BACKGROUND: Surveillance for non-influenza respiratory pathogens is not routinely conducted in Hawaii. In 2014, Hawaii’s Department of Health (HDOH) State Laboratories Division (SLD) and Disease Outbreak Control Division partnered to identify a subset of influenza-negative specimens and perform respiratory virus testing on those specimens. Our goal was to gain insight into circulating non-influenza respiratory viruses in the state and identify potential seasonal trends as well as roles in clusters and outbreaks.
METHODS: Every month, from the population of specimens submitted for influenza testing at Hawaii’s major clinical laboratories that tested influenza-negative and met “priority” criteria, a subset of 20–50 specimens were randomly selected for RVP testing. Priority criteria included Influenza-like Illness (ILI) Surveillance Network provider submissions, hospitalization, pneumonia or acute respiratory distress syndrome, international travel, healthcare workers, those with pertinent comorbidities, those pregnant or six weeks post-partum, ILI cluster specimens, and those with unusual signs or symptoms. SLD utilized Luminex xTAG Respiratory Viral Panel (RVP)[1] multiplex polymerase chain reaction (PCR) for respiratory virus detection.
RESULTS: Three hundred and fifty specimens were collected in 2014, 438 in 2015, and 267 specimens in 2016. Of 1,055 specimens tested, most (759, 86%) were from hospitalized patients, while only five (<1%) were from clusters. Two hundred and eighty-seven (27%) tested positive for a respiratory pathogen: 136 (13%) rhinovirus, 40 (4%) respiratory syncytial virus (RSV), 35 (3%) human metapneumovirus (hMPV), 28 (3%) influenza, 20 (2%) parainfluenza, 19 (2%) adenovirus, and 9 (<1%) coronavirus. Rhinovirus, RSV, parainfluenza, and hMPV were detected consistently throughout the year. Coronaviruses were only detected from January to May. Most adenovirus (79%) was detected from April to September. Among parainfluenza viruses, parainfluenza 1 and 3 were detected in winter and summer, respectively. Additionally, in the 2014–2015 influenza season, one ILI cluster etiology was confirmed as a combination of RSV and parainfluenza 3.
CONCLUSIONS: RVP testing of influenza-negative ILI individuals detected non-influenza viruses in over a quarter of specimens tested. Use of priority specimens may bias towards more severe cases, but our findings suggest non-influenza viruses play a substantial role in ILI morbidity in Hawaii. More attention is needed to address the role these viruses play in respiratory infections and better describe the burden of illness and circulation patterns.
[1]Luminex Corporation, Austin, TX. Luminex RVP detects: adenovirus, human metapneumovirus, influenza A (Matrix/H1/H3), influenza B, RSV A, RSV B, rhinovirus, coronavirus 229E, coronavirus HKU1, coronavirus NL63, coronavirus OC43, parainfluenza 1-4, and bocavirus.