Viral respiratory pathogens associated with medically attended acute respiratory illnesses in older adults in Bulgaria

Korsun, N.; Angelova, S.; Trifonova, I.; Georgieva, I.; Voleva, S.

Acute respiratory infections (ARIs) are a major cause of morbidity and mortality among older adults. This study aimed to determine the viral etiology of these infections in patients aged ≥ 65 years during two successive epidemic seasons in Bulgaria. Nasal and throat specimens were collected from the enrolled patients during the 2015/2016 and 2016/2017 seasons. The viral etiology was determined by individual Real Time PCR assays against 15 respiratory viruses. Of the 160 adults examined, 74 (46.3%) were positive for at least one respiratory virus. Co-infections with two and three viruses were found in 14 (18.9%) of the infected patients. Influenza A(H3N2) (15.6%) and A(H1N1)pdm09 (13.1%) viruses were the predominant pathogens, followed by adenoviruses (5.6%);respiratory-syncytial virus (3.8%);metapneumovirus (3.1%);rhinoviruses (2.5%);coronaviruses - NL63 (2.5%), OC43 (1.9%), HKU1 (1.9%) and 229E (1.3%);influenza type B (1.9%);bocaviruses (1.3%) and parainfluenza viruses 1/2/3 (1.3%). At least one respiratory virus was identified in 50% and 32.3% of the patients with acute lower respiratory tract illnesses and neurological complications, respectively. Respiratory viruses, especially influenza A viruses, are major pathogens of ARIs in persons aged ≥ 65 years. Diagnostic testing for respiratory viruses using molecular methods can help in clinical decision making and may assist in measures to prevent health care-associated infections. © 2020 Academic Publishing House. All rights reserved.