Severe lower respiratory tract infection in infants and toddlers from a non-affluent population: viral etiology and co-detection as risk factors.
BACKGROUND
Lower respiratory tract infection (LRTI) is a major cause of pediatric morbidity and mortality, especially among non-affluent communities. In this study we determine the impact of respiratory viruses and how viral co-detections/infections can affect clinical LRTI severity in children in a hospital setting.


METHODS
Patients younger than 3 years of age admitted to a tertiary hospital in Brazil during the months of high prevalence of respiratory viruses had samples collected from nasopharyngeal aspiration. These samples were tested for 13 different respiratory viruses through real-time PCR (rt-PCR). Patients were followed during hospitalization, and clinical data and population characteristics were collected during that period and at discharge to evaluate severity markers, especially length of hospital stay and oxygen use. Univariate regression analyses identified potential risk factors and multivariate logistic regressions were used to determine the impact of specific viral detections as well as viral co-detections in relation to clinical outcomes.


RESULTS
We analyzed 260 episodes of LRTI with a viral detection rate of 85% (n = 222). Co-detection was observed in 65% of all virus-positive episodes. The most prevalent virus was Respiratory Syncytial Virus (RSV) (54%), followed by Human Metapneumovirus (hMPV) (32%) and Human Rhinovirus (HRV) (21%). In the multivariate models, infants with co-detection of HRV + RSV stayed 4.5 extra days (p = 0.004), when compared to infants without the co-detection. The same trends were observed for the outcome of days of supplemental oxygen use.


CONCLUSIONS
Although RSV remains as the main cause of LRTI in infants our study indicates an increase in the length of hospital stay and oxygen use in infants with HRV detected by RT-PCR compared to those without HRV. Moreover, one can speculate that when HRV is detected simultaneously with RSV there is an additive effect that may be reflected in more severe clinical outcome. Also, our study identified a significant number of children infected by recently identified viruses, such as hMPV and Human Bocavirus (HBov), and this is a novel finding for poor communities from developing countries.
Universidade de Caxias do Sul, Caxias do Sul, Brazil.
Emerson Rodrigues
ER
da Silva
Márcio Condessa Paulo
MC
Pitrez
Eurico
E
Arruda
Rita
R
Mattiello
Edgar E
EE
Sarria
Flávia Escremim
FE
de Paula
José Luis
JL
Proença-Modena
Luana Sella
LS
Delcaro
Otávio
O
Cintra
Marcus H
MH
Jones
José Dirceu
JD
Ribeiro
Renato T
RT
Stein
D000704:Analysis of Variance; D001938:Brazil / Q000453:epidemiology; D002675:Child, Preschool; D015331:Cohort Studies; D060085:Coinfection / Q000453:epidemiology / Q000821:virology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007902:Length of Stay; D008297:Male; D009305:Nasopharynx / Q000821:virology; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction; D018113:Respiratory Syncytial Virus, Human / Q000302:isolation & purification; D012141:Respiratory Tract Infections / Q000453:epidemiology* / Q000821:virology; D012229:Rhinovirus / Q000302:isolation & purification; D012307:Risk Factors; D012621:Seasons; D012959:Socioeconomic Factors