(1) Chapter 14: Principles of Disease and Epidemiology

What is the scientific study of disease called?

Pathology.

What is etiology?

The cause of a disease.

What is pathogenesis?

The manner in which a disease develops.

What is an infection?

The invasion or colonization of the body by pathogenic microorganisms.

What is a disease?

An abnormal state in which the body is not performing its normal functions.

What is the difference between infection and disease?

Infection is the invasion or colonization of pathogens, whereas disease is when the body is no longer functioning normally because of that infection or another cause.

What is a symptom?

A subjective change in body function that can only be felt by the patient.

What are examples of symptoms?

Headache, muscle aches, fatigue, nausea, and dizziness.

What is a sign?

An objective change in the body that can be observed or measured.

What are examples of signs?

Fever, enlarged lymph nodes, rash, and high blood pressure.

What is the difference between a sign and a symptom?

Symptoms are subjective and felt only by the patient; signs are objective and can be observed or measured by others.

What is a syndrome?

A specific group of signs and symptoms that occur together with a disease.

What is a communicable disease?

A disease that is spread directly or indirectly from one host to another.

What is a contagious disease?

A communicable disease that is easily and rapidly spread from one person to another.

What is the difference between communicable and contagious diseases?

All contagious diseases are communicable, but not all communicable diseases are contagious. Chickenpox is contagious, while sexually transmitted diseases are communicable but not considered contagious because they are not readily spread.

What is a noncommunicable disease?

A disease that is not spread from one host to another.

What is incidence?

The number of NEW cases of a disease in a population during a specific time period.

What does incidence indicate?

The spread or risk of developing a disease.

What is prevalence?

The total number of existing cases (new and old) of a disease in a population at a specific time.

What does prevalence indicate?

How widespread a disease is in a population.

What is the difference between incidence and prevalence?

Incidence counts only new cases, while prevalence counts both new and existing cases. Prevalence is always greater than or equal to incidence because it includes previous cases.

What example did your professor use to explain incidence vs. prevalence?

If 100 people develop HIV during one year, the incidence is 100. If 300 people currently have HIV, the prevalence is 300.

What is a sporadic disease?

A disease that occurs only occasionally.

What example of a sporadic disease did your professor give?

Typhoid fever in the United States.

What is an endemic disease?

A disease that is constantly present in a specific population or geographic area.

What examples of endemic diseases did your professor give?

Malaria in Africa and cholera in India.

What is an epidemic?

A disease acquired by many people in a given area during a short period of time.

What is a pandemic?

A worldwide epidemic.

What examples of pandemics did your professor give?

COVID-19 and HIV/AIDS.

What is epidemiology?

The study of where and when diseases occur and how they are transmitted in populations.

Who is considered the Father of Modern Epidemiology?

John Snow.

How did John Snow identify the source of the cholera outbreak?

He mapped where cholera victims lived, traced the cases to the Broad Street water pump, and concluded the contaminated water was the source.

How did John Snow stop the cholera outbreak?

He removed the handle from the contaminated Broad Street pump.

Who was Ignaz Semmelweis?

A physician who demonstrated that handwashing dramatically reduced puerperal fever in hospitals.

Who was Florence Nightingale?

A British nurse who used statistical analysis to show that sanitation and better living conditions reduced epidemic typhus among soldiers.

What is the CDC?

The Centers for Disease Control and Prevention, a branch of the U.S. Public Health Service that collects epidemiological data, investigates outbreaks, and publishes the Morbidity and Mortality Weekly Report (MMWR).

What is morbidity?

The number of people affected by a disease.

What is mortality?

The number of deaths caused by a disease.

What is a notifiable infectious disease?

A disease that physicians are legally required to report to public health authorities.