ABSTRACT Wild birds have great prominence in the transmission of diseases to humans, mainly due to their ease of access to human populations, raising concerns about the potential impact of that proximity on public health. The present study reports ARV and PBV occurrence in wild birds from an environmental protection area in the Amazon biome, in Pará state, Brazil. We obtained 155 fecal specimens from 47 species of wild birds for RNA extraction, ARV and PBV detection utilizing molecular methods, nucleotide sequencing, and phylogenetic analysis. ARV prevalence was 0.6% (1/155), being positive in an individual of Myrmotherula longipennis, and PBV prevalence was 1.29% (2/155), affecting two individuals of Guira guira. The PBV strains were assigned to genogroup I based on phylogenetic analysis, and they shared a strong phylogenetic link with strains isolated from different geographic locations. The ARV strain was more closely related to strains that had previously circulated in the same region. The presence of ARV and PBV in this habitat suggests that infection cycles of these agents occur naturally in the wild ecosystem, potentially triggering transmission events between bird species and humans. This is the first study on ARV detection in wild birds in Brazil and the first report on the occurrence of PBV in wild Guira guira. Additional studies are required to determine the epidemiology, origin, evolution, and emergence of new potentially pathogenic viruses in the Amazon.

RESUMO As aves silvestres têm grande destaque na transmissão de doenças ao homem, principalmente pela facilidade de acesso à população humana, levantando preocupações sobre o potencial impacto dessa proximidade no contexto da saúde pública. O presente estudo relata a ocorrência de ARV e PBV em aves silvestres de uma área de proteção ambiental no bioma Amazônico. Obtivemos 155 espécimes fecais de 47 espécies de aves silvestres, que foram submetidos a extração de RNA, detecção de ARV e PBV por técnicas moleculares, sequenciamento nucleotídico e análise filogenética. A prevalência de infecção por ARV foi 0,6% (1/155), sendo positivo em um indivíduo de Myrmotherula longipennis, e a prevalência de PBV foi 1,29% (2/155), afetando dois insdivíduos de Guira guira. A análise filogenética agrupou as cepas de PBV no genogrupo I, mostrando intensa relação filogenética com cepas isoladas de outras regiões geográficas. A cepa de ARV esteve mais relacionada filogeneticamente a cepas previamente circulantes na mesma região. Este é o primeiro estudo sobre detecção de ARV em aves silvestres no Brasil e o primeiro relato sobre a ocorrência de PBV em Guira guira. A circulação de ARV e PBV nesse ambiente demonstra que os ciclos desses agentes estão ocorrendo de forma natural no ecossistema silvestre, o que pode desencadear possíveis eventos de transmissão entre as espécies aviárias e humanos. Estudos adicionais são necessários para determinar a epidemiologia, origem, evolução e surgimento de novos vírus potencialmente patogênicos na Amazônia.

BACKGROUND Norovirus (NoV) is a major cause of acute gastroenteritis (AGE) worldwide, especially in children under five years. Studies involving the detection and molecular characterisation of NoV have been performed in Brazil, demonstrating its importance as an etiological agent of AGE. OBJECTIVES The objectives of this study were to investigate the frequency of human NoV and to genotype the strains isolated from 0-14-year-old patients of AGE in Manaus, Brazil, over a period of two years. METHODS A total of 426 faecal samples were collected between January 2010 and December 2011. All samples were tested for the presence of NoV antigens using a commercial enzyme immunoassay kit. RNA was extracted from all faecal suspensions and reverse transcription-polymerase chain reaction (RT-PCR) for the NoV-polymerase partial region was performed as a trial test. Positive samples were then subjected to PCR with specific primers for partial capsid genes, which were then sequenced. FINDINGS NoV was detected in 150 (35.2%) faecal samples, for at least one of the two techniques used. NoV was detected in children from all age groups, with the highest positivity observed among the group of 1-2 years old. Clinically, fever was verified in 43% of the positive cases and 46.3% of the negative cases, and vomiting was observed in 75.8% and 70.8% cases in these groups, respectively. Monthly distribution showed that the highest positivity was observed in January 2010 (81.2%), followed by February and April 2010 and March 2011, when the positivity rate reached almost 50%. Phylogenetic analyses performed with 65 positive strains demonstrated that 58 (89.2%) cases of NoV belonged to genotype GII.4, five (7.7%) to GII.6, and one (1.5%) each to GII.7 and GII.3. MAIN CONCLUSIONS This research revealed a high circulation of NoV GII.4 in Manaus and contributed to the understanding of the importance of this virus in the aetiology of AGE cases, especially in a region with such few studies available.