chapter 14

pathology

the study of disease

etiology

the cause of a disease

pathogensis

the manner in which a disease develops

infection

invasion or colonization of the body by pathogens

infectious disease

occurs when an infection results in any change in the state of health

human microbiome project

analyzes relationships between microbial communities on the body and human health

normal microbiota (normal flora)

permanently colonize the host and do not cause disease under normal conditions

transient microbiota

may be present for days, weeks, or months and then disappear

microbial antagonism (competitive exclusion)

a competition between microbes

clostridium difficile

causes severe intestinal infections if normal microbiota are reduced by antibiotic treatment

symbiosis

a relationship between organisms in which at least one organisms is dependent on the other

commensalism

one organism benefits and the other is unaffected

mutualism

both organisms benefit

parasitism

one organism benefits at the expense of the other; many disease-causing microorganisms are parasites

symptoms

subjective changes in body function that are felt by a patient as a result of disease

signs

objective changes in abody that can be measured or observed as a result of disease

syndrome

a specific group of signs and symptoms that accompany a disease

communicable disease

a disease that is spread from one host to another

contagious disease

diseases that are easily and rapidly spread from one host to another

noncommunicable disease

a disease that is not spread from one host to another

incidence

number of people who develop a disease during a particular time period

prevalence

number of people who have a disease at a specified time, regardless of when it first appeared

sporadic disease

disease that occurs only occasionally

endemic disease

disease constantly present in a population

epidemic disease

disease acquired by many people in a given area in a short time

pandemic disease

wordwide epidemic

duration

average time that individuals have a disease from diagnosis until they are either cured or die

acute disease

symptoms develop rapidly but has a short duration

chronic disease

symptoms develop slowly, likely to last for a long period

subacute disease * (carriers)

intermediate between acute and chronic

latent disease

causative agent is inactive for a time but then activates and produces symptoms

herd immunity

immunity in most of a population

severity

the presence and extensiveness of a disease in the body and its ability to cause death

asymptomatic

no signs or symptoms

mild

fever, dry cough, tired, muscle pain, sore throat

moderate

breathlessness, tachycardia, persistent cough, higher fever

severe

pneumonia, extreme breathlessness, chest pain, high temp, bluish lips/face

critical

severe acute respiratory syndrome (SARS) inflamed aveoli, may require ventilator

local infection

pathogens are limited to small area of the body

systemic (generalized infection)

an infection spread throughout the body by the blood and lymph

focal infection

systemic infection that began as a local infection

sepsis

toxic inflammatory condition arising from the spread of microbes, especially bacteria or their toxins, from a focus of infection

bacteremia

bacteria in the blood

septicemia

also known as blood poisoning; growth of bacteria in the blood; bacteria are proliferating the blood

toxemia

toxins in the blood

viremia

viruses in the blood

primary infection

acute infection that causes the initial illness

secondary infection

opportunistic infection after a primary (predisposing) infection

subclinical infection

no noticable signs or symptoms

variables to make you more susceptible

nutrition

sex

genetic inheritance

climate

environment

vaccination

age

lifestyle/behaviors

compromised host

incubation period

interval between initial infection and first signs and symptoms

prodromal period

short period after incubation; early, mild nonspecific symptoms

period of illness

disease is most severe

period of decline

signs and symptoms subside

period of convalescence

body returns to its prediseased state; recovery

zoonoses (animal reservoirs)

are diseases primarily in wild and domestic animals that can be transmitted to humans

nonliving reservoirs

soil and water

foods

direct contact transmission

requires close association between the infected and a susceptible host

congenital transmission

transmission from mother to fetus or newborn at birth

indirect contact transmission

spreads to a host by a nonliving object called a fomite

droplet transmission

transmission via airborne droplets less than one meter

mechanical transmission

arthropod carries pathogens on its feet

biological transmission

pathogen reprodces in the vector; transmitted via bites or feces

healthcare associated infections

nosocomial infections

acquired while receiing treatment in a healthcare facility

compromised host

an individual whose resistance to infection is impaired by disease, therapy, or burns

clostridium difficile

leading cause of HAIs

descriptive epidemiology

collection and analysis of data

analytical epidemiology

analyzes a particular disease to determine its probable cause or risk factor

experiemental epidemiology

involves a hypothesis and controlled experiments

clincial trial

test and control group

morbidity

incidence of a specific notifiable disease

mortality

deaths from notifiable diseases

notifiable infectious diseases

disease in which physicians are required to report occurrence

morbiditiy rate

number of people affected in relation to the total population in a given time period

mortality rate

number of deaths from a disease in relation to the total population in a given time period