Human Respiratory Secretions Research Articles

Investigation of human bocavirus associated with acute respiratory infection in patients treated in health unit in Guarapuava – PR / Investigação de bocavírus humano associado à infecção respiratória aguda em pacientes atendidos em unidade de sáude do Município de Guarapuava - PR

Human Bocavirus (HBoV) is a parvovirus in human respiratory secretions isolates from symptomatic patients. Its prevalence varies from 1.5 to 19% and the most common age for a primary infection is between 6 to 24 months age. HBoV has been associated with infections in the upper and lower children respiratory tract, little is known about HBoV infections among adults and the elderly. The present study objective was to investigate the HBoV occurrence in children and adults with acute respiratory symptoms. One hundred and eighty-theree nasal swab samples from symptomatic patients that are attended in the public health services in Guarapuava city, in Paraná State between 2014 and 2015. The patients´ mean age included in the essay was 35 years old and the 33 years median, varying from less than 1 year and up to 82 years age. The most commonly observed symptoms were coryza, cough and fever. The samples were tested for HBoV DNA presence by standard PCR methodology. No positive samples were detected for HBoV. Thus, we did not demonstrate the HBoV circulation in Guarapuava - PR, but more studies are necessary, taking into account that these new viruses may be important pathogens in respiratory diseases in Brazil.

Highly sensitive scent-detection of COVID-19 patients in vivo by trained dogs.

Timely and accurate diagnostics are essential to fight the COVID-19 pandemic, but no test satisfies both conditions. Dogs can scent-identify the unique odors of volatile organic compounds generated during infection by interrogating specimens or, ideally, the body of a patient. After training 6 dogs to detect SARS-CoV-2 by scent in human respiratory secretions (in vitro diagnosis), we retrained 5 of them to search and find the infection by scenting the patient directly (in vivo screening). Then, efficacy trials were designed to compare the diagnostic performance of the dogs against that of the rRT-PCR in 848 human subjects: 269 hospitalized patients (COVID-19 prevalence 30.1%), 259 hospital staff (prevalence 2.7%), and 320 government employees (prevalence 1.25%). The limit of detection in vitro was lower than 10-12 copies ssRNA/mL. During in vivo efficacy experiments, our 5 dogs detected 92 COVID-19 positive patients among the 848 study subjects. The alert (lying down) was immediate, with 95.2% accuracy and high sensitivity (95.9%; 95% C.I. 93.6-97.4), specificity (95.1%; 94.4-95.8), positive predictive value (69.7%; 65.9-73.2), and negative predictive value (99.5%; 99.2-99.7) in relation to rRT-PCR. Seventy-five days after finishing in vivo efficacy experiments, a real-life study (in vivo effectiveness) was executed among the riders of the Metro System of Medellin, deploying the human-canine teams without previous training or announcement. Three dogs were used to examine the scent of 550 volunteers who agreed to participate, both in test with canines and in rRT-PCR testing. Negative predictive value remained at 99.0% (95% C.I. 98.3-99.4), but positive predictive value dropped to 28.2% (95% C.I. 21.1-36.7). Canine scent-detection in vivo is a highly accurate screening test for COVID-19, and it detects more than 99% of infected individuals independent of key variables, such as disease prevalence, time post-exposure, or presence of symptoms. Additional training is required to teach the dogs to ignore odoriferous contamination under real-life conditions.

Adsorption of surfactant protein D from human respiratory secretions by carbon nanotubes and polystyrene nanoparticles depends on nanomaterial surface modification and size.

The alveolar respiratory unit constitutes one of the main targets of inhaled nanoparticles; the effect of engineered nanomaterials (NMs) on human health is largely unknown. Surfactant protein D (SP-D) is synthesized by alveolar type II epithelial cells and released into respiratory secretions; its main function is in immune defence, notably against inhaled microbes. SP-D also plays an important role in modulating an appropriate inflammatory response in the lung, and reduced SP-D is associated with a number of inflammatory lung diseases. Adsorption of SP-D to inhaled NMs may facilitate their removal via macrophage phagocytosis. This study addresses the hypothesis that the chemistry, size and surface modification of engineered NMs will impact on their interaction with, and adsorption of, SP-D. To this purpose, we have examined the interactions between SP-D in human lung lavage and two NMs, carbon nanotubes and polystyrene nanoparticles, with different surface functionalization. We have demonstrated that particle size, functionalization and concentration affect the adsorption of SP-D from human lung lavage. Functionalization with negatively charged groups enhanced the amount of SP-D binding. While SP-D binding would be expected to enhance macrophage phagocytosis, these results suggest that the degree of binding is markedly affected by the physicochemistry of the NM and that deposition of high levels of some nanoparticles within the alveolar unit might deplete SP-D levels and affect alveolar immune defence mechanisms.

A pandemic influenza preparedness study: Use of energetic methods to decontaminate filtering facepiece respirators contaminated with H1N1 aerosols and droplets

A major concern among health care experts is a projected shortage of N95 filtering facepiece respirators (FFRs) during an influenza pandemic. One option for mitigating an FFR shortage is to decontaminate and reuse the devices. Many parameters, including biocidal efficacy, filtration performance, pressure drop, fit, and residual toxicity, must be evaluated to verify the effectiveness of this strategy. The focus of this research effort was on evaluating the ability of microwave-generated steam, warm moist heat, and ultraviolet germicidal irradiation at 254 nm to decontaminate H1N1 influenza virus. Six commercially available FFR models were contaminated with H1N1 influenza virus as aerosols or droplets that are representative of human respiratory secretions. A subset of the FFRs was treated with the aforementioned decontamination technologies, whereas the remaining FFRs were used to evaluate the H1N1 challenge applied to the devices. All 3 decontamination technologies provided >4-log reduction of viable H1N1 virus. In 93% of our experiments, the virus was reduced to levels below the limit of detection of the method used. These data are encouraging and may contribute to the evolution of effective strategies for the decontamination and reuse of FFRs.

Serologic Evidence of Frequent Human Infection with WU and KI Polyomaviruses

WU polyomavirus (WUPyV) and KI polyomavirus (KIPyV) are novel human polyomaviruses. They were originally identified in human respiratory secretions, but the extent of human infection caused by these viruses has not been described to date. To determine the seroepidemiology of WUPyV and KIpyIV, we used an ELISA to screen serum samples from 419 patients at the St. Louis Children's Hospital and Barnes-Jewish Hospital during 2007-2008. The age-stratified deidentified samples were examined for antibodies to the major capsid proteins of WUPyV and KIPyV. Seropositivity for each virus was similar; antibody levels were high in the youngest age group (<6 months), decreased to a nadir in the next age group (6 to <12 months), and then steadily increased with subsequent age groups, eventually reaching a plateau of approximate, equals 80% for WUPyV and approximate, equals 70% for KIPyV. These results demonstrate that both KIPyV and WUPyV cause widespread infection in the human population.

Human airway epithelial cell culture to identify new respiratory viruses: Coronavirus NL63 as a model

Propagation of new human respiratory virus pathogens in established cell lines is hampered by a lack of predictability regarding cell line permissivity and by availability of suitable antibody reagents to detect infection in cell lines that do not exhibit significant cytopathic effect. Recently, molecular methods have been used to amplify and identify novel nucleic acid sequences directly from clinical samples, but these methods may be hampered by the quantity of virus present in respiratory secretions at different time points following the onset of infection. Human airway epithelial (HAE) cultures, which effectively mimic the human bronchial environment, allow for cultivation of a wide variety of human respiratory viral pathogens. The goal of the experiments described here was to determine if propagation and identification of a human respiratory virus may be achieved through inoculation of HAE cultures followed by whole transcriptome amplification (WTA) and sequence analysis. To establish proof-of-principle human coronavirus NL63 (HCoV-NL63) was evaluated, and the first visualization of HCoV-NL63 virus by transmission electron microscopy (TEM) is reported. Initial propagation of human respiratory secretions onto HAE cultures followed by TEM and WTA of culture supernatant may be a useful approach for visualization and detection of new human respiratory pathogens that have eluded identification by traditional approaches.

Evidence of human bocavirus circulating in children and adults, Cleveland, Ohio

Background Viral respiratory illness is a major cause of morbidity and mortality. The human bocavirus (HBoV) is a recently recognized parvovirus isolated from human respiratory secretions. Objectives To define the clinical and epidemiologic characteristics in adult and pediatric patients with evidence of HBoV. Study design From October 2005 through October 2006, we screened respiratory samples from children and adults negative for common respiratory pathogens for HBoV by PCR. Demographic and clinical characteristics were obtained from medical records of HBoV positive individuals. Results Of 2075 samples screened, 1826 (88.0%) represented distinct respiratory events: 1539 (84.3%) were pediatric (<18 years), and 273 (15.0%) adult (≥18 years). Forty (2.2%) patients had HBoV: 36 (2.3%) children and 4 (1.5%) adults. HBoV positive children had history of prematurity (31.3%) and cardiac disease (18.8%). Adults had underlying pulmonary (100%) and cardiac (50%) disease. Twenty-seven children (84.4%) were hospitalized; 9 (28.1%) required intensive care. All adults were hospitalized; none required intensive care. Nosocomial acquisition likely occurred in 3 patients. Conclusions HBoV circulates in Cleveland, OH, in children and adults with similar frequencies, and can warrant hospitalization and intensive care. Further study would clarify our understanding of this newly recognized human pathogen.

Genotypic comparison of clinical Legionella isolates and patient-related environmental isolates in The Netherlands, 2002–2006

This study investigated the hypothesis that the genotype distribution of Legionella isolates from sporadic patients with Legionnaires' disease differs from that of Legionella strains in the environment. An amplified fragment-length polymorphism (AFLP) assay was used to genotype patient-derived and environmental Legionella isolates. The three Legionella pneumophila genotypes isolated most frequently from human respiratory secretions were AFLP types 004 Lyon, 010 London and 006 Copenhagen. These genotypes were cultured significantly less frequently from environmental samples (50% vs. 4%; p <0.001). The most frequently observed L. pneumophila serogroup 1 genotype among patient-derived isolates was 004 Lyon (32%). This genotype was cultured from only one of 6458 environmental samples. The positive sample contained 1.26 x 10(6) CFU/mL and originated from a whirlpool spa that had not been disinfected and had been maintained at 36 degrees C for several months. Overall, the distribution of genotypes differed significantly among patient and environmental isolates. A possible explanation is that virulent strains may exist in potential environmental sources at undetectable concentrations.

KI and WU Polyomaviruses in Children, France

To the Editor: Two new members of the Polyomaviridae family, provisionally named Karolinska Institutet virus (KIPyV) and Washington University virus (WUPyV), have been recently discovered (1,2). These new polyomaviruses were identified by screening human respiratory secretions with molecular tools. KIPyV and WUPyV are genetically related to the BK virus and the JC virus, the 2 known members of the family Polyomaviridae that affect humans.

Immunodominant antigens of Streptococcus equisimilis shared by other -haemolytic streptococci

Three immunodominant antigens of Streptococcus equisimilis (Lancefield group C) with approximate mol. wts of 46, 66 and 105 kDa were recognised by human serum IgG and IgA immunoblotting. These antigens were identified consistently by various human sera but immunoblots with IgA (heavy chain) and secretory IgA (J chain) from human respiratory secretions gave more variable results. Antigens with similar migration rates were demonstrated in S.pyogenes, large colony human biotype group G streptococci, and streptococci of groups C and G from the "S. anginosus-milleri group". Polyclonal antibody which was eluted from immunoblot substrates that contained the S. equisimilis 66-kDa antigen reacted with the 60-kDa antigen of S. pyogenes. Both polyclonal and monoclonal anti-vimentin antibodies identified the 46-kDa and 66-kDa antigens of S. equisimilis. The homology of these antigens among beta-haemolytic streptococci has the potential to complicate both a strategy for the utilisation of immunoblotting for diagnostic purposes and the understanding of how such antigens may be involved in the pathogenesis of post-infectious sequelae.

Utilization of human respiratory secretions by mucoid Pseudomonas aeruginosa of cystic fibrosis origin

Growth and exoproduct production were examined with sputum from patients with respiratory diseases serving as the growth substrate for mucoid strains of Pseudomonas aeruginosa isolated from cystic fibrosis (CF) patients. Mucoid strains are uniquely common to chronic respiratory infections of CF patients. The mucoid colonial morphology of P. aeruginosa is due to the biosynthesis of the exopolysaccharide alginate. Alginate-producing (Alg+) strains utilized CF sputum for growth and high yields of alginate; however, sputum from patients with other respiratory diseases produced comparable results. Analysis of CF sputum medium indicated that amino acids and small peptides were major substrates for P. aeruginosa in respiratory secretions. Cultures of Alg+ strains in CF sputum medium were inhibited in growth and reduced in alginate yields by a low concentration (1 mM) of D-mannose, suggesting therapeutic applications. The rates of growth of two Alg+ strains in CF sputum medium were found to be slightly lower compared with their respective spontaneous Alg- mutants, indicating that the mucoid phenotype does not enhance the ability of P. aeruginosa to utilize respiratory secretions. At all stages of growth in CF sputum medium, two Alg+ strains produced lower yields of protease than did their respective Alg- mutants. When seven Alg+ strains of CF origin were compared with their respective Alg- mutants, the Alg+ phenotype correlated with reduced yields of extracellular proteases. These data are consistent with the hypothesis that mucoid strains of P. aeruginosa are more suited to chronic rather than to acute respiratory infections in that reduced yields of proteases temper the level of damage to the lungs and result in a reduced infiltration of phagocytic cells.

Respiratory and humoral immune response to aerosol and intramuscular pertussis vaccine

Animal experiments have shown that respiratory administration of pertussis antigen induces a protective immune response. In this study pertussis antibody in human respiratory secretions was measured and the response to aerosol and intramuscular pertussis immunization investigated. Substanial increases in this antibody occurred after aerosol immunization but no changes were found in serum antibody. The reverse was observed after intramuscular pertussis vaccine in adults but not with aerosol immunization. The latter method may be of value for paediatric medical and nursing personnel exposed to the risk of pertussis infection.

Influenza antibody in human respiratory secretions after subcutaneous or respiratory immunization with inactivated virus.

STUDIES with human volunteers have shown that experimental infection with influenza virus is a better stimulus of antibody in respiratory secretions than is subcutaneous immunization with inactivated vaccine, although both procedures result in the production of similar concentrations of serum antibody1,2. The work reported here was undertaken to determine if administration of inactivated virus vaccine through the respiratory tract provokes a similar antibody response in respiratory secretions.

Influenza Virus Neutralizing Antibody in Human Respiratory Secretions

Summary Influenza virus neutralizing antibody titers and immunoglobulin levels were measured in human respiratory secretions. Antibody in the IgA class of immunoglobulins was found in respiratory secretions obtained during life, whereas IgG antibody predominated in secretions obtained at autopsy. The amount of neutralizing antibody per milligram of IgA was found to be similar in sputum and nasal washing, but was significantly lower in saliva. There was a positive association between levels of serum antibody and sputum and nasal washing antibody. The antibody in respiratory secretions formed in response to a strain of A2 influenza virus had similar neutralizing activity against a different but closely related A2 influenza virus strain.