Abstract
Background: Respiratory syncytial virus (RSV) is the leading cause of severe lower respiratory infection and therefore, a major threat to global health. In the Philippines, RSV is the second most common respiratory viral pathogen next to rhinovirus (HRV) among children with severe pneumonia. Since 2006, national ILI and SARI surveillances have been mainly focused only on influenza viruses. The prevalence and genetic diversity of RSV in the last decades were not completely elucidated.
Objectives: This study determined the epidemiological and molecular characteristics of RSV among influenza-like illness (ILI) and severe acute respiratory infection (SARI) cases of children in the Philippines.
Study Design: The Philippine National Influenza Centre (PNIC) collected oropharyngeal swab and nasopharyngeal swab samples from patients under the age of five who are presented with ILI and SARI for the period of 2006-2016. These swabs have been examined for RSV subgroup by multiplex real-time qRT-PCR. Sequencing and phylogenetic analyses were used to determine the genotype of RSV samples.
Results: A total of 1,036 samples were systematically selected and tested. Of these samples, 122 were RSV-positive at 11.8 % prevalence rate, and 58.2% (71/122) were classified as RSV-A. Six genotypes were identified, which includes NA1 (27/122, 22.1%), ON1 (5/122, 4.1%), GA2 (1/122, 0.8%) and GA5 (1/123, 0.8%) for RSV-A; and BA2 (13/122, 10.7%) and BA9 (1/122, 0.8%) for RSV-B. Most RSV-related cases were significantly associated with pneumonia and bronchitis.
Conclusion: The pattern of RSV activity in the Philippines resembles the transmission of RSV globally. Data from this study can be utilized to improve diagnosis and patient management of respiratory infections in the Philippines.
Keywords: RSV-A, RSV-B, genotype displacement, influenza-like illness, severe acute respiratory infection