OBJECTIVE:

To detect and characterize the Human respiratory syncytial virus (HRSV) strains in cases of severe acute respiratory infection (SARI) circulating in Brazilian States of Acre, Amapá, Amazonas, Pará, and Roraima in 2015.

MATERIALS AND METHODS:

A total of 1,082 samples of nasopharyngeal aspirate and combined nasal-throat swabs of patients of different sex and age groups with SARI and submitted to qRT-PCR for HRSV. Positive samples were inoculated in HEP-2 cell cultures and those presenting cytopathic effect were submitted to three steps: extraction of RNA viral load, G-gene amplification by RT-PCR and genetic sequencing.

RESULTS:

Of 1,082 samples, 57 (5.3%) were positive for HRSV, 38 (66.7%) were from patients from 0 to 4 years old. Viral circulation predominated between March and July, period of climate changes in the Region. Only in Acre, Amazonas, and Pará positive samples were detected, 15 (26.3%), 23 (40.4%), and 19 (33.3%), respectively. The cytopathic effect was evaluated in 45 (78.9%) samples with the following viral subgroups: 40 (88.9%) of HRSV-B with BA genotype, and five (11.1%) of RSV-A of ON1 genotype.

CONCLUSION:

This study showed a relevant viral infection rate in children 0 to 4 years old. Viral circulation occurred in Acre, Amazonas, and Pará during the climatic changes period. The circulation of the genotypes BA and ON1 was significant, and the first time that the circulation of ON1 in Pará State was confirmed.