Course Of Respiratory Tract Infections Research Articles

Increased rate of respiratory symptoms in children with Down syndrome: a 2-year web-based parent-reported prospective study

To compare the incidence of respiratory symptoms and short-term consequences between children with Down syndrome and children from the general population, we conducted a prospective parent-reported observational study. Children with Down syndrome (≤ 18 years) were included between March 2012 and June 2014. Caregivers received a baseline questionnaire with follow-up 1–2 years after inclusion. Caregivers received a weekly questionnaire about respiratory symptoms, fever, antibiotic prescriptions, doctor’s visits, and consequences for school and work attendance. Children with Down syndrome were compared to a cohort of the general population (“Kind en Ziek” study) with similar weekly questionnaires. A total of 9,011 childweeks were reported for 116 participants with Down syndrome (75% response rate). The frequency of respiratory symptoms was higher in children with Down syndrome than in children from the general population (30% vs 15.2%). In addition, symptoms subsided later (around 8 vs 5 years of age). The seasonal influence was limited, both in children with Down syndrome and children from the general population. Consequences of respiratory disease were significant in children with Down syndrome compared to children from the general population, with a higher rate of doctor’s visits (21.3% vs 11.8%), antibiotic prescriptions (47.8% vs 26.3%), and absenteeism from school (55.5% vs 25.4%) and work (parents, 9.4% vs 8.1%). Conclusion: Children with Down syndrome have a higher frequency of respiratory symptoms and symptoms last until a later age, confirming the impression of professionals and caregivers. Individualized treatment plans might prevent unfavorable consequences of chronic recurrent respiratory disease in children with Down syndrome.What is Known:• Children with Down syndrome have an altered immune system and are prone to a more severe course of respiratory tract infections.• The overall conception is that patients with Down syndrome suffer from respiratory tract infections more often.What is New:• Children with Down syndrome suffer from respiratory symptoms more frequently than children from the general population.• The respiratory symptoms in children with Down syndrome subside at a later age compared to children from the general population.

Clinical presentation, microbiological aetiology and disease course in patients with flu-like illness: a post hoc analysis of randomised controlled trial data.

BackgroundThere is little evidence about the relationship between aetiology, illness severity, and clinical course of respiratory tract infections (RTIs) in primary care. Understanding these associations would aid in the development of effective management strategies for these infections.AimTo investigate whether clinical presentation and illness course differ between RTIs where a viral pathogen was detected and those where a potential bacterial pathogen was found.Design and settingPost hoc analysis of data from a pragmatic randomised trial on the effects of oseltamivir in patients with flu-like illness in primary care (n = 3266) in 15 European countries.MethodPatient characteristics and their signs and symptoms of disease were registered at baseline. Nasopharyngeal (adults) or nasal and pharyngeal (children) swabs were taken for polymerase chain reaction analysis. Patients were followed up until 28 days after inclusion. Regression models and Kaplan–Meier curves were used to analyse the relationship between aetiology, clinical presentation at baseline, and course of disease including complications.ResultsExcept for a less prominent congested nose (odds ratio [OR] 0.55, 95% confidence interval [CI] = 0.35 to 0.86) and acute cough (OR 0.42, 95% CI = 0.27 to 0.65) in patients with flu-like illness in whom a possible bacterial pathogen was isolated, there were no clear clinical differences in presentations between those with a possible bacterial aetiology compared with those with a viral aetiology. Also, course of disease and complications were not related to aetiology.ConclusionGiven current available microbiological tests and antimicrobial treatments, and outside pandemics such as COVID-19, microbiological testing in primary care patients with flu-like illness seems to have limited value. A wait-and-see policy in most of these patients with flu-like illness seems the best option.

Role of Probiotics in Stimulating the Immune System in Viral Respiratory Tract Infections: A Narrative Review.

Viral respiratory tract infection (RTI) is the most frequent cause of infectious illnesses including the common cold. Pharmacological solutions for treating or preventing viral RTIs are so far limited and thus several self-care products are available in the market. Some dietary supplements such as probiotics have been shown to modulate immune system function and their role in reducing the risk and the course of RTIs has been investigated extensively within the past decade. However, the mechanism of action and the efficacy of probiotics against viral RTIs remains unclear. We searched PubMed, Google Scholar, and Web of Knowledge for pre-clinical and clinical studies investigating the effect of probiotics on respiratory virus infections, immune response, and the course of upper and lower respiratory tract illness. The literature summarized in this narrative review points out that specific probiotic strains seem effective in pre-clinical models, through stimulating the immune system and inhibiting viral replication. Clinical studies indicate variable efficacy on upper respiratory illnesses and lack proof of diagnosed viral infections. However, meta-analyses of clinical studies indicate that probiotics could be beneficial in upper respiratory illnesses without specific etiology. Further studies aiming at discovering the mechanisms of action of probiotics and clinical efficacy are warranted.

The influence of Streptococcus pneumoniae nasopharyngeal colonization on the clinical outcome of the respiratory tract infections in preschool children.

BackgroundStreptococcus pneumoniae (SPn) is an important pathogen causing a variety of clinical manifestations. The effects of SPn nasopharyngeal colonization on respiratory tract infections are poorly studied. We evaluated the association of SPn colonization with features of respiratory tract infections.MethodsChildren under the age of 6 years who visited a primary care physician because of respiratory tract infections were enrolled in the study. History was taken, children were clinically assessed by the physician, and nasopharyngeal swabs were obtained and cultured for SPn. Positive samples were serotyped. Associations of SPn colonization with clinical signs and symptoms, recovery duration, absence from day care centre, frequencies of specific diagnoses, and treatment with antimicrobials were evaluated.ResultsIn total 900 children were enrolled. The prevalence of SPn colonization was 40.8 % (n = 367). There were minor differences between male and female subjects (199 of 492, 40.4 % vs 168 of 408, 41.2 %, p = 0.825). Children with and without siblings had similar colonization rates (145 of 334, 43.4 % vs 219 of 562, 39.0 %, p = 0.187). Clinical signs and symptoms were not associated with SPn colonization. Children colonized with SPn had longer recovery duration compared to non-colonized children (114 of 367, 31.1 % vs 98 of 533, 18.4 %, p < 0.001) and were longer absent from day care (270 of 608, 44.4 % vs 94 of 284, 33.1 %, p = 0.001). Pneumonia, sinusitis, and acute otitis media were more frequently diagnosed in children colonized with SPn. Children attending day care centres had significantly higher prevalence of SPn colonization (270 of 367, 44.4 % vs 338 of 533, 33.1 %, p = 0.001). Children with pneumonia, sinusitis and acute otitis media were more frequently treated with antimicrobials than children with other diagnoses.ConclusionsSPn nasopharyngeal colonization has a negative impact on the course of respiratory tract infection, likely because of SPn being the cause of the disease or a complicating factor. It is also associated with and may be responsible for higher frequencies of bronchitis, pneumonia, acute otitis media, sinusitis and the need of antimicrobial treatment.

Alveolar macrophages are the main target cells in feline calicivirus-associated pneumonia

Feline calicivirus (FCV) is a pathogen of felids and one of the most common causative agents of feline upper respiratory disease (URD). Reports of natural FCV pneumonia in the course of respiratory tract infections are sparse. Therefore, knowledge on the pathogenesis of FCV-induced lung lesions comes only from experimental studies. The aim of the present study was to assess the type and extent of pulmonary involvement in natural respiratory FCV infections of domestic cats and to identify the viral target cells in the lung. For this purpose, histology, immunohistochemistry and RNA-in situ hybridisation for FCV and relevant cell markers were performed on diagnostic post-mortem specimens collected after fatal URD, virulent systemic FCV or other conditions. All groups of cats exhibited similar acute pathological changes, dominated by multifocal desquamation of activated alveolar macrophages (AM) and occasional type II pneumocytes with fibrin exudation, consistent with diffuse alveolar damage (DAD). In fatal cases, this was generally seen without evidence of epithelial regeneration. In cats without clinical respiratory signs, type II pneumocyte hyperplasia was present alongside the other changes, consistent with the post-damage proliferative phase of DAD. FCV infected and replicated in AM and, to a lesser extent, type II pneumocytes. This study shows that lung involvement is an infrequent but important feature of FCV-induced URD. AM are the main viral target cell and pulmonary replication site, and their infection is associated with desquamation and activation, as well as death via apoptosis.

Sea-cod oil supplementation alters the course of Streptococcus pneumoniae infection in BALB/c mice

The existing reports on the role of ω-3 polyunsaturated fatty acids (PUFA) in infectious diseases are contradictory. The present study was conducted to evaluate the effect of sea-cod oil on the course of respiratory tract infection by Streptococcus pneumoniae in BALB/c mice. Animals were given enteral sea-cod oil for a period of 30 and 60days and challenged intra-tracheally with S. pneumoniae D39 serotype 2. The survival of animals and various inflammatory parameters, i.e. myeloperoxidase (MPO), malondialdehyde (MDA), nitric oxide (NO) and leukotriene B(4) in the lung homogenates, were investigated. The inflammatory cytokines levels (IL-1β, TNF-α and IL-10) were also determined. Continuous sea-cod oil supplementation for 60days significantly improved survival among the animals. A significant reduction in the bacterial load in the lungs of sea-cod oil-fed animals compared to the controls was observed. As the disease progressed, the reduced bacterial colonisation correlated well with the histopathological observation. This was accompanied by a decrease in the production of inflammatory mediators and cytokines in the lung homogenates. However, not even a minor difference was seen in animals given sea-cod oil supplementation for 30days duration; therefore, long-term treatment was required to attain an effect. Sea-cod oil supplementation modulated the host immune response and, thus, protected the host from ensuing inflammatory damage due to S. pneumoniae-mediated infection.

Probiotics for the prevention of respiratory tract infections: a systematic review

We evaluated the clinical evidence regarding probiotic use for the prevention of respiratory tract infections (RTIs). Randomised controlled trials (RCTs) studying the effects of probiotics for the prevention of upper or lower RTIs were systematically identified. Fourteen RCTs (twelve involving healthy subjects and two involving patients with RTIs) were included. Various Lactobacillus strains were used in seven RCTs, combinations of Lactobacillus and Bifidobacterium strains were used in five RCTs, and a Bifidobacterium strain and a non-pathogenic Enterococcus faecalis strain were used in one RCT, respectively. In ten RCTs no difference was found regarding the incidence of RTIs in the probiotic arm compared with the control arm, whereas the remaining four RCTs favoured the use of probiotics. Reduction in the severity of symptoms related to RTIs was noted in five of six RCTs that provided relevant data. In three of nine RCTs that provided relevant data, the clinical course of RTIs was shorter in the probiotic arm, whereas no difference was found in the remaining six RCTs. In conclusion, probiotics may have a beneficial effect on the severity and duration of symptoms of RTIs but do not appear to reduce the incidence of RTIs.

P.064 Clinical severity and course of respiratory tract infections and the detection of respiratory viruses detected by multiplex RT-PCR in young hospitalized children

P.064 Clinical severity and course of respiratory tract infections and the detection of respiratory viruses detected by multiplex RT-PCR in young hospitalized children

Respiratory tract infections in cytomegalovirus-excreting and nonexcreting infants.

There is evidence of an immunosuppressive effect of cytomegalovirus (CMV), and CMV has been claimed to be a copathogen in respiratory tract infections (RTI). We therefore studied the significance of CMV viral load in infants with RTI, compared the frequency of infection with respiratory viruses and followed the course of RTI in CMV-excreting vs. nonexcreting infants. We examined 201 infants consecutively admitted to the Department of Pediatrics for RTI. At admission nasopharyngeal aspirates, throat swabs and urine were examined for CMV, and nasopharyngeal aspirates were examined for respiratory viruses. In these patients 23.3% had CMV in the urine, 15.3% had CMV in the throat and 10.9% had CMV in the nasopharynx; 26.2% excreted CMV in at least one site. No relationship was found between CMV viral load and clinical symptoms. Infection with respiratory viruses was as common in infants excreting CMV as in nonexcreting infants. Symptoms and the course of infection were not different in the two groups except that CMV-excreting infants had a significantly higher frequency of rhonchi at admission (P = 0.007) and a tendency for longer duration of cough (P = 0.06). CMV viral load was not related to clinical symptoms. The frequency of infection with common respiratory viruses in infants was independent of CMV excretion. The course of infection was not more complicated in infants excreting CMV; however, a higher frequency of rhonchi was demonstrated in patients with CMV.

Time course of changes in ETB receptor density and function in tracheal airway smooth muscle during respiratory tract viral infection in mice

1. In the current study, the density and function of ETA and ETB receptors in mouse tracheal airway smooth muscle were determined over the time course of respiratory tract infection with influenza A/PR-8/34 virus. 2. Quantitative autoradiographic studies using [125I]-endothelin-1 revealed that the tracheal airway smooth muscle from control mice contained ETA and ETB sites in the ratio of 49%:51% (+/- 2%, n = 29 mice). Respiratory tract viral infection was associated with increases in the density of ETA sites and decreases in the density of ETB sites at days 1, 2 and 4 post-inoculation which were reversible by day 19. For example, at day 4 post-inoculation, a time when the manifestations of viral infection were at or near their peak, the ratio of ETA:ETB sites was 72%:28% (+/- 4%, n = 6 mice, P < 0.05). In contrast, at day 19 post-inoculation, by which time viral infection had essentially resolved, the ratio of ETA:ETB sites was similar to control (51%:49% (+/- 3%), n = 6 mice). 3. Endothelin-1 was a potent spasmogen in isolated tracheal airway smooth muscle preparations from control mice (ED70 = concentration producing 70% of contraction induced by 10 microM carbachol = 6.3 nM (95% confidence limits, 4.0-10; n = 6 mice)). Neither the ETA receptor-selective antagonist, BQ-123 (3 microM), nor the ETB receptor-selective antagonist, BQ-788 (1 microM) alone had any significant inhibitory effect on endothelin-1-induced contractions of mouse isolated tracheal smooth muscle. However, simultaneous treatment with BQ-123 (3 microM) and BQ-788 (1 microM) resulted in a 10 fold rightward shift in the concentration-effect curve to endothelin-1 (ED70 = 60 nM, (44-90; n = 6 mice, P < 0.05)), indicating that contraction was mediated via both ETA and ETB receptors. 4. Endothelin-1 evoked similar concentration-dependent contractions of tracheal smooth muscle isolated from control and virus-inoculated mice. In the presence of the ETB receptor-selective-antagonist, BQ-788 (1 microM), the potency and maximum response to endothelin-1 were similar in preparations from control and virus-inoculated mice at all time points investigated. However, unlike control responses, endothelin-1-induced contractions in preparations from virus-infected mice were significantly inhibited by the ETA receptor-selective antagonist, BQ-123. For example, at day 4 post-inoculation, the contractile response to 30 nM endothelin-1, in the presence of BQ-123 (3 microM), was only 20 +/- 12% (n = 6 mice, P < 0.05) of that produced in control preparations under similar conditions. However, at day 19 post-inoculation, contraction evoked by 30 nM endothelin-1 in the presence of BQ-123 (3 microM), was similar to that in preparations from control mice. 5. In summary, during the early stages (days 1-8 post-inoculation) of respiratory tract infection with influenza A/PR-8/34 virus, we observed decreases in the density of tracheal airway smooth muscle ETB receptors which were reflected in decreases in ETB receptor-mediated airway smooth muscle contraction. In addition, during the same period of viral infection we observed increases in the density of tracheal airway smooth muscle ETA receptors which were not associated with increased function of the ETA receptor-effector system linked to contraction. Virus-associated modulation of ETA and ETB receptor density and function was reversible with recovery from infection.