The Basics of Infectious Diseases

2021 ◽  
Author(s):  
Heinz-Josef Schmitt

Infectious Diseases result from exposure and contact between a host (human being) and an (uninvited) guest (micro-organism). Given the fact that billions of micro-organisms are in and around us at any time, overall, infectious diseases are comparatively rare; of the millions of different microbial species, only about 300 are known to cause human diseases. Besides exposure and contact, factors on the side of the host (genetic background, environment, underlying diseases and their therapy) and on the side of the micro-organisms (pathogenicity / virulence factors) are necessary to result in an infectious disease. “Colonization” means that a micro-organism can attach on skin or mucous membrane for some time or even indefinitely but does not invade host tissue and does not cause any symptoms. Colonizers may even induce an immune response. “Infection” is defined as a micro-organism invading through skin or mucous membranes the tissue of a host, leading to no disease (“asymptomatic infection”); or symptomatic disease. It is followed by health, disability, or death. Following the infection, microorganisms may persist in the body for a long time or even for life without causing any symptoms, which is called “latent infection”. Infectious diseases may not only be due to pathogenicity factors of a micro-organism, but may also result from (i.) direct destruction of host tissues (e.g., from viral replication); (ii.) the acute host (immune-) response; and from late immune responses resulting in immune-mediated “post-infectious diseases”. Some infections may cause an immune response that is directed against host-tissue, resulting in an “autoimmune-disease”. Given the increasing number of microbes, the increasing number of exposures, and the increasing number and fraction of susceptible/predisposed humans, it is obvious that infectious diseases will increase in the future. Vaccines and vaccination may help solve this problem.

2021 ◽  
Author(s):  
Werner Solbach

Microorganisms constitute 70 percent of the biomass on Planet Earth. Comparatively few species are adapted to colonize human surfaces and form a complex Meta-Organism with manyfold mutual benefits. Occasionally, microorganisms may overcome the barriers of the skin and mucosal surfaces and may multiply locally or in multiple sites inside the body. This process is called infection. Infections can be caused by bacteria, viruses, parasites, helminths, and fungi. Immediately after infection, numerous defense mechanisms of the immune system are activated to combat replication of the microbes. There is a balance between microorganism and human defense mechanisms, which may lead to either asymptomatic infection or result in a wide spectrum of symptoms from mild to severe disease and even death. The most important factors in the diagnosis of infectious diseases are a careful history, physical examination and the appropriate collection of body fluids and tissues. Laboratory diagnosis requires between 2 and 72 hours. Wherever possible, antibiotics should only be used when sufficient evidence of efficacy is available. Then, however, they should be used as early as possible and in high doses. In addition to everyday hygiene measures, vaccination is the most effective measure to prevent infectious diseases.


2020 ◽  
pp. 162-165
Author(s):  
Gavin Weightman

This chapter assesses the mystery of immunity. Today, Edward Jenner is often referred to as the 'father of immunology'. But really, Jenner had no more claim to that title than Lady Mary Wortley Montagu, or the Greek women inoculating in Constantinople, or Daniel Sutton. None of them knew anything of the micro-organisms that Louis Pasteur and his contemporaries called 'germs'. It took well over a century after the deaths of Sutton and Jenner for an accumulation of scientific investigation to gain some understanding of what had been going on medically when the inoculators and vaccinators sought to bring smallpox under control. And it was a long time after the identification of 'germs', and the detective work that isolated the elements in them that caused specific infections, that it was understood that inoculation and vaccination worked because they triggered an immune response in the patient.


2020 ◽  
Vol 11 (SPL1) ◽  
pp. 1378-1383
Author(s):  
Kanyaka Bagde ◽  
Bharat Rathi ◽  
Renu Rathi ◽  
Prem Badwaik ◽  
Swapnali Khabde

The greatness of Ayurveda medicine is that it works on your immune system and helps to build up the body to fight against viral invasions. It is the safest, economical and natural way of self-healing. It can quickly spread among masses from rich to poor all over the country. Ayurveda has been dealing with plenty of herbs for a very long time. These herbs include some rare to prevalent herbs which we can found some in the kitchen even though if that is of any commoners. The concern is that these viral infections are very prone to attack weak immunity and take the chance to affect the country to the globe. So the prevalent herbs of Ayurveda available in the kitchen will always be helpful to get through this viral invasion. These herbs are always there to make tasty food as well as to protect the body from infectious diseases by building the immunity strong. Herbs from the kitchen are not complicated to take as a medicine. Regular use of a few herbs in the straightforward form proves its importance as a medicine. In this article a review of herbs is done which we are available in our kitchen, we are using it in our daily life, and we are getting the benefit of these which a common man might not be fully aware of about. 


1990 ◽  
Vol 3 (2) ◽  
pp. 132-152 ◽  
Author(s):  
K James

The immune response to microorganisms not only participates in the elimination of unwanted organisms from the body, but also assists in diagnosis of infectious diseases. The nonspecific immune response is the first line of defense, assisting the body until the specific immune response can be mobilized to provide protective mechanisms. The specific immune response involves humoral or cell-mediated immunity or both, dependent on the nature of the organism and its site of sequestration. A variety of test systems have been developed to identify the causative organisms of infectious diseases. Test systems used in immunoserology have classically included methods of detecting antigen-antibody reactions which range from complement fixation to immunoassay methods. Relevant test systems for detecting antigens and antibodies are described. With numerous test systems available to detect antigens and antibodies, there can be confusion regarding selection of the appropriate system for each application. Methods for detecting antibody to verify immunity differ from immunologic methods to diagnose disease. Techniques to detect soluble antigens present in active infectious states may appear similar to those used to detect antibody, but their differences should be appreciated.


2018 ◽  
Vol 10 ◽  
pp. 175883401774257 ◽  
Author(s):  
Thomas Walle ◽  
Rafael Martinez Monge ◽  
Adelheid Cerwenka ◽  
Daniel Ajona ◽  
Ignacio Melero ◽  
...  

Radiotherapy (RT) is currently used in more than 50% of cancer patients during the course of their disease in the curative, adjuvant or palliative setting. RT achieves good local control of tumor growth, conferring DNA damage and impacting tumor vasculature and the immune system. Formerly regarded as a merely immunosuppressive treatment, pre- and clinical observations indicate that the therapeutic effect of RT is partially immune mediated. In some instances, RT synergizes with immunotherapy (IT), through different mechanisms promoting an effective antitumor immune response. Cell death induced by RT is thought to be immunogenic and results in modulation of lymphocyte effector function in the tumor microenvironment promoting local control. Moreover, a systemic immune response can be elicited or modulated to exert effects outside the irradiation field (so called abscopal effects). In this review, we discuss the body of evidence related to RT and its immunogenic potential for the future design of novel combination therapies.


2016 ◽  
Vol 62 (3) ◽  
pp. 370-376
Author(s):  
Megan Cross ◽  
Emma Klepzig ◽  
Madeleine Dallaston ◽  
Neil D Young ◽  
Ulla-Maja Bailey ◽  
...  

Despite the massive disease burden worldwide caused by parasitic nematodes and other infectious pathogens, the molecular basis of many infectious diseases caused by these pathogens has been unduly neglected for a long time. Therefore, accelerated progress towards novel therapeutics, and ultimately control of such infectious diseases, is of crucial importance. Capitalising on the wealth of data becoming available from proteomic and genomic studies, new protein targets at the pathogen-host interface can be identified and subjected to protein-based explorations of the molecular basis of pathogen-host interactions. By combining the use of systems and structural biology methodologies, insights into the structural and molecular mechanisms of these interactions can assist in the development of therapeutics and/or vaccines. This brief review examines two different proteins from the body wall of blood flukes – annexins and the stress-induced phosphoprotein 1 – both of which are presently interesting targets for the development of therapeutics.


2021 ◽  
Author(s):  
Petros P. Sfikakis ◽  
Kleio-Maria Verrou ◽  
Ourania Tsitsilonis ◽  
Dimitris Paraskevis ◽  
Efstathios Kastritis ◽  
...  

Despite tremendous efforts by the international research community to understand the pathophysiology of SARS-CoV-2 infection, the reasons behind the clinical variability, ranging from asymptomatic infection to lethal disease, are still unclear. Existing inter-individual variations of the immune responses, due to environmental exposures and genetic factors, may be critical to the development or not of symptomatic disease after infection with SARS-CoV-2, and transcriptomic differences marking such responses may be observed even later, after convalescence. Herein, we performed genome-wide transcriptional whole-blood profiling to test the hypothesis that immune response-related gene signatures may differ between healthy individuals with prior entirely asymptomatic versus clinical SARS-CoV-2 infection, all of which developed an equally robust antibody response. Among 12.789 protein-coding genes analyzed, there were only six and nine genes with significantly decreased or increased expression, respectively, in those with prior asymptomatic infection (n=17, mean age 34 years) relatively to those with clinical infection (n=15, mean age 37 years). All six genes with decreased expression (IFIT3, IFI44L, RSAD2, FOLR3, PI3, ALOX15), are involved in innate immune response while the first two are interferon-induced proteins. Among genes with increased expression six are involved in immune response (GZMH, CLEC1B, CLEC12A), viral mRNA translation (GCAT), energy metabolism (CACNA2D2) and oxidative stress response (ENC1). Notably, 8/15 differentially expressed genes are regulated by interferons. Our results suggest that an intrinsically weaker expression of some innate immunity- related genes may be associated with an asymptomatic disease course in SARS-CoV-2 infection. Whether a certain gene signature predicts, or not, those who will develop a more efficient immune response upon exposure to SARS-CoV-2, with implications for prioritization for vaccination, warrant further study.


2020 ◽  
Vol 11 (SPL1) ◽  
pp. 753-757
Author(s):  
Anagha Gulhane ◽  
Shamli Hiware

It is the most unreliable truth that anybody can get infected by the COVID-19, and nobody can escape from the danger of getting tainted by the virus. Yet, the line of hope is that anyone and everyone can boost their resistance, thus avoid the risk of getting affected by the illness. The immunity of humans pulls down as they grow older. If their immune system is robust, them falling sick is feeble. If their resistance is weak, them getting ill is sound. Several factors affect the immune system and its ability, including its nourishment. A two-way connection between nutrition, infection and immunity presents. Changes in one part will affect the others part in our body that's the nature's rule. Well defined immune system quality which is present between each life phase may influence the type, generality and the degree of infections. At the same time, low nutrition to the body will decrease the immune function and expose the body to the danger of getting infected by infectious diseases. Different quantity of micronutrients is required for increasing the immunity power of our body. Generally the vitamins A,C,D,E,B2,B6,B12, iron, zinc and selenium.The deficiencies of micronutrients are acknowledged as a global health issue, and also low nutrition makes it prone to establishes the infections in the body.


2018 ◽  
Vol 24 (14) ◽  
pp. 1533-1550 ◽  
Author(s):  
Jong-Eun Kim ◽  
Ki Won Lee

Skin is a protective organ and the largest of the human body. Due to its pivotal role in aesthetic appearance, skin health has a significant impact on quality of life. Chronic inflammation of the skin often marks the beginning of various skin diseases. Immune-mediated responses serve to protect the body from external insults and require succinct control, and can lead to ongoing cellular damage and various skin conditions if left unchecked. Studies have shown that phytochemicals can alter processes involved in skin inflammation and alleviate the effects of aging, cancer, atopic dermatitis, psoriasis, and vitiligo. Direct molecular targets of some phytochemicals have been identified and their precise mechanisms of action investigated. In this review, we summarize recent findings on the effects of phytochemicals on skin inflammation and the mechanisms of action involved.


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