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Public Health and Viruses
Published in Patricia G. Melloy, Viruses and Society, 2023
Once a pathogen is discovered, epidemiologists can mobilize to characterize the pathogen and the disease it causes. As mentioned in Chapter 1, several major characteristics govern how pathogens spread, including route of entry, vector, virulence, and environmental conditions (Minkoff and Baker 2004). Epidemiologists keep track of the incidence of the disease, which involves recording the number of new cases. They would also determine the prevalence of the disease, that is, the total number of cases in a population (Minkoff and Baker 2004). For pathogens that can be spread from person to person, epidemiologists typically calculate a basic reproductive number, which is the average number of people who will become infected from one infected person. One can also calculate an effective reproductive number for the virus during a disease outbreak that can change over time. For example, using a public health measure like quarantining can lower this effective number. One can also follow the effective reproductive number as the number of vaccinated individuals increases, if a vaccine is made available (Rothman 2012; Christakis 2020).
Acute Otitis Media and Otitis Media With Effusion in Adults
Published in R James A England, Eamon Shamil, Rajeev Mathew, Manohar Bance, Pavol Surda, Jemy Jose, Omar Hilmi, Adam J Donne, Scott-Brown's Essential Otorhinolaryngology, 2022
Proposed treatments for the future include transtympanic or intranasal antibiotics or bacteriophages, probiotics, vaccination against viral pathogens, and treatment directed at Haemophilus-associated biofilm. There is limited evidence to support the use of systemic steroids, although they are not used commonly.
Pathogenicity and Virulence
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Any microorganism that is able to infect a host and produce disease is a pathogen. IVllcroorganisms vary in their ability to produce disease; some organisms such as Vibrio cholerae, the agent of cholera, or Yersinia pestis, the cause of plague, are able to produce disease in normal healthy hosts. These bacteria are thus overt pathogens and must be distinguished from those organisms which function as opportunists and produce disease only when a break in the host′s normal defense mechanisms enables them to become established. Included in this latter group of opportunists are members of the normal flora such as Escherichia coli, Staphylococcus aureus, and certain fungi such Candida albicans, as well as some free-living bacteria such as Pseudomonas aeruginosa and Legionella pneumophila.
The Immunologic Profiles of Kawasaki Disease Triggered by Mycoplasma pneumoniae Infection
Published in Fetal and Pediatric Pathology, 2023
Hong-bo Hu, Xiao-peng Shang, Jian-gang Wu, Ya-ling Cai
Although KD and HSP are both diseases characterized by vasculitis, in the present study, significant differences were observed in the indicators of the complement system, cellular immunity, and humoral immunity between the two groups. In the MP-KD group, the levels of C3 and C4 and the ratio of CD4/CD8 were higher than those in the MP-HSP group, while the levels of IgA and CD56 were lower than those in the MP-HSP group. HSP patients had lower levels of CD4+T cells and a lower CD4/CD8 ratio, while having higher levels of CD8+T lymphocytes [27,28]. By encouraging the release of other cytokines and chemokines, the TNF-α secreted by activated CD8+ T cells can cause tissue damage, induce mesangial and endothelial cell mitosis, and cause vascular inflammation in conjunction with IgA [29–32]. According to Jiang et al., CD8+ T cells are significantly elevated in the acute phase of MP infection, whereas increased specific CD4+ T cells in MP infection was strongly associated with the development of interstitial pneumonia [33,34]. The preceding findings have confirmed that, despite being infected with the same pathogen, patients may exhibit diverse clinical manifestations and symptoms due to various induction mechanisms and immune response patterns.
Three-dimensional (3D) cell culture studies: a review of the field of toxicology
Published in Drug and Chemical Toxicology, 2023
Seda İpek, Aylin Üstündağ, Benay Can Eke
The gastrointestinal tract plays an important role in digestion, electrolyte and fluid transport, drug absorption and metabolism as well as nutrient absorption (Markus et al.2021). Intestinal permeability affects drug bioavailability (Marrella et al.2020). The small intestine, the longest segment of the gastrointestinal tract (GIT), serves as a protective barrier against pathogenic and opportunistic microbial infections (Markus et al.2021). Considering the function of the gastrointestinal tract, it is common for drugs to cause gastrointestinal toxicities (Peters et al.2019). However, the lack of in vitro intestinal tissue models that accurately reflect the architecture and physiology of the gut has hampered research on drug absorption, metabolism, and gastrointestinal toxicity. On the other hand, the physiology and the outcomes of humans cannot be predicted by animal models. Moreover, some human pathogens are species-specific, which means they cannot infect other hosts. Therefore, human intestinal tissue models resembling in vivo microenvironments and providing physiologically relevant cellular responses are needed so that pharmaceuticals and toxicants can be predictably and effectively tested (Markus et al.2021).
Host factors subverted by Mycobacterium tuberculosis: Potential targets for host directed therapy
Published in International Reviews of Immunology, 2023
Rashi Kalra, Drishti Tiwari, Hedwin Kitdorlang Dkhar, Ella Bhagyaraj, Rakesh Kumar, Anshu Bhardwaj, Pawan Gupta
An alternate theory of disease causation as proposed by Pierre Jacques Antoine Bechamp (1816–1908), advocates that the human body’s “internal milieu” or “terrain” is responsible for development of disease post infection [187]. After several years of research, it is now well established that a wide range of “host factors” modulate the body’s “internal milieu” and influence disease susceptibility, treatment response and mortality rates. Therefore, host immunity is of paramount importance. In order to be a successful host, one should be able to tolerate damage caused by the pathogen and the immune system along with efficient pathogen clearance. This ability of tolerance is described as “host resilience” and is a relatively unexplored research niche [188,189]. The available treatment options predominantly target pathogen clearance; hence are antimicrobial in nature. However, proper attention has not been given to molecules that enhance host tolerance and target pathogens in a “non-microbial” fashion. Given this, there arises a need for understanding the host factors behind resilience for tailoring appropriate treatment options. It is believed that host molecules aiding M. tuberculosis during pathogenesis might be one of the factors responsible for this tolerance. Thus, detailed identification of the host molecules subverted by the pathogen for immune evasion is cardinal for pathogen clearance as well as for boosting the immune system in times of pandemics, such as the recent coronavirus (COVID-19). In the coming years, an investment of scientific efforts in this discipline will be required and is anticipated.