Disease severity and viral load are correlated in infants with primary respiratory syncytial virus infection in the community

Abstract

Respiratory syncytial virus (RSV) is a major cause of respiratory tract infections in infants, with remarkable variability in disease severity. Factors determining severity of disease in previously healthy infants are still unclear. It was hypothesized that disease severity is correlated with viral load in primary RSV infection. Infants of a healthy birth cohort were included at signs of their first respiratory tract infection. Nasopharyngeal aspirate was obtained within 48-96 hr and disease severity was assessed with a previously published severity scoring model. PCR was applied to test the aspirates in a semi-quantitative way for the presence of 10 respiratory pathogens. In case of multiple infection, the pathogen with the highest load was defined as the primary pathogen. The correlation between disease severity and viral load was analyzed. A total of 82 infants were included over a period of 2 years. Median age at first respiratory tract infection was 3 months. Pathogens were detected in 77 (94%) infants; more than one pathogen was detected in 35 (43%) infants. RSV was present in aspirates of 30 infants; in 16 aspirates RSV was the primary pathogen. A negative correlation between RSV CT-value and disease severity was found in all RSV cases (rho = -0.52, P = 0.003) and in cases with RSV as the primary pathogen (rho = -0.54, P = 0.03). In conclusion, this is the first report on viral loads in previously healthy infants with RSV infection in the community. Disease severity correlated positively with viral load during primary RSV infection.

IL10 Family Member Genes IL19 and IL20 Are Associated With Recurrent Wheeze After Respiratory Syncytial Virus Bronchiolitis

“…To confirm our main finding, we genotyped IL20 SNP rs2981573 (c.379 -152 A3 G), IL19 SNP rs2243188 (c.552 ϩ 49 C3 A), and IL19 SNP rs2243191 (Ser213Pro) in 90 infants recruited from an ongoing prospective unselected birth cohort of healthy newborns (10,11). The replication cohort was unselected with regard to RSV LRTI.…”

Specific Dietary Oligosaccharides Increase Th1 Responses in a Mouse Respiratory Syncytial Virus Infection Model

“…Viral replication in lung homogenates was determined, as earlier described, via plaque assay (24). To measure total virus copy numbers by PCR, total RNA from lung homogenates was extracted using MagnaPure LC equipment, cDNA was synthesized, and viral loads were determined by real-time PCR as recently described (19). In short, viral genomic RNA was isolated using a MagnaPure LC total nucleic acid kit (Roche Diagnostics, Mannheim, Germany).…”

Serum Antibodies Critically Affect Virus-Specific CD4+/CD8+ T Cell Balance during Respiratory Syncytial Virus Infections

“…In parallel, RSV was preincubated with 1 mg/ml anti-F [humanized IgG1 mAb, Synagis, MedImmune (8)] or 1 mg/ml anti-G (mouse IgG1, MAB858-2-5, Chemicon International, Temecula, CA). After 24 h, total RNA was extracted from these cells using MagnaPure LC equipment, cDNA was synthesized, and viral loads were determined by real-time PCR as recently described (30). In short, RNA extraction was performed using a MagnaPure LC total nucleic acid kit (Roche Diagnostic Systems, Somerville, NJ).…”