Lower Respiratory Tract Infection In Infants Research Articles

Lung Function and Cognitive Ability in a Longitudinal Birth Cohort Study

The objective of this study was to examine the association between forced expiratory volume in 1 second (FEV1) and cognitive ability in midlife in the normal population. Multiple regression was used to test associations between FEV1 and cognitive function in 1778 men and women in the MRC National Survey of Health and Development, also known as the British 1946 birth cohort. Analyses were adjusted for sex, body size (birth weight, adult height, weight, and chest circumference), socioeconomic status, lifetime smoking, and a range of health indicators, including early respiratory vulnerability (infant lower respiratory infection, childhood asthma, and exposure to atmospheric pollution). FEV1 at 43 years was associated with slower psychomotor speed (peg placement) at the same age and with slower decline in psychomotor speed (letter search speed) from 43 to 53 years, independently of the previously mentioned potential confounders. These independent associations were not observed, however, for adult verbal ability, verbal memory, or rate of decline in memory, which were significantly explained by socioeconomic status and adolescent cognitive ability. In a subsequent analysis, adolescent cognition was positively associated with FEV1, although not with rate of decline in FEV1 from 43 to 53 years, again independently of the previously mentioned confounders. Cognitive function and FEV1 are positively associated across the life course. One possible explanation lies in the parallel action of endocrine, autonomic, and motor control systems on respiration and higher mental function. Because respiration and mental function are both associated with functional capacity and survival, this is a matter of potential clinical significance.

Differential production of inflammatory cytokines in primary infection with human metapneumovirus and with other common respiratory viruses of infancy.

Viral respiratory infections are the most frequent cause of hospital admission for infants and young children during winter. However, the mechanisms of illness that are associated with viral lower-respiratory-tract infection (LRI) are unclear. A widely accepted hypothesis attributes the pathogenesis of viral LRI in infants to the induction of innate inflammatory responses. This theory is supported by studies showing that Toll-like receptor 4 is activated by respiratory syncytial virus (RSV), leading to production of inflammatory cytokines. We prospectively examined previously naive infants in Buenos Aires, Argentina, who had either upper- or lower-respiratory-tract symptoms. Infection with human metapneumovirus (hMPV) was second only to RSV in frequency. Both viruses were associated with rhinorrhea, cough, and wheezing; however, hMPV elicited significantly lower levels of respiratory inflammatory cytokines than did RSV. Symptoms in infants infected with influenza virus were different from those in infants infected with RSV, but cytokine responses were similar. These findings suggest that hMPV and RSV either cause disease via different mechanisms or share a common mechanism that is distinct from innate immune activation.

Parainfluenza viruses.

Human parainfluenza viruses (HPIV) were first discovered in the late 1950s. Over the last decade, considerable knowledge about their molecular structure and function has been accumulated. This has led to significant changes in both the nomenclature and taxonomic relationships of these viruses. HPIV is genetically and antigenically divided into types 1 to 4. Further major subtypes of HPIV-4 (A and B) and subgroups/genotypes of HPIV-1 and HPIV-3 have been described. HPIV-1 to HPIV-3 are major causes of lower respiratory infections in infants, young children, the immunocompromised, the chronically ill, and the elderly. Each subtype can cause somewhat unique clinical diseases in different hosts. HPIV are enveloped and of medium size (150 to 250 nm), and their RNA genome is in the negative sense. These viruses belong to the Paramyxoviridae family, one of the largest and most rapidly growing groups of viruses causing significant human and veterinary disease. HPIV are closely related to recently discovered megamyxoviruses (Hendra and Nipah viruses) and metapneumovirus.

Ultrafine carbon black particles enhance respiratory syncytial virus-induced airway reactivity, pulmonary inflammation, and chemokine expression.

Exposure to particulate matter (PM) may exacerbate preexisting respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), bronchitis, and pneumonia. However, few experimental studies have addressed the effects of PM on lower respiratory tract (LRT) viral infection. Respiratory syncytial virus (RSV) is a major etiological agent for LRT infections in infants, the elderly, and the immunocompromised and may lead to chronic wheezing and the development of asthma in children. In this study, we examined the effects of carbon black (CB) on RSV-induced pulmonary inflammation, chemokine and cytokine expression, and airway hyperresponsiveness in a mouse model of RSV. Female BALB/c mice were instilled via the trachea (i.t.) with 1 x 106 plaque forming units (pfu) RSV or with uninfected culture media. On day 3 of infection, mice were i.t. instilled with either 40 micro g ultrafine CB particles or with saline. End points were examined on days 4, 5, 7, and 14 of RSV infection. Viral titer and clearance in the lung were unaffected by CB exposure. Neutrophil numbers were elevated on days 4 and 7, and lymphocyte numbers were higher on days 4 and 14 of infection in CB-exposed, RSV-infected mice. CB exposure also enhanced RSV-induced airway hyperresponsiveness to methacholine, bronchoalveolar lavage (BAL) total protein, and virus-associated chemokines monocyte chemoattractant protein (MCP-1), macrophage inflammatory protein (MIP-1 alpha), and regulated upon activation, normal T cell expressed and secreted (RANTES). MIP-1 alpha mRNA expression was increased in the alveolar epithelium, where ultrafine particles deposit in the lung. These data demonstrate a synergistic effect of ultrafine CB particles on RSV infection, and suggest a potential mechanism for increased respiratory infections in human populations after PM exposure.

Peptide Inhibits Infection with Common Childhood Respiratory Viruses

Two related viruses, respiratory syncytial virus (RSV) and parainfluenza virus type 3 (PIV-3), are the most common causes of lower respiratory infection in infants. No immunizations are currently available for these viruses. Both RSV and PIV-3 have fusion proteins on their surfaces that attach to a normal …

Therapeutic effect of clarithromycin for respiratory-tract infections in children caused by Chlamydia pneumoniae

Children infected with Chlamydia pneumoniae sometimes experience lower respiratory tract infections such as pneumonia and bronchitis. Although numerous anti-microbial compounds have been reported to be active against the organism, most of them have not been in a clinical trial in infants and children with C. pneumoniae infection. Clarithromycin has been shown to express anti-chlamydial effects in vitro. In this study, we evaluated the clinical anti- C. pneumoniae properties of clarithromycin in children with mainly lower respiratory tract infection. We administered clarithromycin orally to 21 infants and children at a dose of 10–15 mg/kg/day divided into two or three doses for 4–21 days. Clinical symptoms, roentgenographic and laboratory abnormal findings improved. The overall clinical efficacy rate was 85.7% (18 of 21 cases). Administration of clarithromycin was considered to be a suitable treatment for improving lower respiratory infections in infants and children caused by C. pneumoniae.

Daily zinc supplements reduced the incidence and severity of acute lower respiratory infections in children in India

Sazawal S, Black RE, Jalla S , et al. Zinc supplementation reduces the incidence of acute lower respiratory infections in infants and preschool children: a double-blind, controlled trial. Pediatrics1998 Jul;...

Lower respiratory infection and inflammation in infants with newly diagnosed cystic fibrosis

The nature and timing of lower respiratory infections in infants with cystic fibrosis is largely unknown1 because infants do not produce sputum and throat cultures may not predict lower respiratory pathogens.2 We performed a prospective cross sectional study of an unselected cohort of infants with cystic fibrosis in which bronchoalveolar lavage was used to determine lower respiratory infection and inflammation during the first three months of life. The state of Victoria, Australia (66000 births per year) has a cystic fibrosis screening programme, all patients being managed by one centre. Between February 1992 and September 1994 we recruited 45 (27 boys) of the 52 infants with newly diagnosed disease; 32 were identified by screening, 12 from meconium ileus, and one by failure to thrive, and all cases were confirmed by sweat testing. Sixteen infants had respiratory symptoms, and seven of them were receiving oral antibiotics when bronchoalveolar lavage was performed at a mean age of 2.6 (SD 1.6) months. Nine otherwise healthy infants (five boys) aged …

Respiratory syncytial virus infections in children in a desert country.

The role of respiratory syncytial virus (RSV) in acute lower respiratory infection in infants and young children in Kuwait was investigated in a prospective study. Of the 523 children under 13 years of age admitted to Mubarak Al-Kabeer Hospital between August 1993 and June 1994 209 (40%) had RSV infection. 170 (81%) of these children had no underlying symptoms 25 (12%) had asthma 6 (3%) had neurologic diseases 3 (1.4%) had congenital heart disease and 2 (1%) were preterm. The median age of RSV-positive children was 7.2 months. 89% of RSV cases occurred during the winter months. Acute bronchiolitis was the most frequent clinical feature followed by pneumonia and croup. The median duration of hospitalization was 6 days. In most cases treatment was supportive (e.g. oxygen administration in 90% and intravenous fluids in 65%); 30% of children received antibiotics. There were 3 deaths in this series for a case fatality rate of 1.4%. The 3 children who died had underlying conditions and were not treated with ribavirin.

Respiratory syncytial virus-induced cytokine production by a human bronchial epithelial cell line

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory infection in infants and young children, but the pathogenesis of RSV-induced inflammation is not well defined. We hypothesized that in vitro infection of a human bronchial epithelial cell line (BEAS) would induce production of proinflammatory cytokines. BEAS cells were infected with RSV, and cells and supernatants were assayed for cytokine mRNA and protein changes at several time points after infection. Cytokine mRNA in BEAS cells was measured by polymerase chain reaction of reverse-transcribed RNA from whole cell lysates; cytokine levels in supernatants were measured by bioassay or immunoassay. Our results indicated that interleukin-5ay or immunoassay. Our results indicated that interleukin-8 (IL-8) was induced at 4 h after infection (during the eclipse phase of RSV infection) with accumulation of IL-8 in supernatants by 24 h after infection. Increased levels of IL-6 and granulocyte macrophage colony-stimulating factor in supernatants were only detected by 96 h after infection, during the RSV replicative phase. Interferon-alpha and -gamma transcripts were not detectable at any time point. We conclude that the effects of RSV on airway inflammation may be at least partly mediated by sequential production of proinflammatory cytokines in infected airway epithelium.

Evaluación de la administración rutinaria de antibióticos en lactantes con infecciones respiratorias agudas bajas

Routine administration of antibiotics in the treatment of acute lower respiratory infections in infants wasevaluated in a open randomised prospective trial. Sixty one infants between the age of 1 month and 2 years wereallocated to one of two treatment groups. Group A patients were treated with antibiotics but those in Group B werenot. Antibiotics were not given to this patients before hospital admission. There were no differences in the durationof the acute disease, the frecuency of fever relapse and pulmonary complications. Four patients from Group B weresubsequently treated with antibiotics, all them had radiologic evidence of bronchopneumonia. These results do notsupport the routine use of antibiotics in infants admitted to hospital with acute lower respiratory infections, exceptin those with radiologic evidence of bronchopneumonia.(Key words: Acute lower respiratory infections, routine antibiotic therapy, treatment evaluation).

SEROLOGICAL STUDIES IN CHLAMYDIA TRACHOMATIS ASSOCIATED PNEUMONIA IN INFANTS

Chlamydia /C./ trachomatis harboured in the maternal genital tract can be transmitted from mother to infant during parturition. Infection of the neonate may lead to colnjunctivitis in the first life days or/end after a few weeks to atypical pneumonia with or without conjunctivitis, Serology is a most reliable approach to verification of C. trachomatis as the causative agent in lower respiratory infection in infants between 1-6 months of age. In 1983-85 1 to 3 serum samples of 76 young infants with atypical pneumonia were tested for A-K serotypes of C.trachomatis antibodies with indirect microimmunofluorescent method. Detection of antibodies was also carried out in serum samples of mothers whose children had a positive serological result. Serology provided evidence for chlamydial pneumonia in 9 patients. Elevated Chlamydia-specific antibody titres/128-2048/were registered. High serum concentrations of antibodies in titres 512-8192 were found in the sera of mothers, proving genital C.trachomatis infection. Positive chlamydial serology in atypical pneumonia of infants defines antibacterial therapy: erythromycin is the antibiotic of choice in infantile chlamydial infection.

Seasonal pattern in childhood viral lower respiratory tract infections in Melbourne.

Respiratory syncytial virus and parainfluenza viruses are the major pathogens in acute lower respiratory infection in infants and younger children. They show distinct seasonal patterns. An annual epidemic of respiratory syncytial virus infection is seen in Melbourne and this coincides with the coldest months of the year. Parainfluenza virus Type 1, the most frequent cause of laryngotracheobronchitis, occurs as an autumn epidemic every second year. Parainfluenza virus Types 2 and 3 are present most years and do not show a clear seasonal pattern.

Neutralisation of respiratory syncytial virus by cat serum.

RESPIRATORY SYNCYTIAL (RS) virus has been identified as a major cause of lower respiratory infection in infants, and the epidemiology of RS virus infection is characterised uniquely by annual winter outbreaks in the infant population and by antigenie stability of the virus1. The initial isolation of RS virus was from a captive chimpanzee2 and more recently an antigenically similar virus has been associated with respiratory disease in cattle3–5. The bovine and human RS viruses, although antigenically similar, can be differentiated by their different host range in vitro6. The bovine RS virus had a wider host range, multiplying in bovine, hamster, swine and primate cells, whereas the human RS virus multiplied only in bovine and primate cells. We have observed recently, however, that human RS virus (but not bovine RS virus) can multiply efficiently in secondary cultures of feline embryo cells. The cytopathology induced by RS virus infection of feline embryo cells was similar to that described previously for African green monkey (BS-C-1) cells7: the surfaces of infected cells were seen to be covered by long slender filaments when viewed by scanning electron microscopy or by immunofluorescent staining (C.R.P. and J. E. Parry, unpublished data). The susceptibility of feline embryo cells to RS virus, and an observation that the sera of some laboratory cats in the USA inhibited RS virus (R.M. Chanock, personal communication), suggested that cats might be susceptible to RS virus infection. We therefore examined a random sample of cat sera, and we show that antibody to RS virus is widespread in domestic cats in Britain.