Rhinovirus wheezing illness in infancy is associated with medically attended third year wheezing in low risk infants: results of a healthy birth cohort study.

Rhinoviruses may be pathogens contributing to the development of childhood wheezing. However, their role in low risk infants without an asthmatic predisposition is unknown. Knowing which healthy, low risk children are at increased risk for childhood wheezing after rhinovirus wheezing illness (RV-WI) in infancy, might help in developing prevention and treatment strategies for childhood wheezing.

Frequency and Duration of Rhinovirus Infections in Children With Cystic Fibrosis and Healthy Controls: A Longitudinal Cohort Study.

Background: Respiratory viral infections are an important cause of morbidity in patients with chronic respiratory diseases, such as cystic fibrosis (CF). We hypothesized that patients with CF are more susceptible to human rhinovirus (HRV) infections than healthy controls.

Methods: In a 6-month winter period, 20 young children with CF (0-7 years) and 18 age-matched healthy controls were sampled biweekly for HRV-polymerase chain reaction using nasopharyngeal swabs, irrespective of respiratory symptoms.

Decreased lung function precedes severe respiratory syncytial virus infection and post-respiratory syncytial virus wheeze in term infants.

It is unknown why respiratory syncytial virus (RSV) causes mild disease in some children and severe disease, requiring hospitalisation, in others. We aimed to assess whether diminished premorbid lung function in healthy term infants predisposes to hospitalisation during RSV bronchiolitis, and to post-RSV wheeze. In a prospective birth cohort study of unselected term healthy children, neonatal lung function was measured before the age of 2 months (n=2133).

Human rhinovirus and wheezing: short and long-term associations in children.

Objectives: Human rhinoviruses (HRVs) have been suggested to play a role in the development of childhood wheezing. However, whether HRV is causally related to the development of wheezing or HRV-associated wheeze is merely an indicator of disease susceptibility is unclear. Our aim was to study the role of HRV during infancy in the development of lower respiratory disease during infancy and childhood.

High concentrations of amniotic fluid proinflammatory cytokines in healthy neonates are associated with low risk of respiratory syncytial virus bronchiolitis.

Background: The burden of respiratory syncytial virus (RSV) bronchiolitis in individual children and their families, the medical system and society is considerable. Mechanisms underlying RSV bronchiolitis in healthy term infants are largely unknown. Sterile intraamniotic inflammation and chorioamnionitis have been associated with increased lung volume and compliance.

Low neonatal Toll-like receptor 4-mediated interleukin-10 production is associated with subsequent atopic dermatitis.

Background: Atopic dermatitis (AD) and respiratory syncytial virus lower respiratory tract infection (RSV LRTI) are common diseases during early life. Impaired Th1-cell polarizing Toll-like receptor (TLR) responses play an important role in the pathogenesis of both diseases. Neonatal TLR-mediated production of Th1-type cytokines is decreased at birth, but rapidly increases during the first month of life.

Highly frequent infections with human rhinovirus in healthy young children: a longitudinal cohort study.

Background: Human rhinoviruses (HRVs) are an important cause of respiratory tract infections.

Objectives: We questioned whether the high prevalence rates of HRVs found in epidemiological studies is due to long-term individual continuity or a result of frequent infections with different HRV subtypes.

Study Design: In a 6-month winter period 18 healthy controls, aged 0-7 years, were at least sampled every two weeks for HRV-PCR, irrespective of respiratory symptoms.

Cord blood vitamin D deficiency is associated with respiratory syncytial virus bronchiolitis.

Background: Respiratory syncytial virus (RSV) is the most important pathogen causing severe lower respiratory tract infection (LRTI) in infants. Epidemiologic and basic studies suggest that vitamin D may protect against RSV LRTI.

Objective: To determine the association between plasma vitamin D concentrations at birth and the subsequent risk of RSV LRTI.

Clinical prediction rule for RSV bronchiolitis in healthy newborns: prognostic birth cohort study.

Objective: Our goal was to determine predictors of respiratory syncytial virus (RSV) lower respiratory tract infection (LRTI) among healthy newborns.

Methods: In this prospective birth cohort study, 298 healthy term newborns born in 2 large hospitals in the Netherlands were monitored throughout the first year of life. Parents kept daily logs and collected nose/throat swabs during respiratory tract infections.

The influence of neonatal lung function on rhinovirus-associated wheeze.

Rationale: Several studies have shown that the occurrence of wheezing illnesses during the first year of life is associated with lower levels of lung function shortly after birth and before any respiratory illness. It has been suggested that reduced lung function early in life predisposes infants to wheezing during viral respiratory infections, but the association between neonatal lung function and subsequent confirmed viral infections has never been investigated.

Objectives: To study the influence between neonatal lung function and the occurrence of human rhinovirus (HRV)-associated wheeze.

Respiratory pathogens in respiratory tract illnesses during the first year of life: a birth cohort study.

Background: Respiratory virus infections are the most important trigger of respiratory illnesses in childhood. Data on the occurrence and the clinical impact of respiratory pathogens in the general population of infants are scarce. Therefore, we described the occurrence and clinical impact of respiratory pathogens in infants with respiratory tract infections during the first year of life.

Prevalence and impact of respiratory viral infections in young children with cystic fibrosis: prospective cohort study.

Objective: We aimed to investigate differences in upper and lower respiratory tract symptoms in relation to respiratory viral infections detected with polymerase chain reaction assays in young children with cystic fibrosis and healthy control subjects.

Methods: In a 6-month winter period, 20 young children with cystic fibrosis and 18 age-matched, healthy, control subjects were contacted twice per week for detection of symptoms of an acute respiratory illness. If any symptom was present, then a home visit was made for physical examination and collection of nasopharyngeal swabs for viral analysis.

Prevalence and pathogenicity of WU and KI polyomaviruses in children, the Netherlands.

A longitudinal study in 2004 and 2005 detected polyomaviruses WU and KI in 44% and 17% of children with and without respiratory symptoms, respectively, in the Netherlands. In some children both viruses were detected for long periods. In several symptomatic children no other respiratory pathogen was detected.

Respiratory pathogens in children with and without respiratory symptoms.

Objectives: To investigate the occurrence of respiratory pathogens in samples from children with and without respiratory symptoms and to identify whether age and/ or coinfections modify the impact of respiratory pathogens on symptoms.

Study Design: In a prospective longitudinal study, 18 children were sampled biweekly for respiratory pathogens, irrespective of respiratory symptoms. Polymerase chain reaction was performed for 13 respiratory pathogens.

Long time trends in influenza-like illness and associated determinants in The Netherlands.

We analysed long-term epidemiological trends in influenza-like illness (ILI) in The Netherlands and used an ecological analysis to estimate its relationship with age, influenza vaccination, and virological aspects. This study used data from weekly ILI consultation reports from sentinel general practitioners (1986/1987 to 2006/2007), virological data from sentinel ILI patients (1992/1993 to 2006/2007), and data for influenza vaccine uptake (1991-2005). The incidence of ILI consultations, although varying during the study period, was estimated to decrease in the total population by 12.

Risk factors for acute respiratory tract infections in general practitioner patients in The Netherlands: a case-control study.

Background: Acute respiratory tract infections (ARTI) are an important public health problem. Improved identification of risk factors might enable targeted intervention. Therefore we carried out a case-control study with the aim of identifying environmental risk factors for ARTI consultations in the Dutch general population.

Human coronavirus 229E encodes a single ORF4 protein between the spike and the envelope genes.

Background: The genome of coronaviruses contains structural and non-structural genes, including several so-called accessory genes. All group 1b coronaviruses encode a single accessory protein between the spike and envelope genes, except for human coronavirus (HCoV) 229E. The prototype virus has a split gene, encoding the putative ORF4a and ORF4b proteins.

Measurement of antibodies to avian influenza virus A(H7N7) in humans by hemagglutination inhibition test.

During the epizootic of highly pathogenic avian influenza A(H7N7) in 2003 in The Netherlands, RT-PCR and culture confirmed infection was detected in 89 persons who were ill. A modified hemagglutination inhibition (HI) test using horse erythrocytes and 2 hemagglutinating units of virus was applied to assess retrospectively the extent of human (subclinical) infection. Validation of the HI-test with sera from 34 RT-PCR and culture confirmed A(H7) infected persons and sera from 100 persons from a human influenza vaccine trial in autumn 2002 showed that this HI-test had a sensitivity of 85% and a specificity of 100% when using a cut-off titer of > or =10.

Community-acquired pathogens associated with prolonged coughing in children: a prospective cohort study.

A 2-year prospective study was performed of children with prolonged coughing to investigate the frequency of different respiratory pathogens, the rate of mixed infections, and possible differences in severity of disease between single and mixed infections. Sera from 135 children (136 episodes of prolonged coughing lasting 1-6 weeks) were tested for antibodies to different viruses and bacteria. Swabs were taken for culture and PCR to detect different viral and bacterial pathogens.

A case-control study of acute respiratory tract infection in general practice patients in The Netherlands.

Background: Acute respiratory tract infections (ARTIs) are responsible for considerable morbidity in the community, but little is known about the presence of respiratory pathogens in asymptomatic individuals. We hypothesized that asymptomatic persons could have a subclinical infection and thus act as a source of transmission.

Methods: During the period of 2000-2003, all patients with ARTI who visited their sentinel general practitioner had their data reported to estimate the incidence of ARTI in Dutch general practices.

No evidence of Legionella infection in general practice patients presenting with acute respiratory infections in The Netherlands.

The role of Legionella spp. in the aetiology of acute respiratory infections (ARIs) is largely unknown. In this case-control study, conducted in a general practitioner setting during 2000 and 2001, nose and throat samples from patients presenting with ARIs (n = 230) and controls (n = 200) were analysed for the presence of Legionella spp.

Influenza-associated encephalopathy: no evidence for neuroinvasion by influenza virus nor for reactivation of human herpesvirus 6 or 7.

During 2 consecutive influenza seasons we investigated the presence of influenza virus, human herpesvirus (HHV) type 6, and HHV-7 in cerebrospinal fluid samples from 9 white children suffering from influenza-associated encephalopathy. We conclude that it is unlikely that neuroinvasion by influenza virus or reactivation of either HHV-6 or HHV-7 is involved.

[The 2003/2004 influenza season in the Netherlands with a limited epidemic of the virus variant A/Fujian, and the vaccine composition for the 2004/2005 season].

In contrast to the three previous influenza seasons, the influenza epidemic of the 2003/2004 season started early in week 49 of 2003. The epidemic was predominantly caused by influenza-A viruses of the H3N2 subtype. All isolated influenza-A viruses were antigenically related to influenza virus A/Fujian/411/02, which was already detected in the influenza season 2002/2003 and that deviated from the vaccine-reference strain A/Moscow/10/99 to a certain extent.