MOD 4 Infectious Disease Flashcards
Prions
A mutated protein molecule causes brain disease in humans and animals
-Mad cow disease (encephalitis)
-Incubates for decades before s/s appear
no cure
-nerve condition
-doesn’t reproduce but recruits
Virus
Requires a host cell (often bacteria) to inject its “virion” particle into the host cell, which then triggers the host cell’s DNA or RNA to replicate a virus.
NEEDS A HOST TO REPLICATE AND SURVIVE
Bacteria
Single-cell organisms classified as either REPRODUCES INDEPENDENTLY DOES NOT NEED A HOST
Gram Positive
Exotoxin producing
releases a toxin while alive and reproducing
some exotoxins are potent enough to kill the host
EX: botulism, diphtheria, and tetanus
needs toxoid immunizations: DPT shot (diphtheria, pertussis, and tetanus
Gram Negative
Endotoxin producing
does not release its toxin until the bacteria dies
high levels of endotoxin can trigger a systemic inflammatory response leading to SEPTIC SHOCK, DIC, AND ARDS
Chlamydia and rickettsia
REPRODUCE INDEPENDENTLY LIKE BACTERIA, BUT NEED A HOST CELL FOR ENERGY, LIKE VIRUSES
Chlamydia
is a sexually transmitted disease
Rickettsia
Carried by ticks and lice
causes Rocky Mountain Spotted Fever and Typhus
Fungal pathogens
Transmitted by spores (molds and yeast) the cause of many OPPORTUNISTIC INFECTIONS in an immunocompromised host
EX: people with AIDS or on chemotherapy are prone to get oral thrush
women taking antibiotics can develop a vaginal overgrowth of candida albicans
Protozoal Pathogens
Protozoa are parasitic animals that infect or colonize other animals, which then transmit them to humans.
parasites can be transmitted by food/water, feces, or insects (worms or ticks/fleas/lice)
Stages of infectious disease
Incubation
prodome or prodromal
acute
resolution or convalescence
Incubation period
NO S/S the number of pathogens in the body have not reached a large enough number to cause symptoms
Prodrome or Prodromal
First onset of signs and symptoms of an infection
EX: malaise and fever etc.
Acute
phase of maximum effect (damage) to the body. Can be further delineated by the invasive and decline phases of acute infection
Resolution of convalescence
the body’s defenses begin to overcome the pathogen and signs and symptoms decrease
Sign
Objective information regarding an illness. Can be SEEN FELT HEARD AND SMELLED by another person and or “measured”
Ex: temp, weight, condition of a wound, pulse, breath sounds, etc.
Symptom
subjective information regarding an illness. cannot be seen felt heard or smelled by another person or measured
Pain is always a subjective finding
Epidemiology
Study of health in populations to understand the causes and patterns of health and illness. Epidemiologists get to the root of a public health problem or emerging public health event affective a specific population.
Chain of infection
Transmission occurs when the agent leaves its RESERVOIR or host through a PORTAL OF EXIT is conveyed by some MODE OF TRANSMISSION and enters through an appropriate PORTAL OF ENTRY to infect a susceptible host.
Portal of entry
the routes an infection agent can infect a susceptible animal.
there is always a primary and secondary route for each agent
Salmonella primary: oral
Salmonella secondary: conjunctival or rectal
Portal of exit
the routes by which an infectious agent exits its host.
ex: feces, urine, saliva, expired air, blood, semen, or urogenital secretions
Primary: fecal for enteric infections
secondary: blood saliva or urine during septicemia
Vector
Blood-sucking insects such as mosquitoes, fleas, lice, biting flies, bugs, mites, and ticks
The term “vector” refers to any arthropod that transmits a disease through feeding activity.
Vectors typically become infected by a disease agent while feeding on infected vertebrates (birds, rodents, other larger animals or humans) and then pass on the microbe to a susceptible person or other animal
Reservoir
Carries of the disease
the reservoir is the habitat in which the agent normally lives, grows, and multiplies
include humans, animals, and the environment.
the reservoir may or may not be the source from which the agent is transferred to a host.
EX: the reservoir of Clostridium botulinum
Human Reservoir
Disease that are transmitted from person to person without intermediaries
Ex: sexually transmitted diseases, measles, mumps, streptococcal infection, and many respiratory pathogens
carriers are commonly transmitted because they do not realize they are infected.
Animal reservoir
Humans are also subject to dieseases that have animal reservoirs. Many of these diseases are transmitted from animal to animal, with humans as incidental hosts
EX: rabies, plague,
HIV, AIDS, Ebola, and SARS have been thought to be examples too
Environmental reservoir
plants, soil, and water in the environment
Fomites
Inanimate objects that pathogens live on. Any surface. Doorknobs, bedding, drinking glass, stair railing, etc.
Morbidity
an incidence of ILL health
classified by how many individuals got SICK per thousand people from a given disease
Mortality
Incidence of death in a population. measured in various ways
classified by how many individuals DIED per thousand people from a given disease
Comorbidity
The simultaneous presence of 2+ morbid conditions or diseases in the same patient,
EX: a person with heart failure should have a “comorbidity” of diabetes that will have to be treated also
-could make the primary condition harder to treat/ heal
Agent
Microorganisms that actually cause the diease in question
-bacteria, virus, fungus, or parasite
“what” the disease-causing organism
Host
The agent infects the host which is the organism that carries the disease
host can act as carriers for an agent without displacing any outward symptoms of the disease. Some part of their physiology is hospitable or attractive to the agent
“who” the person or population with the disease
