An Overview of Microbes Pathogenic for Humans
Nancy Khardori in Bench to Bedside, 2018
Respiratory syncytial virus (RSV): a very common virus that is responsible for respiratory infections throughout the world, especially during the winter months and in younger individuals. It is believed that by the age of 2 years most children will have experienced at least one RSV infection (Borchers et al. 2013). The most common manifestation of the virus in infants and young children is bronchiolitis. It is also a significant, but often unrecognized cause of respiratory tract infections in adults, and there is an increased risk in individuals who are immunocompromised or have pre-existing cardiopulmonary disease. The virus is usually transmitted by direct contact; however, aerosol droplets have been implicated as well (Pfaller and Herwaldt 1988). Presently, immunoprophylaxis with the monoclonal antibody Palivizumab is available for high-risk/immunocompromised infants; however, a vaccine is not yet available.
Mucosal basophils, eosinophils, and mast cells
Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald in Principles of Mucosal Immunology, 2020
Eosinophils are also important in viral infections. Human respiratory syncytial virus causes respiratory tract infection, primarily among infants and toddlers. The severity of infection can extend from mild upper respiratory symptoms to severe bronchiolitis and pneumonia, and may progress to acute respiratory distress syndrome and death. Human respiratory syncytial virus infections are associated with significant eosinophilia in the bronchoalveolar fluid. This is most likely because eosinophils are attracted to the site of inflammation by chemokines such as RANTES and MIP-1α. The role of eosinophils in this disease is uncertain, as there is no clear evidence from human studies as to whether they promote host defense or enhance pathology. Among these pathologies, there is a clear association between severe human respiratory syncytial virus infection, particularly among young infants, and the development of postinfection asthma.
Nutrition and Immunity
R. J. Jarrett in Nutrition and Disease, 1979
This immune response may include the formation of IgE antibodies and give rise to allergic conditions. Milk allergy with predominantly gastrointestinal symptoms is one, and will be discussed in full in section 6. This sensitisation has also been implicated in the cot death syndrome, as the frequency of IgE antibodies to the 0-lactoglobulin of cow’s milk, as well as to other non-dietary allergens, was found to be increased in the blood of infants dying of no apparent cause. Another abnormality of secretory immunity may also exist in this syndrome, as a marked decrease in secretory component has been reported at post mortem in the lungs of a group of children dying in this way. Respiratory syncytial virus infection was also found in some.
Economic burden of respiratory syncytial virus infection in adults: a systematic literature review
Published in Journal of Medical Economics, 2023
Mei Grace, Ann Colosia, Sorrel Wolowacz, Catherine Panozzo, Parinaz Ghaswalla
Respiratory syncytial virus (RSV) is a seasonal virus that commonly affects infants and children, but the virus poses a risk for severe disease in adults as well1,2. Most people experience an RSV infection as an infant or young child and have some immunity to further exposures during their lifespan, but the immunity from childhood exposure does not provide complete or sustained immunity3. In older adults, changes in the immune system and lung function regarding clearance of microbes lead to an inflammatory state that impairs responses to infection and prolongs inflammation after an infection has cleared4. Therefore, older adults in the general population or in long-term care facilities (LTCFs) are susceptible to severe RSV infection1. In addition, adults with comorbidities such as chronic heart or lung disease, functional disability, frailty, and compromised immune systems are susceptible to severe RSV disease and are more likely to require hospitalization than healthy older adults1,2,5–9. After older adult patients are diagnosed with RSV infection, their return to pre-RSV respiratory functioning and ability to perform activities of daily living may take several months10. Additionally, at hospital discharge, a substantial proportion of older adults or adults with comorbidities require discharge to a skilled nursing facility, rehabilitation facility, or assisted living facility not needed before RSV infection11–14.
Pharmacological management of human respiratory syncytial virus infection
Published in Expert Opinion on Pharmacotherapy, 2020
Alexis M. Kalergis, Jorge A. Soto, Nicolás M. S. Gálvez, Catalina A. Andrade, Ayleen Fernandez, Karen Bohmwald, Susan M. Bueno
The number one cause of hospitalizations for children under two years old and elderly are respiratory illness caused by infectious pathogens such as viruses and bacteria [1]. Among the viruses causative of acute lower respiratory tract infection (ALRTI), human respiratory syncytial virus (hRSV) remains the most prevalent one [2–4]. hRSV was first isolated the year 1956, was recently renamed human orthopneumovirus, and was also reassigned into the Pneumoviridae family and the Orthopneumovirus genus [5]. hRSV is an enveloped virus, with a single-stranded (ss), negative-sensed and non-segmented RNA genome, of about 15.2 kb [4, 6]. This virus replicates mainly in the cytoplasm of epithelial cells, where the viral RNA-dependent RNA-polymerase (L protein) is required for the synthesis of its ssRNA anti-genome (+). This positive sensed genome will serve as a template for the synthesis of new genomic ssRNA and viral proteins [7,8]. The viral transcription starts as soon as the fusion with the target cell occurs -with viral antigens being detected as early as 9 hours post-infection and new virions being released within 11 to 13 hours post-infection, as reported by different in vitro studies [9–11]. The released viral particles exhibit a pleiomorphic form and a diameter ranging between 60 and 350 nm [12].
Severe autoimmune hemolytic anemia complicating hereditary spherocytosis treated successfully with glucocorticoids and cyclosporine: a case report
Published in Hematology, 2023
Na Wang, Hongkai Lu, Linzhang Li, Ming Gong, Yongtong Cao
In November 2021, a 25-year-old woman developed moderate to severe edema with no obvious cause, especially in both lower limbs, accompanied by abdominal distension, weakness, heart palpitations, dyspnea, inability to lie down at night, and splenomegaly. On January 29th 2022, she was admitted to the Emergency Department of China–Japan Friendship Hospital with a fever of up to 39°C. The results of laboratory tests conducted on admission are provided in Table 1. A peripheral blood smear showed mature erythrocytes of variable size, heterogeneous erythrocytes, and a count of 2 nucleated erythrocytes per 100 leukocytes. Based on the patient's decreased hemoglobin level; elevated reticulocytes, lactate dehydrogenase, bilirubin, and indirect bilirubin levels; and direct anti-human globulin test (DAT) positivity [anti-immunoglobulin (IgG) 2+ and anti-C3d 1+; Table 1], the diagnosis of AIHA was considered. Tests performed to exclude infectious causes of the fever detected IgM antibodies against respiratory syncytial virus (RSV). It is worth noting that her platelet count decreased during the initial period of hospitalization (Table 1). This thrombocytopenia may have been mediated by immune-related factors and may have been due to the patient's hypersplenism.
Related Knowledge Centers
- Bronchiolitis
- Epithelium
- Pneumonia
- Respiratory Tract
- Syncytium
- Virus
- Common Cold
- Pathogen
- Negative-Strand Rna Virus
- Immunodeficiency