intro to infectious disease – Flashcards
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| what probably killed mozart? |
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| strep throat |
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| what are the 3 outcomes if a microbe infects a host? |
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| host resolves infection, latency (TB, herpes, toxoplasmosis), or death |
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| what does infectious disease result from? |
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| an encounter of a potential pathogen with a susceptible host in conjunction with a suitable portal of entry |
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| what are the "sexy" infectious diseases that garner most of the media attention? how many deaths are they responsible for? |
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| CJD, SARS, Ebola, Anthrax, Smallpox, Monkeypox, West Nile. < 1000 deaths |
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| what are the "killers" in terms of infectious disease? how many deaths are they responsible for? what is the order of the top 3 killers? |
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| TB, HIV, ARI, Diarrhea, Malaria, Rotavirus, Hepatitis, Influenza. > 100,000 deaths. top three are: HIV 3m, TB 2m, Malaria 1m |
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| what does DALY stand for? |
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| diability adjusted life years - a time-based measure that combines years of life lost due to premature mortality and years of life lost due to time lived in states of less than full health |
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| how many DALYs are lost to infectious and parasitic diseases? |
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| 445 million total |
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| what is the delicate balance between the host and their microorganism? |
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| as long as the immune system is healthy, the host can fight back against the innoculum/virulence of the pathogen |
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| where do most pathogenic organisms start? |
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| in an animal host |
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| what do organisms that transmit via direct transimission (sexual, kissing, animal bite, transplacental, droplet infection) have minimal ability to survive? |
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| stressful conditions |
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| what is the difference between a droplet nuclei and droplet in terms of disease transmission? |
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| droplet nuclei are 5mm in diameter, close mucosal contact is needed, (within 2 m) eg SARS, influenza, pertussis, (whooping cough) |
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| what are the modes of transmission of infectious agents? |
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| contact, (direct-body to body or indirect- fomites/environment, HCW's hands), large droplet, (>5um, travels 3 ft), small droplet, (<5um, airbone), endogenous, (auto-innoculation and device related, common, source and vector borne |
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| what are some examples of ways organisms that transmit indirectly? |
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| vector borne, airborne (aerosol – e.g. TB, measles, chicken pox), vehicle borne, (water, food, blood, tissue, fomite, and surgical instruments). this is an example of adaptation for survival. |
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| what is an example of a reservoir for infectious disease? what growing problem is this related to? |
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| a hospital full of C. difficle colonized patients (most w/noscomial infections), and only a few symptomatic patients with obvious infections (tip of the iceberg). this is related to growing antibiotic resistance. |
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| what is an index case? 1st, 2nd generation case? |
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| and index case would be an unvaccinated pt traveling somewhere and bringing back a disease. 1st and 2nd generation cases would be siblins, schoolmates, and other children in contact who contract the disease |
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| what is isolation? |
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| the process of separating persons known or suspected of being infectious from others, to prevent the spread of disease |
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| what is quarantine? |
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| a compulsory period of isolation/sequestration imposed on a person(s), animal, or thing (exposed but asymptomatic) that might otherwise spread a disease |
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| what might be presenting symptoms of infectious disease? |
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| fever, rash, lymphadenopthy, discharge, (diarrhea, urogenital, eye, etc), cough, mental status change, headache |
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| what is an example of an invasive infection? |
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| candidemia which is a blood borne infection, the 4th leading infection in ICUs, where sterile body fluids become infected. the patient will have to be hospitalized and put on IV antifungal |
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| what does gram staining bacteria help? |
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| it helping determing what kind of antibiotic should be used, ideally narrow spectrum antibiotics should be used |
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| what color are gram positive bacteria? |
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| violet |
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| what color are gram negative bacteria? |
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| red |
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| what are common intra-abdominal pathogens? |
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| gram negatives, followed by anaerobes |
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| what are common skin and soft structure pathogens? |
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| gram positive, (staph/strep/enterococcus) |
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| what do only 40% of physicians comply with? |
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| hand washing, extremely important in patient care. it was pioneered by Ignac Semmelweis who discovered the importance of hand washing in patient care after a study of puerperal sepsis in women giving birth whose deliveries were done by medical students vs. midwives |
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| what is traditional (long sleeves, neck tie, jewelry) physician attire changing to? why? |
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| sleeves rolled up, gloves, mask, plastic apron, no tie, no jewelry - to keep disease from spreading |
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| what is the definition of public health? |
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| the art and science of preventing disease, promoting health, and extending life through the organized efforts of society |
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| what does the "superior doctor" do? |
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| prevents the disease instead of just treating it |
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| what was the first cancer vaccine? |
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| hepatitis B vaccine, causes the hepatocelluar carcinoma |
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| what was the second cancer vaccine? |
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| gardasil/cervarix for HPV which can cause cervical cancer, (men can also be vaccinated) |
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| what has been one of the major public health interventions? |
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| vaccines |
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| what is a public health intervention that has been helpful with HIV? |
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| condoms |
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| what has been a major public health intervention in terms of diarrhael related deaths? |
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| oral rehydration therapy |
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| are insecticides/bed nettings, potable water improvements and TB education public health interventions? |
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| yes |
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| non-infectious diseases such as cancer can be caused by infectious agents? |
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| yes, 16-18% of cancers are caused by infectious agents such as HPV, helicobacter pylori, HBV, EBV, HIV, and helminths. |
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| what causes kaposki's sarcoma? burkitt's lymphoma? |
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| HHV-8 causes kaposki's sarcoma. EBV causes burkitt's lymphoma |
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| what are some contributing factors to growing antimicrobial/antibiotic resistance? |
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| fear of malpractice suits, patient volume, time and expectations (some doctors find it easier to just write out a prescription), lack of knowledge of natural course of viral disease, diagnostic and prescribing habits, need to return to work, school or day care, release of enormous quantities of antibiotics into agriculture, fisheries, and animal husbandry, inappropriate use, company sponsored symposium (CME) |
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| what are some environments were antbiotic resistance develops? |
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| community hospitals, tertiary hospitals, VA, daycare, feedlots |
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| what is a better way to refer to bronchitis so that pts don't expect antibiotics they dont need? |
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| "chest cold" |
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| what are internationally notifiable infectious diseases that must be reported to the world health organization for quarantine? |
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| plague, cholera, yellow fever, smallpox, wild type poliovirus, SARS, novel influenza |
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| where do infectious threats come from? |
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| bioterrorism,new infections emerging, “old” Infections resurging, anti-microbial resistant infections, infections that produced chronic disease |
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| what is norovirus associated with? |
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| cruise ships |
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| what is the highest WHO alert level, when did H1N1 get there? |
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| alert level 6, H1N1 appeared in april, and was at level 6 by june 11 |
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| what are the pandemic phases? |
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| 1. no new subtype in human 2. circulating animal subtype posing risk to humans 3. human infection with a new subtype 4.small clusters and localized spread 5. large clusters 6.increased and sustained transmission |
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| what was important about the H1N1 pandemic? |
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| it was the first time in history that we have been able to follow a pandemic from the start |
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| what are the essential elements in management of acute respiratory illnesses? |
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| cough ettique, hand-washing, and social distancing |
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| what are "super-spreaders" of SARS? |
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| aerosol and fomites |
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| Antisepsis |
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| the process used to decontaminate the skin of a patient/HCW |
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| Attack rate |
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| proportion of persons at risk who develop symptoms of that disease |
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| Bacteremia |
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| the presence of viable bacteria in the blood |
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| Biofilm |
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| organized communities of (mixed) microorganisms enclosed in a self-produced polymeric matrix attached to an inert or a living surface. Bacteria are difficult to culture in vitro because of their reduced metabolic and divisional rate |
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| Booster effect |
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| antibody levels rise higher after revaccination than they did after initial vaccination. |
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| Carrier |
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| an asymptomatic person who is colonized with a microorganism and has a positive culture |
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| Case Fatality rate |
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| (CFR) the percentage of people diagnosed as having a specific disease who die as a result of that disease |
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| Cluster |
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| a group of two or more cases (with the same subtype) among persons (in different households) sharing at least one meal/food item at an event |
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| Cold chain |
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| the standard recommendations for storage, and transportation of the vaccine, including appropriate equipment |
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| Colonization |
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| presence/multiplication of microorganisms in/on a host in a non-sterile site, without apparent evidence of invasiveness or tissue injury |
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| Contact |
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| a person who may have been exposed to the excreta/secretions of an infected person |
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| Contagious |
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| capable of being spread by contact with sick persons |
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| Contamination |
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| presence of microorganisms on body surface without tissue invasion or presence of microorganisms on inanimate objects. |
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| Control |
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| reduction of disease incidence, prevalence, and morbidity/mortality to a locally accepted level as a result of deliberate efforts requiring continuous intervention |
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| DALYs |
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| to weigh and cumulate the burden imposed by premature death plus years lived with disabilities due to the diseases and conditions considered |
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| Diagnosis |
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| confirming a disease process in symptomatic patients |
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| Disease |
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| (Dis-ease) clinical expression of signs and symptoms |
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| (Dis-ease) clinical expression of signs and symptoms |
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| reduces but does not eliminates, the microbial burden. |
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| Dissemination |
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| invasion of non-contiguous organs secondary to hematogenous spread. |
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| Elimination |
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| can also be defined as reduction in the prevalence of disease to the point at which it ceases to be a public health problem. |
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| Empiric |
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| carefully considered presumptive Rx prior to making the microbiological diagnosis |
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| Endemic |
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| low level frequency of disease at moderately regular intervals, constant presence of a disease/infectious agent in a given geographic area. |
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| low level frequency of disease at moderately regular intervals, constant presence of a disease/infectious agent in a given geographic area. |
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| low level frequency of disease at moderately regular intervals, constant presence of a disease/infectious agent in a given geographic area. |
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| Eradication |
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| reduction of disease incidence to zero (worldwide); intervention efforts are no longer required |
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| Exposure |
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| Contact with a microbe or harboring a microbe w/o clinical evidence of disease (eg anthrax, TB). |
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| Extinction |
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| eradication of the pathogen and the destruction of all laboratory isolates |
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| Fomite |
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| an object that can harbor a pathogenic organism (door knob, diaper changing table, keyboard, stethoscope, thermometer, long necktie) |
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| Food security |
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| access by all members at all times to enough food for an active, healthy life (USDA) |
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| Gold Standard |
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| a relatively irrefutable standard that constitutes recognized and accepted evidence that a certain disease exists |
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| Health |
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| (WHO) a state of complete physical, mental and social well-being and not merely the absence of disease/infirmity. |
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| Health literacy |
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| the degree to which individuals have the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions (IOM) |
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| Host |
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| a person/living animal affording subsistence or lodgment to an infectious agent under natural condition. |
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| Incidence |
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| the rate at which people without disease develop disease (number of new cases per year) measures appearance of disease. It is the gold standard for assessing prevention. |
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| Incubation Period |
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| time interval between initial contact with infectious agent (exposure) and first appearance of symptoms |
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| Infection |
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| multiplication of infectious agent in host; clinical, histological or immunological evidence of host injury. |
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| Infectivity |
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| ability of a pathogen to enter, survive and multiply in host. |
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| Invasive |
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| an illness, in which isolation of the organism from a normal sterile site occurs, e.g. CSF, blood, synovial fluid, amniotic/pleural/peritoneal fluid. |
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| Isolation |
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| the process of separating persons known or suspected or being infectious from others, to prevent the spread of disease |
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| Latency |
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| carriership of the pathogen’s genome in a seropositive individual with a primary low-grade, persistent infection, but w/o signs of active replication |
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| Neglected diseases |
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| are those that exhibit a considerable and increasing global burden, and impair the ability of those infected to achieve their full potential, both developmentally and socio-economically |
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| Nosocomial Infection (Health-care associated) |
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| hospital/nursing home-acquired infection after 72 hours of admission. |
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| Opportunist |
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| organism causing disease in a compromised host. |
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| Outbreak |
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| occurrence of two or more symptomatic cases in different households with a common exposure |
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| Pandemic |
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| spread of epidemic among continents |
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| Parasite |
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| an organism living in or on another living organism (a host), which obtains part or all of its organic nutrients from the host, and causes a degree of damage to its host. |
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| Pasteurization |
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| the critical reduction of pathogens in a substance, especially a liquid, at a temperature and for a period of time that destroys objectionable organisms without major chemical alteration of the substance (milk, fruit juice). |
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| Pathogen |
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| microorganism capable of causing disease by its ability to cross epithelial barriers and/or intact cells. |
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| Pathogenesis |
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| changes that occur when the host interacts with the microorganism |
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| Pathogenicity |
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| ability to produce disease. |
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| Pathogenicity islands |
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| novel genes working together to enhance the virulence potential of a species |
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| Prevalence |
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| number of people who have the disease/currently infected (measures existence of disease). |
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| Prevention |
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| action aimed at eradicating, eliminating or minimizing the impact of disease and disability |
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| Probiotic |
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| a preparation of or a product containing viable, defined microorganisms in sufficient numbers, which alter the microflora (by implantation or colonization) exerting beneficial health effects in the host |
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| Prophylactic |
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| antimicrobial Rx from the earliest possible moment to prevent an infection that is common and important enough to justify such a commitment |
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| Quarantine |
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| compulsory period of isolation (sequestration) imposed on a person/s, animal or thing that might otherwise spread a contagious disease |
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| Quorum sensing |
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| cell-to-cell signaling mechanism in which bacteria respond to hormone-like molecules (auto inducers) produced by other growing bacteria of the same species in the same environment. |
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| Recrudescence |
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| a new outbreak after a period of abatement or inactivity |
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| Reinfection |
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| infection with the same organism (genus) but different species |
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| Relapse |
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| infection with the very same organism/pretherapy isolate (genus and spp |
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| Reproductive rate |
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| the extent to which an infectious disease spreads in a population (the average number of susceptible people infected by an index case over his lifetime). To maintain an epidemic, its reproductive rate must be greater than one. Measure of transmissibility of an infection. |
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| Reservoir |
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| source of a microorganism in the environment/host |
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| Resident flora |
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| colonizes deeper skin layers, multiplies in hair follicles (e.g. coagulase negative Staphylococci, Corynebacteria). |
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| Resistance |
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| a relative insensitivity of a microbe to an antimicrobial drug as tested in vitro and compared with other isolates of the same species |
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| a relative insensitivity of a microbe to an antimicrobial drug as tested in vitro and compared with other isolates of the same species |
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| test(s) done on asymptomatic patients to identify those at an increased risk of a disease |
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| Sensitivity |
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| percentage of people with the disease who test positive (inclusion of the infected), “detection rate”. |
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| Septicemia |
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| systemic disease associated with presence and persistence of pathogenic microorganisms or their toxins in the blood |
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| Sequela/e |
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| an after effect of disease or injury, a secondary result. |
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| Specificity |
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| percentage of people without the disease who test negative (exclusion of the noninfected). In other words, the ability to reject the Dx correctly |
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| Sporadic |
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| occasional cases of disease at fairly regular intervals |
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| Sterilization |
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| completely eliminates or destroys all forms of microbial life. |
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| Subclinical infection |
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| reaction between pathogen and host is limited by host’s immune response. |
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| Success |
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| large-scale disease program (national scope), uses cost-effective interventions, has been sustained for >5 years, and has a major health impact. |
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| Surveillance |
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| the continuing scrutiny of all aspects of occurrence and spread of a disease that are pertinent to effective control. |
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| Symptoms |
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| (Greek) “to fall together” or coincide (manifestation of illness) |
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| Therapeutic |
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| treatment based on the presence of established infection |
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| Transient flora |
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| colonizes superficial skin layers for short periods and is usually acquired by contact with a patient or contaminated environment (e.g. Staph. aureus, gram-negative bacilli, Candida |
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| Triage |
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| sorting, screening and prioritizing victims in a resource-constrained environment. |
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| Vector |
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| a living transmitter of disease (mosquito, tick, fly). |
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| Virulence |
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| (Latin – virulentus “full of poison”) ability of microorganism to produce disease in a given set of circumstances (quantitative measure of pathogenicity). In other words it is the degree of harm imposed on the host. |
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| Zoonosis |
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| diseases and infections which are naturally transmitted between vertebrate animals and man. |
