Microbiology - Chapter 14

Pathology

What is the study of disease?

Etiology

What is the study of what causes a disease?

Pathogenesis

What is the manner in which a disease develops?

Infection

What is an invasion or colonization of the body by pathogens?

Infectious disease

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

In utero

When does the human microbiome begin to establish?

4 ×10^13 bacterial cells

What is the estimated size of the human microbiome?

Human Microbiome Project

What analyzes relationships between microbial communities on the body and human health?

Normal microbiota

What permanently colonizes the host and doesn’t cause disease under normal conditions?

Transient microbiota

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

Normal microbiota

What plays a role in the development of the immune system?

Lactobacillus and Bacteroides

What is prevalent in vaginal birth?

Staphylococcus aureus

What occurs in cesarean birth?

Microbial antagonism

What is a competition between microbes?

Compete with invading microbes for nutrients, produce harmful substances to invading microbes, and affect pH and available oxygen

What are three ways that the normal microbiota protect the host?

Clostridium difficile

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

Symbiosis

What is a relationship between organisms in which at least one organism is dependent on the other? (Ex. normal microbiota and the host)

Commensalism

What occurs when one organism benefits and the other is unaffected? (Ex. Staphylococcus epidermis on the skin).

Mutualism

What occurs when both organisms benefit? (E. coli in the large intestine).

Parasitism

What occurs when one organism benefits at the expense of the other? (Influenza virus on a host cell).

Opportunistic pathogens

What does not typically cause disease in healthy individuals but can take advantage of weakened immune systems or other underlying conditions to cause infection?

Koch’s Postulates

What has the four following rules? (Proves the cause of an infectious disease)

• The same pathogen must be present in every case of the disease.

• The pathogen must be isolated from the diseased host and grown in pure culture.

• The pathogen from the pure culture must cause the disease when it’s inoculated into a healthy, susceptible laboratory animal.

• The pathogen must be isolated from the inoculated animal and must be shown to be the original organism.

Some pathogens can cause several disease conditions, some pathogens cause disease only in humans, some microbes have never been cultured, and several different pathogens may cause the same signs and symptoms.

What are four exceptions to Koch’s postulates?

Symptoms

What are subjective changes in body function that are felt by a patient as a result of disease and not apparent to an observer?

Signs

What are objective changes in a body that can be measured or observed as a result of disease?

Syndrome

What is a specific group of signs and symptoms that accompany a disease?

Communicable disease

What is a disease that is spread from one host to another? (Ex. COVID-19, chicken pox, measles, influenza, genital herpes, tuberculosis).

Contagious diseases

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

Noncommunicable disease

What is a disease that is not spread from one host to another? (Ex. tetanus)

Incidence

What is the number of people who develop a disease during a particular time period?

Prevalence

What is the number of people who have a disease at a specified time, regardless of when it first appeared? Takes into account both old and new cases. 

Sporadic disease

What is a disease that occurs only occasionally?

Endemic disease

What is a disease that is constantly present in a population?

Epidemic

What is a disease that is acquired by many people in a given area in a short time?

Pandemic

What is a worldwide epidemic?

Duration

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

Acute disease

What occurs when symptoms develop rapidly but has a short duration?

Chronic disease

What occurs when symptoms develop slowly, likely to last for a long period?

Subacute disease

What is intermediate between acute and chronic?

Latent disease

What occurs when a causative agent is inactive for a time but then activates and produces symptoms?

Herd immunity

What is immunity in most of a population?

Severity

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

Asymptomatic

What describes no signs or symptoms?

Mild

What severity level is fever, dry cough, tired, muscle pain, sore throat?

Moderate

What severity level is breathlessness, tachycardia, persistent cough, higher fever?

Severe

What severity level is pneumonia, extreme breathlessness, chest pain, high temperature, bluish lips/face?

Critical 

What severity level is severe acute respiratory syndrome (SARS), inflamed alveoli, may require ventilator?

Sepsis

What severity level is a toxic inflammatory condition arising from the spread of microbes, especially bacteria or their toxins, from a focus of infection?

Infection fatality ratio (IFR)

What divides the number of deaths attributed to a disease by the total number of infected individuals within a specific time period? The lower this value is, the lower number of fatalities.

Case fatality ratio (CFR)

What is the proportion of individuals diagnosed with a disease who die from that disease within a certain period of time?

Local infection

What occurs when pathogens are limited to a small area of the body?

Systemic infection

What occurs when an infection spread throughout the body by the blood and lymph?

Focal infection

What is a systemic infection that began as a local infection?

Bacteremia

What is bacteria in the blood?

Septicemia

What is also known as blood poisoning, growth of bacteria in the blood, or proliferation in the blood?

Toxemia

What are toxins in the blood?

Viremia

What are viruses in the blood?

Primary infection

What is an acute infection that causes the initial illness?

Secondary infection

What is an opportunistic infection after a primary (predisposing) infection?

Subclinical infection

What has no noticeable signs or symptoms (inapparent infection, asymptomatic infection)?

Nutrition, sex, genetic inheritance, climate, environment, vaccination, age, lifestyle, and compromised host.

What are nine predisposing factors that make a body more susceptible to disease?

Incubation period

What is an interval between initial infection and first signs and symptoms?

Prodromal period

What is a short period after incubation; early, mild nonspecific symptoms?

Period of illness

What period is the disease most severe?

Period of decline

What period do signs and symptoms subside?

Period of convalescence

What period does the body return to its prediseased state? (Recovery)

Human reservoirs

What are people with signs and symptoms or carriers (asymptomatic, incubating, convalescent, chronic, passive) that may have inapparent infections or latent diseases?

Zoonosis

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

Nonliving reservoirs

What are soil, water, and foods?

Direct contact transmission

What requires close association between the infected and a susceptible host?

Congenital transmission

What is a transmission from mother to fetus or newborn at birth?

Indirect contact transmission

What spreads to a host by a nonliving object called a fomite?

Droplet transmission

What is transmission via airborne droplets less than 1 meter?

Vehicle transmission

What is transmission by an inanimate reservoir (airborne, waterborne, or foodborne)?

Cross-contamination

What is the transfer of pathogens from one food to another?

Arthropods, fleas, ticks, and mosquitoes

What are four common examples of vectors?

Mechanical transmission

What arthropod carriers pathogens on its feet?

Biological transmission

What pathogen reproduces in the vector; transmitted by bites or feces?

Healthcare-Associated Infections (HAIs)

What is acquired while receiving treatment in a health care facility? Also known as nosocomial infections. (Affects 1 in 31 hospital patients in the US)

Microorganisms in the hospital environment, weakened status of the host, and chain of transmission in a hospital.

What three things do HAI (Healthcare Associated Infection) result from?

Compromised host

Who is an individual whose resistance to infection is impaired by disease, therapy, or burns? Could have broken skin or mucous membranes, suppressed immune system, and invasive procedures and devices.

Universal precautions

What is designed to reduce the transmission of microbes in health care and long-term care settings and to protect patients, residents, staff, visitors from contact with pathogens?

Standard precautions

What are basic, minimum practices that are applied to every person, every time, at all levels of heathcare? They include hand hygiene, personal protective equipment, respiratory hygiene, cough etiquette, disinfection of equipment, environmental cleaning and disinfection, safe infection practices, patient placement.

Transmission-based precautions

What is supplemental to standard precautions; designed for known or suspected infections that are highly transmissible or involve epidemiologically important pathogens?

Contact, droplet, and airborne precautions

What are three categories of transmission-based precautions?

Reduces number of pathogens

What is the point of handwashing, disinfecting tubs used to bathe patients, cleaning instruments scrupulously, and using disposable bandages and intubation equipment?

Improving patients’ resistance to infection

What is the point of prescribing antibiotics only when necessary, avoiding invasive procedures, and minimizing use of immunosuppressive drugs?

Infection control committees

What oversees and monitors infection control in hospitals?

Contributing factors of emerging infectious diseases

What are the following: genetic recombination between organisms, evolution of existing organisms, widespread use of antibiotics and pesticides, inherent genetic instability of some microbes, changing global climate and weather patterns, modern transportation, insect vectors transported to new areas where they become established, ecological disaster, war, expanding human settlement, animal control measures, public health failure, and bioterrorism.

Epidemiology

What is the study of where and when diseases occur and how they are transmitted in populations?

John Snow

Who mapped the occurrence of cholera in London in 1848-1849?

Ignaz Semmelweis

Who showed that handwashing decreased the incidence of puerperal sepsis in 1846-1848?

Florence Nightingale

Who showed that improved sanitation decreased the incidence of epidemic typhus in 1858?

Descriptive epidemiology

What is a collection and analysis of data? (Ex. Snow’s search for the source of the cholera outbreak).

Analytical epidemiology

What analyzes a particular disease to determine its probable cause or risk factors? (Ex. Nightingale’s work).

Experimental epidemiology

What involves a hypothesis and controlled experiments? (Ex. Semmelweis)

CDC

What collects and analyzes epidemiological information in the United States?

Morbidity

What is an incidence of a specific notifiable disease?

Mortality

What are deaths from notifiable diseases?

Notifiable infectious diseases

What are diseases in which physicians are required to report occurrence?