Microbial Pathogenesis & Infectious Diseases

BRI researchers, in partnership with Virginia Mason clinicians, are studying the impact of COVID-19 to understand the immune response to the deadly virus. They are aiming to learn what predicts whether someone will have a good versus poor outcome when infected and how that will inform treatments and vaccines. The severity of an infection is in part dependent on the strength of a person’s immune system, since most people mount an immune response to the infection which kills or inactivates the pathogen. In this regard, the character of the immune response helps determine the consequences of a particular infection. And for some infections, an excessive immune response is actually bad, as it can cause symptoms such as high fever and inflammation, which have the potential to be more devastating than direct damage caused by a pathogen.

Coronavirus Disease 2019 (COVID-19) has become a major health problem causing severe acute respiratory illness in humans. It has spread rapidly around the globe since its first identification in Wuhan, China, in December 2019. The causative virus is called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and the World Health Organization (WHO) named the new epidemic disease Coronavirus Disease (COVID-19). The incidence of COVID-19 continues to increase with more than three million confirmed cases and over 244,000 deaths worldwide. There is currently no specific treatment or vaccine against COVID-19. Therefore, in the absence of pharmaceutical interventions, the implementation of precautions and hygienic measures will be essential to control and to minimize human transmission of the virus. In this review, we highlight the epidemiology, transmission, symptoms, and treatment of this disease, as well as future strategies to manage the spread of this fatal coronavirus.

The infections caused by germs and they may infect any part of the body, so they are called infectious diseases. Infection prevention and management demands a basic understanding of the epidemiology of diseases; risk factors that increase patient susceptibility to infection and the practices, procedures and treatments that may result in infections. Infection prevention and management is useful to prevent the transmission of infectious diseases. Some infectious diseases are often prevented by avoiding direct contact with the contagious person.  Infections can even be controlled and prevented by making public awareness on various infectious diseases and their outbreaks.

Diagnostic microbiology deals with the latest developments in clinical microbiology and the diagnosis and treatment of infectious diseases. It relates with bacteriology, immunology, infectious diseases, mycology, parasitology, and virology. The analysis of a microbial disease starts with an appraisal of clinical and epidemiologic elements, prompting the plan of a symptomatic theory.  Diagnostic microbiology can also be a part of developing a treatment plan. Organisms, for example, microbes and protozoans assume a part in numerous illness forms. A considerable lot of the procedures like microscopy, immunological tests, radiology, biomarker tests, ELISA, serology tests, immunization vectors are the major demonstrative tests that are as of now being used. Many microbes have developed resistance to medications. Thus, it is important for the researchers to discover more brilliant methods for diagnosing these microorganisms and their pathogenic instruments.

Infectious diseases are only caused by infectious organisms. Typically, these may be some bacteria, viruses, fungi or worms/ helminths. Under normal environments, when the immune system of the host is fully functional then, these disease symptoms may not be develop. But, if the host immune system is compromised or less then the infectious agent overwhelms the immune system, an infectious disease ensues. Most common infections diseases are caused by bacteria, viruses, protozoa, helminthes, rickettsia, and fungi. Prions are responsible for slow-progressing neurological disorders such as Creutzfeldt-Jakob Disease.

A vaccine is a biological preparation that gives dynamic procured safety to a specific malady. A vaccine typically contains an agent that look like a disease-causing micro-organism and is often made from weakened or killed forms of the microbe, its toxins or one of its surface proteins. The agent releases the body's immune system to recognize the agent as a threat, destroy it, and keep a record of it, so that the immune system can more easily recognize and destroy any of these micro-organisms that it later encounters. A drug may be classified by the chemical type of the active ingredient or by the way it is utilized to treat a specific condition. Each drug can be classified into one or more drug classes.

Immunodiagnostics is a diagnostic process that uses an antigen-antibody reaction as their primary source of detection. To detect the disease caused by infectious microorganisms, immunoassays have been developed. These biochemical and serological methods depend on the discovery of antibodies produced against infectious agent, a microbe, or non-microbial antigen. Serological tests are performed on blood serum, and body liquids, for example, semen and salivation. It’s usually refers to the diagnostic identification of antibodies in the serum or the detection of antigens of infectious agents in serum. Enzyme-linked immune sorbent assay is a measurement technique for identification an antigen immobilized on a strong surface and uses a particular immune response with a covalently coupled compound. The measure of immune response that ties the antigen is relative to the measure of antigen present, which is dictated by spectrophotometry technique.  Diagnostic immunology created for progression in mechanized fields. Diagnostic immunology takes a shot at the immunization field for security against HIV infection.

Microbial genetics provides powerful tools for deciphering the regulation, as well as the functional and pathway organization/association of cellular processes. This involves both discovering the regulatory genes as well as sites that control individual gene expression and determining which genes are coregulated and thus, likely to participate in the same process. Often genes that are coregulated and located next to each other in the same transcriptional unit (an operon), but there are numerous/abundant cases of dispersed sets of genes that are coregulated (regulons).

Clinical microbiology is a discipline that comprehends a broad range of testing methodologies and it is complex in terms of organisms and methods used to isolate and identify them. Although significant improvements in testing methodologies have been made, clinical microbiology remnants heavily reliant on culture-based methods and phenotypic methods for identification of culture organisms. The clinical microbiology laboratory also plays a critical role in diagnosis and management of patients with lower respiratory tract infections. By providing pathogen detection and identification and susceptibility testing the laboratory delivers the source of optimal empirical antimicrobial therapy and individually tailored regimens.

Medical Microbiology is the branch of medicine that basically involved with the prevention, diagnosis and treatment of the infections and communicable diseases. There are mainly four kinds of microorganisms that cause infectious disease, and they are: bacteria, fungi, parasites and viruses, and one type of infectious protein called prion. A medical life scientist studies the characteristics of pathogens and their modes of transmission, mechanisms of infection and about its growth. Medical microbiologists usually serve as consultants for physicians, providing identification of pathogens and suggesting treatment options. The interaction between a pathogen and its host cell has become increasingly significant to understand and interfere with diseases caused by microbial pathogens.

An antimicrobial is an agent that kills or inhibits the growth of microorganisms in a human body. The microbial agent may be a chemical compounds or may be a physical agents. Antimicrobial medicines may be sorted in keeping with the microorganisms and they act as a primarily against. As an example, antibiotics are used against bacteria and antifungals, can also be used against fungi. They can also be classified according to their function. Agents that kill microbes are also known as microbicidal, whereas those who simply inhibit their growth are called biostatic. The utilization of antimicrobial medicines to treat infection is known as antimicrobial chemotherapy, whereas the utilization of antimicrobial medicine to prevent infection is known as antimicrobial prophylaxis. These agents interfere with the growth and reproduction of causative organisms like bacteria, fungi, parasites, virus etc. The main categories of antimicrobial agents are disinfectants, which kill a wide range of microbes on non-living surfaces to prevent the spread of illness, antiseptics which are applied to living tissue and help to reduce infection throughout surgery, and antibiotics that destroy microorganisms inside the body.

A review of fungal pathogenesis mechanisms must first define the important yet controversial terms “virulence” and “pathogenesis.” The microbial pathogenesis literature is rich with debate on the definitions of these often misused terms. Yet, a clear understanding of how these terms are utilized by individuals is important for gaining an understanding of fungal pathogenesis mechanisms. A full discourse on the complicated history of these terms is not appropriate here and the reader is referred to recent articles discussing the history of “virulence” and “pathogenesis” for more in-depth analyses of these terms. Here, we briefly discuss our preferred use of these terms, how they relate to human fungal pathogenesis, and why correct use of these terms is critical to our understanding of human fungal pathogenesis mechanisms.

Viral pathogenesis is the procedure by which infections produce disease in the host. The elements that decide the pathological transmission and advancement of illness in the host include complex and dynamic connections between the infection and the susceptible host. Infections cause malady when they break the host's indispensable physical and normal defensive barriers; evade local, tissue, and immune defences; spread in the body; and destroy cells either specifically or through observer safe and provocative reactions. Viral pathogenesis can be partitioned into a few phases, including transmission and passage of the infection into the host, spread in the host, tropism, virulence, patterns of viral infection and disease, host factors, and host defence. An important part of viral pathogenesis is virus-related the study of disease transmission since it permits doctors to contemplate the dissemination of determinants of sickness in human populations.

Pathogenic bacteria are specially adapted and capable with mechanisms for overcoming the normal body defence and can attack parts of the body, such as the blood, where bacteria are not founded normally. Many of pathogens occurred only at the surface epithelium, skin or mucous membrane, but some travel more deeply, spreading through the tissues and disseminating by the lymphatic and blood streams. In some of the rare cases a pathogenic microbe can infect an entirely healthy person too, but infection usually occurs only if the body's defence mechanisms are damaged by some local trauma or an underlying incapacitating disease, such as wounding, intoxication, chilling, fatigue, and malnutrition. In many the cases, it is very important to differentiate infection and colonization, when the bacteria are causing little much or no harm.

The battle between pathogens and the host immune defences has raged for thousands of years.  The immune system has developed a variety of methodologies to controlling viral and bacterial infection which ranges from direct killing of pathogen to elaborating cytokines, which inhibit replication.  Pathogens have countered by developing a variety of immune circumvention mechanisms that inhibit cytokine function and prevent immune gratitude of infected cells.  Immunology describes how the body copes with microbial, viral or parasitic infections, cancer and all other diseases. It needs expertise and analysis from the level of the molecules and cells of the immune system all the way up to disease dynamics in populations and ecosystems. Infectious and immune-mediated diseases currently under study include HIV/AIDS, Tuberculosis, Chagas, Malaria, Pneumonia, Enteric Diseases, Inflammatory Bowel, and Autoimmune diseases.

Microbial Pathogenesis basically deals with the molecular and cellular mechanisms of infectious diseases. It almost covers microbiology, host-pathogen linking and immunology related to infectious agents, including microorganisms, growths, infections and protozoa. Microbial pathogens incorporate microscopic organisms, infections, growths and parasites, together record for a huge rate of intense and unending human illnesses. To understanding the instruments by which different pathogens cause human malady, research in microbial pathogenesis likewise addresses systems of antimicrobial resistance and the advancement of new antimicrobial specialists and immunizations. Host-microorganism associations require an interdisciplinary methodology, including microbiology, genomics, informatics, molecular and cell science, natural chemistry, immunology and the study of disease diffusion.

Coronavirus disease 2019 (COVID-19) is a major health concern and can be devastating, especially for the elderly. COVID-19 is the disease caused by the SARS-CoV-2 virus. Although much is known about the mortality of the clinical disease, much less is known about its pathobiology. Although details of the cellular responses to this virus are not known, a probable course of events can be postulated based on past studies with SARS-CoV. A cellular biology perspective is useful for framing research questions and explaining the clinical course by focusing on the areas of the respiratory tract that are involved. Based on the cells that are likely infected, COVID-19 can be divided into three phases that correspond to different clinical stages of the disease.

Sexually transmitted diseases(STDs) or sexually transmitted infections (STIs) are infections that are passed from one person to another through sexual contact. The contact is usually vaginal, oral, and anal sex. But sometimes they can spread through other intimate physical contact. This is because some STDs, like herpes and HPV, are spread by skin-to-skin contact. Sexually transmitted diseases (STDs) or sexually transmitted infections (STIs) can be caused by:

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  Bacteria (gonorrhea, syphilis, chlamydia)


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  Parasites (trichomoniasis)


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  Viruses (human papillomavirus, genital herpes, HIV)

The incidence of food and waterborne diseases has increased sharply in current years, partly due to increased international travel and import of food. Many diseases are possibly not registered, such as from contaminated water and infection with norovirus (“stomach flu”). Several infectious food and waterborne diseases are notifiable to the Norwegian Surveillance System for Communicable Diseases (MSIS) (NIPH, 2016b). In addition, outbreaks are monitored by the NIPH’s rapid alert system, Vesuv. An outbreak is defined as more cases of disease than expected with a suspected common source of infection. Outbreaks related to food and water should be reported immediately (NIPH, 2016d).

Pathology is the branch of medical sciences that deals with the examination of organs, tissues, and body fluids for the diagnosis of disease. Pathology describes the scientific study of disease which can be described as any abnormality that is causing changes in the structure or function of body parts. In pathology, the causes, mechanisms and extent of disease may be examined. Although Microbiology and Pathology deals with the same theme, the microorganisms, the two fields differ in many aspects. Microbiology is a field in the medicine that includes the study of various microorganisms like bacteria, fungi, viruses, etc.

Epidemiology is the study of disease occurrence and transmission or programme in a human population; epidemiological studies basically focus on the distribution and determinants of the disease. Epidemiology may also be considered as the method of public health—a scientific approach to studying disease and health problems. Epidemiology consists of research methods and specific strategies for counting and calculating the occurrence and risk of disease. Therefore, epidemiological studies of drug use employ these methods and statistical measures to study the occurrence and distribution of drug use and its associated problems. Examples of epidemiology applied to drug use include adverse drug reaction reporting, post marketing surveillance studies, and clinical drug trials.