Genotyping of Respiratory Syncytial Virus among influenza-like illness
and severe acute respiratory infection cases of children in the
Philippines from 2006-2016
Abstract
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 among children with severe pneumonia. Since
2006, national influenza-like illness (ILI) and severe acute respiratory
infection (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. This study determined the
epidemiological and molecular characteristics of RSV among (ILI) and
(SARI) cases of children in the Philippines. 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. 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 included 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. The pattern of
RSV activity in the Philippines resembles the transmission of RSV
globally.