Samya Thalita Picanço da Costa1, Tulio Machado Fumian2, Ian Carlos Gomes de Lima3, Jones Anderson Monteiro Siqueira3, Luciana Damascena da Silva3, Juliana das Mercês Hernández4, Maria Silvia Souza de Lucena3, Tammy Kathlyn Amaral Reymão4, Luana da Silva Soares3, Joana D’Arc Pereira Mascarenhas3, Yvone Benchimol Gabbay3+
1Universidade do Estado do Pará, Programa de Pós-Graduação em Biologia Parasitária na Amazônia, Belém, PA, Brasil
2Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Virologia Comparada e Ambiental, Rio de Janeiro, RJ, Brasil
3Secretaria de Vigilância em Saúde, Instituto Evandro Chagas, Seção de Virologia, Ananindeua, PA, Brasil
4Instituto Evandro Chagas, Programa de Pós-Graduação em Virologia, Ananindeua, PA, Brasil
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.
Financial support: IEC/SVS/MS, CAPES.
Received 8 August 2016
Accepted 10 February 2017