Term
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Definition
When an infectious agent capable of causing disease meets a susceptible host that is vulnerable to the agent in an environment that allows the agent and host to interact. |
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Term
What is the most effective way to control the spread of disease? |
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Definition
Breaking the chain of infection is the most effective way. |
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Term
Define communicable disease. |
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Definition
An illness due to a specific infectious agent or its toxic product that arises through transmission of that agent or its products from an infected person, animal, or inanimate reservoir to a susceptible host. |
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Term
What are the 6 essential elements of disease? |
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Definition
Infectious agent, Reservoir, Host, Portal of Exit, Portal of Entry, and Mode of Transmission. |
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Term
What is an infectious agent? |
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Definition
Organisms that live on or in the body of a host and can produce disease. |
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Term
What is the primary goal of an infectious agent? |
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Definition
To invade, grow, and reproduce. |
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Term
What steps must be taken to describe an infectious disease? |
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Definition
Identify the agent, Describe signs and symptoms, how the disease is transmitted, and disease prognosis. |
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Term
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Definition
The ability of an agent to invade survive, and multiply in a host. |
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Term
True or False. Infectivity always leads to disease. |
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Definition
False. Infection does NOT always lead to disease. |
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Term
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Definition
The ability of an agent to cause clinical disease in a susceptible host. |
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Term
True or False. A highly pathogenic infectious agent will produce disease in virtually all infected persons. |
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Definition
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Term
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Definition
The ability of an agent to cause severe disease in a host. |
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Term
What can be used as an indicator for the virulence of an infectious agent? |
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Definition
Case fatality rate, and/or the ability of the infectious agent to damage tissue of the host. |
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Term
Define Reservoir as it pertains to the essential element of a disease. |
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Definition
Where an infectious agent normally lives, multiplies, and primarily depends upon for survival. |
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Term
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Definition
Human, animal, arthropods, plants, soil, water, or inanimate objects. |
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Term
Define Host as it pertains to the essential elements of a disease. |
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Definition
A living person or animal, to include birds and arthropods, that provides, subsistence(food) or lodgment(living space) to an infectious agent under natural conditions. |
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Term
What is a susceptible host? |
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Definition
A person or animal lacking sufficient resistance to prevent disease if exposed to a pathogenic agent. |
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Term
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Definition
An infected or diseased person or animal having specific clinical, laboratory or epidemiologic characteristics (person ill with disease). |
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Term
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Definition
A person who contracts a disease and infects a population. Also known as patient zero. |
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Term
What is a Secondary Case? |
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Definition
Persons who subsequently contract the infection from the primary case. |
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Term
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Definition
A person or animal that has been exposed to an infected person/animal or a contaminated environment. |
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Term
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Definition
A person or animal that harbors a specific infectious agent without obvious clinical disease and serves as a potiential source of infection. They don't have symptoms, but are unable to completely eliminate the infectious agent. |
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Term
What are the most common types of carriers? |
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Definition
Disease-producing agents in the intestines. |
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Term
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Definition
Characteristics that increase the likelihood that a person will acquire a specific disease. |
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Term
List a few common risk factors that could determine if someone will become ill when exposed to an infectious agent. |
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Definition
Genetics of host, Characteristics of infectious agent (Infectivity, pathogenicity, and virulence), Physical condition of the host, host immunity, conditions that impair immunity, dose and duration of exposure to the infectious agent. |
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Term
Define Portal of Exit as it pertains to the essential elements of a disease. |
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Definition
The path by which an agent leaves the source reservoir or host. Must leave to infect others. |
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Term
What are some common Portals of Exit? |
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Definition
Blood, Nose/Mouth, Sexual Organs, Fecal Waste. |
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Term
Define Mode of Transmission as it pertains to the essential elements of a disease. |
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Definition
Transmission of the infectious agents to a receptive portal of entry. |
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Term
Name 3 main modes of transmission. |
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Definition
Direct, indirect, and/or airborne exposure. |
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Term
How are most direct contact diseases transferred? |
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Definition
Carried on the skin, many times transferred by the hands. |
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Term
What are some ways direct contact may occur? |
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Definition
Touching, biting, kissing, or sexual intercourse. |
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Term
How are droplets spread in direct transmission? |
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Definition
Occurs by the direct projection of droplet spray onto the conjunctiva or onto the mucous membranes of the eye, nose, or mouth during sneezing, coughing, spitting, singing, or talking thats within 3 feet or less. |
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Term
How are infectious agents frequently spread during indirect transmission? |
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Definition
Through contamination of foods and water. |
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Term
Explain Vehicle-borne transmission. |
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Definition
Occurs through contaminated inanimate objects or materials (fomites). Basically, non-living carriers of an infectious agent from its reservoir to a susceptible host. |
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Term
Explain Vector-Borne transmission. |
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Definition
Occurs through exposure from living things, nameley insects or other animals, that have been infected by or in contact with pathogenic microbes before transmitting these microbes to the human body. |
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Term
What are some examples of arthropods of medical importance as vectors. |
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Definition
Ticks, fleas, flies, lice, and mosquitos. |
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Term
Describe Mechanical Transmission. |
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Definition
Occurs when the infectious agent is spread by crawling or flying insects, usually on their feet or mouthparts. |
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Term
Describe Biological transmission. |
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Definition
Occurs when the infectious agent multiplies and/or undergoes further development before the arthropod can transmit the infective form of the infectious agent to humans. Different from mechanical in that the arthropod itself is infected with the organism. |
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Term
Describe Airborne Transmission. |
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Definition
Occurs when an infectious agent is carried from a reservoir to a susceptible host by suspended air particles. |
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Term
When are pathogens considered to be airborne? |
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Definition
If they travel more than 3 feet through the air. |
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Term
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Definition
Consists of dried mucous, which protects the embedded infectious agent as it is suspended airborne. |
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Term
Describe how dust particles can be a form of airborne transmission. |
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Definition
Airborne pathogens fall to the ground, on clothing, or bedding, and combine with dust particles of varying sizes and then are disrupted by activities such as sweeping, changing clothing, or exchanging linens, allowing them to be inhaled by a susceptible host. |
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Term
Define Portal of Entry as it pertains to the essential elements of disease. |
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Definition
The path by which an infectious agent enters the susceptible host. The portals of entry for a disease agent may be the same as the portals of exit. |
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Term
What are the most common portals of entry? |
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Definition
The mouth, nose, eyes, genitals, and skin (via cuts, scrapes, scratches, and sores). |
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Term
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Definition
The entry and multiplication of an infectious agent in the body of persons or animals. The pathogen establishes itself in or on the host, overcoming host defenses and allowing it to grow and reproduce. |
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Term
What are 3 major categories of infections caused by microbes? |
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Definition
Acute infections, Chronic infections, and Latent infections. |
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Term
What is an Acute infection? |
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Definition
Lasts a short time, but can make you feel very uncomfortable, with signs and symptoms such as tiredness, coughing, and sneezing. Intensity varies with the disease. |
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Term
What is a Chronic infection? |
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Definition
Usually develops from acute infections and can last for days to months, up to a lifetime. |
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Term
What is a Latent infection? |
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Definition
Hidden or silent infections that may or may not cause symptoms again after the initial acute episode. Can "wake up" and become active again, sometimes on and off for months or years. |
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Term
What is a Nosocomial infection? |
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Definition
Infections acquired in a medical treatment facility. |
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Term
What makes hospitalized patients more susceptible to nosocomial infections? |
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Definition
Breaks in the skin and mucous membranes from lesions and wounds, low immunity resistance, or the immune system is compromised due to treatment from immunosuppressant drugs. |
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Term
What is an incubation period? |
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Definition
The time interval between initial contact with an infectious agent and the first appearance(onset) of symptoms associated with the infection. |
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Term
What is a subclinical case (asymptomatic)? |
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Definition
A person with a disease and does not show any identifiable symptoms. |
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Term
What do Initial Symptoms refer to? |
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Definition
The first symptoms that clearly demonstrate an illness. |
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Term
What is the Period of Communicability? |
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Definition
Time during which an infectious agent may be transferred directly or indirectly from an infected person to another person, from an infected animal to humans, or from an infected person to animals, including arthropods. |
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Term
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Definition
The period during which symptoms decline and the patient recovers. |
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Term
What are some of the paths that recovery may take? |
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Definition
1) Infectious agent is eliminated from the body and patient returns to full health, 2) patient becomes a carrier, meaning the patient recovers but infectious agent is still present in body and able to shed(spread) to others, 3) Patient can make a partial recovery, resulting in disability and contious relapses. |
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Term
What is the difference between Prevention vs. Control? |
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Definition
Prevention is a way to stop the occurrence of disease or injury, whereas control is a way to reduce or stop further spread of disease or injury once it has already occurred. |
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Term
What characteristics of a disease must you know in order to use Prevention and Control measures effectively? |
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Definition
Characteristics of the infectious agent, mode of transmission, and susceptible hosts. |
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Term
What is the best way to prevent and control disease? |
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Definition
Break the Chain of Infection! |
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Term
What are the 3 links in the chain of infection? |
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Definition
Source (reservoir), Mode of transmission, and Susceptible hosts. |
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Term
Which control measures can break the chain of infection at all three links? |
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Definition
Personal hygiene and patient education. |
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Term
Which control measure is the simplest, easiest, and most effective way to prevent acquiring/carrying most pathogenic organisms? |
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Definition
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Term
What are the Five F's on Personal Hygiene? |
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Definition
Most important parts of the body that need to be washed are the fingers, face, front, fanny and feet. |
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Term
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Definition
The separation of infected individual/animal from others who are not infected during the period of communicability. |
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Term
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Definition
The separation of exposed (well) persons or animals during the incubation period from those who are infected. |
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Term
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Definition
The means of not only resolving the patient's infection, but will likely prevent spreading disease to others in the community. |
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Term
What is the focus of PH Education? |
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Definition
Focus on improving general health, personal hygiene, how to avoid infection, and preventing spreading the infection to others. |
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Term
What prevention and control measures are used to break the Modes of Transmission link? |
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Definition
Includes preventing contact with the source or vehicle. Also includes personal hygiene, environmental sanitation, air, water, food, waste, insects/vector control, and education. |
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Term
What is the focus of environmental control/prevention measures? |
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Definition
Focus on controlling pollution of the air, dust, soil, and water. |
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Term
What prevention and control measures are used to break the Susceptible Host link? |
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Definition
Personal hygiene, immunizations, prophylaxis, and education. |
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Term
What is the goal of prevention and control measures in the Susceptible Host link? |
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Definition
To protect the host from the infectious agent. |
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Term
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Definition
Preventive measures taken to prevent disease. |
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Term
What is an example of prophylactic prevention and control measures for protecting Susceptible Hosts in the Chain of Infection? |
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Definition
Use of personal protective devices and equipment such as condoms, gloves, barriers, etc. that prevent the likelihood of contracting infections through contact. |
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