and HBoV-4 are often detected in fecal samples. Coinfections involving HBoV and other enteric viral agents are common. Enteric viruses can be preserved in frozen feces for long periods. The aim of this study was to investigate the frequency and genotypic diversity of HBoV in stored historical fecal samples collected before 2005, in order to understand the natural history of HBoV in patients with diarrhea in the South and Southeast regions of Brazil. The association of HBoV with other gastroenteric viruses of epidemiological importance in diarrheal disease was also explored. A total of 3347 selected samples were tested for HBoV by qPCR. Positive samples were genotyped by conventional PCR followed by Sanger sequencing. Samples positive for HBoV by qPCR were also tested for the presence of Norovirus (NoV) by RT-qPCR and Human Adenovirus (HAdV) by conventional PCR and sequencing. HBoV was detected in 5.8% (195/3347) of samples. Coinfection with NoV was found in 25.6% (50/195), HAdV in 8.2% (16/195), and triple infection in 1% (2/195), totaling 34.9% (68/195) of coinfection cases. These findings indicate that HBoV may play an important epidemiological role as a single causative agent of diarrheal disease in patients (65.2% of monoinfections). The detection rate varied significantly according to the years 2000-2001, 2002-2003, and 2003-2004 (p<0.05), reinforcing that HBoV is an important pathogen in childhood diarrhea. The genotype was obtained in 32.8% (64/195) of positive HBoV samples, and genetic analysis identified the circulation of HBoV-1