Chapter 11 - Epidemiology and Public Health

Reservoirs

place in which infectious agents live, grow and reproduce (people, water, food)

Six Components in the Infectious Disease Process

1. a pathogen 2 a source of the pathogen (a reservoir) 3. a portal of exit 4. a mode of transmission 5. a portal of entry 6. a susceptible host

Epidemiologists

also develop ways to prevent, control, or eradicate diseases in populations.

2002 to 2003

an epidemic of West Nile virus (WNV) infections.

2003

an outbreak of monkeypox infections.

Zoonotic Diseases

are diseases that humans acquire from animal sources.

Epidemiology

can be loosely defined as the study of disease.

Tuberculosis

caused by Mycobacterium Tuberculosis

Susceptible Host

individuals may have traits that affect their susceptibility and severity of disease (immune deficiency, diabetes, burns, surgery, age)

Contagious Disease

it is a communicable disease that is easily transmitted from person to person. (ex. Influenza)

Pandemic

it is a disease that is occurring in epidemic proportions in many countries simultaneously. (e.g., Influenza, HIV/AIDS, Tuberculosis, Malaria).

Communicable Disease

it is an infectious disease that can be transmitted from one person to another. (ex. Gonorrhea)

Epidemic Disease

it is defined as a greater than usual number of cases of a disease in a particular region, usually within a short period of time (e.g., the cryptosporidiosis epidemic of 1993).

Endemic Disease

it is one that is always present within the population of a particular geographic area (e.g., staphylococcal and streptococcal infections and STDs).

Sporadic Disease

it is one that occurs only occasionally within the population of a particular geographic area (e.g., tetanus).

Malaria

it is the fifth leading cause of death from infectious diseases worldwide after respiratory infections, HIV/AIDS, diarrheal diseases, and TB.

ID50

it is the infective dose that it takes to infect 50% of a population

LD50

it is the lethal dose that results in the death of 50% of the population.

Point Prevalence

it is the number of cases of a disease existing in a given population at a particular moment in time (e.g., right now).

Period Prevalence

it is the number of cases of a disease existing in a given population during a specific time period (e.g. during the year 2010).

Morbidity Rate

it is the number of new cases of a particular disease that occurred during a specified time period per a specifically defined population (usually per 1,000, 10,000, or 100,000 population).

Incidence of a Particular Disease

it is the number of new cases of that disease in a defined population during a specific time period.

Mortality Rate

it is the ratio of the number of people who died of a particular disease during a specified time period per a specified population.

Pathology

it is the study and diagnosis of disease through the examination of organs, tissues and body fluids. Main way to study: Autopsy

Epidemiology

it is the study of the frequency and distribution of disease in order to identify its cause, source, and route of transmission.

Arthropods

many different types of arthropods serve as reservoirs of infection, including insets and arachnids.

Infectious Agent

micro-organisms capable of causing disease or illness (bacteria, fungi, parasites, prions)

Epidemiologists

study the factors that determine the frequency, distribution, and determinants of diseases in human populations.

Portals of Exit

ways in which infectious agent leaves the reservoir (blood, secretions, excretions, skin)

Portals of Entry

ways in which the infectious agent enters the susceptible host (mucous membrane, respiratory system, digestive system, broken skin)

Modes of Transmission

ways in which the infectious agent is spread from the reservoir to the susceptible host (physical, contact, droplets, airborne)

Vectors

when arthropods are involved in the transmission of infectious diseases.

2017

a multistate outbreak of Seoul virus

2012

a multistate outbreak of fungal meningitis.

HIV/AIDS

AIDS can take 10 years to develop, following HIV infection.

2017

Mumps

2015

a large multistate outbreak of measles.