Chapter 14 Flashcards
Commensalism
One organism benefits, and the other is unaffected. (e.g. epidermis on skin)
Pandemic disease
Worldwide epidemic (e.g. AIDS)
Infection
Invasion or colonization of the body by pathogens
What predisposing factors make the body more susceptible to disease?
Gender Inherited traits, such as the sickle cell gene Climate and weather Fatigue Age Lifestyle Nutrition Chemotherapy
Contributing factors to Infectious Disease
- Genetic recombination (E. coli and avian H5N1) - Evolution of new strains (vibrio cholerae O139) - Widespread use of antibiotics and pesticides (antibiotic-resistant strains) - Changes in weather patterns (hantavirus) - Modern transportation (chikugunya and west nile virus) - Ecological disaster, war, and expanding human settlement (coccidoidomycosis) - Animal control measures (lyme disease) - Public health failure (diptheria)
Sepsis
Toxic inflammatory condition arising from the spread of microbes, especially bacteria or their toxins, from a focus infection
Prodromal period
Short period after incubation; early, mild symptoms
Notifiable infectious disease
Diseases in which physicians are required to report occurence
Etiology
Cause of the disease
Noncommunicable disease
A disease that is not spread from one hose to another
Three types of symbiosis
Commensalism Mutualism Parasitism
Animal reservoirs
Zoonoses are diseases transmitted from animals to humans
Normal microbiota
permanently colonize the host and do not cause disease under normal conditions
Systemic (generalized) infection
An infection throughout the body e.g. mea
Viremia
Viruses in the blood
Focal infection
Systemic infection that began as a local infection
Mutualism
Both organisms benefit e.g. E. coli
Toxemia
Toxins in the blood
Incubation period
Interval between initial infection and first signs and symptoms
Secondary infection
Opportunistic infection after a primary (predisposing) infection
Septicemia
Also known as blood poisoning; growth of bacteria in the blood
Communicable disease
A disease that is spread from one host to another
Subclinical disease
No noticeable signs or symptoms (inapparent infection)
Period of decline
Signs and symptoms subside
Symbiosis
The relationship between normal microbiota and the host
Epidemiology
The study of where and when diseases occur and how they are transmitted in populations
Normal microbiota protect the host by:
- Competing for nutrients - Producing substances harmful to invading microbes - Affecting pH and available oxygen
Local infection
Pathogens are limited to a small area of the body e.g. boils
Contagious disease
Diseases that are easily and rapidly spread from one host to another
Prevalence
Number of people who develop a disease at a specified time, regardless of when it first appeared (takes into account both old and new cases)
Human reservoirs
Carriers may have inapparent infections or latent diseases
CDC
Centers for Disease Control and Prevention -Collects and analyzes epidemiological information in the United States
Indirect contact transmission
Spreads to a host by nonliving object called a fomite
Mortality rate
Number of deaths from a disease in relation to the population in a given time
Period of illness
Disease is most severe
Droplet transmission
Transmission via airborne droplets less than 1 meter
Herd immunity
Immunity in most of a population-acquired by vaccination
Analytical epidemiology
Analyzes a particular disease to determine its probable cause (nightingale)
Incident
Number of people who develop a disease during a particular time period
Compromised host
Individual whose resistance to infection is impaired by disease, therapy, or burns
Morbidity
Incidence of a specific notifiable disease
Period of convalescence
Body returns to its pre-diseased state
Transmission by an inanimate reservoir… Name 3
Waterborne Foodborne Airborne
What do HAIs result from?
Microorganisms in the hospital environment Weakened status of the host Chain of transmission in a hospital
Syndrome
A specific group of signs and symptoms that accompany a disease
Example of opportunistic pathogens
Pathogens that normally would not affect someone with a healthy immune system could be devastating to those with HIV
Latent disease
Causative agent is inactive for a time but then activates and produces symptoms
Signs
Changes in a body that can be measured or observed as a result of disease
Distribution and composition of normal microbiota are determined by many factors including…
- Nutrients (e.g. secretions) - Physical and chemical factors (e.g. pH, temperature, salinity) - Host defenses (e.g. phagocytes) - Mechanical factors (e.g. chewing, flushing)
Zoonoses
Diseases transmitted from animals to humans
Methods for controlling of HAIs
Reduce the number of pathogens - Handwashing - Disinfecting tubs used to bathe patients - Cleaning instruments scrupulously - Using disposable bandages and intubation Infection control committees
Experimental epidemiology
Involves a hypothesis and controlled experiments (semmelweis)
Nonliving reservoirs
Soil and water
Symptoms
Changes in body function that are felt by a patient as a result of disease
Parasitism
One organism benefits at the expense of the other (e.g. infection)
HAIs
Healthcare-Associated Infections (nosocomial infections) -Acquired while receiving treatment in a health care facility - Affect 1 in 25 hospital patients (2 million per year infected; 20,000 deaths)
Descriptive epidemiology
Collection and analysis of data (snow)
Endemic disease
Disease constantly present in a population
Three major continual sources of infect
Human reservoirs Animal reservoirs Nonliving reservoirs
Direct contact transmission
Requires close association between the infected and susceptible host
Chronic disease
Symptoms develop slowly
Disease
An abnormal state in which the body is not performing normal functions
Example of mechanical transmission
Arthropod carries pathogen on its feet
What do epidemiologists do?
- Determine etiology of a disease - Identify other important factors concerning the spread of disease - Develop methods for controlling disease - Assemble data and graphs to outline incidence of disease
Acute disease
Symptoms develop rapidly but the disease lasts only a short time
Example of biological transmission
Pathogen reproduces in the vector, transmitted via bites or feces
Mortality
Deaths from notifiable diseases
Fomite
non-living object that spreads disease (tissue)
Pathology
Study of disease
Sporadic disease
Disease that occurs only occasionally e.g. typhoid
Morbidity rate
Number of people affected in relation to the total population in a given time period
Bacteremia
Bacteria in the blood
Microbial antagonism (competitive exclusion)
competition between microbes
What does the CDC publish?
Morbidity and Mortality Weekly Report (MMWR)
Transient microbiota
May be present for days, weeks, or months and then disappear
Primary infection
Acute infection that causes the initial illness
Epidemic disease
Disease acquired by many people in a given area in a short time (e.g. influenza)
Human microbiome project
Analyzes relationships between microbial communities on the body and human health
Name a few vectors of disease and what two general methods are used for transmission
Arthropods (fleas, ticks, and mosquitoes) 1. Mechanical transmission 2. Biological transmission
Pathogenesis
The development of a disease
