General Approach To Infectious Diseases PDF

General Approach To Infectious Diseases Dr. Esra Ergün Alış İstanbul Aydin University Diseases caused by microorganisms Diagnosis – Laboratory Treatment – Clinician Clinical Microbiology Laboratory İnfectious Diseases Clinic İnfection Control Programs Consultation  An in...

General Approach To Infectious Diseases Dr. Esra Ergün Alış İstanbul Aydin University Diseases caused by microorganisms Diagnosis – Laboratory Treatment – Clinician Clinical Microbiology Laboratory İnfectious Diseases Clinic İnfection Control Programs Consultation  An infectious disease can be defined as an illness due to a pathogen or its toxic product, which arises through transmission from an infected person, an infected animal, or a contaminated inanimate object to a susceptible host.  In 2013, infectious diseases resulted in over 45 million years lost due to disability and over 9 million deaths  Infectious diseases also include emerging infectious diseases; diseases that have newly appeared (e.g., Middle East Respiratory Syndrome) or have existed but are rapidly increasing in incidence or geographic range (e.g., extensively drug-resistant tuberculosis (XDR TB) and Zika virus (Morse, 1995).  A classic model of infectious disease causation, the epidemiological triad (Snieszko, 1974), envisions that an infectious disease results from a combination of agent (pathogen), host, and environmental factors (Figure 1 ). The epidemiological triad model of infectious disease causation. The triad consists of an agent (pathogen), a susceptible host, and an environment (physical, social, behavioral, cultural, political, and economic factors) that brings the agent and host together, causing infection and disease to occur in the host.  Infectious agents may be living parasites (helminths or protozoa), fungi, or bacteria, or nonliving viruses or prions. Environmental factors determine if a host will become exposed to one of these agents, and subsequent interactions between the agent and host will determine the exposure outcome. Agent and host interactions occur in a cascade of stages that include infection, disease, and recovery or death  Following exposure, the first step is often colonization, the adherence and initial multiplication of a disease agent at a portal of entry such as the skin or the mucous membranes of the respiratory, digestive, or urogenital tract. Colonization, for example, with methicillin-resistant Staphylococcus aureus in the nasal mucosa, does not cause disease in itself. For disease to occur, a pathogen must infect (invade and establish within) host tissues.  Infection will always cause some disruption within a host, but it does not always result in disease. Disease indicates a level of disruption and damage to a host that results in subjective symptoms and objective signs of illness. For example, latent TB infection is only infection – evidenced by a positive tuberculin skin test or interferon gamma release assay – but with a lack of symptoms (e.g., cough or night sweats) or signs (e.g., rales on auscultation of the chest) of disease. This is in contrast to active pulmonary TB (disease), which is accompanied by disease symptoms and signs. HIV-AIDS Anthrax (bioterrorism) influenza (H5N1) resistant bacteria Hepatitis B and C west nile fever CCHF –Kırım kongo Ebola resistant tuberculosis Malaria Covid 19 Monkey Pox Virus  Lower respiratory tract infections, diarrheal diseases, HIV/AIDS, malaria, and tuberculosis (TB) are among the top causes of overall global mortality  Disease: A pathological condition that can be identified in a region, organ, or tissue of the body, causing signs and symptoms Infectious disease: disease caused by infectious agents Infection: The entry and reproduction of an infectious agent in the human body (with or without a disease picture) Pathogen: Infectious agent that creates the disease picture Host: The organism where the infection occurred Virulence: ability to cause disease  Endemic: The occurrence of a disease with a certain or habitual frequency in a population. Epidemic (epidemic): The occurrence of an infectious disease in a region more than expected in a short time is called Pandemic: A very large epidemic affecting a continent or continents. Sporadic: An infection occurs as sporadic cases in an area.  Isolation: As a word, it means separation, abstraction, isolation. Separation of the infected person from other people during transmission is called Quarantine: Restricting the freedom of movement of people or animals that come into contact with a contagious disease during the contagious period of that disease. Vector: Animals that carry the infectious agent such as flies, lice, ticks, and mice. Porter: Persons and animals that do not show signs of illness, although they carry a microorganism in their body and transmit it to others, are called porters.  Incubation period: The period between the introduction of the infectious agent into the host and the appearance of disease symptoms Prodromal period: It is the period in which nonspecific general symptoms appear before the specific symptoms of the infectious disease Disease period: It is the period in which the disease is observed Convalescent period: It is the recovery period of the disease  Asymptomatic infection: Infection with no symptoms or signs (clinical or laboratory) Subclinical infection: Infection without symptoms but with abnormal laboratory findings Acute infection: It is the period when the disease progresses with acute symptoms and both clinical and laboratory findings are seen. Latent infection: After acute infection, the microorganism settles in different cells of the body and continues to live without any signs or symptoms. Chronic infection: Used to describe long-course infectious diseases Focal infection: Infection that affects a particular area or organ of the body Systemic infection: Infection that affects the whole body and systems Infectious Diseases - Resources - Reservoir People animals inanimate environment Water foods Soil Things  bacteria viruses Parasites Fungi