Received: 6 July 2017
Accepted: 19 December 2017
Human respiratory syncytial virus load normalized by cell
quantification as predictor of acute respiratory tract infection
José A. Boga
Marta E. Álvarez-Argüelles
María J. Menéndez
María de Oña
Servicio de Microbiología, Hospital
Universitario Central de Asturias,
Miriam Gómez-Novo, Servicio de
Microbiología, Hospital Universitario Central
de Asturias, Avenida de Roma s/n,
33011 Oviedo, Spain.
PCTI (Principado de Asturias), Grant numbers:
GRUPIN14-071, GRUPIN14-099; FEDER
Human respiratory syncytial virus (HRSV) is a common cause of respiratory infections.
The main objective is to analyze the prediction ability of viral load of HRSV normalized
by cell number in respiratory symptoms. A prospective, descriptive, and analytical
study was performed. From 7307 respiratory samples processed between December
2014 to April 2016, 1019 HRSV-positive samples, were included in this study. Low
respiratory tract infection was present in 729 patients (71.54%). Normalized HRSV
load was calculated by quantification of HRSV genome and human β-globin gene and
expressed as log10 copies/1000 cells. HRSV mean loads were 4.09 ± 2.08 and
4.82 ± 2.09 log10 copies/1000 cells in the 549 pharyngeal and 470 nasopharyngeal
samples, respectively (P < 0.001). The viral mean load was 4.81 ± 1.98 log10 copies/
1000 cells for patients under the age of 4-year-old (P < 0.001). The viral mean loads
were 4.51 ± 2.04 cells in patients with low respiratory tract infection and 4.22 ± 2.28
log10 copies/1000 cells with upper respiratory tract infection or febrile syndrome
(P < 0.05). A possible cut off value to predict LRTI evolution was tentatively established.
Normalization of viral load by cell number in the samples is essential to ensure an
optimal virological molecular diagnosis avoiding that the quality of samples affects the
results. A high viral load can be a useful marker to predict disease progression.
cell counting, evolution, fusion protein, genetic variability, infection, pathogenesis, research
and analysis methods, respiratory syncytial virus, respiratory tract, virus classification
Human respiratory syncytial virus (HRSV) is the main etiologic
agent of lower tract infections, including bronchiolitis and
pneumonia, and a leading cause of hospitalizations among infants
in both developing and developed countries.
with HRSV are common throughout life.
No effective vaccine
is available for prophylaxis, and ribavirin therapy is of modest
benefit. Currently, our understanding of the pathogenesis of HRSV
in humans is incomplete; in fact, RSV strains are separated into two
major groups (A and B) on the basis of antigenic and genetic
variability. This variability might contribute to the ability of the
virus to cause yearly outbreaks.
Ontheother hand, the study of therelationshipamongviralload, viral
dynamics, and disease severity will expand our understanding of HRSV
pathogenesis and they can be useful for infection management.
quality of respiratory viral diagnosis, a rich cell collection appears to be an
important prerequisite but this situation is not always present. Therefore,
the main objective of this work is to analyze the prediction ability of the
HRSV load normalized by the number of cells, measured by quantification
of the gene of β-globin, in samples belonging to patients with different
J Med Virol. 2018;90:861–866. wileyonlinelibrary.com/journal/jmv © 2018 Wiley Periodicals, Inc.