Epidemiology SG

Pathology

Pathology

The study of disease

Etiology

cause of disease

Pathogenesis

manner of disease development

infection

The invasion or colonization of the body or area of the body by a pathogenic microbe

disease

A change from a state of health where part of the body cannot function properly

normal microbiota are permanent microbes that do not cause disease under normal conditions. Transient microbiota is microbiota that you acquire and cause problems more often.

Compare and contrast normal microbiota (resident) versus transient bacteria

microbial antagonism

The normal microbiota prevents the overgrowth of harmful microbes, therefore protecting the host.

opportunistic pathogen

A normal microbiota that is normally not a problem, but if given the opportunity, it can become a problem

Synergism

Two or more organisms working together

Commensalism

one organism benefits and the other is unaffected

Skin microbiota (hosts are humans)

Example of commensalism

Mutualism

both organisms benefit

Gut microbiota (hosts are humans)

Example of mutualism

Parasitism

One organism living at the expense of another (one benefits and one is harmed)

HIV and Leprosy

Examples of parasitism

subjective

A symptom is _________ and changes in the body's function

Pan and malaise

Examples of symptoms

objective

A sign is ____________ and changes in body function

Fever, blisters, paralysis

Example of signs

signs and syptoms

A doctor uses both ______ and ______ to diagnose a disease

communicable disease

A disease that spreads from one host to another and is contagious

chickenpox, herpes

Examples of communicable diseases

noncommunicable disease

A disease that does not spread from one host to another, and is not contagious

Tetanus, Lyme disease

Examples of non communicable diseases

contagious disease

A disease that easily spreads

chickenpox and measles

Examples of contagious diseases

Incidence

The number of people that contract a disease during a period of time

Prevalence

The fraction of the population that has the disease at one time

frequencey

How often a disease is seen in a population

sporadic

Occasional disease

Typhoid fever or chickenpox

Examples of sporadic disease

endemic

A disease that is constantly present in the population

Colds, cholera in india

Examples of endemics

epidemic

Many people contract the disease over a short period of time (1-2 years)

Cholera in South America, influenza

Examples of epidemics

Pandemic

An epidemic that is worldwide

HIV and COVID

Examples of pandemics

acute disease

develops rapidly, lasts a short time

Influenza

Example of an acute disease

chronic disease

develops slowly and lasts a long time

TB

Example of a chronic disease

subacute disease

intermediate between acute and chronic (develops kind of quickly)

Measles

Example of a subacute disease

latent disease

The causative agent remains inactive for a while

Shingles

Example of a latent disease

Local infection

contained to small area

focal infection

enter as local and spread through blood or lymph but confined to specific area

systemic infection

spread throughout body by blood or lymph

primary infection

acute infection that causes the initial illness

secondary infection

caused by opportunistic pathogen after primary infection has weakened host defenses

subclinical infection

An infection that does not cause noticeable illness

Humans Animals Nonliving (soil and water)

What are all of the sources/reservoirs of infection?

Zoonoses

A disease that occurs in wild or domestic animals, and then the infectious microbe is transmitted to humans

Direct Indirect Droplet

What are three ways of contact transmission?

direct transmission

Physical contact with a person

indirect transmission

Fomites —> nonliving objects

droplet transmission

Microbes spread up to one meter

Fomites

nonliving objects that may transmit infectious material

vehicle transmission

A transmission via a medium

waterborne, foodborne, airborne

3 types of vehicle transmission

Vectors

Animals that carry pathogens (mainly insects)

Mosquito, tick, rat

Examples of vectors

Healthcare-associated infection (HAI)

An infection that is acquired through a healthcare facility

you have to go to the doctor to get better, and it has gone up 36% in 20 years

Why are HAI's a problem?

5-15%

_________ percent of patients get HAIs

Through staff, catheters/needles, and biofilms

How are HAIs transmitted?

By hand washing, following sterile procedures, and using the advice from infection control person

How can HAIs be controlled?

Predisposing factors of disease

A factor that makes you more susceptible to a disease

Age, gender, nutrition, lifestyle, job, immune system

Examples of predisposing factors of disease

incubation period

Infection before the first symptoms arrive

prodromal period

Early, mild symptoms or signs

period of illness

Acute stage, more serious symptoms/signs

period of decline

signs and symptoms subside

period of convalescence

The body returns to its original state

emerging infectious diseases

A new or changing disease or a disease that is incidence increasing

WHO, NIH, CDC

Who is responsible for monitoring EIDs?

Widespread use of antibiotics and pesticides Global climate change Transportation Ecological changes from war Natural disaster/population Animal control Failure in public health

Factors that contribute to EIDs..

Epidemiology

the science that studies when and where diseases occur and how they are transmitted in populations

1. Determines the etiology of the disease.

2. Identifies other important factors and patterns concerning the people affected.

3. Concerned with various methods for controlling a disease.

What does an epidemiologist do?

Cholera

John Snow investigated ________ outbreaks in London (shut off contaminated water pipes)

Ignaz Semmelweis

The person who investigated childbirth fever